The Commission for Water Sustainability of the International Geographical Union (IGU) is hosting an international conference on

“Environmental change and rational water use”

Buenos Aires, Argentina, 29^th August – 1^st September 2005

Session 1. Management of surface and groundwater resources

THE RESTLESS WATER CYCLE AND RAGING DEMAND: TWIN BARRIERS TO SUSTAINABILITY

J.A.A. Jones

Institute of Geography and Earth Sciences, University of Wales, Aberystwyth SY23 3DB, UK - jaj@aber.ac.uk

The paper presents current results of research undertaken for the IGU World Atlas of Water Sustainability. It focuses on trends and variability in global and regional water balances, and links these with the latest indications of rising demand for water.

WATER SHARING CONFLICT IN TRANSBOUNDARY CATCHMENT OF GANGES RIVER AND DEGRADING OF MANGROVES WETLANDS ECOSYSTEMS IN THE SUNDARBANS OF BANGLADESH

S. N. Islam¹ and A. Gnauck²

1. Department of Ecosystems and Environmental Informatics, Study Course Environmental and Resource Management, Brandenburg University of Technology at Cottbus, P.O. Box-101344, D-03013 Cottbus, Germany. Phone: +49-0355-692831, Fax:+49-355-692743 - shafinoor@yahoo.com; 2.umweltinformatik@tu-cottbus.de

The Sundarbans is part of the coastal complex lying west of the delta formed by the Ganges-Brahmaputra-Meghna (GBM) rivers system. Bangladesh through its complex network of river systems drains an area of about 1.76 million Sq.km of the catchment areas of the Ganges, the Bramaputra and the Meghna of which only 7.5 percent lies in Bangladesh. The Ganges basin is one the most densely populated river basin in the world with a population of 340 million. The Sundarbans is situated in the Ganges catchment area which is known as the single largest stretch of productive mangrove forest and unique mangrove ecosystems in the world. The 700,000 hectares of mangrove forest is a natural shield that protects the coastal area from storm surges and cyclones in pre and post-monsoon periods. It provides direct employment opportunity to 600,000 people (UN/ESCAP 1988) and 6 million people indirectly dependended. The Sundarbans region is characterised by close network of interconnect tidal rivers and creeks and suffer from salinity problems due to tidal flooding and direct induction by saline or brackish waters into the estuarine surface water system during the period of low river flow in the month of December through April. Since the diversion of Ganges water at Farakka Barrage in India from early 1975, salinity levels have increased drastically in the south western part of the coastal region in Bangladesh. After withdrawal the upstream surface water almost 57 percent in summer season, and capillary upward movement of soluble salts due to presence of high saline ground water table at shallower depth and soil salinity. The reduction of Ganges flows while the industries are facing serious problems in quality control of products and disastrous effects on agriculture, fisheries, navigation, hydromorphology, drinking water , wetlands and forestry. Chemical factors like salinity, pH, oxidation reduction, potential mineral contents, marine pollution, sedimentation etc are the major ones which influence the development of management forest. Seawater contains about 35g of solute per litre, mostly as NaCl (other salts include Na₂So₄, MgSo₄, CaSo₄, MgCl₂, KCl, Na₂Co₃ etc) and has an osmotic potential. Consequently both siltation and salinity have increased in the Sundarbans region. Sediment trapping has been aided by pneumatophores and dense roots of mangroves. Top dying of Sundari (Heritiera fomes) which is cover 52.7 percent of the area and constitute about 63.8 percent of the standing three volume has assumed serious proportion and is now recognised as a key management concern. The Ganges water sharing issues is a long disputed matter between the two neighbours Bangladesh and India. Ganges water sharing is not just a geo-techno-political problem it is also a human problem. Interaction is needed between states where it is a common concern. Environmental damage to major ecosystems must be recognised by all. The community as a whole may participate in and all classes benefits from biodiversity conservation and mangrove wetlands ecosystems. The objectives of this paper is to formulate a long-term management plan for mangrove resources through ensure to supply Ganges water into Sundarbans. GIS and hydrological modelling would be a proper tools for decision making and make recommendations for the future development of Ganges water sharing conflict and protection of Sundarbans mangroves wetlands ecosystems.

IRRIGATION AND FLOOD CONTROL STRATEGIES IN SOUTHERN INDIAN STATE

S.Thomas¹, S. Nair ² and J. S. Paimpillil³

1. Former Chief Engineer, Irrigation Department, Government of Kerala - paimjose@rediffmail.com

2. Dept. of Geology & Geophysics, Cochin University of Science & Technology, Cochin 16, India

3. Center for Earth Research & Environment Management, 37/1387, Elemkulam Road,

Cochin 17,India, 682017.

Optimal utilization of the water resources through appropriate conservation and management measures assumes critical importance in sustaining the life support systems. The southern Indian state (Kerala) has 44 rivers and has ample rainfall for about 72,000 million m³ of water every year, only 5.5 % gets stored in medium irrigation and hydro-electric dams. Nearly 40 per cent of the resources are lost as run off causing heavy floods. The ground water resource is estimated at 7048 MCM. Its ground water levels are falling, its rivers, canals, lakes and backwaters are shrinking, and its people are reeling under a severe shortage of potable water. Priority in resource allocation (69% of total) in Kerala was given for major and medium irrigation projects for rice crops, but not succeeded in increasing the area irrigated or productivity or in returns. Minor irrigation schemes are best suited for irrigation in Kerala, but adequate priority was not given in the allocation of resources. Ground water development also comes under minor irrigation. Around 25 per cent of the ground water resource potential has been tapped and the coastal and low-lying regions of the midland offer good scope for ground water development. Out of the 152 blocks in Kerala, eight have been identified as critical, six as semi critical, two as over exploited and 136 as safe. Traditionally irrigation management has been considered as a departmental exercise without any provision for participatory approach either in the selection of the works or in their execution and management. Local level Water Resources Development and Management through participatory approach to be given a thrust to attain sustainable local self-sufficiency regarding water requirements. Recent communities Irrigation Project with the active participation of the beneficiary communities have drilled 131 bore wells. Several minor irrigation schemes have been taken up recently as local governments have to spend about 40 per cent of their allocation in productive sector. A good number of schemes have not resulted in increasing water availability as undue emphasis was given to protective structures. In flood control, most of the schemes are related to relief work for the affected areas. Flood control works continue to be on conventional lines. The identification and execution of works are on adhoc basis and largely based on public pressure and there is no system for the assessment of needs and priorities. Basin wise studies are required for the identification of flood prone areas. A strategy for water resources development and utilization for irrigation and other purposes envisaged for the coming years includes the revamping of 1st and 2nd generation irrigation projects to improve the current level of utilization by taking into account the changes that have taken place over time and bringing about necessary modifications with the partnership with local governments and user groups. Water resources planning and management to be taken up by the river basin level by aggregate watershed based plans prepared locally. Special focus would be given to revival, conservation and up gradation of local water resources and traditional systems of water management. Ground water exploitation would be based only after proper zonation and with the involvement of farmers at the local level. Technical support for development of groundwater sources and helping farmers for acquiring sources of irrigation on individual as well as self help basis are features included under future programme.

USING ENVIRONMENTAL ISOTOPES FOR ESTIMATING THE RELATIVE CONTRIBUTIONS OF GROUNDWATER RECHARGE MECHANISMS IN AN ARID BASIN, CENTRAL SAUDI ARABIA

N. A. Alsaaran

Department of Geography, College of Arts, King Saud University - P.O. Box 2456, Riyadh 11451, Saudi Arabia Fax: 4675366 - alsaaran@ksu.edu.sa

Stable isotope composition of water (²H and ¹⁸O) were utilized to estimate the relative contributions of diffused recharge (DR) through the soil matrix from direct precipitation and concentrated recharge (CR) through coarse-textured ephemeral streambeds to groundwater in the arid granitic basin of Alquway, central Saudi Arabia. Groundwater ranged in its stable isotope composition from –2.51‰ to –2.03‰ for δ¹⁸O and from –12.7‰ to –10.1‰ for δ²H. Local groundwater line (LGWL) is defined by: δ²H = 4.72 δ¹⁸O – 0.57.

Average stable isotopic content of CR is -2.58‰ for δ ¹⁸O, and -12.37‰ for δ ²H. Local CR line (LCRL) is given by: δ²H = 5.28 δ¹⁸O + 1.24. Its slope indicates that CR experiences significant kinetic fractionation resulting in a greater relative enrichment of ¹⁸O than ²H. DR is more enriched in the heavy isotopes with means of -0.38‰ for δ¹⁸O and -9.8‰ for δ²H. Local DR line (LDRL) is given by: δ²H = 2.01 δ¹⁸O - 9.03. Its slope is much lower than that of LCRL, indicating that DR goes through more stable isotopic fractionation than CR due to experiencing more evaporation from unsaturated soils.

Recharge-inducing rainfalls in this basin were estimated to be relatively depleted in the heavy isotopes suggesting that groundwater recharge in this basin originates only from heavy downpours. Using mean values of δ ¹⁸O in a mass-balance equation, the relative contributions of CR and DR to groundwater were estimated to be 84% and 16%, respectively. The very high relative contribution of CR to groundwater suggests that rainfall harvesting efforts in this basin should be directed toward techniques enhancing transmission losses in streambeds and storm-runoff generation from the alluvial plains. Furthermore, this gives more reasons to abandon gravel mining from active channels, which is currently a common practice in this basin and similar basins in the area.

STOCHASTIC MODELING OF PLUVIOMETRIC REGIONAL SCALE FOR THE FORECAST OF FLOWS IN NORTHERN MEXICO

A. Gutiérrez-López

Instituto Mexicano de Tecnología del Agua, IMTA. Subcoordinación de Hidrología y Mecánica de ríos Paseo Cuauhnáhuac 8532; C.P. 62550 Jiutepec, Morelos, México - agutierrez@tlaloc.imta.mx

The spatial and temporal rainfall distribution in a region of Northern Mexico is analysed using an ensemble of methods with the aim of producing a regionalisation of both the drought and flood risks. The various methods used are presented in detail. They include classical statistical methods as well as the less well known Vecteur Régional method. The Leak distribution, a particular form of CPP process is then used for characterising the regional patterns of the drought risk and of the extreme rainfall risk. Its formulation, parametrisation and validation on the study area are given. A classification is also carried out by statistical analyses (clusters and EOF’s analyses) allowing the determination of rainfall homogeneous areas. Using this statistical characterisation of rainfall patterns over the region for flood prediction is illustrated by applying the Gradex method in order to estimate the flood discharge of high return periods (100 and 1000 years) for a 2300 km² watershed. This paper aims at developing an integrated approach for an optimal use of the numerous rainfall data existing in Mexico, with the objective of improving the management of hydrologic hazards.

MANAGING THE WATER RESOURCES OF PENINSULAR INDIA IN CHANGING ENVIRONMENTS

K. Shadananan Nair

Cochin University of Science & Technology - Vallayil House, North Gate, Vaikom-686 141 Kottayam Dt., Kerala, India, Tel: (+91)-484-2363950, nair59@yahoo.com

Managing water resources to satisfy the multiple needs of increasing population in a changing climate and deteriorated environment is a global challenge, especially in developing countries like India with inadequate finance to implement adaptive mechanisms. Indian population has crossed 1Billion and the increase is likely to continue at least for another five decades. By that time, demands in food, water and land will be tremendous. Water resources in India are being fast depleted due to overuse, pollution and encroachments. Decreasing water availability leads to social issues like competition and transboundary disputes in regions with wide variability in the distribution of rainfall and water resources. Present paper analyses the water management issues in the peninsular part of India in changing environments. This region has varied geography and rainfall. The west coast receives very heavy rainfall because of the orography of the north-south running Western Ghats Mountain, whereas the interior peninsula is short of rainfall. East coast is vulnerable to severe tropical storms and floods. There are number of rivers originating in the Western Ghats, most of them wastefully flowing west to the sea, before effectively harnessed. Some of the rivers flow east through the drier interior and there exist a number of severe disputes over water sharing among different states, regions and users. Failure in conservation management causes seasonal water shortages even in the coastal belt with more than 3000mm rainfall. In the interior, overdraft of groundwater is far above replenishable limit. Overdraft and coastal aquaculture has invited salinity far inland even in deep aquifers. Encroachment has destroyed large number of wetlands, ponds and canals, affecting millions that depended on them. Deforestation in hill region and sand quarrying in riverbeds and watersheds have made some of the once perennial rivers seasonal and caused the groundwater level to recede by one metre in two decades. Entire water bodies in the peninsular area are highly polluted from industrial and domestic effluents and fertilizers and chemicals from farms.

Water availability in the peninsular region is assessed at the present level and in an altered climate using models, taking into consideration the population growth. Result shows a drastic reduction in availability in few years from now. Existing water issues are likely to worsen and new ones are likely to originate soon. Harnessing some water from west flowing rivers and making it available to the rich agricultural lands in the interior could make another revolution in agriculture and water, solving many of the water issues and bringing overall prosperity in the entire region. A regional environmental policy including land and water, and in agreement with a national policy and a strong and impartial political will to implement regulations are urgently needed. Some guidelines to face the challenges of water shortages in a changing environment have been presented, based on the economic, environmental and political scenarios.

RAINFALL DISAGGREGATION USING ARTIFICIAL NEURAL NETWORKS

N.V. Umamahesh and I. Srinivasulu

Water and Environment Division - Department of Civil Engineering - National Institute of Technology, Warangal – 506004, AP, India - mahesh@nitw.ernet.in

The main problem faced in hydrologic analysis and simulation is the need for long term precipitation records at shorter time intervals. A precipitation time series is often a necessary input for the analysis and design of hydrologic and hydraulic systems. The precipitation records employed for these purposes can be either measured observations or generated by stochastic simulation. One common problem with recorded and generated precipitation data is that often it is not in small enough time increments for use in engineering applications (e.g., continuous hydrologic simulation). To solve this problem, rainfall amounts can be disaggregated into shorter time increments. Several empirical methods are developed for disaggregating the daily rainfall data to hourly rainfall. Many of these methods are based on rigorous statistical analysis.

In the present engineering environment where time efficiency and cost effectiveness are paramount characteristics of engineering tools, disagregation techniques must be practical and accurate. One particularly attractive technique for disaggregating long-term daily rainfall records into hourly increments involves the use of artificial neural networks (ANNs). In the present study ANN based model is developed to disaggregate daily rainfall data to get hourly rainfall data. The model developed is applied to a small ungauged urban watershed located in the city of Hyderabad in India. The results of the study indicate that the ANN can be a viable alternative model for disagregation of rainfall data.

PLANNING FOR SUSTAINABLE DEVELOPMENT AND MANAGEMENT OF WATER RESOURCES OF BRUNEI DARUSSALAM

K. U. Sirinanda

Department of Geography, Faculty of Arts & Social Sciences, University of Brunei Darussalam, Jalan Tungku Link, BE1410 Brunei Darussalam - kus@fass.ubd.edu.bn

Brunei Darussalam (hereinafter, Brunei) is a country of 5,765 km² and a population of about 350,000. Its rainforest climate with a space-averaged annual rainfall of about 3,000 mm, ensures plentiful water supplies throughout the year although relatively dry spells can occur. By 2005, the total daily water supply made available in the country has reached 580 million litres compared to 400 million litres in the year 2000. On the other hand, the total daily water usage has increased from about 177 million litres in 1991 to 337 million litres in 2001 (an increase of 90 per cent in 10 years). The daily per capita water consumption (around 450 litres) in Brunei (compared, e.g. to 200 litres in neighbouring Malaysia, and 168 litres in Singapore) is one of the highest in the world. With no appreciable economic activities related to agriculture or manufacturing industries, the bulk of the water demand is for domestic consumption. The high per capita consumption is often attributed mostly to the high per capita availability of renewable water supplies as well as the very low water rates payable by consumers. It appears that the main thrust of the development strategy of the Department of Water Services is managing the supply rather than demand or consumption patterns, although some top decision makers have from time to time stressed the need to be economical in water use.

Brunei has been into planning for economic development for the past 50 years or so. Beginning in the early 1950s, there has been a succession of 5-year Development Plans, the current version being the 8^th National Development Plan 2000-2005. While the earlier plans were nothing more than statements of development goals and targets, planning in earnest has been evident only from 1973 when the Economic Planning Unit was established in the Secretariat Department. However, it is only after Brunei resumed full control of its affairs in 1984, as a sovereign state, that planning as an exercise towards the judicious utilization and management of natural resources and the environment began.

The paper reviews the evolution of planning for water resources development and management in Brunei, and the current state of the policies and strategies in the efforts towards achieving sustainability.

EFFICIENCY ASSESSMENT OF RUNOFF HARVESTING TECHNIQUES

K. Verbist¹, D. Gabriels², E. González³ and G. Soto¹

1. University Ghent (Belgium), Centro de Agua para Zonas Áridas y semi-áridas en Latino

America y el Caribe (CAZALAC) in Chile. Koen.Verbist@UGent.be - Gsoto@cazalac.org

2. University Ghent (Belgium). Donald.Gabriels@UGent.be

3. University of La Serena (Chile). Egonzalez@userena.cl

In arid and semi-arid zones runoff harvesting techniques are often applied to increase the water retention and infiltration on steep slopes. Additionally, they act as a erosion control measure to reduce land degradation hazards. Both in literature and in the field, a large variety of runoff collecting systems are found, as well as large variations in design and dimensions. Therefore, a field campaign was initiated in 2004 to assess the efficiency of water harvesting systems. Six different sites in the IV region of Chile were selected, based on their textural and morphological properties. At every site a set of rainfall simulations were performed on a representative area (10 m²), to determine the infiltration capacity of the different soils, as well as their erodibility. These measurements were replicated on three slope gradients (10%, 20% and 30%) to allow identification of this parameter in the runoff process. Additionally, infiltration measurements were performed in the runoff collection zones using a Guelph permeameter in order to assess the infiltration capacity of the runoff collectors.

Finally, all field results were imported into the physically-based Sediment Transport Model (STM-3D). After field calibration, this model was used to simulate the runoff routing and the soil loss at every point along the slope for some typical rainstorms. For the different soil types, a scenario analysis was performed to obtain the optimal configuration and dimensions for the runoff collection systems along the slope.

These simulations, based on field measurements, were found useful in predicting runoff containment and identification of potential soil erosion hazards. The proposed methodology therefore can be used to optimally apply scarce financial sources in order to obtain maximal efficiency from runoff harvesting techniques.

SOLUTIONS TO HIGH WATER LEVELS IN PEHUÁJO.

M. Danes and P. Gussenhoven

Instituto Nacional de Tecnología Agropecuaria - Instituto de Clima y Agua De las Cabañas y Los reseros S/N - B1712WAA Castelar Bs. As. - Matthijs.danes@wur.nl - Pieter.gussenhoven@wur.nl

Argentina suffers from a change in climate, which has caused more precipitation on average. Higher groundwater levels measured since the seventies have caused an agronomical crisis on parts of the famous fertile Argentine Pampas.

The province of Buenos Aires consists mainly out of flat agricultural land: the Pampas. These are the largest agricultural areas in Argentina and are of great influence on the economy. This area is threatened by intervals of floods. In the early 70’s this situation changed dramatically with the beginning of a humid period. As a result of immense quantities of rainfalls and the subsequent rise of the ground water to ground level and above, the productive agricultural landscape changed into an area of ecological crisis with the emergence of large lagoons and bordering marshland areas.

The difference in height between the area around Pehuájo (35º54’S) and the average sea level is around 80 till 90 meters. Due to this low gradient difference and the distance to the Atlantic Ocean, the hydrological gradient can be neglected: the slope can be assumed to be zero. Therefore water is almost unable to be transported by ways of ground- and surface water. During heavy rainfall the existing canal Mercante is not able to drain the region. In addition the use of the remaining farmland was restricted by the affected infrastructure of the area, e.g. flooded roads.

Until now the reason for this environmental change in not understood sufficiently. However, it can be deduced that flooding is a result of an interrelation between fluctuations in the climatologic system (El Niño), anthropological influence in the affected region and/or of the special morphological situation in the area.

As far as known there has not been any water management in the past. Local farmers are not able to resist the threat of heavy rainfall.

Funds providing money to prevent flooding are limited, so it is unlikely that large investments can be made to solve the water issues. The only suitable solution is to deal with the problems in the area itself. These small-scale investments will be focused on a change in land-use in order to evaporate more water. A result will be a decrease in the discharge of the watercourses.

INTA from Argentina -Instituto Nacional de Technologia Agropecuria- in cooperation with Alterra from the Netherlands (which is a government related technological institute) are suitable authorities to offer solutions to this problem.

This research will investigate several solutions to solve the water issues. One of them shall be a change in land use. The goal in the other solutions is to try to achieve the same outcome as with changing land use by managing the water.

To come to the right results the model SIMGRO will support the research. SIMGRO simulates water streaming in surface water, groundwater and in the saturated zone. In order to calculate this simulation, the model needs data like discharge, precipitation, soil-layers, land-use and crop factors.

INTEGRATING ENGINEERING AND BIOLOGICAL TOOLS TO ASSESS WATER SUPPLY AND ENVIRONMENTAL SUSTAINABILITY

J. Nestler¹, R. A.Goodwin¹, C. R. M. Baigún², N. Oldani³ and C. Vionnet⁴

1. U.S. Army Engineer Research & Development Center, Vicksburg, MS; 2. IIB-INTECH, Camino de Circunvalación Laguna, Km 6 (7120) Chascomus, Argentina - claudiobaigun@intech.gov.ar; 3. Instituto de Desarrollo Tecnológico para la Industria Química (INTEC-CERIDE), Santa Fe Argentina; 4. Dept. of Eng. & Water Resources Universidad National del Littoral, Santa Fe, Argentina

Linking ecologic response to design elements of hydraulic structures is one of the greatest challenges preventing accurate and complete assessment of water resource systems. The outputs of engineering models, typically used to describe detailed physical and chemical processes associated with water supply project design or operation, cannot be directly linked to ecological response models. Similarly, ecological response models typically represent physical and chemical processes using low-resolution methods that cannot accurately describe hydraulic or water quality patterns associated with specific design or operational alternatives. A retrospective shows that each modeling tradition can be generally assigned into either an Eulerian or Lagrangian reference framework. We show how these reference frameworks can be coupled to create a new integrated tool capable of simulating processes of the suite of scales typically encountered in water resource systems. The computational backbone of the integrated tool is a modified particle-tracking algorithm that allows interpolation of hydraulic and water quality information generated within an engineering mesh (Eulerian grid) to interior points located in continuous space (Lagrangian particles) of interest that could represent the location of real or virtual aquatic biota components. The integrated tool is able to aggregate, disaggregate, and translate information, as required by each framework, so that processes that differ substantially in scale, such as ecological response and hydrodynamics, can each be accurately simulated. Such models are useful tools for assessing highly disturbed systems, such as tailwaters, where extrapolated patterns derived from normal environmental conditions often fail to predict fish responses. We illustrate the integrated tool with a specialized application in which a fish swim path selection model is coupled to a computational fluid dynamics model. We believe this robust concept can be expanded to better describe the benefits and impacts of water resource alternatives.

INTERHEMISPHERIC COLLABORATION ON THE MISSISSPPI AND MIDDLE PARAŃA RIVERS FOR KEY INSIGHTS INTO LARGE RIVER SUSTAINABILITY AND BIODIVERSITY PATTERNS?

C. R. M. Baigún¹, J. Nestler², N. Oldani³ and C. Vionnet⁴

1. IIB-INTECH, Camino de Circunvalación Laguna, Km 6 (7120) Chascomus, Argentina - claudiobaigun@intech.gov.ar; 2. U.S. Army Engineer Research and Development Center, Vicksburg, MS; 3. Instituto de Desarrollo Tecnológico para la Industria Química (INTEC-CERIDE), Santa Fe Argentina; 4. Dept. of Eng. and Water Resources Universidad National del Littoral, Santa Fe, Argentina

The normal functions of most of the world’s great floodplain rivers are disrupted because the blend and scaling of processes that characterize them in their natural states have been shifted to new states. The altered states are often associated with major environmental quality problems that prevent environmental and water supply sustainability. Such degraded systems must be naturalized or restored to achieve a balance between water use and environmental quality. Restoration of large rivers is typically guided by the concept of a historical or a site “reference condition”. However, most of the world’s large rivers were already extensively modified from their initial states before the systematic collection of monitoring data. Using ordination analysis, we show that the Mississippi River of North America and the Middle Paraná River of South America are relatively similar and can, therefore, be considered references for each other. The unleveed mid and lower reaches of the Paraná River provide insight into probable conditions that existed in the Mississippi River more than one hundred years ago. In contrast, the present state of the Mississippi River can serve as a negative reference for the Paraná River and demonstrates what may happen to the middle reach of the Paraná River with unsustainable water resources development and with unplanned occupation of its floodplains. We propose that scientists and engineers working in North America and South America should collaborate to take advantage of the unique opportunity presented by the similarity of two of the world’s great rivers. Their synergy will improve water resources management in both continents.

HYDROLOGIC SCENARIOS APPLIED TO THE AGRICULTURE MANAGEMENT OF THE NORTHWEST OF THE BUENOS AIRES PROVINCE (ARGENTINA)

J. A. Forte Lay¹, E. Kruse² and J. L. Aiello³

1. CONICET jaflay2004@yahoo.com.ar

2. Universidad Nacional de La Plata - CONICET. kruse@fcaglp.unlp.edu.ar

3. Consultant jlaiello2005@yahoo.com.ar

The main features of the Northwest region of Buenos Aires Province (50,000 km2) are its small topographic slope, the lack of a drainage network and the presence of permeable sediments near the surface. As a consequence of these factors, there is no fluvial network and the ponds located in the depressions are important.

The area is a great plain with a small topographic slope of about 0.1 m/km. Minor topographic forms that are important hydrologically can be differentiated within the general morphology. There are slightly noticeable elevations alternating with depressions that give a relief of soft, somewhat aligned crinkles. They represent typical forms of paleodune environments.

The social and economic activities (mainly agriculture), in this region are strongly influenced by the availability of water resources. The study of their variability is an important issue for the analysis and prediction of the behavior of this productive system.

A characteristic of this flatland is the low morphological energy of its terrain. As a consequence, the natural storage (depression and groundwater storage) and vertical movement of water (evapotranspiration and infiltration) dominate over horizontal movement (surface and subsurface runoff).

The mean annual rainfall in the region is about 850 mm/year and the mean temperature 16°C (60°F). A rainfall pattern in the region shows an alternating between dry and humid periods.

In a humid period, the input of water to the hydrological system exceeds the output. It generates a rise of the water table and an increase in the pond areas. The water table is shallower, usually producing overflows and negatively affecting agricultural production. The magnitude of the overflowing areas associated with the shallow depth of the water table directly affects sowing and harvesting operations. It determines the available area to cultivate.

In a dry period, as a consequence of low rainfall, the water table deepens and some existing depressions become dry. The water table depth, as much in its magnitude as in its intensity shows a relationship with the reduction of the pond areas. The deepening water table makes satisfaction of agricultural demands difficult. The depressions are empty, as the water table increases its depth. Under these conditions the soil water content is low and may reach drought levels.

The water table is often very close to the surface, which indicates that surface waters (ponds) and groundwater are strongly related, so they should be treated as a single unit. The water table fluctuations are important indicators of hydrologic behavior. On the other hand, knowledge the current water table state and the historical data of the other indicators allow us to predict future hydrologic scenarios.

DROUGHT RISK IN THE PAMPEAN REGION USING SOIL WATER STORAGE ANALYSIS

J. Forte Lay¹, O. E. Scarpati^{1, 2}, L. Spescha ³ and A. Capriolo¹

1. National Council of Scientific and Technical Research

2. Geography Department, Humanities and Education Sciences Faculty, La Plata National University

3. Faculty of Agronomy, Buenos Aires University

This paper analyses the drought risk in the Pampean region using statistical results of soil water storage. These are calculated by daily soil water balance whose methodology has been tested with values obtained in situ. This has been described in published papers and newly, it is used to monitor the soil moisture and its anomalies.

The anomalies are obtained by fitting the series of soil water data with the Beta (I) distribution, using a long period of data (40 years), for each one of the 76 meteorological stations used, and in each moment of the year. After they are calculated, the results are mapped using different isolines of equal probability.

A new concept is proposed in this paper, it is to define a level of drought or minimum level of soil water storage for the entire region as the minimum optimum for crops. Over this moisture level, crops can yield with all their potential without being affected by soil water deficit and hence it is proposed to obtain the probability of occurrence of values under that minimum for the average of a determined period of time (a month, a week, etc.).

The established level of drought is considered as the half of the available soil water capacity, which coincides with the minimum limit of optimum soil moisture (so called conditional drought level).

So maps with isolines of equal probability of drought risk are obtained, and with the quick visualization of them by the use of a fitted scale of colours. The maps can show the other possibility: the probability of good soil moisture content. All of them can be seen for every moment of the year and to every zone of the region.

Even the main crop region of Argentina, so called “Humid Pampa”, has possibilities of drought risk, mainly during the summer season. However, it will show several areas with different drought degrees, according to their seasonal precipitation and soil water regimes.

The use of lower drought levels, like permanent wilting point, is proposed too, to evaluate the risk of more dangerous situations, like those conducting to the lost of crops.

The possibility of the use of crop and/or soil management coefficients, allowing a more particular evaluation for different agricultural exploitation, is also analyzed.

The need of soil water economy can be deduced by means of an appropriate soil management and /or the implementation of complementary irrigation, when it is possible.

WATER USE EFFICIENCY OF THE MAJOR GRAIN CROPS GROWN IN THE “PAMPA” REGION

G. M. Murphy, L. B. Spescha, M.E. Fernandez Long and R.H. Hurtado¹

Cátedra de Climatología y Fenología Agrícolas - Facultad de Agronomía Universidad de Buenos Aires. Av. San Martín 4453 – (1417) Buenos Aires. murphy@agro.uba.ar

The different agro-ecological units that integrate the “Pampa” region possess particular climate and soil characteristics that define their capacity for grain production. During their growth and development, the grown species change their water requirements establishing a direct relationship with water availability which, for non-irrigated systems such as those utilized in the “Pampa” region, is represented by rains.

The objective of this study is to analyze some relevant aspects related to the utilization of water in the rural production, and linked to environmental, productive, and management issues.

For such purpose, the water use efficiency (WUE) index, which represents the millimetres of precipitation required by kg /ha of grain produced, was utilized. For different districts of the “Pampa” region, yield, cultivated area, and major grain crops (wheat, corn, sunflower and soybean) production data, belonging to the period 1970/2003 was used, as well as the rains produced during the phenological cycle of each one for the same period.

The temporal evolution of the described variables and the degree of interaction among them allowed the understanding of the variation in WUE during different stages of the analyzed period and in different zones of the “Pampa” region, when considering the crops both individually and collectively. The effects of new technological advances, different soil and topography combinations, as well as the precipitation inter-annual variability and tendencies over the efficiency on the utilization of this natural resource were also analyzed.

ASSESSING THE LAND SUITABILITY FOR EUCALYPTUS AFFORESTATION IN THE LOWER SALADO RIVER BASIN OF BUENOS AIRES PROVINCE, ARGENTINA

N. Lucioni¹ y R.Díaz²

1. Departamento de Geografía, Universidad de Buenos Aires, Puán 480 – Sistema Integrado de Información Agropecuaria, Secretaría de Agricultura, Ganadería, Pesca y Alimentos, Bs. As, Argentina. noralucioni@arnet.com.ar

2. Instituto de Clima y Agua, Centro Nacional de Recursos Naturales, I.N.T.A., Las Cabañas y Los Reseros s/n, 1712 Hurlingham, Bs. As., Argentina. rdiaz@cnia.inta.gov.ar

The Salado-Vallimanca region, also known as Salado Basin or Flooded Pampa, spans over 94000 km² of land most vulnerable to the vagaries of Nature. Despite a temperate climate with annual rainfall ranging from 600 mm to 1000 mm, successive droughts and flooding events have been driven by extreme shifts in precipitation amounts and frequency. Excess water has been a dominant feature in the last twenty years, causing severe economic and environmental distress to the area. Lowlands close to both the Salado and Samborombón Rivers are more prone to flooding because drainage of huge amounts of water is slow due to the flat relief. Eucalyptus plantations may aid in mitigating the effects in areas impacted by excess water by decreasing water tables and salinity. Our study aims at the assessment of areas suitable for afforestation with eucalyptus in a representative sector matching the INTA Soil Survey Map for Dolores, Buenos Aires at the 1:50000 scale. A first approximation was made using soil maps at different scales, soil profile databases, weather station historical records, land use capability charts and land use statistics. As a result a first mapping of potential forestry areas was made, which improved in definition as we moved from low to high resolution soil maps. Where no land suitability was detected, further analysis was made with Landsat imagery to resolve micro-relief features which may allow afforestation. In addition to landscape placement and flooding risk, soil chemical properties were latter account for, because high salinity levels found may restrict tree growth. After a field survey to check actual soil quality, the boundaries of the potential eucalyptus areas were drawn. The study provided also evidences of how important the social and management factors have been throughout the last decade to shape up the flooding risk in parallel to the natural forces.

FLOODS DANGER AND THREATEN MAP: GOYA CITY CASE, CORRIENTES PROVINCE, ARGENTINA

Álvaro Soldano¹, Dora Goniadzki², Juan Borus³, Daniel Vila⁴, Nathalie Horlent⁵ and Gabriel Martín Barría⁵

Instituto Nacional del Agua (INA):

1. Área Sensores Remotos y Sistemas de Información Geográfica de la Dirección de Sistemas de Información y Alerta Hidrológico (SIAH) - asoldano@ina.gov.ar

2. Dirección de Sistemas de Información y Alerta Hidrológico del INA- dgonia@ina.gov.ar

3. Área Hidrología de la Dirección de Sistemas de Información y Alerta Hidrológico - jborus@ina.gov.ar

4. Área Meteorología de la Dirección de Sistemas de Información y Alerta Hidrológico - dvila@ina.gov.ar

5. Dirección de Sistemas de Información y Alerta Hidrológico - nhorlent@ina.gov.ar - gbarria@ina.gov.ar

Natural disasters produce damages on the mankind that grows year after year. This exponential growth has its origin in multiple factors, being the most outstanding: the demographic growth and urban development. Within the types of the natural disasters, the rivers and streams floods are one of the most contradictory. On one hand, productive benefits in the seasonal occurrence have been valued and, on the other hand, it generates the biggest number of inhabitants “affected”, when its dimensions overcome those established values as acceptable for the social organization.

From historical point of view, the civilizations have used their capabilities in order to mitigate the noxious effects of floods. To attenuate the undesirable impact of flood, the measures can be classified as “structural” and “non structural”. In the last group, the most outstanding measures are: the warning systems and territorial regulation.

The development of the satellital technology has permitted to obtain products based on the information coming from the remote perception, and especially from the sensors located over aerial and satellital platforms. Other complementary measures, as the elaboration of risk maps, has been upgraded and potentialized by the development of this technology. The application of this technique can be divided according to the study purpose: rural and urban risk cartography.

The city risks have largest relevance due to the vulnerability is directly related with population. At most, the anthropogenic modification of the environment introduces more variables to keep in mind in order to reduce the threat or danger. In this sense, the current work tries to contribute to identify and quantify of urban space variables, to prioritize the susceptibility determination before a flood event.

From a theoretical-practical point of view, registered information was used as the base of desktop work to develop an example of urban habitat, which presents structural measures against floods.

Particularly, the Goya establishment, according to its hydrographical, geomorphologic and anthropogenic characteristics, presents a great vulnerability because of this natural phenomenon. In this case, the vulnerability has been reduced by the development of defences against floods coming from the Paraná river overflow. Nevertheless, this engineering works add new factors to keep in mind in order to determine the danger of this threat, far from the possibility of the structural fail. These new factors are: the spatial relationships between the geographical environment and its functional role before the exceeding coming from local rain.

APPLICATION OF REMOTE SENSING AND GIS TOOLS IN THE DETERMINATION OF THE CURRENT USE OF THE AGRICULTURAL SOIL FOR AN EFFICIENT MANAGEMENT OF THE WATERS OF IRRIGATION (RIO CHOAPA BASIN, COQUIMBO, CHILE)

A. Anschau¹ and R. Cabezas²

1. Universidad CAECE. Departamento de Ciencias Biológicas, Sede Abasto. Perón 2933,

Buenos Aires, Argentina. alicia_anschau@yahoo.com.ar

2. Universidad de La Serena. Vicerrectoría Académica, Dirección de Investigación - Av. Raúl Biltrán s/n, Colina El Pino, La Serena, Chile. rcabezas@userena.cl

In a semiarid region, where the agriculture under irrigation constitutes the most important economic activity and water consumption for these purposes represents 90% of the total consumption, it is inexcusable to raise an effective management of this most valuable resource. For this reason becomes indispensable to possess material and information that it should make possible to know exhaustively the dynamics of the resource and to mean a tool that helps to make decisions to whom they administer the waters of irrigation.

For it, the general aim of this work is to characterize and to map across the generation of a System of Geographical Information, the current use of the agricultural soil in the hydrographic basin of the river Choapa, determining, in agreement to the methodology of the Agricultural Census (INE 1997) the different types of use of the agricultural soil.

The area of study corresponds to the geographical space that includes the hydrographic basin of the river Choapa, from Tranquilla's locality up to the confluence with the Rio Illapel, in the IV Region of Chile, with an approximate surface of 5000 km².

This work was realized with scale 1:5000, using aerial photography for almost the totality of the area, though in the highest parts we had to use images LANDSAT 7 ETM +, diminishing in these cases the scale of work. The summary of information was realized using information generated from a survey applied in the zone, tabulated information delivered by the managers of the resource, simultaneously that have carried out field reports for the rectification of incomplete information.

The result obtained is a specializing database, which integrates all the information and allows the generation of different thematic maps (types of soil, current use of the same one, property division, water and irrigation infrastructure, etc) and different digital models of the area (elevation, slopes, solar exhibition)

In a later stage (already in execution) we try to associate this database with agronomical information about water consumption of different plant species (fruit trees in the main) to be able to shape and predict scenes of consumption and availability of the resource.

There is important the incorporation of new technologies, as SIG and Remote Sensing, in the making decisions processes, since they are tools that allow having a major confidence in the decision, because of the support that has the generated information. The managing of information and the form in which it is in use, it is relevant in any process of development, and to rely on tools of this type facilitates the way towards the sustainability.

DEM QUALITY ASSESMENT BY RMSE CALCULATION IN THE ALTITUDE IN AREAS WITH LOW TO MEDIUM SLOPES.

H. G. Rosatto ^{1 y 4}, M. Presutti ^{2 y 3} (ex-aequo), C.A. Grau ⁴ , E. De Luca⁴ , F. A Solari¹, A. L. Alvarez¹, M. Lapido¹ and G. Botta¹

1. Departamento de Ingeniería Agrícola y Uso de la Tierra, Facultad de Agronomía – UBA Av. San Martín 4453, Buenos Aires – Argentina (1417) Tel: 54 – 11 – 4524-8008; Fax: 54 – 11 – 4514-8737 rosatto@agro.uba.ar

2. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales 60 y 118 (1900) La Plata, Buenos Aires, Argentina - miriamp@netverk.com.ar

3. Departamento Ambiente y Recursos Naturales

4. Maestría Manejo de Cuencas Hidrográficas. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales.

The basic information about the relief in a watershed are required to evaluate projects related with natural resources, such as integrated watershed management, environmental impact studies, soil degradation, deforestation, water conservation. These processes are strongly associated with a spatial component and thus a GIS are very useful, being the DEM and its derivatives an outstanding component in these database. The products derived from the DEMs, like slope, aspect or curvature will be as accurate as the input model. On the other hand is important to maximize the hability of the model to represent the terrain variability, so an adequate resolution must be selected, depending on the available data to generate it.

In this framework, the objective of this paper is to evaluate the quality of several elevation models extracted from contour lines digitized from preexisting topographic maps and an equidistance of 2.5 m. The models were generated from algorithms provided by two software: IDRISI and PCI Geomatics and at different resolutions. The resulting models were evaluated by comparison of the height generated by the models and control points acquired on the ground by geometric levelling (Z coordinate) and with GPS for the x and Y coordinates. The errors in the heights models introduced during the interpolation process, where a continuous surface is derived from discrete data, were evaluated. A global measure for the entire DEM is reported, the Root Mean Square Errors (RMSE) which is a common measure to determine the vertical accuracy in these models. From the analysis described above, we conclude that not significant differences were found (within each algorithm) according to the grid size in this type of relief (with low to medium slops). About the RMSE, the models generated in PCI satisfy the requirements cited in the bibliography for all the grid sizes; the same occur in the models generated in IDRISI with small grid size, but not in greater size for the most exigent values mentioned in the bibliography.

VARIOUS HYDROLOGICAL AND SATELLITE ÍNDICES FOR MONITORING RAINFALL EXTREMES IN THE SEMIARID PAMPA REGION

M. Bouza ¹ and B. Scian²

1. Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT)

2. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Dpto de Agronomía, Universidad Nacional del Sur, Bahía Blanca. mbouza@criba.edu.ar

The reflectance received from NOAA operational polar-orbiting satellites provides multiple applications on the surface vegetative conditions detected by means of AVHRR sensors. The Normalized Difference Vegetation Index (NDVI) has been used in designing drought-monitoring techniques. It has been proved to be a reliable indicator of the leaf area index, one of the yield determining factors.

The study area selected for this work is Semiarid Pampas Region which is concurrent with the V South Wheat Region. The phenological stage between the end of heading and the beginning of anthesis takes place around October, period in which the crop presents the maximum light interception. Based in this characteristic images were selected for this date.

Besides, agro-meteorological data allows to compute several hydrological indices related to soil moisture conditions as the Standardized Precipitation Index (SPI), the climatic coefficient a (ratio between actual evapotranspiration (ETR) and potential evapotranspiration (ETP) and the Palmer moisture anomaly index (Z), some of them with proved application as crop yield predictors (Scian-Bouza , 2002). Monthly extreme rainfall conditions in anomaly cycles should be detected and expressed by the NDVI.

The NDVI maximum value for 3x3 pixel windows, centred at each location (17) were computed and compared to the SPI 3, a and Z.

The selected period included three events: ENSO cold phase or La Niña 1995 at the end of the year, followed by neutral (non-ENSO) conditions during 1996 and the setting of ENSO warm phase or El Niño 1997.

The relations between meteorological and satellite based indices show that SPI 3 and a are highly correlated with NDVI for one and two months ahead respectively.

DESERTIFICATION IN SANTA MARIA RIVER BASIN AND IT RELATION

WITH SLOPES

S. Navone, H. Rosatto (ex aequo), M. Bargiela, D. Laureda and D. Perez

CIAT-Facultad Agronomía Universidad Buenos Aires - Av San Martín 4453, Buenos Aires, Argentina - Tel.(5411)-4524-8008-fax. .(5411)-4524-8737 - rosatto@agro.uba.ar, navone@mail.agro.uba.ar

In the Argentine Republic 60.000.000 hectares have severe degradation processes. Those regions generate 50% of the total agriculture and animal productions Thirty percent of the natural population (9.000.000 persons) is established in arid and semiarid valleys (15.000.000 ha). They have desertification problems caused by overgrazing, deforestation and fires.

The Santa Maria river basin (in Catamarca,Tucuman and Salta ) is one of the areas with different degrees of desertification. An accurate measure of the slope should be evaluated in light of other important factors, such as high soil readability that enhances the effect of wind and torrential rain from November to March and scant vegetation cover due to arid conditions.

Torriorthent (Soil taxonomy,1998) are the predominant soils in the alluvial fans and in the highest section of the upper terraces. The soils of the lower terrace of the rivers and their alluvial plane are Torrifluvents (Soil taxonomy ut supra) associated with Torripsament .(Navone et al, 1998). Flora is typical of the “ Monte” formation (Cabrera, 1978). It is a shrub formation of 1 to 1.8 m heights. Two very important human activities take place in this valley: agriculture in the floor of the river basin and mining in the mountains surrounding the basin. The outdated irrigation system is favouring water deficits and soil salinization (CFI, 1987, 1989).

The Digital Elevation Model (DEM) is an useful tool to estimate and evaluate slope. The products derived from the DEMs will be as accurate as the input model.

In this framework, one of the objective of this paper is to evaluate the quality of the DEM generated by satellite radar-interferometry from the Shuttle Radar Topography Mission (SRTM) carried out by the NASA (National Aeronautics and Space Administration) and published by the U.S Geological Survey. The resultant model was evaluated by comparison of the height generated by the models and control points acquired on the ground.

The RMS obtained for the DEM, assured the altimetric accuracy required to evaluate projects related with natural resources, such as integrated watershed management, environmental impact studies, soil degradation, deforestation, water conservation. The relation between the slope grade and the degradation processes is evaluated.

SIMULATION OF SOIL WATER CONTENT USING A SIMPLE BALANCE MODEL

M. I. Gassmann and J. M. Gardiol

Dpto. de Cs. de la Atmósfera y los Océanos – Facultad de Cs. Exactas y Naturales

Universidad de Buenos Aires - Piso 2 – Pabellón 2 – Cdad. Universitaria

C1428EHA – Buenos Aires – Argentina - gassmann@at.fcen.uba.ar

A campaign (1998-1999) of soil water content measurements is done during the development of maize crops (Zea mays L.) in the area of Balcarce, province of Buenos Aires (Argentina). Measurements are by layers and a neutron sonde is used, up to a depth of 100 cm. Field studies were conducted on a Balcarce loam (illitic thermic loam petrocalcic Paleudoll) and 130 m above sea level. Balcarce has an annual average precipitation of 910 mm.

Using a simple balance model, soil water content was simulated by: Cw(i)=[Cw(i-1)ra(i-2)+P(i)+Ir(i)+Dra(i)Cwo(i-1)-Pe(i)-EET(i)-Es(i)]/ra(i) where i is a daily time index, Cw is the soil water content in the root zone, ra is the active root depth, Cwo is the soil water content in the zone without root, P is the rainfall, Ir is the irrigation, Dra is the variation in the root depth, Pe is percolation, EET is the crop evapotranspiration and Es is the surface runoff. Rainfall and irrigation are measured variables. Daily root growth depth is represented by a sin function, with a maximum depth value reached when plants are in bloom. Percolation is estimated as an instantaneous elimination of the exceeded water to the passive root depth for days with soil water content values greater than field capacity in the active root zone. Daily values of surface runoff are estimated using the curve number methodology proposed by the USDA - Soil Conservation Service- National Engineering Handbook (1973). It is considered row crops land use conditions, with straight row practice and good hydrologic conditions. The hydrologic soil group considered is type B. Crop evapotranspiration is determined from the maximum evapotranspiration value. The former variable was estimated using the crop coefficient and the potential evapotranspiration. Crop coefficient is calculated as a function of the thermic time and potential evapotranspiration is estimated using the Penman-Monteith methodology. The fraction of total available water that a crop can extract from the root zone without suffering water stress is considered up to 60% of this value. Simulation results are compared with the observed values, both for the total soil water content of the column and for the active root depth. The model represents adequately daily variations of soil water content, showing better results for the complete soil column than for the active root depth. The values for determinant coefficient and mean square error are 0.90 and 0.0055 for column and 0.77 and 0.0064 for active root depth water content simulation.

Session 2. Methods for evaluating and monitoring the pollution of water resources

War in SOME KARSTIC AREA OF FORMER YUGOSLAVIA, and PCBs Hazards to Karst Water System*

M. Picer¹, N. Picer¹, T. Kovač¹, V. Čalić¹, N. Miošić², Z. Cenčić Kodba³ and A. Rugova⁴

1. Institute Rudjer Boskovic, Bijenicka cesta 54, 10000 Zagreb, Hrvatska, picer@irb.hr, 2. Geological survey Sarajevo, Ustanicka 11, 71210 Ilidza, Bosnia and Herzegovina, 3. Institute for public health, Prvomajska 1, 2000, Maribor, Slovenia, 4. University of Prishtina, Faculty of science, Majke Tereze 5, 38000 Prishtina, Kosovo

During the recent war, the karst area of Croatia, Bosnia & Herzegovina and Kosovo and Metohija has been jeopardized by hazardous waste and deserves particular attention because of its exceptional ecological sensitivity and unfortunately unscrupulous destruction of natural resources, infrastructure, homes and enterprises. Data on contaminant levels from water and soil samples collected before 1995 didn’t show significant contamination of the investigated locations in Croatia (Oštarije, Ogulin, Transformer Station "Konjsko", Rivers Cetina and Jadro) by organochlorinated pesticides and PCBs. Also there were no ecologically significant PCBs contamination of soil near Transformer Stations in Delnice and Kaštela, while in the area of ETS "Komolac", TS "Zadar" and TS "Bilice" significant levels of PCB were observed. Levels of PCBs in soil samples from Bosnia & Herzegovina sampled during autumn 2003 and during June and July 2004 (altogether 47 samples) show significant (more than 10 ppm) of total PCBs levels in Bihać, Tuzla and Tešanj. If we compare the levels of PCB in the soil near TS "Zadar" and TS "Bilice" in Croatia and three locations in Bosnia & Herzegovina (Bihać, Tuzla and Tešanj) by the criteria of tolerance accepted in the Netherlands, the levels of contamination at these locations far exceeds tolerable levels that do not require remediation. During June 2004, 4 soil samples were collected from 4 sites in Kosovo and Metohija, but levels of PCBs were relatively low (under 1 ppm). Taking into account location of destroyed Zadar, Bilice and Dubrovnik Electrical Transformer Stations, there was some speculation regarding the potential hazard from organohalogenated toxicants to the Lake Vransko and the coastal sea around the Zadar, Šibenik and Dubrovnik areas. Sediment and some aquatic organism samples were collected and analyzed from mentioned areas. Results indicate there were no significant or high levels of contaminants in the areas of Lake Vransko, Šibenik, Dubrovnik (Petke location), while in these areas: Mikulandra bay near Šibenik, Rijeka Dubrovačka, Brodanova location, Marina near Vruljica creek in Zadar, significantly higher level of PCBs were observed. During autumn of 2003 and June 2004 (altogether 60 samples) in Bosnia & Herzegovina sediment samples were collected for PCBs analysis from 9 rivers (Bosna, Una, Miljacka, Spreča, Buna, Bijela, Gostilja, Jala and Tešanjka), and from seven water sources and creeks. In some sediment samples from Bosnian rivers significant levels of PCB were observed, even more than 1000 ppb. In Kosovo and Metohija 8 sediment samples were collected during June 2004, from rivers Ibar, and Sitnica, but only in some samples significant levels of PCBs were observed.

POLLUTION OF RIVER SEDIMENTS IN BOSNIA AND HERZEGOVINA AND KOSOVO WITH POLYCHLORINATED BIPHENYLS*

V. Čalić¹, N. Miošić², Z. Cenčić Kodba³, M. Picer¹, N. Picer¹, A. Rugova⁴ and T. Arbneshi⁴

1. Rudjer Boskovic Institute, Bijenicka cesta 54, 10000 Zagreb, Croatia, picer@irb.hr , 2. Geological survey Sarajevo, Ustanicka 11, 71210 Ilidza, Bosnia and Herzegovina, 3. Institute for public health, Prvomajska 1, 2000, Maribor, Slovenia, 4. University of Prishtina, Faculty of science, Majke Tereze 5, 38000 Prishtina, Kosovo

Polychlorinated biphenyls (PCBs) are organic compounds exclusively of synthetic origin and one of the most stable organic pollutants. The latest investigations of their harmful influence on biological systems indicate, how the PCBs are one of the most dangerous organic pollutants in environment generally, and especially in water ecosystems.

Throughout the passed war, areas of Bosnia and Herzegovina and Kosovo have been jeopardized with the formation of dangerous wastes. In the frame of international project APOPSBAL, partially financed from European Commission, investigation the contamination of river sediments with PCBs in these areas have been carried out. Co-workers from Geological survey Sarajevo and Faculty of science Prishtina have suggested the sampling locations for which exist indications for the spilling of these very dangerous and stable organic pollutants into the environment.

Collection of sediment samples from Bosnia and Herzegovina and Kosovo local co-workers have performed. Analyses of the samples have been performed in Rudjer Boskovic Institute and in Institute for public health Maribor. Levels of PCBs were determined by capillary gas chromatography with the electron capture detector. Concentrations of PCBs are expressed in ng/g (ppb) of dry sample weight.

In a few locations in Bosnia and Herzegovina has been a determined exceptionally high level of total PCBs (the wellspring-Bihać 882 ppb; river Miljacka-Sarajevo 1654 ppb; in the region of town Tuzla rivers: Gostilja 2766 ppb, Oskova 1513 ppb, Jala 2048 ppb, Spreča 2257 ppb). The most probable origin of these contaminations is vicinity to the spots where the oil leaking from damaged capacitors has been observed, vicinity of coal mines, industrial areas and places of waste water spilling over, and also damaged military relays. Research of PCB pollution in areas of Kosovo has not been extensive as in Bosnia and Herzegovina. Analyses of sediments were performed in following locations: river Ibar-Mitrovica, river Ibar-Obilić and Plemetin, and also the mud of waste water TE Kosovo B. In these sediment samples obtained range of PCB levels has been from 18 to 248 ppb.

RESEARCH THE TRANSPORT OF PCBs WITH LEACHATE WATER FROM CONTAMINATED SOIL IN KARSTIC AREA OF CROATIA*

V. Hodak Kobasić¹, V. Čalić¹, T. Tarnik², M. Picer¹ and J. Šangulin³

1. Institute Ruđer Bošković, Bijenička cesta 54, Zagreb, Croatia, picer@irb.hr , 2. HEP-Croatian Electricity Utilitiy, Ulica grada Vukovara 37, 10000 Zagreb, Croatia, 3. Institute of Public Health, Zadar, Croatia

During the recent war in Croatia since 1991.-1995. some parts of karstic area of Croatia have been heavily destroyed and jeopardized by the dangerous wastes. This area deserves the special attention due to porosities of soil and dangers of pollution the water by persistent pollutants. Therefore it is of great significance to determining levels of the persistent organic pollutants in the environment of karstic area. Our group has determined the level of PCBs in the soil around the damaged condenser of E.T.S. Zadar. Results of analysis have indicated significant contamination of the soil. Phytoremediation is one of the possible ways to remedy contaminated soils with PCBs. Precondition for the phytoremediation is the choice of appropriate plant species. This experiment performs under natural climatic conditions, and then analyzed level of total PCBs obtained with particular leachate and influences the rhizosphere of selected plants on their retaining in the soil. The experimental surface comprises of 4 plots. On the every plot have been placed three lysimeters. Each lysimeter was filled with a layer of gravel and layer of contaminated soil in the height of the 15 cm. Range of levels of total PCB expressed as AR 1248 + AR 1254 in the contaminated soil are from 44 to 74 µg/g. Under the hole of lysimeter was placed the glass bottle to collect the water, which filters through the experimental surface soils. Three plots have been sowed with plants: Arabidopsis thaliana Heynh. (L.), Alfa alfa (L.) and mixture of Mediterranean grasses, and on the fourth plot are present self-grown plants of this climate. In the dry period from the June to the August (plants have been not sowed) some plots were irrigated with the tap water. Samples of the leachates have been filtered due to relatively large quantity of particular substances leached with the water. It means that it is necessary to analyse percolated pollutants in solid and liquid phases of leached water.

Through the first irrigation of the plot, in the leachates were obtained concentration of PCBs (below the 3 lysimeters) 6180 ± 1687 (SD) ng/l (ppt), while after the second irrigation, i.e. after the one month, average concentration of PCBs in the leachates were 9092 ± 2463 (SD) ng/l. After sowing grasses and coming of rainy period (the September 2004 to February 2005.) has been followed kinetics of leaching PCBs into water from soil in all investigated lysimaters.

ARSENIC POLLUTION IN GROUNDWATER OF BANGLADESH

M. Hamidur Rahman¹ and Hiroaki Ishiga²

1. Department of Geology and Mining, University of Rajshahi, Bangladesh, mhrahman@librabd.net. 2. Department of Geosciences, Shimane University, Matsue, Japan

The scientists of Rajshahi University together with Hokkaido University, Research Group for Applied Geology (RGAG) and Asian Arsenic Network (AAN) of Japan suspect that groundwater of about 60 districts out of 64 districts are seriously contaminated with arsenic. There are 11 Million tube wells in Bangladesh out of which about 5 Million tube wells are highly arsenic contaminated. About 75 Million people of the affected districts are at risk and the total number of patients suffering from Arsenicosis are about 7000 and out of which about 200 persons already died in few years. It is very much essential to arrange safe water supply for the peoples. To give safe arsenic free water to the people more investigations in the whole country is essential. The source of arsenic in groundwater of Bangladesh is as yet unknown. But it is now widely believed that the high arsenic levels in the groundwater in Bangladesh have a natural geological source which may be due to abstraction water from Quaternary confined and semi-confined alluvial or deltaic aquifers. In Bangladesh Groundwater from sandy alluvial deposits are considered to be arsenic free. It is essential to consider the groundwater occurrences, its distribution and geological and hydro geological settings of the country for the mitigation of arsenic problem. To know the basic understanding of the source and mobility of arsenic it is essential to investigate the sampling depth and aquifer provenance. Present study will give some clue about the future action plan for the mitigation of the arsenic problem in Bangladesh. Variation of heart disease mortality have a general relationship with the relative hardness of drinking water. Core boring has been done for the collection of soil samples for Analysis in the laboratory.

LANDUSE AND CHANGES IN THE RIVER IPOJUCA, PERNAMBUCO, NORTHEAST OF BRAZIL

E. Torres Aguiar Gomes¹ and F. Santos de Farias²

1. Av. Boa Viagem 3962 Apto405, 51020-001, Recife,Pernambuco-Brazil. Serrot@elogica.com.br / torres@ufpe.br

2. Olshausenstrasse 68a Z.16 24118 Kiel Germany. ff@gpi.uni-kiel.de

The natural resources water is one of the problems of the modern society. Due to scarcity and badly use in everybody and also in Brazil. This work shows the ambient characteristics through the landuse and polluting sources and uses of the water in the Basin of the river Ipojuca, located in the state of Pernambuco, northeast of Brazil. As well as, to carry through a analyze of the quality of the water through the identification of the natural and socio-economic factors that influence in the environment of the river Ipojuca. The for purpose is to identify elements that compose the river zone, to monitor of the quality of the water in the Basin of the Ipojuca by combining the main natural and socio-economic factors of the last years. Through the data on landuse and the elaboration of a current map was possible representing all the carried through economic activities in the area. For the accomplishment of this map technology of the GPS, given on hydric resources of the area and work of field was used. In that if it relates to the quality of the water, collection of samples and analyses had been carried through, similar to get information on the degree of pollution and the polluting sources. In this way it was possible to make an evaluation of the quality of the water in the basin of the river Ipojuca. The result characterizes the types of use and occupation of the land in the region: environmental relevant, agribusiness, fat stock, dairy cattle, urban and industrial. Thus, it was possible to know exactly where each economic activity takes place and to establish plans for the control of sources of pollution and for the restoration of the river.

POPULATION GROWTH, CONSUMPTION PATTERNS AND WATER QUALITY MANAGEMENT: A CASE STUDY OF NIGERIA

L. E Akeh, E. D Udoeka, A. O. Ediang, A. A. Ediang, S. O. Gbuyiro

Research Division - Nigeria Meteorological Agency - pmb 1215, Oshodi Lagos, Nigeria.

Tel: 2340823241059 7 2340838228005.- ediang2000@yahoo.com, ediang2005@yahoo.com

The UN (1992) projects that world population will, under the most likely scenario have increased from the 5.3 billion of 1990 to 6.3 billion by 2000, growing there after to 8.5 billion in 2025, 10.0 million in 2025, and 11.2 billion in 2100. The world Bank’s project are very similar.

Nearly all of this growth is anticipated to occur in today’s developing countries increase in world population would mean increase global demand of energy, which with current energy technologies would result in increase in green house gases (GHG). Nigeria’S natural environmental resources and the quality of it water is severely threatened, according to a 2002 U.S Agency for International Development (USAID) study of the challenges and possibilities facing the Nigerian environment. The report found that increasing poverty, high population growth and migration, especially into urban area and political/institutional constraints are the underlying causes for environmental degradation in the country.

The paper therefore aims to emphases that when making plans for long term water quality management in Nigeria, dispersion modelling is important top project trends in water quality, which include what to monitor, how to monitor, where to monitor and the data collected from water quality monitoring systems may be used for a variety of purposes.

The paper concluded that in Nigeria, water quality management aims to maintain the quality of the water that protects human health and welfare but also provides protection of animals, plants (crops, forest, natural vegetation), ecosystems, materials and aesthetics, such as natural levels of visibility was also discussed.

WATER QUALITY MANAGEMENT IN NIGERIA: ENVIRONMENTAL REGULATORY ENFORCEMENT AND COMPLIANCE

L. E Akeh, E. D Udoeka, A. O. Ediang, A. A. Ediang, S. O. Gbuyiro

Research Division - Nigeria Meteorological Agency - pmb 1215, Oshodi Lagos, Nigeria.

Tel: 2340823241059 7 2340838228005.- ediang2000@yahoo.com, ediang2005@yahoo.com

WQM is a tool which enables governmental authorities to set objectives to achieve and maintain clean water and reduce the impacts on human health and the environment. Environmental regulatory enforcement and compliance continue to be the main problems in controlling the rapid depletion and degradation of segments on environment (water, etc) in Nigeria.

The paper discuss the federal environmental protection Agency has statutory responsibilities for overall protection of the environmental and its initial functions and priorities included, also the goals of that policy was achieve sustainable development in Nigeria i.e the national policy on environment. Also FEPA is initiating a monitoring programme to ensure that the set standards are met.

This paper objective therefore aims to facilitate law enforcement, to inform, educate and strengthen stakeholder participation in all aspects of water quality management in order to prevent and reduce the impacts of water pollution also to include or strengthen the concept of water quality management in relevant policies and legislation in cities in Nigeria.

The paper gives a good overall recommendations which include policies standards and regulation which is a strategic framework for water quality management in Nigeria.

In conclusion, Clean Water Implementation Plans (CWIPs) in Nigeria are a means of improving urban water quality and are a convenient way of reporting on the different activities in water quality management.

FIELD TESTS OF A SOLAR REACTOR TO PROVIDE DRINKING WATER TO SMALL ISOLATED COMMUNITIES IN THE NORTHWEST OF ARGENTINA

M. A. Blesa¹, M. I. Litter¹, P. Z. Araujo¹, C. Navntoft,¹ M. del V. Hidalgo², M. C. Apella², D. Fernández² and M. E. Puchulu ²

1. Unidad de Actividad Química, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica, Avenida General Paz 1499, 1650 San Martín, Provincia de Buenos Aires, Argentina and Escuela de Posgrado, Universidad Nacional de General San Martín, 1650 San Martín, Provincia de Buenos Aires, Argentina – miblesa@cnea.gov.ar .

2. Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán, Miguel Lillo 205., 4000 San Miguel de Tucumán, Argentina and Servicio Geológico Minero Argentino (SEGEMAR), Miguel Lillo 251, 4000 San Miguel de Tucumán, Argentina

An important fraction of the rural population of Argentina is not served by drinking water grids. They often relay in water extracted from shallow or deep aquifers, and the sanitation conditions of the water are often deficient.

Within the frame of the INCO Project Cost Effective Solar Photocatalytic Technology to Water Decontamination and Disinfection in Rural Areas of Developing Countries (SOLWATER) Contract: ICA4-2002-1000, funded by the European Union, a prototype has been built by an International Consortium that disinfects and decontaminates water by means of a photocatalytic and a photosensitized process. The Consortium is formed by R&D units and companies from Argentina, France, Greece, Mexico, Peru, Portugal, Spain and Switzerland. Further information can be found in the web site http://www.psa.es/webeng/solwater/index/html.

Photocatalysis is based on the use of titanium dioxide that absorbs uv light to generate highly oxidizing species, able to attack bacteria and other microorganisms, and also able to destroy organic matter by oxidation. The photosensitized process makes use of a dye that absorbs visible light and generated excited states of O₂. These excited states are apt to attack cell membranes and are therefore useful to achieve disinfection.

In the SOLWATER reactor prototype, water is recirculated through 2 glass tubes that contain the photosensitizer supported in polymeric stripes and through two tubes with the photocatalyst supported on a cellulose matrix. Previous tests under controlled laboratory conditions were carried out in three laboratories in Europe, demonstrating the capability of the reactor to fulfill its purpose.

The present paper describes the reactor and its operation under real field conditions. Tests are being carried out in the Province of Tucumán, in the Northwestern region of Argentina. The small village of El Churqui was selected as the actual site; the choice was made on the basis of technical and sociological considerations. Similar tests are being carried out in Mexico and Peru.

WATER QUALITY IN THE AREA IRRIGATED BY THE MENDOZA RIVER, ARGENTINA

J. Morábito^1-2, S. Salatino,² R. Medina¹, M. Zimmermann¹, M. Filippini¹, A. Bermejillo¹, N. Nacif,¹ S. Campos¹, C. Dediol¹, D. Genovese¹, P. Pizzuolo^1-2 y L. Mastrantonio^1-2

1. School of Agricultural Sciences (UNCuyo). Alte Brown 500 – 5505 – Chacras de Coria,

Luján de Cuyo, Mendoza. - Argentina. - jmorabito@lanet.com.ar

2. INA – CRA. Belgrano Oeste 210 – 3er Piso – 5500 – Mendoza, Argentina

Population and agricultural and industrial activities in the Province of Mendoza (Argentina) are largely concentrated in oases of rivers rising in the Andes. The Mendoza River oasis is the most important for it is the seat of the Greater Mendoza population (1,100,000 inhabitants). Urban growth has encroached upon areas that were formerly agricultural, surrounding and crisscrossing them with mostly earthen drainage and irrigation canals. Man uses water for drinking, sanitation, irrigation, electricity, recreation and other purposes, and discharges polluting effluents into the irrigation and drainage system. Pollutants such as salinity, organic and inorganic substances, heavy metals and pathogens affect both surface and underground waters. In order to analyze the evolution of water quality in the oasis, three points along the river (starting at the Cipolletti diversion dam), five points along the canal network, and seven along the drainage collectors were strategically selected. The points along the river and the canal network were tested for the following physicochemical and microbiological parameters: electrical conductivity, temperature, pH, anions and cations, SAR, dissolved oxygen (DO), settleable solids, chemical oxygen demand (COD), mesophilic aerobic bacteria (MAB), total and fecal coliforms, and heavy metals. The points along the drainage network were only tested for the first four parameters. This methodology made it possible to detect areas affected by industrial, urban, urban-industrial, and agro-industrial pollution, to identify causes and agents, and to develop management criteria for partial and/or total pollution remediation. Significant differences in mean salinity and SAR values were found between various points along the river, between the head of the system (R_I) and the canals, and between drains.

A comparison of parameters between the head of the system (R_I) and the canal network shows that discharges from Greater Mendoza urban centers located to the west of the “Cacique Guaymallén” canal and discharges from the “Campo Espejo” treatment plant (detected at point C_II) significantly increase water salinity (+55%) and sodicity (+95%) with respect to point R_I (though the sodicity value is still low). Salinity (+140%), COD (+1159%), and MAB (+2873%) also increased with the ensuing decrease in DO (-58%) due to discharges from the Greater Mendoza area and the high industrial pollution load from the “Pescara” Canal (C_V, “Tulumaya” secondary canal) with respect to point R_I. Though no differences have been found in dissolved oxygen values, there are significant differences between COD mean values. As for R_I and canals, significant differences were found between COD and DO mean values. Microbiological tests reveal that bacterial colony-forming unit counts exceed the guidelines set by the Argentine Food Code (1998) for drinking water. Significant differences were also found between ufc means of MAB in the river, R_III being the highest.

EVALUATION OF RISK TO INDUSTRIAL CONTAMINANTS IN WATER, FOR THE CITY OF TANDIL.

M. C. García

Centro de Investigaciones Geográficas y Facultad de Cs. Humanas de la Universidad Nacional del Centro de la Prov. de Buenos Aires - mgarcia@fch.unicen.edu.ar

The present document permits to agree to the advances carried out since the project called Risk to contaminants and adaptation of technicals of processing in dangerous industrialists wastes of Tandil.

It is evaluated if they exist metallics heavy Leads, Mercury, Arsenic, Chromium and Zinc, as well as proportions of Nitrates and Nitritos so much in water of wells as in water of network. It intends to link the diagnosis of risk to the presence of urban industrial uses and to correlate it with the Urban Life Quality conditions of the population in order to determine parameters of Social Vulnerability al risk of industrial contamination.

Since a line of work; itself built a cartographic base in GIS vectorial, with layers zones for Radios Fractions of the Census INDEC 1991, Radios Fractions of the Census Indec 2001, blocks of the city and divisions of the Industrial Park Tandil and Districts Agroindustriales, 1991and 2001 Network Water Covers, Sewers Network Covers 1991 and 2001, among others. In layers of lines itself digitalizaron curves isohipsas (equidistance 20 m.), superficial hydrography basin of the Langueyú and main routes. In layers of points they have been completed: Industries and establishments of manufactures and commerce and services (in 79 layers differentiated by areas according to official listings organized previously), locating of a total of 52 samples of water (of well and of water of public network), and 20 pertaining to witnesses called well water samples that themselves there they are testeado in their locating by means of the employment of GPS.

Employing 8 variables selected from Censuses of INDEC 1991 and 2001, they were built Indices of Quality of Life that varied among 1 to 10, being 1 the worst living condition and 10 the best situation of index. Then it was compared with the essential services provision data and data of the muetras count in field.

By means of LIBs proceeded to the detection of heavy metals focusing radiation laser inside or in the surface of the half a sample in study. By Espectroscopía UB they were carried out analysis of Nitrates, Nitritos, Amonio in wells groundwater samples, of superficial water and in water of network.

Particularly plans of the following heavy metals were detected: Leads, Mercury, Arsenic, Chromium and Zinc, inclusive in water of network. It has been considered alarming the proportions of Nitrates in wells but mainly in water of public network. These values have been translated in Maps of Contaminants, the ones that permitiren the approach to correlate the risk with their possible sources (industrial uses in urban area and upstream of the wells batteries locating DOSBA, as well as problems of operation in the network of water supply), and to the quality of life of the population affected. For the case of Tandil due to the presence of contaminants in water of network and to the life quality conditions of the population affected, presents the revision of the concept téorico of social vulnerability.

MICROBIOLOGICAL POLLUTION INDICATORS IN SURFACE WATERS BELONGING TO THE ARROYO DEL TALA´S BASIN, ARGENTINA.

C. I. Chagas, O. Santanatoglia, J. Morettón, M. Paz, H. Muzio, M. Castiglioni

Facultad de Agronomía. UBA. Av. San Martín 4453. (1417) Buenos Aires, Argentina. chagas@agro.uba.ar

Water erosion is a land degradation process that threats the quality of surface waters. In our country there is scarce information about the extent to which surface waters are sinks of contaminants promoted by uplands and lowlands soil erosion, particularly biological contaminants (bacterias, protozoos etc) which can affect people as well as animals. A long term seasonally monitoring program is being performed at different scales in an agricultural basin belonging to the Rolling Pampa region of Buenos Aires, Argentina subjected to natural rainfall. The uplands are devoted to annual cropping whereas the bottomlands are natural grassland systems. The studied places were the main waterway of the basin, a subasin, and three small watersheds, one of which has a feedlot. From the set of data gathered until the present days two situations were selected, both belonging to summer time under contrasting weather conditions. The results obtained show that moderate intensive rainfalls can detach and transport contaminated sediments and runoff to waterways and natural ponds in which animals drink and also bath during summer time. On the contrary extremely intensive rainfalls can promote intense runoff which may consequently wash away the surface sediments and waters previously accumulated in shores and ponds. This information can be important for designing an early alert water quality program for livestock farmers in the studied region.

MONITORING GROUNDWATER QUALITY IN THE VAQUEROS FREE AQUIFER, SALTA, ARGENTINA

A. Kirschbaum ^1,2 and G. Baudino¹

1. Facultad de Ciencias Naturales. Universidad Nacional de Salta. Av. Bolivia 5150– 4400 Salta. baudino@unsa.edu.ar

2. CONICET – Instituto de Bio y Geociencias (IBIGEO). Museo de Ciencias Naturales.

Mendoza 2 – 4400 Salta. alikir@unsa.edu.ar

Vaqueros is a small village situated on the foot of the homonymous mountain range, in Salta province, north-western Argentina. The town is extended partly over the recharge area of the aquifer system that provides drinkable water to the northern part of Salta city. The aquifer lithology (coarse grain sized quaternary sediments), as well as the aquifer particularities – free and shallow (4 to 8 m below surface) – lead to a very high vulnerability.

At Vaqueros county agronomic activities take place, such as chicken and chinchillas farms and small sized tobacco and cherry crops.

In the past decade urban growing up was accelerated, with decreasing of the cultivated area; this process occurred without territorial planning. There is no sewage system and the home garbage has no proper management.

The geographic proximity of the Universidad Nacional de Salta to the Vaqueros village was a good reason to plan a Cathedrae of Geochemistry and Hydrogeology practical work, including sampling and analyzing of groundwater from Vaqueros shallow free aquifer. This sampling was carried out to evaluate the influence of two contamination sources: the use of fertilizers in the tobacco and cherry crops and the concentration of houses without sewage systems.

In 2002 the studies showed some anomalous physical parameters (turbidity, low pH values) and values below the permissible limit of World Health Organization and the Código Alimentario Argentino.

In 2004 the sampling was repeated. The analytic results show normal physic and chemical parameters (except high turbidity in some samples), but a significant increment in the amount of total coliform bacteria and presence of fecal coliform bacteria is registered.

The obtained information, up to the present, indicate the home sewage systems (consisting in individual infiltration dug wells) as the main source of the free aquifer contamination. The continuity of the sampling program will allow a contamination monitoring in the study area.

The preliminary results show the need of a sewage system to manage the home liquid effluents, as well as the design of a village territorial planning.

In 2005 environmental education activities will be carried out in the Vaqueros schools, as a part of a Universidad Nacional de Salta social-extension project, with the aim to promote activities to reduce contamination, as well as generate a discussion and participation of the community in environmental problems.

ENVIRONMENTAL EFFECTS OF THERAPEUTIC AGENTS USED IN VETERINARIAN MEDICINE

N. Yoshida, C. H. Moscuzza, C. du Mortier, M. Castro and A. F. Cirelli

Centro de Estudios Transdisciplinarios del Agua (CETA), Facultad de Ciencias Veterinarias, Universidad de Buenos Aires, Av. Chorroarín 280 C1427CWO, Buenos Aires, Argentina. ceta@fvet.uba.ar

The evolution of animal raising systems to meet the needs of a growing population is evidenced by a consistent trend toward the replacement of extensive breeding with animal feeding practices that maximize the number of livestock confined in a certain area. Veterinary medicines or drugs have become a critical component of the food-animal production system providing benefits related to animal health and growth efficiency. Animal feeding operations have begun using feedstocks fortified with these compounds for enhancing growth and feed efficiency.

For a long time, the environmental effect of pesticides, detergents and other pollutants have been studied but the effect of compounds that act as therapeutic agents and growth promoters used in veterinarian medicine has been neglected even when the amount of pharmaceutical products used in some countries per year is in the same order than the pesticide amount.. This group of compounds could be interfering with biological processes in soil, development and quality of the crops, and affecting the rest of the trophic chain. A significant proportion of these compounds or their metabolites are excreted. Large quantities of biosolids and cattle excretes are used as manure for land in agriculture. Drugs and their breakdown products, once assumed to be broken down in sewage treatment plants, are showing up in streams, lakes and coastal waters. Moreover, drugs (and their breakdown products) eliminated by animals usually do not go through the same kinds of treatment processes typical for human waste before reaching streams or groundwater.

Among the therapeutic agents most widely used in intensive production systems we can found antibiotics, antiparasites and growth promotors. They may be excreted intact, partial or totally metabolized, or in both forms in urine and/or feces. So, animal excretes are a source of xenobiotic compounds which transport and final fate are related with environmental conditions (precipitations, runoff, slope, characteristics of soil) of the site of emplacement of animals breeding establishments.

Our aim is to study which of these compounds would have influence on the environment in our country depending on their use (amount and frequency) their way of excretion, their physical and chemical properties, their amount of sorption to the soil, their biodegradability, their biological function and the biological function of their potential metabolites.

In order to study their potential risk, we are performing a survey of establishments in which intensive breeding systems are developed. The establishments are being characterized taking into account their areas, use of the land, number of animals, race, sanitary plans (kind of therapeutic used, doses, frequency) characteristic of pastures and other components of the rations, water sources, effluents produced and possible impact on water bodies. Data is complemented with official statistics and enquires addressed to producers.

LONG TERM INVESTIGATION IN THE LOWER BASIN OF SALADO RIVER (BUENOS AIRES, ARGENTINA)

N. A. Gabellone, M. Claps, L. Solari, N. Neschuk and K. Quaini

Instituto de Limnología “Dr. R. Ringuelet” (CONICET-UNLP) - gabellon@ilpla.edu.ar

The Salado River is the southernmost tributary of the Río de la Plata Basin and the major river arising within Buenos Aires province. The basin is considered to be the second South-American wetland in terms of rainfall accumulation. The regime of the Salado River is very variable. Its flow reaches no more than 100 m³ s^-1 in dry periods and increases up to as much as 1,500 m³ s^-1 in flood periods, with consequent variations in conductivity and transport of dissolved and particulate materials. The flooding of large areas during weeks or months is one of the most important characteristics of the Pampean Plain. Cattle rearing and agriculture are important economic activities in the catchment, and represent 30 % and 27% respectively of the national agriculture-cattle gross output. The mouth of the Salado is located at Samborombón Bay, which is included in the Ramsar list of wetlands of international importance. The alternating conditions between dry and humid periods have allowed the development of some soil characteristics that permit intensive agricultural production and the existence of wetlands with a significant biodiversity. The presence or absence of water constitutes a key factor in the structure of ecosystems associated with the low slope and slow drainage that configure the characteristic landscape of this area. This situation demonstrates the importance of regional limnological studies, which indicate the causes, and consequences of changes in land-use. The study was carried out in 31 occasions during the period May 1995-February 2005 in a site named La Postrera located at the lower basin of the Salado River. Plankton samples were collected for qualitative and quantitative analysis. Total phosphorus, conductivity, suspended solids were measured. The study period included dry and rainy years, with noticeable changes in discharge (minimum: 30 m³ s^-1 in February 1996, and maximum: 950 m³ s^-1 in December 2002) and conductivity (minimum: 920 µS cm^-1 in May 1995, and maximum:15110 µS cm^-1 in February 1996).

Rotifers predominated in plankton community except in five occasions when tintinnid ciliates were dominant. Among them, the presence of Codonaria fimbriata was related to the estuary influence and the occurrence of Tintinnidium fluviatile to lower conductivity values and food availability (green algae). The specific richness of zooplankton (the mean value was 25 species) was related to conductivity, with minimum during dry periods. Phytoplankton assemblages included green algae (Chlorophytes) that prevailed (mean dominance: 48%), cyanobacteria, diatoms and others. The phytoplankton specific richness values (mean: 42 species) were very variable, whereas a long term decrease was undetected. The maximum concentrations of suspended solids were estimated in October and November 1995, coinciding with the lower discharge. The total phosphorus concentration were highest in the period 2002-2005. The nutrient increase in the lower basin of Salado River would be related to the more intensive land use in upper basin.

BIODIVERSITY ESTIMATORS AS CONSERVATION PRIORITY TOOLS: THE EXPERIENCE FROM BENTHIC FAUNA FROM THE YUNGAS BASINS.

L. Mesa,¹ H. R. Fernández² and E. Dominguez²

1. Instituto Miguel Lillo. Miguel Lillo 205. 4000, S. M. de Tucumán, Argentina. leticiamesa@yahoo.com.ar

2. CONICET-Fac. Ciencias Naturales e Inst. Miguel Lillo. Miguel Lillo 205. 4000, S. M. de Tucumán, Argentina.

The International Conference on “Biodiversity: Science and Governance” in Paris (February 2005) recalls the commitment of governments to the global target of significantly reduce the rate of biodiversity loss by 2010 as a fundamental condition for sustainable development. They recognized that Biodiversity is a vital and poorly appreciated resource for all humankind that underpins the achievement of the Millennium Development Goals. Also, biodiversity is being irreversibly destroyed by human activities at an unprecedented rate that demands urgent and significant action to conserve sustainable use and equitably share the benefits of biodiversity. Because of its broad scope and multidimensional nature, biodiversity has the potential to serve a unifying role by providing a basis for effective management and restoration initiatives.

Among aquatic organisms, invertebrates are frequently omitted from biodiversity analysis for conservation priorities.

We were committed with the aquatic macroinvertebrate fauna from the NW Argentina Yungas focusing our studies in richness estimations and their possible use for conservation.

This ecoregion includes 3 900 000 ha, between 22º and 28º S. This is one of the biological richest area in Argentina, included in a Tropical Andes hot-spot.

To estimate the richness of four sub-basins of Sali-Dulce basin we used a data base (>2,500 inputs) of macroinvertebrates from this region. Among these, 960 data of 6 orders of arthropods were chosen.

We used Coleman, ICE and Jacknife estimators of richness, focusing in curves and in richness estimation for further comparisons. One basin was very well sampled, considering no gap existence between estimators and observed curves. On the same basis, two other were undersampled, and the last one was intermediate. This situation is observed when data come from undersampled basins. Also, the Jacknife estimator subsample shows no differences (p<0.05) between the two Northernmost basins (>70 taxa each one). On the other hand, the Southernmost basins compared presented lower richness (p>0.05).

The comparation of the estimators of the two well sampled basins, allowed us to determine that one of them presents a higher richness, and suggest it is a potential source of new species. This could represent a higher biodiversity conservation potential. Due to the size and conservation of the two undersampled basins, they are potentially richer than the well-sampled ones. Which would be the picture if the four basins would be equally known? It is necessary to have an accurate estimation of the richness of the considered basins before a conservation decisions can be taken. A database that integrates the systematic, ecological and geographical information represents a tool that provided the basis to logically compare the conservation potential of these different basins.

TOTAL CONCENTRATION OF Pb AND Zn IN RUNOFF SEDIMENTS OF MATANZA-RIACHUELO RIVER BASIN SOILS

M. De Siervi¹, C. I. Chagas² and A. F. de Iorio¹

1. Cátedra de Química Analítica. (FAUBA)

2. Cátedra de Manejo y Conservación de Suelos. (FAUBA), Av. San Martín 4453- (1417) Ciudad Autónoma de Buenos Aires. Argentina. - marcelodesiervi@yahoo.com

Soil profiles near watercourses that drain rural areas with agricultural lands and pastures, as well as recreational zones and densely populated industrial centers are directly influenced by human activities. Therefore, these soils condition the contamination dynamics of the aforementioned watercourses in a remarkable way. The present study deals with the soils of a first order sub-basin located in the headwaters of Morales Stream, main tributary of the Matanza River. Pedons representative of positive areas located in slopes were selected under the denomination of “Backslope” (B) (Brandsen Series and/or Cañuelas Series, Typic Argiudoll) and of alkaline sites close to the alluvial plane (Typic Natracualf), were selected under the denomination of “Toeslope” (T) as study sites. In both cases, the land is used for extensive farming, like in most part of this sector of the Matanza River Basin. Composite samples of the upper 5 cm of both soil types (previously disturbed) were treated either with vermicompost or phosphate fertilizer and finally saturated with water during a whole week before starting the rainfall simulation to study the effect of the addition of these elements on the runoff dynamics of heavy metals. Experiments using a rainfall simulator that formed drops on runoff microplots containing soil samples were carried out under laboratory conditions. The surface runoff obtained was analyzed to determine the heavy metals (Pb and Zn) contained in the particulate fractions (> 0.45mm). Total heavy metal concentrations of the runoff sediments were determined after acidic digestion using HNO₃-HClO₄-HF-HCl. The values Pb content in the sediments of backslope soils in the plot with vermicompost amendment (BV) seems to be higher than control (BC) and fertilized plots (BF) (in µg Pb g^-1 sediment) because of the high concentration of Lead in the amendment. In the case of plots of toeslope soils the total lead in the particulate fraction was lesser because of the lower concentration of sediments. In backslope soils, the total zinc content were influenced by the high concentration of Zn in the vermicompost (900 ppm); the treatments where the amendment was applied showed a high total concentration of this metal. The addition of organic amendment probably increased the number of adsorption sites by rising the ECC; thus, the excess of available Zn contributed by the amendment would take its place in these new sites. The herein obtained results allow us to conclude that the use of high amounts of organic amendment (i.e.: vermicompost) produce important effects on the surface condition of the soil, which in turn determine a highly significant reduction in the emission of suspended solids to watercourses. In spite of the high level concentrations of the studied heavy metals in the vermicompost, the utilization of this organic amendment would not contribute with these elements to runoff ways as particulate form. Therefore, the use of this kind of management practice would be widely recommended concerning the heavy metal dynamics in soil and its influence over the pollution of watercourses by runoff.

THE EXPANSION OF THE MENDOZA RIVER OASIS AND ITS CONSEQUENCES IN THE ENVIRONMENT: POLLUTION OF WATER BY SOLIDS

G.Zamorano de Montiel¹, M. Alessandro de Rodríguez, C. Tejada, N. Pucciarelli, L. Fernández and G. Sari

1. Universidad Nacional de Cuyo, Facultad de Filosofía y Letras, Mendoza, Argentina

Remedios de Escalada 1606, 5519 Dorrego, Guaymallén, Mendoza, Argentina

glozam@arnet.com.ar

Abstract

The Mendoza river oasis, located in the north of the homonymous province, is an irrigated area of 55.000 cultivated hectares. This suffered, outstanding transformations in the soil utilization, that passed from agricultural to urban, industrial, urban, urban-industrial, industrial-agricultural uses, in the last twenty years This process is the effect of a disarranged and spontaneous growth, unless of any planning, that lets the irrigation's net (of 4,200 kilometers of length) introduced in the urban tram. The main extension of the cultivated area is located water below of the Gran Mendoza agglomeration, and consequently receives various kinds of pollutants, as voluminous and heterogeneous urban remainders that obstruct mostly the arrival of the irrigation's water to beds, whether channels, hijuelas or ditches. This has a negative impact over the environment: degrades the quality of agricultural production, modifies rural landscape and, mostly, affects the life quality of the oasis inhabitants.

This problem is the object of a transdisciplinary investigation that will be done in two years. Our principal objective is to inspect the conflicting urban or rural areas on account of the excessive incorporation of solid remainders in the beds of the irrigation net in the Mendoza river oasis.

The fundamental hypothesis are three:

1. The disarranged and heterogeneous growth of urban increasing over the irrigated areas affects the water quality and the distribution to the different users, especially on account of the solids transport of different natures and volumes.

2. There are increasing conflicts between the city and the country related to the usage of water, are generated by the growth of population.

3. There are different grades of pollution in the channels of the irrigation net depending on the population density and soils usages of the area.

With regard to the methodology, in this first stage of the investigation we have divided the study in two parts: territorial occupation and pollution by solids. To study territorial occupation in Mendoza oasis, satellite images and aerial photography are analyzed by superposing or contrasting them. Limits of the latest urbanization period (10 years) are cartographied as well as its extension, estimated with ARC-View software. To evaluate solid waste in the water net, the most significative sites are chosen. Its volume accumulated in different interval of time, its transportation and final storage out of the chosen area are analyzed.

In a second stage of the study, we will analyze and map the kinds of soil utilization, and the carrying of materials out of the conflicted area. In a third stage we will make interviews and to determine the conflicts causes. In a last stage of the investigation, we will create campaigns of actions to attenuate the conflicts between city and country areas.

As a result, we have detected that there are fast twenty important points of accumulation of solid remainders, and they come mostly from the south part of the agglomeration, specially in the departments of Las Heras, Luján de Cuyo et Maipú, where the population life conditions are different.

COULD BE USED SAGITTARIA MONTEVIDENSIS IN PHYTOREMEDIATION STRATEGIES?

R. Serafini and A. F. de Iorio

Area of Analytic Chemistry, Natural Resources and Environment Department, Faculty of Agronomy, University of Buenos Aires, Av. San Martín 4453, C1417DSE, Buenos Aires, Argentina. aiorio@agro.uba.ar

Many plant species can uptake metal ions from the environment. Some ions, like Cu²⁺ and Zn²⁺ are essential trace nutrients and take part into redox reactions and enzyme catalyzed reactions, while other heavy metals like Cd²⁺ and Pb²⁺ are strongly poisonous and result in growth inhibition or eventually in the death of the organisms.

The ideal plant for phytoremediation should posses multiple traits: fast growing, high biomass, deep roots, be easy to harvest and tolerate and accumulate a wide range of heavy metals in its aerial and harvestable parts. Wetlands constitute complex communities with high biomass production. Some authors have investigated the effect of metals on growth of different wetlands plants and evaluated the use of them as phytoremediators. Metal removal by wetland plants could be greatly enhanced by the judicious selection of plant species.

The term vegetation can be defined like the landscape physiognomy conferred by different plant species with common morphological and physiological characteristics. We have followed this ecological approach to evaluate the aptitude of a riparian plant (Sagittaria montevidensis) in phytoremediation.

S. montevidensis specimens were collected as whole plant samples from Matanza-Riachuelo river (at Puente Alsina), and transported to the laboratory in clean plastic bags. Plant samples were washed with tap water and rinsed with deionized water to remove any sediment particles attached to plants. Washed material was separated into rhizomes, roots, leaves and stems, and oven dried at 70ºC for 24 hs. One gram of each plant tissue was digested with HNO₃ and HClO₄. Metal concentrations were determined by atomic absorption spectrophotometry.

Heavy metals concentrations in tissues were: 233 ± 30µgZn/g, 153 ± 26µgCr/g and 17 ± 1µgPb/g in the aboveground biomass (stems plus leaves), and 1056 ± 141µgZn/g, 304 ± 37µgCr/g, 69 ± 2µgPb/g in the belowground biomass (roots plus rhyzomes). Belowground biomass presented the highest metal concentration (p<0.01 for Zn and Pb and p<0.05 for Cr). Lead concentration in roots were higher than concentrations in leaves, stems and rhizomes (p<0.01); Zn concentration in roots were only different of leaves and stems (p<0.05) and showed no differences with rhizomes, while not significant differences in Cr concentration between tissues were found. Translocation factors of Zn, Pb and Cr were 0.22, 0.25and 0.50, respectively.

S. montevidensis showed high metal concentration in their tissues, being able to accumulate in roots and to translocate to potential harvestable parts, suggesting its potential use in phytoremediation.

A METHODOLOGIC APPROACH FOR AN UNGAUGED BASIN (BUENOS AIRES, ARGENTINA)

S. Arreghini ¹, L. de Cabo ², R. Seoane ³, N. Tomazin ³, R. Serafini ¹ and

A. Fabrizio de Iorio ¹

1. Facultad de Agronomía -UBA, Av. San Martín 4453, 1417 Buenos Aires, Argentina. sarreghi@agro.uba.ar.

2. MACN.

3. INA, Facultad de Ingeniería - UBA, CONICET

Reconquista river is a temperate lowland river. It is one of the most polluted river of Latinoamerica, and flows into Río de la Plata estuary, main source of drinking water for Buenos Aires city and environments. Much research has assessed the water quality, although, detailed information at the “background area” for this region does not exist. In Argentina there are numerous ungauged basins, consequently, the parameters of hydrological models must be indirectly estimated.

The aim of this study is to identify a background water quality for Reconquista river. To describe the water quality dynamics in the background area, we propose a methodology based in discharge estimation through instantaneous unit hydrograph model (IUH) and chemical and physical measurements in stream water under different hydrological conditions.

The water quality at Durazno stream (tributary of Reconquista river) is the nearest to that from natural sources respect to the rest of sites of Reconquista river. The oxygen (6.9 mg/l), ammonium (0.40mg/l), nitrate (0.37mg/l), SRP (0.37mg/l) and POC (1.3mg/l) median concentrations allowed to confirm Durazno stream as a background area. Also, this basin presents agricultural land use and low population density.

Nitrates (0.12mg/l), ammonium (0.05mg/l), major ions and conductivity (349µS/cm) were significantly lower during high flow conditions (3.85m³/s). During dry periods (0.07m³/s), chlorides, other anion concentrations and conductivity (1650 µS/cm) were similar to groundwater, showing the main source of streamwater in base flow conditions.

During early storm event studied the discharge was 7.3 m³/s, and nitrates concentration and conductivity decreased (0.73 to 0.27mg/l, and 1537 to 263 µS/cm, respectively). The increment of DOC and E₂/E₃ ratio (9.40 to 19.11 mg/l and 2.2 to 3.8, respectively) suggest a large input of carbon by runoff. Likewise, the increase of E₂/E₃ ratio reflects an increase of fulvic/humic acids ratio. After the discharge peak, the inputs from several ditches dominate the flow generation of Durazno stream. In the receding limb of the hydrograph (1.9m³/s), nitrate concentration was lower (0.02mg/l) than during discharge peak. This variation was the result of rainwater diluting in the ditch. DOC increased and E₂/E₃ ratio did not change (32.63 mg/l and 3.6, respectively), this allows to suggest that the composition of DOC did not change but its concentration increased in the water of ditches. Water quality changes quickly, even in background areas, as a consequence of its interdependence with flow.

The methodology applied in this paper also can be used in others lowland temperate rivers with similar geomorphological, edaphic and lithological characteristics. Due the impossibility to define baseline areas in surface waters, the knowledge of the background water quality and its dynamic is essential to understand pollution trends and anthropogenic impacts on the rivers.

BEHAVIOUR OF MAIN STREAMWATER POLLUTANTS OF RIACHUELO STREAM IN WATERS OF RIO DE LA PLATA ESTUARY: SANITARY WATER QUALITY ASSESSMENT OF RIACHUELO RIVER*

M. S. Fortunato¹, V.Gemini¹, S. Rossi¹, L. de Cabo², A. F de Iorio³_, J. Moretton¹ and

S. Korol¹

1. Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires - sekorol@ffyb.uba.ar

2. Museo Argentino de Ciencias Naturales “B. Rivadavia”

3. Facultad de Agronomía, Universidad de Buenos Aires - aiorio@agro.uba.ar

The Matanza-Riachuelo river, main collector of a basin of 2300 km², is one of the most polluted rivers in the world. The population and industrial activities are concentrated in the lower basin (Riachuelo). The main pollutants are generated by urban runoff, dump leachates, domestic and industrial wastewater effluents discharged to the river or its tributaries. The river flows into Río de la Plata estuary, main source of drinking water for Buenos Aires city and surroundings. The aim of this study was the assessment of the Riachuelo sanity water quality by determining heterotrophic bacteria, thermotolerant coliform and fecal streptococcus counts; biochemical oxygen demand (BOD) and chemical oxygen demand (COD) .Water sampling was performed in 14 stations located as follows: 9 in the Riachuelo navigation channel, upstream (R1 to R9), and 5 in a transect in Río de la Plata estuary (South Channel), downstream the mouth of Riachuelo (LP1 to LP5). Chemical and microbiological parameters were performed in the stream surface water samples. The heterotrophic bacteria counts were between 6.5 x 10⁵ CFU/ml and 2.7 x 10⁶ CFU/ml in the water samples of Riachuelo (R1-R9). On the other hand water samples from Río de la Plata (LP1-LP5) showed a lower number of bacteria, 9.9 x 10⁴ CFU/ml. Thermotolerant coliforms and fecal streptococcus ranged between 2.4 x 10² to 4.4 x 10³ CFU/ml and 1.4 x 0² to 5.7 x 10² CFU/ml respectively in Riachuelo water samples. High thermotolerant coliforms and fecal streptococcus counts detected could be attributed to untreated municipal wastewaters discharges. BOD values were less than 2 mg/l except in R3 station where the stream meandered along 1 Km leading to concentrate organic matter in the waters. The chemical oxygen demand (COD) ranged from 26 to 62 mg/l. Anoxic condition was reached in samples from stations R1 to R9, upstream. However dissolved oxygen values were higher downstream, reaching 90% saturation level in LP4.

High COD/BOD ratio in samples from Riachuelo suggested the presence of non biodegradable organic matter. An inhibitory effect was also demonstrated when these samples were submitted to BOD test. This inhibitory effect could indicate the presence of toxic compounds.

BEHAVIOUR OF MAIN STREAMWATER POLLUTANTS OF RIACHUELO STREAM IN WATERS OF RIO DE LA PLATA ESTUARY*

L. de Cabo¹, A. Rendina², S. Arreghini²_, A. García², M. Bargiela², M. J. Barros²,

J. Moretton ³ and A. F. de Iorio²

1. MACN-CONICET - ldecabo@macn.gov.ar

2. Facultad de Agronomía – UBA - aiorio@agro.uba.ar

3. Facultad de Farmacia y Bioquímica – UBA

The Matanza-Riachuelo river, main collector of a basin of 2300 km², is one of the most polluted rivers in the world. The population and industrial activities are concentrated in the lower basin (Riachuelo). The main pollutants are generated by urban runoff, dump leachates, domestic and industrial wastewater effluents. River flows into Rio de la Plata estuary, main source of drinking water for Buenos Aires city and environs. The studied estuary region is entirely occupied by freshwater. The aim of this study is to assess the behaviour of main streamwater pollutants of Riachuelo in waters of Rio de la Plata estuary.

Fourteen sampling stations were sited: 9 in in the navigation channel of Riachuelo upstream its mouth (R1:14000m; R2:7500m; R3:5500m ; R4:4500m; R5:3000m; R6:2000m; R7:500m; R8:300m; R9:in the mouth), and 5 in a transect in Rio de la Plata estuary, downstream the mouth of Riachuelo stream (LP1:200m; LP2:400m; LP3:600m; LP4:800m and LP5:1000m). Physical and chemical variables were determined in streamwater.

Anoxic condition was reached in sites R1 to R9, downstream, dissolved oxygen (DO) increased, reaching 90% saturation level in LP4. The low DO values may be attributed to high solids load and to untreated wastewater discharge. pH remained close to neutrality in all samples. Soluble reactive phosphorus, bicarbonates, sulphates and nitrites increased toward R7, downstream, the levels decreased. The maximum total sulphides concentration was attained at R5 and R3, sulphides disappeared at LP2, according to DO increasing. The maximum nitrates and minimum nitrites levels were recorded at R7. The maximum conductivity, sodium and chlorides concentrations were obtained in R8 and R9. Apparently, a combination of salt induced flocculation, and settling and colloid aggregation of particles, participate to the decrease of suspended sediment (SS) concentration in R8 and R9. The highest zinc, chromium, and copper levels were observed at R2 and the highest lead concentration was obtained in LP1. The progressive dilution process and the sedimentation of SS and heavy metals associated in the estuary explain their decrease in the mouth. From the mouth, the SS levels trended to increase. The increasing in Zn, Cr and Pb concentrations downstream the mouth is probably related with local resuspension processes. Volatile organic compounds are used extensively in urban areas. Due to their volatility they are found in low concentrations in surface waters. Nevertheless, chloroform (0.74 mg/l) and dichloromethane (1.74 mg/l) have been detected in R1.

The main streamwater pollutants concentrations decrease when the Riachuelo waters income in Rio de la Plata estuary. Nevertheless, as riverine sediments act as both carriers and sinks for contaminants, it is necessary to study the distribution of main pollutants also in bed sediments and suspended sediments both in the mobile and bound phases to determine theirs ecotoxicological potential effects.

WATER AMBIENT INDICATORS OF CHEMICAL STRESS: RECONQUISTA RIVER (BUENOS AIRES, ARGENTINA) CASE STUDY*

A. Puig and H. F. Olguín Salinas

Museo e Instituto Nacional de Investigación de las Ciencias Naturales, División Limnología (Area Ecología). Av. A. Gallardo 470, C1405DJR. Buenos Aires, Argentina. apuig@macn.gov.ar

A conceptual framework about health and stress in ecosystems, bioindicators, and plankton attributes as ecological indicators of freshwater ecosystem health is presented and applied to assess water ambient condition of a highly polluted lowland river. Chemical stress in aquatic ecosystems is increasing worldwide, involving changes in the loading rates of biostimulatory nutrients, oxygen consuming materials, and toxic substances. Physical and chemical analyses, bioassays, and bioassessments may detect each one, essential effects which the other may fail to reveal. Bioindicators, structural or functional ecological properties of different organisational levels, reveal changes of potential ecological signification that cannot be detected by other analyses. These studies may be especially useful in systems where toxicants are intermittently discharged. Although requiring ecological interpretation, the analysis of ecological attributes at the level of a whole community or parts of it, are independent of regional geographic characteristics, which are in turn a limitation for the methods based on indicator species. A recent review of the effects of four types of chemical stresses on plankton proposes a set of phyto- and zooplankton attributes (structural, functional and at system-level) as ecological indicators for assessing freshwater ecosystem health. Results of different approaches potentially useful for the evaluation of water ambient quality were analysed and compared in a small temperate lowland river with mixed diffuse and multiple-point source pollution. The Reconquista River (Buenos Aires Province, Argentina), one of the most polluted watercourses of Latin America, receives agrochemicals as well as domestic and industrial (mostly untreated) effluents. Results from three approaches [1) physical and chemical parameters, 2) monospecific laboratory bioassays on two algal populations, and 3) density and structure of phytoplankton and zooplankton] were compared in a subset of samples representing a range of likely conditions in the river. A general scheme of associations among plankton, bioassays and physical/chemical variables was elaborated and helped to infer possible control factors in this multi-stressed system. Some empirical methods, but mainly mathematical ones including multivariate techniques, were applied for sample evaluation. A preliminary selection of indices and attributes as potential indicators of the water river quality was made, and then applied to provide a tentative integrative ordination of samples. The relative best water quality was recorded when/where oxygen concentration; algal diversity and planktonic crustacean density were higher. The worst water quality corresponded to the lack of cladocerans and lowest crustacean density, and higher: organic and industrial pollution, major nutrients (ammonium and orthophosphates), BOD, hardness, conductivity, algal biomass in bioassays, phytoplankton density (>10,000 ind. mL^-1), dominance of a single algal species (>90%), and rotifer proportion in zooplankton (>85%). Present results agree with several current relevant biotic responses to chemical stresses summarized in the above-mentioned review. The complementation of approaches combined with mathematical methods of data analysis was useful to detect both associations among variables and also potential indicators for the evaluation of water ambient quality in this chemical stressed river.

Session 3. Water ecosystems, their conservation and modeling

INTEGRATION OF GIS AND VISUALIZATION FOR DISTRIBUTED WATERSHED MODELING OF THE GREAT LAKES BASIN

Ch. He¹ and T. E. Croley II²

1. Department of Geography, Western Michigan University, Kalamazoo, MI 49008, U.S.A. he@wmich.edu

2. Great Lakes Environmental Research Laboratory, NOAA, 2205 Commonwealth Blvd.

Ann Arbor, MI 48105-2945, U.S.A.

Distributed watershed modeling requires development of model input parameters over the landscape of the study watersheds from multiple databases. This paper integrates Geographical Information System (GIS), multiple physical and land use databases, and visualization programs to process, extract, analyze, and visualize the input and output parameters for the distributed large basin runoff model (DLBRM) in the Great Lakes Basin of the U.S. Applications of the DLBRM to the Great Lakes watersheds indicate that the GIS-model interface and visualization programs are useful utilities to facilitate model implementation over multiple temporal and spatial scales in support of water resources research and decision making in the Great Lakes Basin.

OBJECTIVE CALIBRATION OF THE HYDROLOGICAL MODEL SEROS

FOR THE ODRA WATERSHED

H. T. Mengelkamp¹, J. Sutmöller², H. Messal¹, K. P. Johnsen¹

1. Institute for Coastal Research, GKSS Research Center , D-21502 Geesthacht, Germany mengelkamp@gkss.de 2. GRISU, Geographic Informations Systems Sutmöller, D- 37085-Göttingen, Germany

Hydrologic models often contain parameters that cannot be measured directly but which can only be inferred by a trial-and-error process that adjusts the parameter values to closely match the input-output behaviour of the model to the real system it represents. Traditional calibration procedures, which involve manual adjustment of the parameter values are labour -intensive, and their success is strongly dependent on the experience of the modeller. Automatic methods for model calibration are objective. However, many studies have shown that such methods have difficulties in finding unique parameter estimates. Most hydrological methods suffer from similar problems, e.g. the existence of multiple local optima in the parameter space with both, small and large domains of attraction (i.e. a sub-region of the parameter space surrounding a local minimum) or discontinuous first derivatives. The consideration of these problems resulted in the development of a robust and efficient global optimisation algorithm called ‘shuffled complex evolution’ (SCE) global optimisation algorithm developed at the university of Arizona.

Within the EU funded project FLOODRELIEF the hydrological model SEROS (Surface Energy and Routing Scheme) is calibrated for the Odra watershed and used for flood forecasting purposes. The calibration is performed by use of the SCE algorithm. SEROS is a grid based model system which solves the coupled surface energy and water balance equations in each grid. Runoff is transported into the river system by use of a unit hydrograph approach and then along the river channel system by a kinematic wave approximation.

The calibration period for the SEROS system is the four years from 1992 until 1995. Data for the period 1996 until 1999 are used for validation purposes. Each of 39 sub-catchments is calibrated separately. The model efficiency shows a large regional variability. The calibration procedure and the validation with observed streamflow data are discussed.

EXPLORATORY SIMULATIONS WITH SPARSE DATA IN INVESTIGATION

OF AQUATIC ECOSYSTEMS.

M. G. Erechtchoukova

TEL Bldg. # 2026, York University, 4700 Keele St., Toronto, ON, M3J 1P3, Canada - marina@yorku.ca

Sustainable development of human society requires ecologically sound, economically viable, socially just and humane decisions affecting all aspects of our life. Decision making process in the environmental area is characterized by a high level of complexity. Sustainable approach to water resources management requires consideration of such characteristics of natural water resources as quantity, quality, conditions of aquatic environment and ecosystems. All four characteristics are interdependent and equally important.

While utilization of water resources depends significantly on their quality and quantity, ecological approach to investigation of aquatic ecosystems takes into account physical, chemical and biological processes. Physical processes include water currents and mixing and dispersion of water ingredients and heat. The available observation data for this type of processes can be considered as the most detailed data. Chemical processes describe chemical reactions in the water. The results of such processes are usually represented by series of observed concentrations of ingredients. Although different ingredients are observed with different frequencies, in general, modern monitoring systems provide decision makers with the data allowing to conclude about the level of concentrations of various chemical matters in natural waters. Biological processes include biogeochemical cycles of the most important elements of an ecosystem, photosynthesis and growth of populations of living organisms. They are undoubtedly more complex. Increasing complexity results in fewer observation data available to investigate all elements of aquatic communities and their interactions with each other and the environment.

Anthropogenic impact onto natural ecosystem affects natural processes significantly and must be taken into account. Such influence is not always adequately represented by observation data. In many cases, observed values correspond to a result of a superposition of various processes. To provide an interpretation additional investigations are required. In order to provide comprehensive analysis of major processes involving in ecosystem’s dynamics, simulation modelling is widely adopted. The advantages of simulation modelling have been demonstrated for the last 30 years in numerous research papers and can be hardly extended. At the same time an acceptable level of model complexity depends significantly on available observation data. Therefore an application of a general framework of simulation modelling to a case study with limited available data of observation can be interesting as it may reveal specific aspects of the framework that need be improved or elaborated.

The proposed paper describes the investigation of eutrophication process in the delta of a large river based on exploratory simulations when sparse data is available. The ecosystem experiences anthropogenic impact. The model created is discussed along with the approaches to model investigation that allowed the author to determine critical limiting factors. Two hypotheses about origination of phytoplankton biomass and factors contributing to its growth were formulated based on available data and were investigated based on exploratory simulations.

VEGETATION PONDERING IN A SECTION OF THE MIDDLE PARANA RIVER

SANTA FE, ARGENTINE REPUBLIC

B. A. Fritschy

CONICET-UCSF - Echagüe 7151 – S3004JBS – Santa Fe, Argentina - bfritschy@ucsf.edu.ar

Interflow and fluvial dynamic patterns interact in the same system. Interactions between mass and energy of the process-answer system are basis to identify –within the present valley of the Paraná River in a stretch of its middle section – geophases. In each of them vegetation phases are delineated in wood, graminoides and hydromorphes communities. These describers are analyzed in their vertical and horizontal structures, having into accounts thus, occupied surface and phytomass of the most representative species.

Aim

To ponder the quantity and quality of vegetable communities which grow in the present valley of the Middle Paraná River so as to contribute to new knowledge of alluvial phytogeography.

Methods

Transect and area patterns in the section between Romang and Santa Rosa (Santa Fe Province) were selected. According to work steps, different techniques developed in the laboratory and field were chosen:

• Reading, analysis and interpretation of satellite images and vertical aerial photos.

· Selection of five 10 km transects from north to south along the broad present valley (representing 7% of the Middle Paraná section and 23% of the Romang-Santa Rosa section).

· Elaboration of vegetation census.

· Systematic determination of vegetable species

· Surface estimates.

· Field verifications in patterned areas.

Results

Calculus carried out to estimate the surface of the different vegetable communities in aerial and patterned transects covering a total surface of 132.760,69 ha and 30.481,9 ha respectively, show that:

• Romang - Patí: The Word occupies 15%; it is located in the packsaddles near the common bed of the Paraná River (thick wood), and on its connected branches. The graminoides and hydromorphas make the 58%, and water bodies, the 27% of the surface of transect.
• Alejandra - Esquina: Word occupies 14%, graminoides 32%, hyidromorphas 34%, and water bodies free from vegetation, 20%.
• San Javier - La Paz: The distribution of the three communities is homogeneous 24%, 24%, and 22%, water bodies occupying 30%.
• Saladero M. Cabal - Santa Elena: The wood with a 10% is restricted to the eastern side. Graminoides, 22%, show a regular distribution in the whole aerea. Hydromorphas occupy 30%, and water bodies, 38%.
• Santa Rosa - Pueblo Brugo: The wood, 16%, is represented by trees and bushes less than 10 m. Graminoides and hydromorphas occupy 14% and 31%, and water bodies, 39%.
• Estimates of the surface covered by vegetable communities in the five transects show that 59% is occupied by water bodies and hydromorpas, 25% by graminoides, and, 16% by wood. On the contrary, of the total of the phytomass estimated, 51,861,688.3 tn, graminoides represent the major weight: 30,483.690 tn (59 %); wood, 16,435,175 tn (32%) and hydromorphas, 4,942,823.3 tn (9%).

strategic Management of pampean Shallow lakes

G. A. Canziani, F. Grosman, R. Ferrati, P. Sanzano, O. Díaz, V. Colasurdo, P. Saavedra, M. Vargas Russo, F. Dukatz and M. Gelmi

Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable - Universidad Nacional del Centro de la Provincia de Buenos Aires Pinto 399 – 7000 Tandil, Prov. de Buenos Aires canziani@exa.unicen.edu.ar

The Pampean plains occupy the Eastern Central region of Argentina. The high content of organic matter and nutrients in their soil has encouraged the development of agricultural activities and the settlement of related industries, turning them into the most densely populated territory with the highest level of economic activity in the country. From the environmental perspective, they comprise a strongly disturbed and scarcely protected area.

The slow slope of the plain generates a dominance of vertical hydrological processes over horizontal flow. Thus, the landscape exhibits characteristic ecosystems formed by hundreds of “lagunas” or shallow lakes of varied extension, naturally eutrophic, with variable salinity and turnover time, and fluctuating dynamics.

We can mention that, among the many services rendered, these lagoons are freshwater and biodiversity reservoirs, recreational environments, and regulators of end products of human activities. Global climate change, expansion of agriculture, increase in waste production, outdoors recreation, among other activities, generate a negative impact on the environmental quality of “lagunas”, hindering present and potential use. So far, their study has been reduced to a fragmented analysis of its components, while integrated research on the ecosystem dynamics and functionality, as well as their interaction with the basin and their natural or man-made environment, is rare.

The goal of this work is to analyze the structure and functioning of the natural and socioeconomic components of lenitic systems and to develop observation tools, mathematical models, and monitoring tools that permit an adequate management of their resources, considering each “lagunas” and the corresponding basin as a physical unit.

Monthly samplings are being performed in Del Estado, El Paraíso, Quilla Lauquen, San Antonio, El Chifle, La Salada and La Barrancosa “lagunas”. Data base is completed with data collected periodically in La Brava, De los Padres, La Peregrina, Indio Muerto, Bragado, Las Mulitas, El Carpincho, Gómez, Blanca Grande, Puán, Los Chilenos, Saavedra and La Segovia “lagunas”. Superficial basins have been delimited, as well as the periods of excess and deficits. Land uses have been identified.

Limnological samplings have determined physico-chemical properties of water (pH, turbidity, conductivity, ionic composition, total phosporous), as well as sediments (organic matter, nutrients) and biotic variables (phyto- and zooplankton, macrophytes, ichthyocenosis). In selected sites, meteorological equipment was installed for gathering data necessary for model calibration.

Human use of the environment is being quantified through interviews and/or survey, and satellite images. Socioeconomic aspects, pertinent to the conservation of the ecosystems under study, are evaluated qualitatively.

Computational models coupled to remote sensor data were used for classifying the “lagunas” according to their status, and for the quantification of chlorophyll-A and suspended solids, also including hydrometeorological and socioeconomic variables reflecting the use of the basin.

Partial results show an acceptable fit to the complex reality of these ecosystems, allowing the integration of very different scales and the generation of a useful novel tool for the analysis of these as well as other Pampean “lagunas”. This tool may be used to design management strategies within the context of social equity, ecological equilibrium and sustainable development.

METHODS FOR ENVIRONMENTAL DEGRADATION DIAGNOSIS IN WATERSHEDS - ITS APPLICATION TO THE BASIN OF SAN TEÓFILO - PROVINCE OF BUENOS AIRES - ARGENTINA.

F. J. Gaspari¹, M.G. Leonart and I. Odhe Cornelly²

1. Curso de Manejo de Cuencas Hidrográficas. Facultad de Ciencias Agrarias y Forestales. Universidad Nacional de La Plata. Diag.113 Nº469. La Plata (1900). Argentina - corrector@agro.unlp.edu.ar

2. Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CICPBA).

The purpose of this work is to analyze the current situation of the basin and the principal factors of environmental risk, formulating a sustainable development project. Its objective is to attend to the problems of agricultural producers and to preserve the environmental patrimony. Producers preoccupations are on one hand, those which are derived from torrential runoffs with erosive effects and floods; on the other, those which are linked with the need to fit productive systems to the new requirements of the outstanding economic policies. The goals pursued by producers include preservation and protection objectives, which could be in conflict with those pursued by agricultural activity. Thus, there becomes the effort to harmonize such discrepancies in order to maximize community benefits from a sustainable point of view. In terms of research hypothesis, the objective is to advance on the basic knowledge of the operational dynamic trends of this kind of systems, particularly those related with erosion processes, their quantification included, influence of production and protection integrated treatments at watershed and microwatershed level, and their application to the formulation of territorial classification patterns taking into consideration the environmental risk limitations. The basin object of study was subdivided in subwatersheds and microwatersheds, the last being defined as Control and Management Units (UMG), to the effect of calculating the conduction coefficient by successive iterations by means of the hydrologic model HYMO, being selected the one which corresponds with the peak flow of the hydrograph. Referring to quantitative approach, hydrologic proccesses of erosion, transport and sedimentation of materials were estimated through the compatibilization of the available information, field data and systematic observations about recurrency and duration, adapted to the requirements of each one of the involved variables. The study of hydric erosion was accomplished applying the integrated methodology of hydric erosion evaluation developed by the Superior Technical School of Forest Engineers of Madrid, through the utilization of the model MUSLE (Modified Universal Soil Loss Ecuation), by means of calculating the conduction coefficient by successive interactions that permit to integrate the total sediments issued by the basin, as of the particular values of the different parameters intervening. The current advance level of the project, the preliminary diagnosis results and some of the main difficulties to its accomplishment are exposed. The standards for the application of Integrated Production Models and Protection (MIPP) are formulated, on the basis of a territorial classification proposal.

MONITORING THE LAKE BUENOS AIRES (SANTA CRUZ) USING NOAA-AVHRR

M.G. Cogliati¹, C. Palese², J. L. Lässig²

1. Departamento de Geografía. Facultad de Humanidades - Universidad Nacional del Comahue. Av. Argentina 1400 Q8302AZN Neuquén. Argentina. TE: 0299-4490300.

cogliati@uncoma.edu.ar

2. Departamento de Mecánica Aplicada. Facultad de Ingeniería. Universidad Nacional del Comahue

Knowledge of water movements in lakes is important because, water circulation influences the distribution of dissolved substances, nutrients, microorganisms and plankton. The structure and life of aquatic ecosystems is an important point to be considered in the management of lakes.

One of the most important characteristics of the lake is its thermal structure. The heat content of a water body is of vital importance in the studies of water quality in lakes. The metabolism and behaviour of aquatic organisms are directly related to the temperature of the water body.

Temperate lakes, as Buenos Aires Lake, are physically divided by their thermal characteristics in three regions: an upper layer of warmer water (epilimnion), where photosynthesis processes prevails, the hipolimnio that is the deepest and coldest zone less affected by the winds, and the metalimnion or thermocline that is the middle layer. The temperature diminishes with increasing depth. In temperate stratified lakes the 85% approximately of primary production is in the metalimnion.

The water balance of a lake or reservoir generally depends on the inflow; outflow, groundwater flow, precipitation, and evaporation over the water shed region of the lake. Wind, solar radiation, stratification, earth’s rotation are important forces causing water movements of lakes. The hydrodynamics of water movements is an integral component of a functional lake system and wind is the principal source of mechanical energy for water movements in lakes. Wind exerts a mean stress or drag on the surface, parallel to the wind direction, and proportional to square of the wind speed.

This paper presents the temperature distribution of the water surface of the lake Buenos Aires in Santa Cruz (Argentina) by means of NOAA-AVHRR imagery. The lake is binational, being called Buenos Aires Lake in Argentina and General Carrera in its Chilean side, its total surface is of 2240 Km2 and is the second more extensive lake of South America. The Argentine side extent is 881 Km2.

The paper describes the flow pattern of the superficial water of the lake under the influence of the wind from NOAA AVHRR satellite information analysis, using the surface temperature of the water, obtained from channels 4 and 5 brightness temperature data of the satellite. The pattern of advective speed on water surface is calculated by means of a sequence of surface water thermal fields by solving an approximation of the equation of local variation of water surface temperature. Preliminary results indicate that the water velocities due to wind forcing during an event with surface wind speed of 8.3 m/s are weak; and some characteristics flow lines are detected in the lake.

CHARACTERISTICS OF THE HYDROGRAPHS FROM A SMALL WATERSHED UNDER NO TILLAGE BELONGING TO THE ROLLING PAMPA (ARGENTINA)

M. G. Castiglioni, C. I. Chagas, M. J. Massobrio, O. J. Santanatoglia, A. Buján,

E. A Palacín and F. Zuberman

Cátedra de Manejo y Conservación de Suelos. Facultad de Agronomía. UBA. Av. San Martín 4453. (1417) Capital Federal, Argentina. Comisión Nacional de Energía Atómica - chagas@agro.uba.ar

During the last decade there has been an outstanding increment of the cultivated surface under no tillage in the Rolling Pampa. It is well known the effect of this tillage system on the soil properties compared to other conventional systems. However, there is little information about the way in which this system influences the hydrological dynamics in small watersheds.

The aim of the present investigation was to compare the shape of the runoff hydrographs obtained from a small watershed (300 ha) belonging to the Rolling Pampa during a period five years under conventional tillage and then during six years under no tillage.

The mean monthly rainfall volume recorded during this experiment was 78 mm under conventional tillage and 98 mm under no tillage. Although conventional tillage was performed in a drier period than no tillage, it was possible to observe that the mean peak flow under the former tillage was 59.5 % larger than it was under the latter system

The mean lag period between the runoff beginning and the peak flow was 61.3 % larger under no tillage than it was under conventional tillage. It was also observed that the mean lag period between the peak flow and the end of the hydrographs was 216 % larger under no tillage than it was under conventional tillage. The mean flow / runoff volume relationship in the decreasing phase of the hydrographs was larger for the conventional tillage system than it was for the no tillage system. The obtained results show the significant incidence of the tillage system on the shape of the hydrographs in small watersheds with low topographical gradients belonging to the Rolling Pampa. This information and other results obtained from this investigation team should be considered for the implementation of water management projects in this region with increasing surface under no tillage.

LIMNOLOGICAL COMPARISON OF TWO SHALLOW LAKES (BUENOS AIRES, ARGENTINA) DURING TURBID AND CLEAR WATER PHASES

M. Claps, D. Ardohain, H. Benítez, M. Cano, M. Casco, N. A. Gabellone, M. Mac Donagh, Lía Solari and G. Ruiz

Instituto de Limnología “Dr. R. Ringuelet” (CONICET-UNLP) - claps@ilpla.edu.ar

The differences of the shallow lakes of the Buenos Aires province can be assigned to their geological features, evolution and land use. Two alternative state of equilibria related to the presence or absence of submerged macrophytes could be observed in these lakes involving changes in their physical, chemical and biological characteristics. The main objective of this study was to compare two lakes with different hydrological and geological features during both phases. The San Miguel del Monte lake (35° 27´ S - 58° 48´W) has an area of 655 ha, and its mean depth is 1.3 m. A town (10,000 inhabitants) is located on the shore. During floods of the Salado River, the lake can be connected to the river. The Lacombe lake is arreic (35º 55` S - 58º 65` W), with an area of approximately 130 ha. Its maximum depth was 2,5 m. Extensive cattle breeding and agriculture practices are developed in the surroundings. Emergent (Scirpus californicus) and submerged macrophytes (Potamogeton pectinatus and Myriophyllum quitense).were recorded in both lakes. Sport fishing is performed all year in both lakes on planktivorous and predator fishes. The study was carried out in both water bodies during rainy periods. Plankton samples were collected for qualitative and quantitative analysis. Total phosphorus (TP), conductivity, particulate organic matter and suspended solids were measured. Transparency (Secchi disk) increased during the growth of P. pectinatus, reaching 0.7 m in Monte and 1.0 m in Lacombe, whereas the minimum occurred during the turbid phase (0.20 m in Monte and 0.30 m in Lacombe). Values of conductivity decreased throughout the sampling period (Monte: 2500 to 1190; Lacombe: 4240 to 1294 µS/cm). The decrease of TP concentrations in both lakes is related to the growth of P. pectinatus. The composition of suspended solids differed in the lakes (Monte: clay and particulate organic matter; Lacombe: particulate organic matter). In Monte, the highest density of phytoplankton was reached in spring with dominance of Oscillatoria limnetica and Rhapidiopsis mediterranea and late summer (Aphanocapsa delicatissima, Coelosphaerium kuetzingianum and Chroococcus dispersus). In Lacombe, a much smaller phytoplankton peak was recorded in winter, due to the striking contribution of Lyngbya limnetica and A. delicatissima. The zooplankton is dominated by rotifers (Monte: Brachionus caudatus, B. havanensis, and Filinia longiseta, Lacombe: B. havanensis and Keratella lenzi) and nauplii stages of copepods in both shallow lakes. The importance of cladocerans increases when the macrophytes beds are developed. In spite off marked hydrological and geological differences, these lakes showed similar change patterns in biological and physical characteristics. Decrease of TP, conductivity and suspended solids and increase of transparency were recorded. In a first view, the plankton of these lakes showed clear quantitative and qualitative differences. Nevertheless, the annual cycle analysis reveals the same responses to the alternative phases. The unpredictably external forces (rainfall, flood conditions) coupled with internal characteristics (clear and turbid phases) facilitate to understand the main differences between Monte and Lacombe lakes.

METHODOLOGIES FOR THE RUNOFF CALCULATION IN THE FELICIANO BASIN (ENTRE RÍOS, ARGENTINA)

G. V. Zucarelli, D. F. Barrera, E. B. Ceirano and M. del V. Morresi

Departamento Hidrología, Facultad de Ingeniería y Ciencias Hídricas - Ciudad Universitaria, Paraje El Pozo. (3000) Santa Fe, Argentina - TE: 0054-342-4575244 (interno 167) FAX: 0054-342-4575224

zuca@fich1.unl.edu.ar / barrera@at1.fcen.uba.ar / eceirano@evarsa.com.ar / valle@fich1.unl.edu.ar

In this work the application of two methodologies is presented for the calculation of the flow in Feliciano basin (Entre Ríos, Argentina): one of them based on the Thornthwaite-Mather method and the other one based on the Budyko formula, in which the flow is obtained in function of the precipitation and a parameter that it depends on the evapotranspiration. On the base of their original formulation, for this application they are carried out modifications that consider the propagation of the direct excesses through lineal reservoirs.

The evaluations are for precipitations and evapotranspirations daily between January of 2001 and April of 2002. The computed flows were compared with the observed flows, being obtained good adjustments for this stage of the investigations. In general terms, both methodologies showed a very homogeneous behaviour, with coefficients of determination between observed flows and computed acceptable.

CHEMICAL CHARACTERIZATION OF SEVEN PAMPEAN SHALLOW LAKES IN ARGENTINA

O. Díaz¹, V. Colasurdo¹, F. Grosman², P. Sanzano² and N. Lopez¹

Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable.

1. Facultad de Ingeniería. Avda. Del Valle 5737, 7400-Olavarría

2. Facultad de Ciencias Veterinarias. Paraje Arroyo Seco, Campus Universitario, 7000-Tandil

Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA).

The Pampean plains occupy the Eastern Central region of Argentina, and exhibit characteristic ecosystems formed by hundreds of “lagunas” or shallow lakes of varied extension which are naturally eutrophic.

They are freshwater and biodiversity reservoirs, recreational environments, and regulators of end products of human activities. Nevertheless, present knowledge is not sufficient for the elaboration of management strategies, which can be scientifically supported.

The results in this presentation are part of a project, intending to contribute with information in this sense. The goal is to analyze the water quality and the trophic state of seven “lagunas”, as well as to evaluate the aptitude of water for different uses, following the guidelines of Argentine water quality regulations.

Physico-chemical analyses are performed monthly in Del Estado, El Paraíso, Quilla Lauquen, San Antonio, El Chifle, La Salada and La Barrancosa shallow lakes. They are located in the center of the Province of Buenos Aires, between latitudes 37º17´ and 37º 37´(S) and longitudes 60º 48´ and 59º 52´ (W) close to the divide of large drainage basins. The soils are rich in nutrients and organic matter and there is a high development of agriculture and cattle in the zone.

Samples are collected monthly at the subsurface, in polypropylene bottles. Temperature, pH, electric conductivity and transparency (Secchi disk) are determined in the field. Analysis of carbonate, bicarbonate, sodium, potassium, calcium, magnesium, nitrate, fluoride, sulfate, chloride, nitrite, ammonium, dissolved and total solids, chlorophyll-a and total phosphorous, are performed in the laboratory, by Standard Methods.

Results indicate that they all present the characteristic of being alkaline (pH from 8.95 to 10.1) and oligohaline (dissolved solids from 496 to 1764 mg/L). Sodium is the most abundant of the cations (85%) and carbonate-bicarbonate are the predominant anions (71%) in every shallow lake. Nutrients (PT: from 0.378 to 0.597 mg/L), chlorophyll concentration (from 26.7 to 464.6 mg/m³), and transparency (from 0.07 to 0.38 m of Secchi disk) indicate that they are all in a high degree of eutrophication.

Some of the analyzed parameters don’t meet the criteria for the protection of aquatic ecosystems, for potable water, for agricultural uses or for contact recreation activities. The possible sources affecting the water quality, both natural and antropic, are analyzed in each case.

Since groundwater is the main source of surface water, a cation exchange process in the loessic sediments of the basin may explain high sodium concentration in the water bodies, where calcium is replaced by sodium.

TEMPORAL EVOLUTION ANALYSIS OF HYDROLOGICAL VARIABLES IN FLOODED AREAS OF CHASCOMÚS LAKE (BUENOS AIRES PROVINCE, ARGENTINA) AND THE LAND RE-USE.

L. de Cabo, R. Seoane, L. Urgu, M. E.Koutsovitis, A. Dini and I. Obertello

MACN-CONICET. Av. Angel Gallardo 470 (1405) Buenos Aires, Argentina. ldecabo@macn.gov.ar

A valuable service provided to humans by naturally functioning ecosystems is their avoidance of adverse threshold conditions, or “Critical Zones”.

Chascomús shallow lake is part of the ‘‘Sistema de las Encadenadas de Chascomús’’ in the Salado river basin. The flooded area in the Salado River depression expands to 10.4% of the area of the basin. Series of floods have covered till the 25% of the area, probably due to the increase of rainfall during the last 30 years (Malagnino, 1988). This fact justifies the importance of studying, by means of mathematical modelling, the presence of trends in the annual rainfall series, and the performance of biological tests, in order to define the water stage range for optimum growth of the Schoenoplectus californicus (the main emergent macrophyte in coastal areas of lakes in Salado river depression) and its explotation alternatives.

Rainfall records correspond to the nearest pluviometer (Dolores). Positive trends were detected in annual rainfall serie through Mann-Kendall non parametric test.

Sediments and rhizomes of S. californicus were collected from coastal area of Chascomus lake, and were placed in plastic containers. Three treatments with different water layer (T0:0 cm, T1:20cm, T2:40cm and T3:70 cm) were assayed in triplicate. The height of each shoot was measured each 15 days. Shoot heights were converted to shoot biomass using a height-weight curve, obtained by harvesting of 200 shoots of the same area and drying them to constant weight. Experiment was carried out from December to February during 58 days.

Treatment 3 did not show growth. Total shoot biomass showed significant differences between the rest of treatments. Total shoot biomass was significant higher in T1 (7458 kg/ha), respect to T0 (873 kg/ha) and T2 (1472 kg/ha).

We considered that the effective bulrush growth occurs between 0-40 cm water depths. These areas were located outward lake, between the area occuped by maximum and minimum lake. Taking into account the different level values of Chascomus lake, areas flooded with water depth of 1-10; 10-20; 20-40 cm and areas not flooded were estimated. The surface of effective bulrush growth varied from 4336,7 ha (for lake level values between 7.5 to 8 m) to 637 ha. (for lake level value of 10 m).

Taking into account the shoot biomass in each treatment and the flooded area with each water depth assayed, the bulrush yield was estimated in function of the lake level. The maximum amount was 5626 ton for 7.9 m of level value and the minimum was 2114 ton when lake level attained 10 m.

The important flood occurrence in Salado River depression (April 2003), justifies the development of options for land use using a natural resource (bulrush) to reduce the negative economic impact.

INCIDENCE OF LOCAL AND GLOBAL CHANGES ON THE DYNAMICS OF PAMPEAN SHALLOW LAKES: THE CASE OF BLANCA GRANDE.

F. Grosman¹, P. Sanzano¹ and G. Rudzik²

1. Fac. de Cs. Veterinarias. 2. Fac. de Agronomía

Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable

Universidad Nacional del Centro de la Provincia de Buenos Aires - Pinto 399 – 7000 Tandil,

Prov. de Buenos Aires - fgrosman@faa.unicen.edu.ar

Blanca Grande is a typical shallow lake of the Pampean plains, situated nearly Olavarría, centre of Buenos Aires Province. It covers 410 hectares with rushes on its margin, a brook that flows in and another that flows out, and is surrounded by land used for agriculture. It is relevant from the socioeconomic point of view since historically its fishing resources have been exploited, but at present only for sport purposes. The shallow lake is managed by the local fishing club which has noticed a significant decrease in the captures of pejerrey or silverside Odontesthes bonariensis, the species of greatest interest. The existing sequential bibliography (1985, 1991 and 2003) on its limnological aspects coincides with this view and allows for the visualization of the recorded temporal changes.

The aim of this paper is to characterize the present status of Blanca Grande shallow lake from the limnological point of view with an emphasis on its fish community and to identify the causes that may have led to this situation. Given the strong interactions among the different components of the system, as well as, the influence of external factors to the shallow lake, variables in different space and time scales were analyzed.

A sampling of the different physical, chemical and biological components was carried out in summer 2004; historic monthly local rainfall information was used and the hydrometric level was measured daily.

The high value of phosphorus in sediments seems to show an extra input of nutrients; although turbidity was high (Secchi disc = 13 – 17 cm), it is due to inorganic components since the concentration of chlorophyll-a was low. The phytoplankton is dominated by diatoms and chlorophytes. The zooplankton of the shallow lakes was scarce in density and average size of its components, but better than values of the past.

The fish community is dominated in number and weight by “sabalito” Cyphocharax voga, carps Cyprinus carpio, “bagarito” Parapimelodus valenciennesi and “dientudo” Oligosarcus jenynsi. Pejerrey is very scarce.

The presence of carps in Blanca Grande correlates with the time of sowing of this exotic fish in different basins of the pampean region. The capture of “bagarito” is astonishing since the shallow lake is south of its normal distribution; this aspect is linked to the increase of the regional average minimum temperature which allowed for the shifting of the typical “paranoplatense” ichtyofauna. The analyses of digestive tracts show that both species occupy a similar trophic niche to that of the pejerrey.

The rainfalls in the high basin are the main source of water for the shallow lake and determine its level. New canals in that area have accelerated drainage increasing silting up with sediments rich in nutrients. Besides, great as well as abrupt oscillations of the level of the shallow lake take place. In years of excessive rainfalls the water overflows the retention floodgate during long periods.

The increase in rainfalls over the last years, water management in the high basin and the increase of the average minimum temperature are the main factors responsible for the changes observed in the structure and functioning of the ecosystem which consequently affect the fish community.

Session 4. New approaches to the evaluation and forecasting of changes in water resources under global warming

A NEW APPROACH TO EXTENDING RIVERFLOW RECORDS AND RECONSTRUCTING PAST RIVER REGIMES

N.C. Mountain and J.A.A. Jones

Institute of Geography and Earth Sciences, University of Wales, Aberystwyth SY23 3DB, UK

jaj@aber.ac.uk

The estimation of the risk of extreme hydrological events is often hampered by shortness of discharge records or even their total absence. This paper offers a method for the reconstruction of flood and low flow frequencies. The resulting extreme flow sequences may be used to improve estimates of present-day risks by extending the flow records or else to study past hydrological regimes in their own right. The method uses a technique developed to estimate the hydrological impact of future climate change and uses either observed or calculated meteorological parameters. It is possible to use this approach directly without modification to ‘hindcast’ events within the period of regional meteorological records, which in areas like the UK extend back over the last 150 years. It should also be possible to extend the approach to earlier periods using reconstructed meteorological parameters based on surrogate data, such as tree rings or ships’ logs.

The technique uses an airflow index based stochastic weather generator to create hydrometeorological parameters to input into a physically based hydrological simulation model. The method is illustrated here in a reconstruction of daily flow series for the River Wye catchment above Rhayader, mid-Wales, for the period 1889-1998. The method makes use of observed climatic variables for the entire period, with the aim of capturing actual climate variability occurring over the 110-year period. Changes in high flow characteristics are assessed using the mean annual flood (MAF), Q5 flow and peaks-over-threshold (POT) calculated from the 110-year simulated daily flow series. This particular application shows evidence of a possible trend towards increasing magnitude and frequency of high flow events, which, if continued, would have implications for flood and water resource management. It is likely, looking at evidence from the last 110 years, that these recent increases may be just part of natural fluctuations in high flow extremes rather than evidence of anthropogenic climate change.

THE EVA-GRIPS PROJECT: IMPROVING THE EVAPORATION PARAMETERIZATION IN ATMOSPHERIC AND HYDROLOGICAL MODELS

H.-T. Mengelkamp¹, F. Beyrich², F. Ament³, J. Bange⁴, F. Berger², J. Bösenberg⁵, T. Foken⁶, G. Heinemann³, B. Hennemuth⁵, C. Heret⁷, S. Huneke¹, K.-P. Johnsen¹, W. Kohsiek⁹, J.-P. Leps², C. Liebethal⁶, M. Mauder⁶, W. Meijninger¹⁰, S. Raasch⁸, C. Simmer³, T. Spiess⁴, A. Tittebrand⁷, J. Uhlenbrock⁸, P. Zittel⁴

1. GKSS Research Center, D-21502 Geesthacht, Germany (mengelkamp@gkss.de), 2. German Weather Service, Met. Obs. Lindenberg (Frank.Beyrich@dwd.de), 3. Meteorological Institut, University of Bonn (ament@uni-bonn.de), 4. Technical University Braunschweig (jbange@tu-bs.de), 5. Max-Planck-Institut for Meteorology, Hamburg (hennemuth@dkrz.de), 6. University Bayreuth, Dept. of Micrometeorology (foken@uni-bayreuth.de), 7. Technical University of Dresden (cheret@forst.tu-dresden.de), 8. University Hannover, (uhlenbrock@muk.uni-hannover.de) , 9. KNMI, The Netherlands (kohsiek@knmi.nl), 10.Wageningen University, The Netherlands (wouter.meijninger@user.metair.wau.nl)

The project EVA-GRIPS (evaporation over grid and pixel scale) is part of the current Climate Research Programme (DEKLIM) of the German Federal Ministry of Research and Education and part of the german contribution to BALTEX. EVA-GRIPS aims at testing and implementing concepts for the description of area-averaged turbulent fluxes into land surface schemes. The spatial scale considered in EVA-GRIPS corresponds to the grid scale of a regional atmospheric NWP or climate model and to the pixel scale of satellite images. Through a combination of near-surface and boundary layer observations, the analysis of satellite data and numerical simulations area averaged surface fluxes will be estimated independently, and compared and will finally result in validated parameterization schemes.

The activities focus on an area of roughly 20 x 20 km² around the Meteorological Observatory in Lindenberg close to the city of Berlin. The continuous measurement program of the observatory as a CEOP reference site formed the basis for a major field experiment in May and June 2003. Energy and water vapour fluxes at different scales were determined from a combination of ground-based in-situ and remote sensing instruments as well as airborne probes. Eddy correlation instruments were placed at 13 sites over different land use types and vertical profiles in the boundary layer were sampled by lidar and radar. A set of scintillometers, a helicopter borne turbulence probe HELIPOD and an infrared camera for surface photography on board a Tornado aircraft as well as satellite images completed the set of instruments. The spatial sampling and footprint scales of this suite of measurement systems covered five orders of magnitude (10-1 .. 10⁴ m for the sampling scale) and three orders of magnitude (10¹ .. 10⁴ m for the footprint scale), respectively

EVA-GRIPS combined model results and satellite data with the in-situ measurements to finally analyse the validity of the evaporation parameterisation in atmospheric models. Focus of the modelling activities lies on the objective calibration of three land-surface schemes for all different vegetation types and for the composite of water and energy fluxes representing the whole experimental area. The simulation of the turbulent fluxes using effective parameters, the tile and the mosaic approach is compared to the observations and to results from a routine weather forecast model. All three approaches are implemented in the regional mesoscale models LM (Lokal Modell of the German Weather Service) and FOOT3d (University of Cologne). It turned out that the mosaic approach coincides most closely with the observed composite flux time series.

An overview of the EVA-GRIPS project will be given and results from the field experiment and modelling activities will be presented.

DANGEROUS HYDROLOGICAL PROCESSES AND THEIR INFLUENCE ON POPULATION AND ECONOMY SAFETY IN THE NORTH OF EUROPEAN

PART OF RUSSIA*

N. I. Alekseevskiy, V. A. Zhuk and N. L. Frolova

Hydrology Department, Geography Faculty, Moscow State University, Leninskie Gory,

Moscow, 119992, Russia - hydro@hydro.geogr.msu.su

North of European part of Russia is enormous region with inclement climate and unique natural landscapes. Though density of population is relatively low many industries are developed intensively, oil and gas production increases. Water routes are actively used for freight hauling and conveyance of passengers.

Safety of population, which lives mainly in valleys of large rivers, of social and industrial objects, of ecosystems of this Russian region essentially, depends on natural factors. Dangerous hydrological processes are the principals among them. They are: extreme discharges and water levels, water resources changes due to negative combination of water balance components, channel processes, pileups, ice phenomena. Ice jams cause disastrous floods on northern rivers.

Investigations carried out in Moscow State University showed that global and regional climate fluctuations caused growth of annual runoff volume and its amplitude for majority of north rivers since the 1970-s. For latest 15 years runoff increasing reached 3% for Onega and Pechora and 8% for Northern Dvina (in comparison with 1961-1990 period). Majority of climate scenarios forecast further growth of north rivers runoff and more often floods in nearest decades.

Disastrous flood occurred at the end of 20^th century in the basin of Northern Dvina, one of the largest northern Russian rivers, induced improvement for methods of forecast of extreme water levels and protection of population, social and industrial objects. Authors of this article performed such work in junction of rivers Sukhona and Youg, at the location of one of the oldest Russian towns, Velikiy Ustyug. In 20^th century 21 large floods occur there. All of them were caused by ice jams. Investigation covered floods mechanism, factors influencing on water levels under fluctuation of inflow, jams formation, instability of riverbed enable to work out measures for protection of the town from flooding.

LONG TERM VARIATION ON RAIN EROSIVITY IN URUGUAY: A PRELIMINARY FOURNIER APPROACH

C. Munka¹ , G. Cruz¹ and R. M. Caffera ^2-3

1. Unidad Sistemas Ambientales, Facultad de Agronomía, Universidad de la República, Uruguay - munka@fagro.edu.uy - gcruz@montevideo.com.uy

2 . Colegio de Posgraduados, Facultad de Agronomía, Universidad de la República, Uruguay

3. Sociedad Amigos del Viento, Uruguay - caffera@fisica.edu.uy

There are two main forcing factors modifying the Environment in the Uruguayan territory: changes in land use and climatic change. The first deals with an increase in the area occupied by rice and soybean, seeding grasses, and forestry. The second is manifested mainly by an increase in precipitation rate. Although almost all USLE factors are under the influence of changes in climate, it is evident that the rain factor (R) is the primary and directly involved. In order to explore the consequences of the precipitation rise on soil erosion, the Fournier Index (FI) during the core season months (January for summer), and the Modified Fournier Index (MFI) for the entire year, are used as a preliminary indicator. Data were collected from 13 stations distributed over the country from 1931 to 2000. The great intraseasonal variability in rainfall, characterizing the whole country regional climate, imposes high values of MFI. This erosive characteristic, impact the epigenic environments, large part of them having shallow quaternary soil layer, and results on high vulnerability in the disrupted, both agricultural and overgrazing surfaces as seen from profuse bibliography. MFI shows a decrease in the 40s, an increase during the 50s, then a little decrease during the 60s and 70s and an increase in the 80s, remaining near these last values during the 90s. In July and in October, for the last two decades while FI decreases in the NE region of the country – the region with major annual precipitation – there is a slight increase of the Index over the SE, a region with minimum annual precipitation and the solely region with winter maximum rain. That means that at least for the core months of winter and spring, there is a declining in erosivity in the Northeast, and appears an intensification in the Southeast. Consequences of this enhancement of the erosive power of the rain in this region remain uncertain. The area having heavy soils and very flat terrain, with irrigated rice as the main agricultural activity. January shows a decrease in erosivity in the South during the last two decades. On April there is a peak in precipitation variability all along the country. FI shows an early increase during the 40s, in the NW, very low generalized values during the 70s, and a return into high values in the 90s, especially in the Northern corner. This could be an issue in vulnerability of both agricultural and natural environments, since an increase of rice crop extent is observed in the region during the last period. As intensifying erosion implies growing sediment depositories and water turbidity, the results pose a challenge in order to improve erosion research, since the main source of freshwater nationwide remains surface river flow.

PRECIPITATION AND EVAPORATION IN THE SOUTHEAST UNITED STATES DURING THE 20^TH CENTURY

P.J. Robinson

Department of Geography - CB# 3220, Saunders Hall - University of North Carolina

Chapel Hill NC 27599-3220 - USA

The change in precipitation regime occurring in North Carolina during the second quarter of the 20^th century has been found to be typical of changes in many of the coastal and mountain regions of the southeast United States. Fall and winter became wetter, summer became drier. Spring was slightly drier in the middle of the period and then amounts increased slightly. Although creating no annual change, the trends were not complimentary, the summer decrease leading to more frequent and larger soil water deficits, while the extra fall and winter precipitation commonly fell onto soils already at field capacity, and gave an increase in surface runoff. Regions further inland had fewer changes in precipitation regime, but increasing temperatures encouraged increased evaporation and thus decreasing water availability. It appears that changes in the strength and position of the offshore subtropical high pressure region may have played a prime role in the variations. This is likely to become more marked as global warming continues, with implications for the amounts and spatial and temporal distributions of water resources in the region.

DEVELOPING A GEOGRAPHIC INFORMATION SYSTEM IN A

RURAL COMMUNITY OF CHUBUT STATE, PATAGONIA ARGENTINA TO ANALYZE THE IMPACT OF EL NIÑO – LA NIÑA EVENTS.

D. F. Vergani,¹ J. C. Benedetti,² Z. B. Stanganelli ¹ and M. S. Lopreiato ¹

1. Centro Nacional Patagónico, CENPAT-CONICET, Boulevard Alm. Brown 3500, (9120) Puerto Madryn, Chubut Argentina, Fax 54-2965-451024 - atlas@cenpat.edu.ar

2. Sistema de Información Geográfica del Ejercito Argentino (SIGEA)

In Chubut State, Patagonia, rural migration has been pointed out as one of the main causes of increase of the crime index in regional urban centers. People from rural areas are forced to migrate as a cause of low rent ability of their products to marginal urban peripheries without appropriate skills to get a job position.

We have chosen this rural area of Chubut State to develop a Geographic Information System to better understand this problematic. The selection was made analyzing the impact and vulnerability to El Niño and La Niña events as main cause of climatic variability in the Chubut State. Vulnerability was determined according to social structure and impact of ENSO events. The area chosen for the study is the Gualajaina region in the Northwest of Chubut State. GIS is being building up with information from:

1. Environmental Information
2. Land Ownership
3. Farmer production
4. Social and demographic information

The project include the participation of local technical people being trained in the use of GPS. The project foresees the development of the appropriate software and interfaces to facilitate the use by the future beneficiaries and in the last stage the personalized installation.

In the first diagnosis carried out during 2003 and 2004 the main axis was established defining the necessities of information to give the conceptual structure to the GIS. One of the main results of the diagnosis was the visualization of the incompatibility of cartographic official unit of information that make difficult to do the appropriate analysis of the situation. The information unit is incompatible from the productive and social point of view because of the different desegregation units used to obtain and to process the data. From the environmental point of view the official desegregation unit areas employed are so extensive including a wide range of ecological conditions; as an example the average rainfall in Cushamen Department varies annually between 200 mm to 3000 mm.

Main objective of this pilot project is to bring to the authorities a tool to better analyze this problematic of the State and rural communities.

ASSESMENT CLIMATE CHANGE IMPACTS ON THE WATER RESOURCES AT THE NORTHERN OASES OF MENDOZA PROVINCE, ARGENTINE.

J. C. Leiva

CONICET, Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales,

CC N° 330 - 5500 Mendoza – Argentina - jcleiva@lab.cricyt.edu.ar

This paper aims to evaluate the climate change impacts on the water resources of the northern oases of Mendoza, Argentine.

The semiarid conditions of the Cuyo region in the west part of Argentina make economic activities highly dependent on the melt water yielded by snow and ice. The importance of glacier contribution to runoff has increased during the last 40 years owing to the scarce snow precipitation.

The water discharge of the Central Andes rivers shows a decreasing tendency that would lead soon to critical conditions for the irrigated oases and urban populations even if the efficiency of water distribution and use were improved. The glaciological research done by the IANIGLA is the local main attempt to quantify the glacier contribution to runoff, to know the mass wastage of the glaciers of the region during the last century, and, to understand how climate change and glacier fluctuations would affect this region. Mainly it describes the fluctuation at the Plomo glacier system and the mass balance behaviour of the Piloto Este glacier, near the Mt. Aconcagua, at the Las Cuevas river basin

GLACIER VARIATIONS IN THE CENTRAL ANDES OF MENDOZA, ARGENTINA, SINCE 1896 TO 2005

L. E. Espizua¹ and G. I. Maldonado²

1. Instituto Argentino de Nivologia, Glaciología y Ciencias Ambientales (IANIGLA) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Casilla de Correo 330, 5500. Mendoza, Argentina. lespizua@lab.cricyt.edu.ar

2. IANIGLA - CONICET. Casilla de Correo 330. 5500. Mendoza, Argentina - gabyinesm@yahoo.com.ar

Glaciers respond to slight but prolonged changes in climate. As glaciers store or release water, this “natural regulation” of runoff from glacierized areas is critical to water supply and use in mountain areas. This work presents the response of four glaciers to climate change in the Andean Central Cordillera of Mendoza (33º and 35º S latitude) since the early 19^th century. The use of the Landsat thematic mapper (TM) scenes was essential for measuring the glacier fluctuations and the area of the glaciers. Description is given of the geometric and atmospheric corrections for the detection of glacier snow and ice in the TM scenes. The method of Dark Object Subtraction (DOS) for atmospheric corrections was applied as per Chávez (1996). The surface of the glaciers was detected using the Dozier (1989) criterion. The fluctuations of De las Vacas, Güssfeldt, El Azufre and El Peñón glaciers have been studied since the early 19^th century to 2005, through the use of historical records data, topographic maps, aerial photographs taken in 1963 and 1974, satellite images (TM) of different years, and GPS measurements in the field. Landsat data have been found to be useful for delineating snow-free and snow-covered glacier areas and for estimating the AAR (accumulation area ratio) in the final classification.

HYDROLOGICAL VARIABLE ANALYSIS FOR CLIMATE VARIATION IN THE LIMAY RIVER BASIN

R. Seoane^1,2 and P. Lopez¹

1. National Water Institute (INA)

2. National Research Council (CONICET)

This study examines the presence of trends in streamflow series, which reflect an integrated response of the catchment area to the input variables. Statistical tests and several mathematical models are applied in the Limay river basin (Argentina).

This basin has an area of 26400 km², a great amount of hydro power stations and many lakes, being the main ones Aluminé (937 km²) and Nahuel Huapí (3900 km²). Hydrological analysis shows that the annual hydrograph has two maximums produced by two different processes: precipitation (June-August) and snowmelt (October-December).

The non-parametric Mann-Kendall test is a helpful exploratory method for identifying monotonic changes during some time interval and has been used in a considerable number of studies to detect trends in hydroclimatic time series during the last decade.

This test and an estimator that express the magnitude of the trend per unit of time (Hirsch et al., 1982) are applied in order to identify and quantify changes in observed streamflow series in Lago Aluminé (59 years), Junín de los Andes (42 years) and Paso Limay (94 years). Changes in the last period of minimum streamflow series are studied by the likelihood test.

Because streamflows can show serial dependence, which can distort the detection and assessment of trends, a modified Mann-Kendall test for autocorrelated data (Hamed and Rao, 1998) is employed.

The results show decreasing trends in minimum and in monthly streamflows, corresponding to the low flow season in Aluminé and Paso Limay, the outlet of the basin.

With the purpose of evaluating how changes in input variables affect the output, the elasticity of streamflow to precipitation and temperature are estimated in the Nahuel Huapi lake basin using a regression model with the available observed data.

The effects of forecasted changes on temperature and precipitation for 2050 under different scenarios are estimated studying the elasticity variations through simulation using General Circulation Model forecast inputs into the water balance model proposed by Thomas (1981).

The analysis of these results could contribute to the better planning and management of the basin water resources under changes in climate conditions.

ENVIRONMENTAL CHANGES AND CONSERVATION OF WATER RESOURCES IN INDIAN HIMALAYA

P. C. Tiwari

Department of Geography - Kumaon University Naini Tal – 263 001 - Uttaranchal, India

pctiwari@yahoo.com

The traditional resource use pattern in Himalaya is closely interlinked with forests, cultivated land, and livestock. During the recent past, a variety of changes have emerged in the traditional resource utilization pattern in the region, mainly in response to rapid population growth and resultant increased demand of natural resources, which compelled people to utilize the critical biophysical resources, such as, land, water and forests beyond their ecological carrying capacity. Large-scale deforestation, mining and quarrying, and extension of cultivation, excessive grazing, rapid urban growth and development of tourism contributed significantly to the depletion of natural resources in the entire region including the headwaters. As a result, water resources of Himalaya are diminishing and depleting fast owing to the rapid land use changes and resultant reduced water-generating capacity of land. These hydrological imbalances are discernible in terms of (i) retreating glaciers and their diminishing regulatory effect, (ii) long-term decreasing trend of stream discharge, (iii) diminishing discharge and drying of springs, (iv) dwindling capacity of lakes, (v) biotic impact on surface run-off flow system and channel network capacity. These geo-hydrological transformations in headwaters have not only disrupted the fragile ecosystem of the Himalayan watersheds, but have also affected the sustainability of rural communities in the region as well as in the adjoining plains ecosystem lying to its south.

The main objective of the study has been to evolve an integrated and participatory watershed management action plan for conservation, regeneration and sustainable development of dwindling water resources in Himalaya. Kosi Headwater situated in the Lesser Himalayan Ranges of Uttaranchal was taken as area of study for the investigation. The works carried out for attaining the objectives of the study include (i) Development of Natural Resources Information System (ii) Delineation of critical headwaters/watersheds and their prioritization for water conservation, (iii) Documentation of local indigenous knowledge and traditional water management system and its incorporation in conservation and management of water resources, (iv) Evolving optimal land use framework and integrated land, water and forest development action plan and conservation strategy for environmentally critical areas, (v) Evolving mechanism for grass root institution building for participatory resource management (vi) Designing participatory water conservation plan for prioritized headwaters, (vii) Capacity building of line departments for making use of GIS database in implementation of sustainable resource development programs.

CHANGES IN HYDROTHERMAL CONDITIONS UNDER GLOBAL WARMING IN CASPIAN SEA REGION, RUSSIA

N.a. shumova

water problems institute of ras, 3 gubkina st., moscow, 119991 russia

shumova@aqua.laser.ru

The growth of intensity of human activity promotes increase of carbon dioxide concentration in atmosphere absorbing a long-wave terrestrial radiation that involves global air temperature rise and changes in atmospheric circulation. It in turn leads to changes of hydrothermal conditions on local scale. For evaluations of the tendencies of possible changes in hydrothermal conditions the outputs from the general circulation models giss (goddard institute for space studies), gfdl (geophysical fluid dynamics laboratory), CCCM (Canadian Climate Center Model) and ukmo (united kingdom meteorological office) are used. These models make it possible to obtain the average monthly air temperature and precipitation due to current atmospheric carbon dioxide concentration and its doubling, which is predicted for 2075. On the base of obtained values of precipitation and air temperature for territory under investigation were calculated moistening coefficient (ratio of annual precipitation to annual potential evaporation determined as function of air temperature) and selyaninov hydrothermal coefficient (ratio of precipitation during the period with air temperature above 10 celsius degree to the sum of mean daily temperature divided by ten for the same period) due the present-day atmospheric carbon dioxide concentration and due its doubling. At expected doubling atmospheric carbon dioxide concentration the moistening coefficient can decrease on 10-26 % depending on climate change scenarios. And in this case it is possible to expect some move of the desert zone to the north. Selyaninov hydrothermal coefficient describing growing season changes from +10 (model giss) up to -12 % (model cccm). According to models gfdl and ukmo the changes in hydrothermal coefficient are not expected. Differently, according to the giss model it is possible to expect some move of the desert zone to the south, and according to the cccm model the tendency opposite is possible. According to the gfdl and ukmo models the changes in natural zones localization due to doubling atmospheric carbon dioxide concentration in caspian sea region are not expected. Estimating the possible climate change impacts on hydrothermal conditions in caspian sea region it is possible to make a conclusion, that the most radical results give estimations executed through moistening coefficient, which is an integral annual index. Calculated values of hydrothermal coefficient describing the period with air temperature above 10 celsius degree (growing season), do not give an unequivocal picture of possible changes. In this case the carried out estimations of influence of expected climate change only in a general view and not always unequivocal have shown the possible tendencies and scales of change in hydrothermal conditions and changes in natural zones localizations in caspian sea region. The received ambiguous results allow to make a conclusion about necessity of using the diversified approaches to an estimation the possible changes in hydrothermal conditions and changes in natural zones localizations due to doubling atmospheric carbon dioxide concentration for obtaining of more certain results. Besides of the reliability of estimations of expected changes in researched coefficients depends mainly on reliability of the prognosticated climatic data, in particular on the prognosticated values of air temperature and precipitation.

Monitoring the GLOBAL change detection USING LANDFORMS and landsat 5 tm

A. Maggi; S. Navone; M. Bargiela and R. Introcaso

Centro de Investigaciones y Aplicaciones a la Teledetección CIATE - Faculty of Agronomy, University of Buenos Aires (C1417DSQ) Av. San Martín 4453 Capital Federal Argentina

maggi@agro.uba.ar

There are several papers in remote sensing that was applied change detection techniques, but none of this compared the states of landforms like dunes, salt water lagoon, valleys, during a long time term. Most of this use the availability of vegetation resources, although in the Andes the climate change affected landform processes, in particular erosion and the deposition of sediments. The present landforms and vegetation reflect past as well as present climates.

In this paper we set out to describe and assess the utility of Landsat 5 TM scenes in monitoring of climatic variability and the impact in the natural environment by mean of the environmental change detection in geomorphologic units such as land dunes and salt water lagoon in the Puna Jujeña between 1986 and 2004.

The study areas chosen for this project were the salt water lagoon of Guayatayoc between 23º 08´ 48.76´´ S, 65º 56´ 21.05´´ W and 23º 47´ 38.00´´ S, 65º 46´ 37.08´´ W coordinates because the excess of evaporation over precipitation results in saline accumulations in the soils and around the lake shores and the another area was the land dunes between 23º 20´ 03.98´´ S, 65º 41´ 14.86´´ W y 23º 28´ 55.58´´ S, 65º 29´ 48.04´´ W coordinates. Three imagines Landsat 5 TM Path Row: 231-076, acquisition dates: 11 September 1986, 09 September 1997 and 28 September 2004 were used and registered.

The climate is characterised by marked seasonal differences in precipitation, where 90% of the annual rainfall falls in the months of November to March. This is the wet season.

The average of annual rainfall recorded by Abra Pampa Meteorological Station is 282mm considering a long term (1934 a 1990). The monthly rainfall totals (in mm) from 1986 to 2004 was obtained by the Campo Experimental de Altura INTA Abra Pampa - Jujuy. -

In spite of all the scenes were selected for the El Niño Southern Oscillation (ENSO) phases and the same season station, more than 10% increase or decrease in the digital numbers were found for the Band TM 3. The precipitations between January to September in 1986 were lower than 2004 so the scene was showed more drier in September of 1986 because the soil water content was lower too Thus the reflectance from the high hills on the land dunes were decreased more between 1986 and 1997 than 1986-2004 term.

In these landscapes such as the Puna region without enough meteorological stations, when monitoring the drought is necessary, the size, remoteness, and harsh nature make it difficult and expensive. For this reason, the rainfall and the soil water content can be linked with the pixel value in landforms such as land dunes or the salt water lagoon, at the end of the drier season.

The Oscillation within the El Niño Southern Oscillation (ENSO) could be detected in La Puna.

RUNOFF ESTIMATION IN A WATERSHED BY CURVE NUMBER (SCS-CN) METED USING SATELLITE IMAGES AND GIS.

M. Presutti^{1 y 3}, H. G. Rosatto^{2 y 4}, C. A. Grau⁴, E. De Luca⁴ and G. Villalba² (ex-aequo)

1. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales - 60 y 118 (1900) La Plata, Buenos Aires, Argentina. Tel: + 54-221-4236616 - Fax: +54-221- 425-2346 miriamp@netverk.com.ar

2. Departamento de Ingeniería Agrícola y Uso de la Tierra, Facultad de Agronomía – UBA Av. San Martín 4453, Buenos Aires – Argentina (CP= 1417) Tel: 54 – 11 – 4524-8008; Fax: 54 – 11 – 4514-8737 rosatto@agro.uba.ar

3. Departamento Ambiente y Recursos Naturales

4. Maestría Manejo de Cuencas Hidrográficas. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales.

Runoff is a general term used to indicate the precipitation excess within a particular area and time period. The knowledge of the runoff volume is essential for several applications, such as soil erosion, water supply for human, agricultural or industrial uses, etc. In the estimation of runoff volume in a watershed diverse variables are involved which interact in a complex way.

In this paper a methodology to estimate the runoff in a watershed by the Curve Number method from the Soil Conservation service, USA (SCS-CN) using satellite imagery and GIS is proposed.

The methodology is divided in four steps: i) Pre-Processing of satellite data by radiometric calibration and geometric corrections ii) Processing of the original data in order to get new information bands: Vegetation Index (NDVI) and tasselled Cap Transformation obtaining new images of Brightness, Geenness and Wetness, iii) information extraction of land use by object-oriented classification and iv) land use and soil type integration in a GIS environment.

Two Landsat ETM+ images were used, acquired on October 7^th and November 24^th 2002. The radiometric calibration were performed to ensure that the differences between both images are due to real changes in the targets and not to seasonal change due to different sun illumination. The classification results are polygons corresponding to each land use, treatment and hydrologic condition of the vegetation; on the other hand the soils type present in the area were assigned to the different hydrologic groups (A,B,C or D) according to the information contained in the soil map. Finally the vegetation and soil data were integrated within a GIS environment to determine the Curve Number for each polygon and for the total watershed.

The test area is located in Buenos Aires province, Municipality of Azul, covering approximately 39.000 ha.

SEA LEVEL RISE AND CLIMATE CHANGE, ITS IMPACT ON THE LOWER DELTA OF PARANA RIVER

V. Medina, L. Díaz, M. Figueroa and P. Giofre

Departamento de Geografía, Universidad de Buenos Aires. - valeriafmedina@hotmail.com

Past and present greenhouse gase emissions are increasing the global temperature, inducing oceans thermal expansion and polar ice melting. This, in time, increases the mean ocean level affecting low coastal areas. An example of this is the lower and overflowing coast of the Lower Delta of Parana River, in Argentina. The aim of this study is to introduce the sea level rise topic and its effects on the Lower Delta of Parana River. For the present study we have analyzed a number of papers and bibliography and interviewed some experts.

In the last century an increase of 1.6 ± 0.1 mm/year was recorded in the study area. This fact seems to be an unequivocal positive trend, in relationship with the global stages of increasing sea level reported by IPCC. The Delta area is influenced by climatic factors which affect water level: tide waves coming from the sea, water coming from tributary rivers and the Sudestada. When this factors act together the situation in the coastal areas becomes critical, with floods impacting negatively on the population (around 15,700 inhabitants) and on their economic activities such as forestry, cattle ranch and tourism. In addition, the South Atlantic Anticyclone has moved southwards, winds coming from East are most frequent and the ENSO generates a growth in the discharge of the Parana’s tributary rivers aggravating the general situation. All these factors generate a concerning situation in the Lower Delta. The emergency and evacuation hydrometric levels for the different Departments in the area are below 3 m, even when historical record levels fully surpass 4 m.

It would be convenient to begin organizing the towns which are under the 5 m cota. These towns will be exposed to most dangerous situations. The government institutions involved, are not fully aware of the problem, they tend to undervalue the problem for the development of tourism in the area. Also, they do not care much about long term problems and there is no interaction between the different Departments to establish a common policy of action to face this problem.

On the other hand, it is important to recognize some positive facts, such as: the Low Delta area has low population density and its inhabitants are adapted to continuous flood events. The creation of a Biosphere Reserve in San Fernando, should help to prevent and protect the area, even though the aim of its creation is not to mitigate the possible effects of water level rise.

Session 5. The problems of sustaining freshwater supplies

TOWARDS SUSTAINABLE FRESH WATER SUPPLY FOR THE CITY OF RIYADH SAUDI ARABIA

A. A. Alhawas

King Saud University - P.O.Box 25999 - Riyadh 11764 - Saudi Arabia aalhawas@yahoo.com

The city of Riyadh is a fastly growing city. Being the capital of Saudi Arabia, a developing country, with an oil rich economy, agricultural and industrial sectors are rapidly growing. In addition to the wide base of the population pyramid, the country receives millions of foreign workers from the surrounding countries. Natural and total population growth numbers are very high (%5.26/yr ). Such factors and many others impose serious stresses on the scarce fresh water resources all over the country. The problem is more evident in Riyadh city, as its population have grown hastily the last few years to exceed 4million, with an annual rate of > 3.2%.

Riyadh city covers a vast area in the central part of the arabian peninsula. Located in the middle of a tropical arid region, where no rivers, no lakes, and the scarcy rainy events are anomalous in their timing and their amounts. Sustaining water supply to the city requires careful investigation, and cautious evaluation of the limited resources available from ground water reservoirs, water desalination plants and water reclamation. Optimization analysis is needed to help manage the division of the very limited amounts of water available between the municipal, agricultural and industrial uses.

Looking at the future projections of the city growth, and the growth of the three main sectors of water consumption, and looking at the decaying (quantity& quality) ground water reservoirs available to supply the city, this paper aims at evaluating future sustainability of fresh water supplies to the city of Riyadh. And the best optimizing management policies to be recommended.

WATER PRICING OF LAGUNA LAKE: AN APPROACH TO SUSTAINABLE MANAGEMENT

M. C. N. Rivera

Forest Hydrology Section, Forest Ecosystem Research Division, Ecosystems Research and Development Bureau, College, Laguna 4031, Philippines, mcnriv@yahoo.com

Population and economic activities have exerted pressure on the Laguna de Bay, the largest lake in the Philippines and second largest in Southeast Asia. The lake is being used for a multitude of purposes. Studies to regulate its use are inadequate but the need for the strengthening of the management system for the country’s water resources such as the adoption of market – based instruments is now recognized. It has been observed that there are indications of increasing water scarcity both in quantity and quality.

The study was intended to: (1) determine the existing and potential users of the Laguna Lake and its tributaries; (2) determine the current and future demand of Laguna Lake and its tributaries; (3) compute for the scarcity rent for the use of Laguna Lake water and its tributaries; (4) determine the degree of complementation/competition among the various uses; and (5) come up with a proposed framework for the use of the tradable water user rights.

A total of 57 municipalities, identified as lakeshore (28) and offshore (29), which extract water from the lake and its tributaries were surveyed. Data were gathered through personal interviews of the various water users of the lake and its tributaries, which include the municipal officials and the water extractors (individual, groups, private and government corporations). The triangulation method, which involved the retrieval of published and unpublished literature, gathering of primary information and validation on site was adopted.

The one-year study focused on the extractive uses of the lake, both consumptive and non-consumptive. The consumptive uses of the lake include irrigation, domestic and industrial (cement manufacture, washing of crushed stones/aggregates). Thermal cooling and power generation on the other hand, are examples of non-consumptive uses of the lake waters. The economic rent theory and the concept of opportunity cost were used in the estimation of water prices per use.

The estimated economic rents varied for each use depending on the differences in costs and returns. For the consumptive uses, rent for crop irrigation was computed at P0.10/cu m or P1, 396/ha per season. The present amount paid by the Ayala Land, Inc. (ALI) for raw water, which is P1.85/cu m, corresponds to 24% of the computed rent.

Water from waterworks, mostly sourced from springs, may be given a value of P0.38/cu m while the rent for companies using water to wash crushed stones/aggregates was estimated at P0.56/cu. m.

The rent for water used to generate power was estimated at P0.74/cu m while rent for industrial cooling plants was computed at P0.0004/cu m.

Price adjustments must be done in the future when the costs of degradation and rehabilitation have already been estimated. Lake water users may be tapped as partners to protect and maintain the condition of the lake. An incentive mechanism must be established for the protection or rehabilitation of the lake. Furthermore, an effective monitoring system such as the creation of a water users council likewise needs to be put in place.

INVESTIGATING THE DYNAMICS OF AQUATIC ECOSYSTEMS UNDER THE STRESS CONDITIONS

P. A. Khaiter

School of Analytic Studies and Information Technology, Atkinson Faculty of Liberal and Professional Studies, York University, 2005 TEL Building, 4700 Keele Street, Toronto, Ontario, M3J 1P3, CANADA pkhaiter@yorku.ca

Numerous empirical studies have revealed the rapid rates of the anthropogenic changes compared to the time scales of the ecosystem’s natural succession. It is of critical importance for the sustainability to understand the ecosystem’s response pattern to stress. In general, prediction of the ecosystem’s reactions to the stress conditions of different kind, magnitude and duration including ecosystem’s stability limits, resistance and resilience are among most fundamental questions in both theoretical and applied ecology.

We are proposing a typology of the ecosystem’s responses to anthropogenic stress which includes five possible patterns:

1. Resistance (RT-type).

2. Deformation (DF-type).

3. Resilience (RL-type).

4. Degradation (DR-type).

5. Shift (SS-type).

When planning for this or another scenario of development pertaining aquatic ecosystems, it is necessary to evaluate and predict what kind of behaviour they will follow in terms of resistance stability, resilience stability or loss of stability under the given circumstances.

It should be noted that being affected by anthropogenic perturbations, an ecosystem reacts to those disturbances as a single whole. All the changes taking place in an ecosystem are in fact adaptive reactions to external disturbances. Adaptive reactions serve a purpose of establishing certain equilibrium between the changing environment, on the one hand, and the ecosystem’s metabolism, on the other hand. There are built-in mechanisms of adaptation that operate at each level of life organization, including: (1) the mechanisms of population self-regulation, (2) individual regulatory mechanisms, (3) adaptive changes of certain organs of the vegetative and animal organisms, and (4) compensatory-adaptive reactions at cellular and sub-cellular levels. As a synergetic response, an ecosystem will demonstrate some adaptive transformations.

In my presentation I am planning to discuss the results of the study of the adaptive reactions obtained on several fresh water bodies and to demonstrate the possibility to utilize this information for the needs of ecological monitoring.

SURFACE AND GROUND WATER MANAGEMENT: BANGLADESH PERSPECTIVE

A.H. Chowdhury

Institute for Environment and Development Studies – Bangladesh – iendesbk@accesstel.net

In the present day world, the problems of too much, too little or too polluted water are increasing at a rapid rate. These problems have became particularly severe for the developing countries, adversely affecting their agriculture, fisheries, navigation, drinking water supply and sanitation. Water resource management is no more just a challenge, it is a declared crisis.

Bangladesh is deltaic land and blessed with the Ganges-Brahmaputra-Meghna rivers systems. The problem is Bangladesh has too much water in the monsoons and too little in the dry season. Unless the country could conserve water when it is in excess for use when scarcity follows, the problems for flooding and drought will continue. Besides, demands for freshwater are growing rapidly in the urban and industrial sectors, in agriculture, in fisheries, in inland navigation and for controlling salinity.

Callous interventions along the course of common rivers, at the cost of Bangladesh, are nothing new. India unilaterally diverted the flow of water during the dry season, depriving of its proper share, during the rainy season the swollen water was going unobstructed abruptly flooding Bangladesh. In fact Bangladesh is under Indian water aggression. Its impact in Bangladesh is disastrous and severe, both in the immediate and long term.

Nearly two decades ago Bangladesh made a massive shift from drinking surface water to ground water to save her people from waterborne and water-contaminated diseases. Now it has been discovered that groundwater, in some areas, contain arsenic at levels for higher than good for human consumption. Many people do not know, and will not know, whether or not they are affected because it takes10-15 years for the symptoms to surface. Estimates suggest that nearly 77 million people are at risk. No where else in the world has ground water consumption put such a large part of the population to such a slow but mortal danger.

The rivers are used indiscriminately as dumps. Untreated domestic wastes and raw sewage are further degrading water resources. Water logging and salinity are no longer problems of the coastal area alone but occur in and around embankments and dams. Construction of flood-control embankments and roads and impeding water flows and both the wetlands and their fishery resources are under threat.

Experts suggest Bangladesh must efficiently use the surface water, i.e. the water of rivers, lakes, seas and other water bodies. The other countries of the world that have suffered from arsenic poisoning found remedy in stopping the use of ground water. Instead, they developed and executed pragmatic plans of efficient management of their surface water resources.

GROUNDWATER BALANCE IN THE ALLUVIAL FAN: A CASE STUDY AS A CLUE TO THE MANAGEMENT OF WATER RESOURCES

K. Mori

Department of Geosystem Sciences, Nihon University, Setagaya-ku, Tokyo 156-8550, Japan

kzmori@chs.nihon-u.ac.jp

Groundwater is increasing in importance as a usable resource in meeting the rising demands imposed by human activity. Concurrently, the development of groundwater resource has sometimes been counterproductive with environmental damage due to improper utilization. That is why a full understanding on quantitative as well as qualitative properties of groundwater under the individual hydrogeological characteristics is significant for sustainability. In the present paper, groundwater balance was investigated in the Kurobe Alluvial Fan as a case study, where both extensive utilization and positive conservation of groundwater resources has been practised over a long term of years. The main purpose of this paper is to evaluate the constituent element of groundwater balance with a research focus on establishing the way of management of water resources.

The Kurobe Alluvial Fan fronting on the Sea of Japan develops in the lower reaches of the Kurobe River with an angle of 60 degrees. This particular alluvial fan has an area of approximately 120 km², a relative height of 130 m and a mean inclination of 10-11 permillage. The maximum depth of bedrock reaches up to 200 m, and the permeability of aquifer consisting of granitic gravel is comparatively law with an order of 10^-3-10^-1 cm/sec. In littoral area of the study area, spring and artesian well are widely distributed where groundwater has been used as a resource of daily necessity for local people.

From the result of observation on discharge of the Kurobe River and groundwater flow system, it is estimated that the amount of groundwater recharge in the Fan is in the region of 220-440 x 10⁶ m³/year by influent seepage and 360 x 10⁶ m^3/year by irrigation water, respectively. Secular changes in groundwater level have a tendency to lower of late years. The amount of flowing confined groundwater is also on the decrease especially in the left bank area of the channel. In regard to the annual change in groundwater level, a decline in the winter months is remarkably recognised as a result of concentrated withdrawal of groundwater for melting fallen snow on a road surface. Meanwhile, the role of groundwater comes up as an important problem in order to provide drinking water under the state of emergency including an earthquake disaster.

The study area is fortunately blessed with relatively short mean residence time of groundwater (for five to six months) due to much precipitation, high recharge rate, sharp hydraulic gradient and pervious geological conditions. It is pointed out that coactions by local people, enterprises and administrative office in the study area have been fulfilled in order to proceed with the proper management and to preserve better environment for groundwater. An administrative body has also driven forward the actual enforcement of policy concerning a conservation of groundwater resources and an origination of symbiotical water environment.

THE ANTHROPOGENIC CHANGES OF WATER COMPONENT OF THE ENVIRONMENT IN THE REPUBLIC OF ARMENIA

T. G. Vardanian

Yerevan State University,Yerevan, Armenia - tvardanian@ysu.am

In Armenia water resources have been affected by intensive anthropogenic impact for more than one hundred years. All types of water basins, rivers, lakes and ground waters in Armenia have slightly or considerably undergone human impact.

The water resources of the Republic of Armenia were considerably affected by anthropogenic impact at the beginning of the 20^th century, when decision about use of ancient reserves of the largest fresh-water basin in the region, namely, Lake Sevan (to use for hydro-energy generation and irrigation of Ararat valley) was drawn.

The world lymnology has no recorded case when the level of lake water would drop by 17-18m within three or four decades. In this respect, Lake Sevan is a unique case and it is regarded a large natural laboratory containing processes connected with the lowering of erosion basis of the rivers which flow into the Lake; these processes can scarcely be studied in laboratory conditions.

Despite the economic development in the country, the condition of the lake deteriorated, causing eutrophication.

As a result of anthropogenic activity, ground artesian basins have also undergone serious changes. Ararat artesian basin, where on a small area there are about 2100 boreholes, is under poor condition. These boreholes were dug mainly for irrigation. However, they were not equipped respectively and could not be operated. Water has leaked out of the boreholes very easily for years, causing damage and creating marshes in the valley.

Water of rivers has been considerably affected as well. River water composes about 70 % of the total amount of water use. For better understanding, it is enough to note that 1/3 of perennial mean annual river runoff (6,5 billion m³) is regulated, i.e. accumulated in the reservoirs.

The dynamics of water use has also increased. In perennial view, the amount of water use in utility services and industry has increased almost twofold, while in fish farming – by 7-8 times. Water is mostly used for irrigation (75,8 %), utility services rank second (10,8%) and industry is on the last place (10,7 %).

These amounts of water use have extremely reduced after the collapse of the Soviet Union, as a result of present complicated socio-economic situation peculiar to any country with transitional economy.

The anthropogenic load, i.e. the relation of the population number to the water resources of rivers is the simplest, but at the same time the most important index of evaluation of anthropogenic impact of water resources. This index for Armenia represents 585 thousand people/km³, which is very high. If we compare it with Former Soviet Union republics, particularly, with Russia, which was the richest in water resources among all the republics, we will see that the anthropogenic load composes only 40 thousand people/km³.

Thus, on the small territory of Armenia, both surface and ground waters have been subject to anthropogenic considerable changes, which have influenced the environment as well.

ENVIRONMENTAL AND FINANCIAL ECONOMY IN LATINOAMERICAN CITIES. THE DRINKING WATER IN BUENOS AIRES – SAN PABLO – MEXICO (1940–2000)

J. E.Grassi

Banco de la Provincia de Buenos Aires. Archivo y Museo Históricos. Sarmiento 362 (1014) Buenos Aires jgrassi@bpba.com.ar

Which are the environmental circumstances that developing countries should face during the new century? What risks will their inhabitants be exposed to?. Some of these queries can be analyzed through concrete cases such as those of Latinoamerican countries with extreme situations regarding demographic pressure and poor public service conditions. In this research, I have analyzed the metropolitan area of Buenos Aires specifically in relationship with the supply of drinking water and sewage and its comparison with the cities of Mexico and San Pablo.I have estimated the levels of service supply and the economic and institutional feedback between the 1940-2000 period.

In this analysis of the metropolitan area of Buenos Aires- San Pablo and Mexico, I have included three important historical, political and economic moments to make it clearer to understand the patterns of demographic and spatial growth and the environmental impact that is produced by the high demand of the service of drinking water and the consequent growth of the population.

In this context, we can see that the construction work demands high financial costs. If these projects are plannified and fulfilled at the right time and in the right way, these costs can be afforded. Postponing payment in investment programmes can bring about economic risks which will require much more money for the same work or the collapse of the production owing to the lack of a basic source such as water.

Finally, the purpose is to diagnose and provide an answer to prevent structural and institutional risks through a group of actions that can anticipate an efficient coverage of the services of drinking water and sewage. The objective is to develop a sustainable plan for our cities so that we can make this service better and improve the quality of life of their inhabitants.

IRRIGATED AREA DETERMINATION: A CASE STUDY IN THE SAN JUAN PROVINCE (ARGENTINA)

G. Salinas de Salmuni¹, I. Velasco², M.E. Fresina³ and A. L. Flores²

1. Universidad Nacional de San Juan – Centro de fotogrametría, Cartografía y Catastro

2 – 3. Universidad de Buenos Aires – 2. Departamento de Ciencias de la Atmósfera y los Océanos

3. Departamento de Ciencias Geológicas - Ciudad Universitaria, Pab. 2 - 1428 Buenos Aires - Argentina

velasco@at1.fcen.uba.ar

Irrigated agriculture has the challenge to produce more food from less water resources. Water scarce conditions require an alert and wise management of water as a commodity. Managers have to develop targets to plan and evaluate their policy. This requires an advanced quantitative approach and a well-thought data acquisition system. New developments in remote sensing, GIS and modelling have provided water resource researchers and managers many interesting tools for obtaining accurate spatial data on actual water use, water demand, allocation and productivity.

Much of the central-western region of Argentina, where San Juan Province is located, experiences arid to semi-arid climatic conditions with low average annual rainfalls accompanied by substantial evapotranspiration. Consequently, a viable crop industry depends to a large extent upon irrigation from major river system.

The area of study, the Tulum Valley (San Juan Province) has dry climate characteristics such as very low annual rainfall (100 mm), high frequency of sunny days and extreme water deficit. The need of water for agriculture is completely supplied through irrigation provided from San Juan River (more than 80%). There exists a distribution network formed by irrigation channels which are approximately 1,183 km long. Irrigation practices are mainly done by surface irrigation and channels (90%) and 10% by pressurized irrigation (drip and micro-aspersion).

The area presents vast zones with generally flat topographic conditions which make the natural soil drainage difficult. This situation together with the bad use of the irrigation water, losses due to infiltration in the distribution channels and lack of efficient drainage collectors, have contributed to the salinity of important areas caused by the phreatic waters with high saline content nearby the surface, causing an important degradation in the Valley. Consequently, the production in these sectors decreased.

The San Juan River itself receives major inflows from seasonal snows in the Andes Mountains, and in dry years can run at very low levels or stop flowing altogether, leading to increase the salinization of the water supplies of the cities downstream. Consequently, additional demands on the river made by irrigation must be carefully controlled. In San Juan such control is exercised by issue of irrigation licenses to farmers. It is then necessary to monitor their usage of water to ensure licenses are not infringed. This, of course, is the situation in many parts of the world were extensive irrigation systems are in use.

The water demand by a particular crop is very closely related to crop area, because most water taken up by plants is used in transpiration. As a result, it is sufficient to monitor crop area under irrigation as an indication of water used. In this study, Landsat multispectral image data for different seasons and classification techniques are used to provide crop area estimates.

The goal of this work is the development of new technologies tending to satisfy continuous demands and applications of satellite data, in the short, medium and long term, for the study, management and sustainable development of the renewable natural resources of the region. Also, the articulation of the regional available technological infrastructure, so the products derived from the digital images processing can be transferred to the final users widening of the fields of application and seeking for potential users who could be benefited from the use of these technologies.

DRINKING WATER SUPPLY SYSTEM IN THE CITY OF CORONEL SUÁREZ, CORONEL SUÁREZ COUNTY, BUENOS AIRES PROVINCE

M. N. Prieto and O. M. del Pozo

Departamento de Geografía y Turismo - Universidad Nacional del Sur mnprieto@uns.edu.ar

Water is essential for the development of life on Earth. In the last decades, this resource has become scarce and its management one of the most urgent problems. In this sense, water preservation shall depend on the “rationality” governing the society – nature relationship.

This research project attempts to begin an environmental diagnosis on the water supply system in Coronel Suárez county and in its main city, located in the Southwest of Buenos Aires Province, within the thesis “Environmental Diagnosis of Water Resources in Coronel Suárez County, Buenos Aires Province”, corresponding to the career of University Graduate in Geography (Licenciatura en Geografía) at the Universidad Nacional del Sur.

Drinking water supply and access to this utility are significant contributions to progress and life quality improvement since they allow to preserve the health of the population and to reduce the risks of disease.

In Coronel Suárez county this utility has been available since August 1975. Deep water extraction by pumping allows for the supply of this utility to the local population. Before the installation of the running water network, supply characteristics were represented by the existence of pumping wells in each home that still exist in some cases.

Water for human consumption must meet certain physical, chemical and bacteriological characteristics in order to guarantee that it is suitable as a supply resource, which determines the type of treatment to be performed before delivery for consumption. In our case study, water naturally meets the conditions that define its drinkability, therefore the supply system consists in a simple process based on the addition of chlorine to prevent from accidental contamination in the distribution network. This system meets the requirements of the local community regarding water supply.

The sustainability of the resource is only possible if the company responsible for this utility follows the procedures necessary towards building and strengthening the environmental awareness of the local community in order to contribute to a use of water based on rationality.

The methodology implemented in order to develop this presentation consisted in the search for bibliographic material, as well as interviews with key stakeholders such as municipal authorities and system users, and the study of press information and relevant statistics.

CIENAGAS EVALUATION TECHNIQUE IN PRECORDILLERA OF SAN JUAN PROVINCE

E. Suárez Montenegro

Instituto de Geografia Aplicada - Universidad Nacional de San Juan – CONICET Avenida Benavides 5548 (oeste). Rivadavia C. P. 5407.  Provincia de San Juan. República Argentina.
elvirasuarezmontenegro@hotmail.com

The "Ciénagas" are very important natural environments for the development of arid areas such as San Juan Precordillera. They share common characteristics with wetlands like presence of water, biological diversity and a variety of natural resources. Even though they are not characterized by their big extensions, they are associated with the wide neotectonic manifestation in our province. And this makes an important contribution to complex natural system. Because its conservation is very necessary it is then intended to make an evaluation model, useful for their handling and plan administration.

As a systematic unit of study it was selected the research of the river basin in the Ciénaga River, which shows a number of these environments that flow, to a great extend, in the water quality used by people in San Juan. As a first step a number of different techniques were used for the elaboration of this environmental work. This work shows the results and conclusions in which the relationship among the tectonic, paleoperiglaciers and thermal areas describes their biological evolution.

MARINE FISHING REVIEW IN ARGENTINA – THE LAST DECADE OF THE 20TH CENTURY “MINING” EXPLOITATION QUESTIONING RESPONSIBILITIES AND PROMOTING POTENTIAL ALTERNATIVES TO SOCIO-TERRITORIAL JUSTICE

J. M. Cóccaro¹, C. Carut² and A. Boetto³

1. Grupo de Estudio de Litorales de América Latina (G.E.L.A.L) - Universidad Nacional de La Plata (Departamento de Geografía) - Universidad Nacional de Mar del Plata (Grupo Ambientes Costeros-Departamento de Geografía) y Universidad de Bretagna Occidental, Francia. - Universidad Nacional de Río Cuarto. Dto de Geografía. - scoccaro@satlink.com.ar

2. Departamento de Geografía-Facultad de Humanidades y ciencias de la educación de la Universidad nacional de la Plata - ccarut@ciudad.com.ar

3. Departamento de Geografía –Facultad de Ciencias Humanas-Universidad nacional de Río Cuarto Tel: 0358- 464 38 86

Fishing mining is not exclusive to the last decade of the 20th Century. From the 18th Century, a diverse and prized biological capital was the loot of an indiscriminate hunting, fishing, and catching within various historical contexts: the southern right whale, the blue whale, the South American fur seal, the elephant seal, the southern sea lion, the tope shark, the hawkfish, the scallop, the mussel, the yellow clam, the argentine hake, the squid, the southern blue whiting, the Patagonian toothfish, the argentine red shrimp…

However, the effects of the fishing impacts did not and do not currently reach social conscience dimensions. These impacts have indeed a short term-space social horizon, only interwoven with that of the social actors involved in different moments of our history. They are not rooted in the collective imaginary due to an infertility deliberately provoked to uproot the belonging sense of the maritime territory and the appropriateness sense, as result of a production process. Moreover, on its basis we may find the lack of manure to stimulate its fertilization: the educative intention has allowed legitimizing – in different historical periods- actions of real mining exploitations and plundering. This occurred since the social conscience of these actions could not play their role due to a subjectivity colonization process carried out by the construction of a value, knowledge, and behaviour hierarchy imposed in function of the different stages of the capitalism, particularly during the last expansion phase of the conservative neo-liberalism in Argentina, during the last decade of the 20th Century.

This context has triggered the historical dismantling between the scientific-knowledge production and the territory as productive, production, and social use basis. Evidence of this underlying matrix is the historical pressures over the fishing resources of the common social heritage, which not only attempts on the biodiversity but also on the sociodiversity disinheriting the fisher and his community from the empirical, popular and vernacular knowledge.

Nevertheless, well-defined emerging responses start coming to light, arising as new articulation sceneries between social agents and actors involved in the craftsman-fishing activity so as to build a culture more intimately linked to the social and productive life of the country and to the entire ethical commitment with the joint-interests of the community which questions the social responsibility at stake before this challenge.

CONSCIENTIZATION FOCUSED ON AQUATIC POLLUTION IN THE MATANZA-RIACHUELO RIVER BASIN, ARGENTINA*

A. Puig

Museo e Instituto Nacional de Investigación de las Ciencias Naturales, División Limnología (Area Ecología). Av. A. Gallardo 470, C1405DJR. Buenos Aires, Argentina. apuig@macn.gov.ar

A presentation at the Forum “Sustainable Development of the Matanza-Riachuelo basin” addressed to nearly 300 participants, who will deliberate about ‘development options’ and ‘management options’ for this basin is shown as a conscientization experience. The Matanza-Riachuelo River basin (2,200 km²), that involves the south area of Buenos Aires city and 14 municipal districts of Buenos Aires province, presents a high degradation of both the environment and the population's quality of life. The Matanza-Riachuelo, a small temperate lowland river (65 km), represents the oldest case of water pollution in Argentina and one of the most severe in Latin America. Its mixed diffuse and multiple-point source pollution, involving agrochemicals as well as domestic and industrial (mostly untreated) effluents, derives from nearly 10,000 industries and more than four million people. Considering the variety of the Forum audience (more than 300 residents, government officials, industry managers, professionals, non-governmental organisations members, students, teachers, journalists, legislation representatives, etc.), the transfer of summarised messages oriented to the comprehension and integration was procured in order to motivate the subsequent reflexive analysis. Several relevant concepts (as sustainable development, ecosystem health and stress; ecosystem management approach integrating natural and social dimensions; hydrographic basin; multiple approaches for pollution assessment) were exposed in the presentation. Moreover several findings, poorly disseminated, of our research (generated by a group of researchers from units of the Argentinean Museum of Natural Sciences and the Buenos Aires University) were reported focusing on water pollution (toxics, organic pollution, bioassessment, bioassays) in watercourses from this basin. On these bases suggestions and guidelines were provided which may contribute for the subsequent deliberation. At present the water of courses from this basin only acts as pollutant transport also affecting the uses of adjacent systems, such as the Río de la Plata, a bi national estuary (source of drinking water, fish, etc.). Consequently it is imperative to stop the environment deterioration and to restore the water quality in order to allow the conversion to alternative uses. These goals coincide with the ones proposed in nine case studies from developing countries (four from Latin America), compared by the ‘International Network of Basin Organisations’. Useful learned lessons provided by the long experience obtained in the Rhur River basin (affluent of the Rhin, Germany) were presented. As recommendations, an ecosystem management approach, using adaptive management (adjustable according to successes, failures, and new challenges and knowledge), with a committee operating at basin level, even if management may be potentiated by regional projects; to take advantage from international experience; to achieve the active participation of scientists and society in all the process, were proposed. Suggestions directed to scientists, management representatives, population and entrepreneurs were presented. As main results of the deliberation (to be presented to authorities and the communication media) the participants have reached consensus on the sustainable development, prioritising the integral river restoration, and on the participatory management, involving the establishment of a representative entity-committee of the basin.

RESIDUAL USEFUL LIFE ESTIMATE OF THE BUENOS AIRES DRINKING WATER NETWORK

B. M. Rosales

Researcher of the CONICET - CIDEPINT, Av 52 s/n entre 121 y 122 (B1900AYB) La Plata, Buenos Aires, Argentina. - brosales@fibertel.com.ar

The most frequent corrosion problems in drinking water distribution networks are the accumulation of inner deposits and tubing perforation. Both types of failures gradually reduce the normal water provision and repairing lead to unscheduled service interruptions.

Differences in water quality in big towns network trigger uneven failure distribution and the necessity of frequent follow-up of the most susceptible areas. The solution proposed and applied to the Buenos Aires distribution system had twofold main purposes: corrosion and microbial proliferation control. During microbial biofilm build-up and detachment, the risks of pathogenic microbes spreading were also considered amongst urban health concerns.

To avoid these failures and risks a tailored program is being applied during the last 7 years, consisting on periodic sampling of the most susceptible sections of the tubing network. Updated residual life and microbial control of the circulating water as also of the biofilms accumulated inside the tubing characterization minimized unexpected interventions.

The methodology applied consisted on:

Electrochemical assessment of deposits porosity. This was measured through anodic and cathodic limiting currents, and was expressed comparatively amongst distinct tubing sections of the net.

Scanning electron microscopy (SEM) was also applied to verify the uneven availability of difusional ways through the deposits and the effect of microbial biofilms in their consolidation, compactness and adherence.

Microbial analyses of the circulating water and of deposited solids allowed determining the existing flora and the risks of spreading pathogenic microbes throughout the drinking water net. Assimilable organic carbon was a complementary measurement allowing microbial assessment.

The spurious solids contained in the river water source, as well as the coagulants used during the clarification treatment, unevenly contribute to increase protectiveness against inner tubing corrosion, as was determined by using energy dispersive X ray analysis (EDAX).

Radiography and g-graphy was applied to determine the mean residual wall thickness of each section, in connection with previously existing blowholes in the tubing material and the suspected further corrosion.

This set of results, obtained from the application of techniques based on analysis of different characteristics of the materials involved, allowed us to design tailored intervention policies for the network different sections related to the installation date.

As a consequence, an improved service is being provided and a reliable and less expensive maintenance schedule was formulated, replacing the costly cleaning and painting operations applied to its homologous in London at a cost of 350 million dollars.

DROUGHT, WATER SHORTAGE, AND DEGRADATION

I. Velasco

Mexican Institute of Water Technology – Paseo Cuauhnáhuac 8532, Colonia Progreso. Jiutepec, Mor. MEXICO. 62550 - ivelasco@tlaloc.imta.mx www.imta.mx

Water shortage is probably the most urgent problem. If water is absent or scares, it is a strong factor for poverty, wars, illnesses and underdevelopment. Environmental degradation, drought and desertification are closely tied, and they affect fresh water quantity and quality. Drought, as a natural phenomenon, can produce severe water imbalances, which causes wide repercussion and difficult recovery, when the breach between natural water offer and human demand is wider. And we are still far from to reach and to preserve the necessary balance between available resources and their appropriate use, without degrading them beyond their recovery capacity.

This is a decisive factor for increasing poverty conditions that face wide population sectors, particularly in non-industrial countries. None strategy is able for poverty reduction without considering water supply as a fundamental and vital human necessity, and without a fair and sustainable water management, which is crucial for each region and country. To integrate the environment conservation and its fresh water relations is firstly necessary to understand the ecosystem, in order to assist the ecological, institutional and social characteristics of the region.

This way, under drought conditions, water management must to foresee how to confront the risk, instead of not foreseeing to support the crisis. Drought, as an unavoidable phenomenon, barely predictable, without defined trajectory and epicenter, progressive and frequently catastrophic, it requires attention so much institutional as social. Due to its complexity, drought requires necessarily to generate and apply indices and parameters, in order to detect and evaluate its presence and its main characteristics. Therewith, in this way basic elements are obtained to confront with success the drought menace, and they can help to mitigate the dramatic effects, which by themselves overcome to all the other natural phenomena effects together. Equity, efficiency and social justice are factors that determine if drought presence is just a natural unsuitability or a true catastrophe; in this sense, governance, expressed in laws and regulations, joined to the necessary water culture, they are, among the non-structural measures, decisive factors in achieving that a natural phenomenon has a reduced and bearable impact.

RUNOFF QUALITY OF LIVESTOCK FIELDS IN THE ROLLING PAMPA, ARGENTINA, OBTAINED BY SIMULATED RAINFALL

C. I. Chagas, O. Santanatoglia, J. Morettón, M. Paz, M. V. Piazza, C. Irurtia, M. De Siervi, H. Muzio and M. Castiglioni.

Facultad de Agronomía. UBA. Av San Martín 4453. (1417) Buenos Aires - Argentina. chagas@agro.uba.ar

Water quality for different uses is conditioned by urban, periurban and rural pollution, although frequently the main and most difficultly controlled contamination is generated by agriculture. According to FAO, the sediments generated by water erosion are usually the main pollutant of surface waters because, along with its physical effects, they have the capacity to carry and transport many toxic elements, which promote chemical and biological consequences. The aim of the present investigation was to study the quality of runoff water from livestock fields belonging to a representative basin of the Rolling Pampa, subjected to water erosion.

Experiments with high energy simulated rainfall were carried out in two contrasting livestock management systems, an extensive cattle grazing field and a cattle feed lot.

The former consisted in a natural grassland field with infrequent pulses of grazing animals per ha. The later had permanently a high number of feeding animals per ha

The results showed that the feed lot yielded a significant quantity of fine sediments associated with high concentration of viable mesophile bacteria, total coliform bacteria and Enterococci in the water. The laters are indicators of biological contamination. The runoff water also had high values of CE and pH, and high concentration of HCO₃ ^- and PRS. It is important to highlight that the pH and the high concentration of solids can enhance pathogenic bacteria survival in the runoff waters.

The runoff belonging to the extensive grazing fields, although being performed in areas with relatively fresh livestock feces, contained significantly lower concentration of bacteria and sediments compared to the feed lot system. A tendency to higher bacterial concentration was observed in runoff plots with higher sediment yield in the studied systems. These results corroborate the significant association between water erosion sediments and bacterial concentration that can be find in runoff waters belonging to both extensive and intensive livestock fields.

APPRECIATION OF A DEGRADED RIVER SYSTEM: THE MANANTIAL STREAM (TUCUMÁN, ARGENTINA)

E. Guido and P. Sesma

Professorship of Physical Geography, Faculty of Natural Sciences and Institute Miguel Lillo, National University of Tucumán. San Martin 1545, 4000, San Miguel of Tucumán, Tucumán. E-mail: gyetomas@sinectis.com.ar

The Manantial stream, motive of the present study, represents a special case that does not respond at river system of Schumm (1977): basin of drainage, transfer zone and sedimentation zone. Its beginnings are in a spring area between the foot mountain and the oriental plain of Tucumán. Its more important source of alimentation is a basin of the Hill of San Javier, situated at western that is invested foot of this hill and reappears in surface in the locality of “Ojo de Agua”. The Manantial stream is situated in one of the agronomics regions richer of the province and close to capital city of San Miguel of Tucumán and its original landscape has been degraded for the intense landuse: urban, industrial and agricultural. To ours understood, the political management and the population that lives on its border have an ambiguous and erroneous perception of the stream. It is conceived like a “channel of discharge” and not as a water system with all his attributes and functionalities. On the other hand, recent studies tending toward correcting the peaks of discharge of the channels that surround to San Miguel of Tucumán, glimpse the Manantial stream as a viable alternative to derive part of the volume (liquid and solid) that generate the rains, mainly during the summer station. This project opens the possibility of a new environmental impact on the stream and all its area of influence.

The objectives of this work were to characterize the environmental system of the Manantial stream and their surroundings, to define their capacity of reception and to know the potential answer before the execution of the projects predicted in the zone.

Cartographic and bibliographical materials were used for this study. The characterization and environmental inventory were based on works of Sesma et al (2004) and the capacity of reception of Gómez Orea (1992) criteria. The cartographic base was taken of the Letter Image “San Miguel of Tucumán, 2766-17”, scale 1:100.000 of the Military Geographical Institute. The work was complemented with controls and measurements field.

The results reached permit to characterize the Manantial stream as a river system with a plain meander design, a length of 17 kilometers and a variable wide river bed (1,5 to 2 meters until more than 20 meters). Geomorphologically, they have developed three levels terraces, asymmetric and the limited surface. By its private position and geographical characteristics, the area has favourable conditions for environmental, social and economic appreciation. Likewise, the geomorphologic conditions of the stream and their environment (design, stability of margins, litology, etc.) have a high erosive susceptibility. The projects in study (bypass of peaks of flow) should consider these factors.

LAND USE CONDITION CHANGE INDICATORS IN IRRIGATED SOIL OF THE NEGRO RIVER HIGH VALLEY (ARGENTINA)

J. M. Mendía and J. Sassi

Facultad de Ciencias Agrarias – Universidad Nacional del Comahue - Los Ceibos 1120 (8324) Cipolletti. Río Negro. Argentina. - mendiaju @ infovia. com. ar

The surface of irrigated soil in the world decrease to a rate from the 2% to 8% annually by salinization, drainage, compaction, sodification and loss of structure, that raises the necessity of a greater demand of actions, more and more expensive, of land rehabilitation and, possibly, to the abandonment of the same ones.

The soil sustainability in the High Valley of the Negro river, is expressed by the Land Quality Indicators that reflect the superficial dynamic characteristics, in the first 30 cm soil depth, and define the land condition as result of the use and management.

Superficial soil samples of 84 representative control sites of different Land Unit Types (TUTs) were taken: Uncultivated soils (I), abandoned (A10) and implanted with red apple trees of 25 (M25), 45 (M45) and 65 (M65) years old.

The contents of Organics Matter (MO), soil reaction 1:2.5 (pH) and soil Salinity (CEe) determined in laboratory, were used like Land Quality Indicators.

The flood border irrigation method is used in the apple orchards. The amount of irrigation water applied to the field during the growth season is 1700 mm in depth. The electrical conductivity of the irrigation water is 0.250 dS / m.

The changes observed in the Land Quality Indicators for different TUTs are: MOI 0.91%; MOA10 1.25%; MOM25 1.32%; MOM45 1.67%; MOM65 1.72. pHI 8.0; pHA10 7.74; pHM25 7.73; pHM45 7.58; pHM65 7.50. Ce eI 11.99 dS / m; CEeA10 4.15 dS / m; CEeM25 0.50 dS / m; CEeM45 1.33 dS / m; CEeM65 1.38 dS / m.

The diminution of salinity and pH values as well as the increase of the organic matter through the time in the fruit crops, is because of the high quality and quantity of water irrigation.

The reduction of soil salinity in the apples orchards show the efficiency leaching.

The diminutions of pH by the increase of the organic matter become avaible greater part of nutrients.

The flood border irrigation method allows to supply the crops water requirements and the intercrops grass development, that increase the organic matter levels to the soil.

The High Valley Land Quality Indicator´s show that the fruit activity maintains or even improve the health soil for future generations.

EFFICIENCY OF DEFLATION HOLLOWS IN STORAGE OF NUTRIENTS AND SALT OF THE WASTEWATER AND FEEDLOT RUNOFF IN SANDY PAMPA-ARGENTINA

A. R. García¹, M. Massobrio², A. F. de Iorio¹

1. Química Analítica 2. Manejo y Conservación de Suelos. Facultad de Agronomía-UBA agarcia@agro.uba.ar

The deflation hollows associated with parabolic dunes are geoforms of semiarid environments. These are used for containment y storage of feedlot runoff. If the deflation hollows do not present a suitable capacity of retention and accumulation of nutrients in these environments there would be favoured the pollution of the underground waters. This work studies the influence of superficial microtopography and the depth of the clay (argillic) layer in the distribution of nutrients and salts in the deflation hollows soils that receive feedlot runoff and wastewater in order to evaluate its effectiveness.

The research was conducted on a feedlot located in the Sandy Pampa. A systematic sampling at different depths was carried out in the hollows and in other peripheral environments. At each sampling site it was measured the distance to the clay layer. The concentrations of nutrients and salts, pH, texture and electrical conductivity were analyzed applying analytical standardized methods.

It was observed an accumulation of salts, total P (TP), bioavailable P (BP) and NO₃^- in surface that significantly diminished in depth. The % Na exchangeable (PSI) changed among 10 and 15 % in surface, to an average value of 8 % to depths greater than 50 cm. The NH₄⁺ decreased in the first centimeters, it could be due to a process of volatilization, according to the values of pH measured in surface. Nevertheless it was observed a significant increase at depth of 20 cm. This increase is explained by the cationic adsorption processes in clay layer which has 30 % of clay whereas the superficial layer has 13 %.

The comparison of the different environments allowed clarifying the behaviour of the hollows as zone of accumulation and retention of nutrients and salts. The depth of the clay horizon determines the vertical dynamics in this microcosm.

WORKSHOP PROPOSAL MEANT FOR THE 2°CYCLE OF E.G.B.

V. de la Concepción, S. González and J. Cóccaro

Mundo Nuevo. Program on Science Dissemination and Education. Academic Affairs Secretary. National University of La Plata. - mundo.nuevo@presi.unlp.edu.ar - T.E.: 0221- 427 23 93

If you are going to drink the water, don’t let it run is a proposal to value the responsible and cooperative use of water resources, emphasizing the fact that the water is inseparable from health conditions: safe water is not a service; rather, it is a public good, and constitutes an unrenounceable human right.

Our power over water is temporary. When we make use of it, we “borrow” it, since we are just delaying its return, sooner or later to participate in the functioning of that water machine made up by the water cycle, driven by the solar energy. All of this always within the framework of a thermal-water dialogue between the atmosphere and water. This is why, water is re-usable and non-renewable.

Within this context, the great challenge consists in realizing and being aware of the misalignments present between the demand of different scale consuming requirements and inseparable water availabilities, and their ecological, political, economic, social and scientific framework. Here, we pose the unavoidable need of carrying out a social management of the water resource, in its significant role played in the organization of the space and life quality.

The objetives of this proposal are promote the reflection on the water qualities, a common but extraordinary substance. and encourage and realize the need of increasing the safe water supply, as basic and unavoidable condition for the improvement of the life quality and sanitation of the environment.

We choose in this context as contents: The Earth, as the planet with water, ice and steam; The water machine as the thermal dialogue between water and atmosphere(processes, transferences and distribution);The meaning of proportions (surface and volume of oceanic and non-oceanic deposits); Water as life framework and availability matrix; Water and health.

As we attempt to “promote” the treatment of “part” of some of the water issues, we are posing the need of articulating a contextualizing framework in order to make an “integrating view” allowing the possibility of opening analysis “windows” according to the meaningful spaces of the different “participant” (involved) school populations.

We suggest for this purpose a list of questions:

Why is water present in “our” Solar System?

Which are the reasons supporting its existence in the Earth, almost in its totality as “water”, and not as ice or steam? (stage 1)

Is the Earth the water planet? (stage 2)

Is water a renewable availability –resource? (stage 3)

Can we easily access the water of the planet so as to satisfy our needs? (stage 4)

How are the assessment of the water consumption needs and the quality of life levels at domestic, urban (collective and public), agricultural, and industrial levels scales related (or correlated)? (stage 5)

Why is it necessary to pose an evolving differentiation of concepts and relationships when we are taking about water purification? (It involves the distillation, sterilization, de-ionization –salts elimination- , and potabilization processes) (stage 5)

Is safe water supply just a service? (stage 5)

Which are the proper treatment and distribution processes to encompass the whole population? (stage 6)

These questions and all of those related to different expectations, perceptions, questions, and gaps emerging from the interchange with the participants of the workshop will constitute the articulating–methodological axis in order to achieve, in the “other”, the proposed objectives.

PROTECTION OF THE ENVIRONMENT AND REUSE OF WATER RESOURCE

M. Bossolasco and R. Crespi

Universidad Nacional de Río Cuarto.

Agencia Postal Nº 3 0358-4676503 Fax 0358-4680280 - rcrespi@ayv.unrc.edu.ar

In year 2000 it was implemented in the National University of Río Cuarto, a Pilot Plant for the treatment of effluent generated in a small well-known population as the University Student Residences in which the ecosystem management of the water was prioritized. The objectives consisted of evaluating different techniques from purification and reuse of wastewater; to fit technologies of fast transference to the society and to conscience to the educative sector on the importance of diminishing the environmental impact, management the water resource with a cyclical concept that implies the generation of money. Different techniques from treatment were used of domiciliary wastewater to protect to the environment of the polluting agents, reuse the water for the production of soybean, rape, garlic and eucalyptus. In this work the treatment of effluent by means of a combined process of conventional and non conventional techniques and its reuse in soybean appears. The decontamination was made using activated sludge and lagoons of stabilization with an efficiency of purification of the DBO of 60 %, of N of 70 %, P of 44 % and K of 0 %; diminishing the pathogenic germs in 1*10⁷ NMP/100 mil using light UV. The concentration of macronutrients of the regenerated water fue 32,00 mg/l, 4,50 mg/l and 16,00 mg/l of N, P and K respectively. In agricultural cycles 01/02 and 02/03 the applied water use was analyzed of different chemical quality by means of subsurface irrigation to a soybean culture (Glycine max L), evaluating its answer to treated wastewater (AR) and of perforation (clean) (AL) with different doses from inoculation (Bradyrhizobium japónicum): Witness (T), Minim (DM), Normal (DN) and Double (DD). With treated wastewater, the most stable yields and of greater magnitude surpassing 6800 kg/ha and the 4800 kg/ha were obtained according to the years. Independently of the amount of inoculate, the yield average of the soybean irrigated with treated water surpassed in 694 kg/ha with clean water irrigate; but without inoculants the difference for these conditions was of 935 kg/ha. The different doses from inoculants showed an increasing answer of single yield when it was irrigated as much with clean water and nodulation as the water use efficiency, increased with the increase of the doses of inoculants. The limit nutrient to obtain high productions in soybean was the nitrogen that did not produce an inhibition of the nodulation, but a temp cancellation of the biological fixation by the contribution of the wastewater. The use of water treated for irrigation, allowed to obtain a very high water use efficiency, with values that varied between 8,14 and 13,18 kg/ha mm; however, the harvest index was affected when being generated a great production of biomass necessary to obtain so high yields.

RESIDUAL USEFUL LIFE ESTIMATE OF THE BUENOS AIRES DRINKING WATER NETWORK

B. M. Rosales

Researcher of the CONICET - CIDEPINT, Av 52 s/n entre 121 y 122 (B1900AYB) La Plata, Buenos Aires, Argentina. - brosales@fibertel.com.ar

The most frequent corrosion problems in drinking water distribution networks are the accumulation of inner deposits and tubing perforation. Both types of failures gradually reduce the normal water provision and repairing lead to unscheduled service interruptions.

Differences in water quality in big towns network trigger uneven failure distribution and the necessity of frequent follow-up of the most susceptible areas. The solution proposed and applied to the Buenos Aires distribution system had twofold main purposes: corrosion and microbial proliferation control. During microbial biofilm build-up and detachment, the risks of pathogenic microbes spreading were also considered amongst urban health concerns.

To avoid these failures and risks a tailored program is being applied during the last 7 years, consisting on periodic sampling of the most susceptible sections of the tubing network. Updated residual life and microbial control of the circulating water as also of the biofilms accumulated inside the tubing characterization minimized unexpected interventions.

The methodology applied consisted on:

Electrochemical assessment of deposits porosity. This was measured through anodic and cathodic limiting currents, and was expressed comparatively amongst distinct tubing sections of the net.

Scanning electron microscopy (SEM) was also applied to verify the uneven availability of difusional ways through the deposits and the effect of microbial biofilms in their consolidation, compactness and adherence.

Microbial analyses of the circulating water and of deposited solids allowed determining the existing flora and the risks of spreading pathogenic microbes throughout the drinking water net. Assimilable organic carbon was a complementary measurement allowing microbial assessment.

The spurious solids contained in the river water source, as well as the coagulants used during the clarification treatment, unevenly contribute to increase protectiveness against inner tubing corrosion, as was determined by using energy dispersive X ray analysis (EDAX).

Radiography and g-graphy was applied to determine the mean residual wall thickness of each section, in connection with previously existing blowholes in the tubing material and the suspected further corrosion.

This set of results, obtained from the application of techniques based on analysis of different characteristics of the materials involved, allowed us to design tailored intervention policies for the network different sections related to the installation date.

As a consequence, an improved service is being provided and a reliable and less expensive maintenance schedule was formulated, replacing the costly cleaning and painting operations applied to its homologous in London at a cost of 350 million dollars.

Session 6. South America water resources: Problems, possibilities and management

APPLICATION AND WATER USE EFFICIENCY AND THE PROFIT INDEXES FOR RICE IN MORADA NOVA IRRIGATION DISTRICT, CEARÁ - BRAZIL.

R. N. Távora Costa¹, D. Santana Colares² and R. Sonsol Gondim³

EMBRAPA Agroindustria Tropical

1. rntcosta@ufc.br; 2. dsantanacolares@yahoo.com.br; 3. rubens@cnpat.embrapa.br

The main objective of this study was to determine the water use efficiency, the economic efficiency and the profit indexes for rice (Oryza sativa, L.) in the Morada Nova Irrigation District, state of Ceará, Brazil, from July to December, 2003. EPAGRI 109 cultivar was cropped in three different soil units: sandy-loam, silt and clay loam, the last two called units I and II, respectively. Parshall flumes and siphon tubes were used to measure and apply water to the field basins. The irrigation system used was level basin irrigation. Data used for the economical analysis were obtained from costs and revenues surveyed in each plot evaluated. Irrigation period for planning for the soil and climate conditions of Morada Nova was 120 days. The water use efficiency for sandy soils presented average values of 0.2 kg.m^-3; in the case of heavy soils such value was 0.43 kg.m^-3. The water application efficiency for clay-loam soils was 66% in average, whereas for sandy-loam was 35%, considering, in both cases, irrigation without deficit. Net profit for a thousand cubic meter, using diverted and applied water methodology, showed superiority for clay-loam soils with values between R$179.00 and R$94.00, while for sandy soils the values were less than R$58.00. Profit analysis for sandy-loam and clay-loam showed feasibility for both soil units, based on conventional criteria of investment analysis, but considering in the simulation a minimum wage of R$240.00/worker, crop plan for the sandy-loam unit was not feasible, according to the obtained results: cost-benefit relation (B/C) equal to 0.98; net present value (VPL) of – 603.9 and “internal rate of return” (TIR) equal to 3.5%. For the case of clay-loam soil the indexes presented feasibility: B/C = 1.145; VPL = R$4.204.10 and TIR = 60.33%.

THE FEASIBILITY OF HYDROLOGICAL FORECASTS USING PRECIPITATION ESTIMATES OBTAINED FROM GEOSTATIONARY SATELLITES

D. F. Barrera

Departamento de Ciencias de la Atmósfera y los Océanos- Universidad de Buenos Aires / CONICET

Ciudad Universitaria, 1428 Buenos Aires. Argentina - barrera@at.fcen.uba.ar

Rainfall-runoff mathematical models of any type need rainfall areal estimates as input. Due to the existence of a lag-time, rainfall estimates can be used for prediction of hydrological variables such as runoff, soil moisture, and phreatic level by means of such models. The accuracy of areal rainfall estimates obtained from a rain gauge network was investigated and discussed by several authors, who showed that because of rainfall variability these estimates are strongly affected by errors in most cases. On the other hand, remote sensing methods provide full spatial coverage, and even when rainfall estimates at a single pixel are not precise they introduce smaller errors in area-averaged estimations over sub-basins. The techniques using data from geostationary satellites proved to be the best for estimating accumulated rainfall due to the high frequency of images than these satellites provide, which allow to account for the temporal variability of rain. Some of these proposed techniques gave promising results. They involve two steps:

1. Estimation of mean spatial rain intensity at each pixel of the analyzed image (or, in case of multi-spectral techniques, the selected set of images for different wavelength channels and the same scanning time).
2. Time integration over a specified lapse assigned to the images at current scanning time.

Regarding step 1, the “auto-estimator” (AE) technique was been run operationally by NOAA to have estimates of rain intensity from GOES IR images. It uses data of infrared outgoing radiation in the spectral channel of 10.7. Recent studies made in Argentina showed that a set of daily rainfall values estimated each one over an area of about 100 km² by using the AE technique allow to better map the precipitation field at a meso-scale region than the respective set of rain gauges values at the same locations, which implies that the first ones give a better representation of the regional phenomena and can provide better estimates of sub-basin model inputs than point observed values. Also, multi-spectral approaches (such as the GMSRA algorithm) have been developed to improve the detection of rain from warm clouds, as well as to better screen out the no raining clouds. In addition, multi-sensor techniques for quantitative estimation of stratiform rainfall have been proposed and applied with success. Regarding step 2, an increase in the frequency of images allow to reduce the integration lapse assigned to each image and to better describe the evolution of cloud systems and raining cells, which permit to better account for the time variability of precipitation. In order to increase the frequency of images, the generation of synthetic brightness temperature images interpolated between two consecutive satellite images was recently proposed and applied with GOES data in southern South America. Significant improvements in estimated precipitation at pixel locations and area-averaged rainfall depth over a mid-size basin where found when the AE technique was applied to a set of observed plus synthetic images instead of the observed ones only. In addition, the newer generations of geostationary satellites will provide higher frequency of imaging and sounding, better spectral resolution, more spectral channels and smaller pixels, which, along with more sophisticated algorithms, will conduct to better rainfall estimates. With continuously improved rainfall model inputs, the digitalization of basin limits and drainage river systems, as well as the development of digital elevation models (DEM) will allow the meteorological and hydrological services to enter in a new era of prediction on ungaged basins.

ANALYSIS OF IMPACT AND VULNERABILITY TO EL NIÑO AND LA NIÑA EVENTS IN RURAL COMMUNITIES OF CHUBUT STATE, PATAGONIA.

D. F. Vergani,¹ Z. B. Stanganelli and J. C. Labraga

1. Centro Nacional Patagónico,CENPAT-CONICET, Boulevard Alm. Brown 3500, (9120) Puerto Madryn, Chubut Argentina, Fax 54-2965-451024¡Error! No se encuentra el origen de la referencia. - atlas@cenpat.edu.ar

Large proportion of inter-annual variability in the global climate system is associated with El Niño Southern Oscillation (ENSO) phenomenon. ENSO is considered in most theoretical studies as a coupled instability in the ocean-atmosphere system triggered by the feedback between sea surface temperature (SST) anomalies, wind stress and convective activity in the tropical Pacific Ocean. The effects of ENSO on a regional ecosystem, both in the warm (El Niño) and cold (La Niña) phases, depend on how the phenomenon influences physical processes that determine ecosystem productivity.

Every climatic ecosystem impact assessment assume, explicitly or implicitly, certain underlying relationship among climatic events and ecosystem productivity. If some human community depends on this productivity, the climatic impact must be associated to a social impact too, depending on the economic strength of the community involved the magnitude of such impact.

To understand the observed behaviour within an ecosystem and the effect of regional climate variability time series analysis on biological parameters seems to be a useful tool. This synthesis provides insights supporting the design of future research and may contribute to better understand this complex process.

Patagonia ecosystem has been modified by anthropogenic influence and we do not have access to wild population with representative foraging areas to select biological parameters to assess the impact of climate variability in the ecosystem. Population of aboriginal wild mammals like guanaco (Lama guanicoe) where it would be possible to identify some useful biological parameter to study this phenomenon are actually confined to a few number of small reserves and are not representative of the whole region. Instead of that we have farms with an extensive sheep production development feeding exclusively on natural pastures without any improvement of grazing system that, if would had existed, it could had buffered the environmental impact.

Main product of sheep farmer in Patagonia is wool, according to Vidal and Barros (1982) variation in wool yield in Patagonia could be related to variation in rainfall probably the main impact of ENSO in Patagonian terrestrial ecosystem (Schneider and Gies 2004, Labraga 2002, Grimm et al 2000). As representative time series data of rainfall for the whole Chubut State are not available we analyze variation in wool yield of the Chubut State during a ten-year time series (1991-2000) as an Index of Ecosystem Productivity in relation with the presence of ENSO anomalies determining possible regions of the state and segment of producer more sensitive to this impact.

HYDROCHEMISTRY AS A DIAGNOSIS FOR A SUSTAINABLE EXPLOITATION IN THE AO. NAPOSTÁ GRANDE

C. E. Florentino and C. Ferrarello

Dpto. de Agronomía-Univ. Nac. del Sur. San Andrés 850. (8000) Bahía Blanca. Argentina. T.E. 54 –291-4595102. FAX: 54- 291-4595127. fiorenti@criba.edu.ar

Water quality changes as long as the hydric resource circulates and disperses through the different environments, due to the chemical interactions among waterflow, lithology and anthropic actions. Therefore, it is a need to develop an adequate water resource management from the regional perspective focussed in the ecosystem biotic and abiotic components.

Consequently, an assessment on the hydrochemistry of the Arroyo Napostá Grande (Buenos Aires province, Argentina) is presented. Sampling sites were selected in the maximum, middle and minimum discharge sectors, whilst samples were collected according the annual rainfall regime during two cycles (spring/summer-autumn/winter). The chemical analyses were carried out in surface and groundwater. Statistical analyses were performed on the studied variables and the results were graphically presented.

According to our results, salinity (0.6-2.8 dS/m) and trace elements contents (arsenic: 0.04-0.06 p.p.m., boron: 0.08-0.59 p.p.m., fluoride: 0.01-2.2 mg/l) increase towards the discharge being water quality restricted for agriculture and cattle production. Those levels of trace elements limit water use for sensitive crops. Low contents of dissolved oxygen (0-11.2 mg/l) and presence of nutrients (nitrates: 0-3.5 mg/l, phosphates: 0-0.03 mg/l) modify biocenosis processes in the brook. Water quality is not acceptable for human consumption. The inventory of chemical elements indicate non point sources of contamination that require fixed monitoring stations strategically allocated were toxic elements have been detected.

It is recommended to develop complementary sedimentary analyses and to inform on results to the local population to aware them about the magnitude of local contamination and to accomplish strategies to avoid or prevent degradation of the natural ecosystem.

PUBLIC POLICY ANALYSIS UPON THE FLOOD PROBLEMS IN THE BASIN OF LA PICASA LAGOON*

M. J. García Montaldo and L. P. Schejtman

Centro Estudios Sociales y Ambientales. Av. Pte. Roque Sáenz Peña 1142, 5º Piso cesam@datamarkets.com.ar

Due to the devastating effects and the ever-worsening conditions in which a disaster is generated in Argentina, this work focus on floods as an expression of social, political, economical and institutional disarticulations. Therefore, it considers that in order to manage this kind of disasters it is necessary to identify the multiple factors that might have contributed to its constitution and intervene over this process.

This work presents the advances of a research whose chosen case, the La Picasa Lagoon basin, becomes paradigmatic because it allows observing the way in which the risk conditions are generated.

The idea that guides this study is that in Argentina neither the disasters nor the risk are conceived as socially built processes. In general means, they are seen as isolated and causal events induced by nature. This short vision implies the lack of a risk hypothesis in the design of public policies, which prevents a suitable management of them.

The matter to be analysed is a consequence of the interaction between certain hazards and social vulnerabilities. The central questions examine the causes by which the floods in the La Picasa Lagoon basin turned into a social problem issue, and over the way in which it is incorporated to the State agenda through the creation of the Federal Plan of Flood Control.

The elements taken into account in this analysis are related to:

· The way in which floods had affected the production –both positively and negatively– the communication and the transport, interrupting the normal use of railroad trains and the National Road Nº 7.

· The difficulties that imply the water resources management of a basin that involves more than one jurisdiction and several governmental levels, which are related to coordination and decision-making.

· How the complexity of the problem is conceived, and as a consequence, the kind of views and biases that prevail –in a professional and institutional level, and in people’s expectations–.

· The grade of participation among population, social organizations, and the various technical and governmental offices.

· Physical, hydrological, biological and climatic characteristics of the basin.

Water management is a complex task that requires a significant role played by governmental actors, from different sectors and levels -national, regional or local- and furthermore from citizenship. Hence “the debates around water issues are discussions over the nature of society, its productive structure and the access of different social groups to the opportunities they create” (Barkin, 2001).

The reverting of a process of risk social construction requires, above all, a study that allows displaying the elements that contribute to its constitution. Ultimately, this work attempts to make a contribution to the development of the fundamental policies aimed to enforce the safeguarding of a sustainable environment in which we can be able to manage suitably our water resources.

ENVIRONMENTAL DEGRADATION AND ALLUVIUM HAZARD. PROPOSALS FOR ITS MITIGATION AND CONTROL IN THE CENTER WEST OF ARGENTINA

A. Vich¹, R. A. Ojeda², D. Cobos¹ and A. Pedrani¹

1. CONICET, Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales, Unidad Ecología y Manejo de Cuencas Hídricas CC N° 330 - 5500 Mendoza – Argentina - aijvich@lab.cricyt.edu.ar

2. CONICET, Instituto Argentino de Zonas Aridas, Grupo de Investigación en Biodiversidad CC N° 330 - 5500 Mendoza – Argentina - rojeda@lab.cricyt.edu.ar

The Gran Mendoza is placed over the piedmont of the oriental precordilleran foothills and it is the urban center of higher rank in the Argentine west center. The region is under strong pressures of anthropic origin because of the rapid growth and population expansion over the piedmont surface. This fact has generated significant changes in the dynamics of the piedmont-city ecotone, particularly in the rain-runoff relations. The manifestations are: open garbage dumps with not very precise limits, arid extraction (rubble and soil), excessive felling of woody species, non-discriminated grazing, natural and provoked fires, four-wheel vehicles, motocross, hunting, bird trapping and human settlements.

The use of new marginal lands has noticeably speeded the degrading process. Buildings increase the elimination of the vegetal cover, the decrease of natural infiltration, augments the process of runoff formation and alters the natural system to evacuate the surplus. Even though historically the damage has been important, the solution found to diminish the alluvium hazard was the design of dams for flood control, diversion works and collectors through the urban area, without actions oriented to the control of environment degradation. The mitigation of the floods effect only through works located close to the city is a very critical and imprudent situation.

In the search for alternatives to the traditional engineering conception, we are carrying out a project for the development of appropriated technologies and management of the piedmont ecosystems. The area is between the parallels 32° 55’ and 32° 58’ south latitudes and the 68° 53’ and 69° 05’ west longitude meridians, covering 800 km2 surface. The Program encloses restoration works for the reconstruction of the environment original conditions; rehabilitation for the recovering of the ecosystem functions, preservation and protection, diminishing of the flood hazard catastrophe and, maximization of benefits as per use and control. The work was oriented toward the correction of torrents, erosion control, forestation, management of habitat and wild life, design of strategies and regulations and the environmental education. With all these is expected to reduce the production of water and sediments to augment the useful life of defence works, to increase the in-situ productivity, biodiversity conservation, development of tourist and free-time sites, strengthening of educational aspects and the creation of participation mechanisms. Given the magnitude of the present problems and the size of the area, we have used the basin as planning unit. This allows for an optimization of the resources and explicitly makes it a must to acknowledge that the safety of the urbanized area and oases (lowlands) is depending on the interaction of all the activities and works that take place in the basin, given that the high and low lands are physically connected through the hydrological cycle.

The work done is of intensive and extensive character. The intensive actions have the goal to retain and retard the runoff and of reducing the erosive activity. This is feasible to be done through small hydraulic works (gabion dykes, water catchment, etc) and building terraces on slopes. Those works of extensive character aim to create conditions for bettering the habitat, for an efficient natural regulation of alluvial water and reinsurance of intensive interventions. Because of the obtained experience in carrying out the mentioned works, it has been determined that they constitute the better alternative, as they have lower unitary costs for water retention, large environmental benefits and are considerably less costly and more efficient than the traditional solutions.

TENDENCIES IN THE FLUVIAL REGIME OF THE MAIN RIVERS IN THE CUYO REGION. 1. PROVINCIA DE MENDOZA (ARGENTINA)

A. I. J. Vich1¹, P. M. López² y L. I. Villegas³

1. CONICET, Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales, Unidad Ecología y Manejo de Cuencas Hídricas - CC N° 330 - 5500 Mendoza – Argentina - aijvich@lab.cricyt.edu.ar

2. INA, Centro Regional Andino, Belgrano 210 - 5500 Mendoza – Argentina pmlopez@ina.gov.ar

3. UNCuyo, Centro de Estudios Interdisciplinarios del Ambiente y los Recursos Natura, Facultad de Filosofía y Letras - Centro Universitario, Parque Gral. San Martín,5500 Mendoza - Argentina

lauravillegas10@hotmail.com

The present climate is the product from the combination between climatic variations induced by human activities superimposed in the natural variability belonging to the climatic system. The hydrological systems are potentially sensitive to the climatic change and this is evident, not only because of the warming up of the earth’s surface and the consequent modification of the conditions for air masses circulation, but also because it brings important modifications to the magnitude and temporality of the runoff (floods and low water). These being a product of the interactions between precipitation fluctuations and temperatures recorded in the basin. There are clear evidences that climatic changes occurred during the 20^th century have already altered the water cycle in the Andean basins. The most visible change is given by the mountain glaciers, which have diminished their thickness, lost part of the their mass and have substantially receded during the last 100 years. This regression process of the glaciers has been more accelerated during the last decades.

The goal of this project is to respond to some of the many questions posed by the future climatic changes in relation with the Andean environment and particularly, in relation to the hydric availability of their basins. It is essential to detect the possible changes in the runoff regime of the cordillera rivers in the province of Mendoza. The used methodology is based on parametric (Student t) and non-parametric (Mann-Kendall) statistical tests applied to temporal series with 21 variables of the maximum-minimum monthly volume, and daily characteristic volumes derived from the permanence curve. An exploratory analysis of data is previously done (AED) that allows for synthetically characterizing the different analyzed variables., assessing some basic assumptions subjacent in the design of statistic tests (normality and independence) and to identify possible atypical data, as well as evaluating their potential impact.

Some tests had similar results for a 5% significance level. No tendency was detected in the series of: monthly volume, annual volume, maximum, minimum and characteristic volmes corresponding to the Mendoza river at Cacheuta, the Diamante river at La Jaula, and Grande river at La Gotera. The end of spring and summer volumes in the Mendoza river at Guido show increasing tendencies. In the Atuel river at La Angostura, the volumes with increase are verified every month, excepting the period between December to February. The annual volume of the Tupungato and the Mendoza rivers at Guido, the daily minimum in the Vacas and Atuel rivers at La Angostura, and the characteristic drought one in the Vacas, Tunuyán and Atuel rivers has a significantly growing tendency. The Atuel river at Puesto Sosneado is the only one station with negative tendencies in the series of volumes from February to April, annual and characteristic beyond the 90, 180, 270 and 355 days. In brief, from the 210 analyzed temporal series, changes were detected in only 40, and most of them corresponded to periods of low water.

DIFFERENT METHODS OF DETECTION OF GLACIER SURFACE

IN THE CENTRAL ANDES, ARGENTINA.

G. I. Maldonado¹, L. E. Espizua² and S. Delgado²

1. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales (IANIGLA) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Casilla de Correo 330, 5500 Mendoza, Argentina. gabyinesm@yahoo.com.ar

2. IANIGLA - CONICET. Casilla de Correo 330, 5500 Mendoza, Argentina - lespizua@lab.cricyt.edu.ar sdelgado@lab.cricyt.edu.ar

This work deals with the results from comparison of different methods for glacier mapping with remote sensing data, applied to two glaciers in several years in Mendoza Province, Argentina.

Detection of glacier changes is an important issue not only for discussions about global climate change, but also because their disappearance might have large economic and social impacts as water is the principal component in the regional economy.

Satellite remote sensing is an excellent tool for monitoring glacier fluctuations, because it gives information about areas that are very difficult to access. There are frequent images since 1975 and they offer a less expensive alternative. In this study we used four Landsat 5 satellite images for the study of two glaciers: De las Vacas Glacier, located north of Mt. Aconcagua, the highest peak in the Western Hemisphere, (from 1987 and 2004); and El Peñón Glacier in the south of Mendoza Province (from 1990 and 2004).

All satellite images were geometrically and atmospherically corrected, because the Landsat scenes were acquired on different dates and under varied atmospheric conditions.

Digital methods were used for the glacier fluctuations study and were compared with manually-derived outlines from the same satellite image. Four different ice-snow surface detections were applied: Dozier method, ratio TM4/TM5, ratio TM3/TM5 and Normalized Difference Snow Index (NDSI). The accuracy of each method is presented here. The best result was obtained with the Dozier method, with a 99 percent of accuracy.

TOPIC: EXTRAORDINARY STORMS AND RISK OF FLOODS IN PIGÜÉ CITY, BUENOS AIRES PROVINCE, ARGENTINA.

M. P. Rosell and A. S. Zinger

Universidad Nacional del Sur - 11 de abril 554 Bahia Blanca - Prosell@uns.edu.ar - Azinger@uns.edu.ar

Today, one of man’s greater concerns is water scarcity. However, water has other features –the knowledge of which still requires great research efforts- that are relevant for an adequate management of this resource from the perspective offered by the basic principles of environmental rationality, among them, attributes such as quality, abundance and distribution.

At present, the problem of floods –abundance of the resource- has an impact on an increasing number of activities and populated centers, both in Buenos Aires Province and in the rest of Argentina.

Therefore, this study is based on the following consideration: a greater knowledge of the causes and consequences of the problem under the traditional point of view, although very important, is not enough. The knowledge of data such as rainfalls during a certain period of time, shape and size of a water basin, energy of land forms and land uses, among others, does not reduce the effects of floods in the area under analysis.

Consequently, and assuming that the knowledge supplied from physical and natural sciences is essential in every decision-making process, in this case an attempt is made in order to carry out a methodological effort in integration and information transfer so as to introduce the knowledge provided by social sciences to help in the design of measures towards minimizing the impact of this phenomenon in Pigüé city.

In this sense, the analysis was performed according to the perspective provided by the Social Theory of Risk; adding concepts that are comprehensive for such analysis, for example risk and vulnerability, which involve a thread or danger, physical vulnerability (exposure), social vulnerability and uncertainty.

It is worth mentioning that the singularity of the study case lies in the fact that the phenomenon of floods is not always linked to the intensity of a humid cycle but, in many cases, to the development of local storms during dry periods.

Research results show the absence of the flood risk variable in the urban planning process. The lack of measures regarding floods leads to the extension of urban areas towards flood-vulnerable areas, thus generating an uncoordinated management of this phenomenon with regard to the city growth.

HOW OBSERVED MERIDIONAL CIRCULATION DISTRIBUTE THE WATER

VAPOR OVER SOUTHERN SOUTH AMERICA EAST ANDES:

ANALYSIS FROM RADIOSONDE DATA

A. E. Fernández and M. E. González

Sea and Atmospheric Research Center – CONICET - Department of Atmospheric and Oceanic Sciences – University of Buenos Aires - 2º piso, Pabellón 2, Ciudad Universitaria , 1428, Ciudad Autónoma de Buenos Aires, Argentina - aefernandez@fibertel.com.ar

The spatial distribution of available water vapor for precipitation depends of the evaporation and transports processes. The main goal of this paper is to characterize, spatial and temporally, the mean meridional circulations east Andes and determinate their influences on humidity distribution in southern South America, using radiosonde data.

Statistical analysis was carried out with 25 years of data from 10 stations in Argentina during 1958-1982 period. Mean zonal and meridional wind components and mean water vapor fluxes were monthly calculated for each aerological stations. The data set used in this study, is the more complete one available for the region. Intra-seasonal variation of the regional meridional circulation was analyzed by mean of meridional wind component vertical cross sections at each radiosonde location. Also monthly and seasonal meridional displacement of the convergence zone of subtropical and polar air over Argentina was studied using meridional and zonal cross sections of meridional wind components.

Over subtropical and central east region, the most important feature is the establishment of the convergence zone (with northerly circulation on lower levels and inverse meridional circulation on the upper levels) during the whole year except at the beginning of spring, when the whole subtropical troposphere is dominated by an enhanced northerly circulation. During July, northerly circulation in mean and lower troposphere, also reaches the central Argentina between 31ºS and 38ºS. Southerly circulation penetrate into Central region west of 64º W (Santa Rosa location, 36,4ºS, 64.1ºW) during fall and early winter (from March to June) extending in the whole troposphere. At the same time a weakness of the southerly circulation is observed near Andes over Mendoza (32.9ºS; 68.9ºW ) and Neuquen (38.6ºS; 67.6ºW) and an enhanced northerly branch anticyclonic circulation domain in lower levels mainly from April to July. These characteristic of meridional circulation influence meridional humidity fluxes over the region, how it was observed in the annual evolution of humidity fluxes cross sections for Mendoza and Neuquén.

In the Central region, the subtropical and polar air mass convergence zone is clearly settled over the 64º West meridian between Cordoba (31.2ºS; 64.1ºW) and Santa Rosa locations. During January and July, the meridional circulation met in the area with the northerly (southerly) branch in lower (upper) levels from ecuatorial side and the southerly (northerly) branch in lower (upper) levels from the polar side.

From May to August an intensification of the northerly circulation is clearly observed in the subtropical area over Resistencia (27.3ºS; 59ºW) (the warm branch in the front waves). Observed humidity fluxes from northwest at lower level are more intensive during winter, indicating the occurrence of fluxes from Amazonas region.

The reverse of meridional circulation (from North to South) can be appreciated in a 30º south zonal cross section located over Ezeiza (the cold branch in the front waves). This fact means that the mean position of cold fronts associated with the subpolar lows displacement, is located in the littoral area, neighborhood of Resistencia and Ezeiza (34.4ºS; 58.3ºW) locations, during the above mentioned period.

WATER RESOURCE AND ITS TREATMENT ACCORDING TO THE FRAME SET BY THE REGULATIONS CONCERNING ENVIRONMENTAL PROTECTION MINIMUM BUDGETS

M. López Alfonsín, A. N. Martínez, A. N. Iglesias and A. Rosenfeld

proiap@ciudad.com.ar - anmart@sinectis.com.ar

Article 41 of the National Constitution was introduced in the 1994. Amendment and in its third paragraph it establishes the Nation's powers to pass "the regulations concerning the protection minimum budgets", clarifying that the already mentioned laws do not alter the local or provincial jurisdictions to complete the legal rules passed by the National Congress on that subject. In this way the power distribution criterion on environmental issues within our federal state framework is stated.

It should be borne in mind that Article 121 of the National Constitution is the general principle that states National and Provincial powers. It follows that the Nation is in charge of special power since that power must be derived from an express delegation made by the provinces involved, whereas the provinces have a general power composed by all the remaining attributions, i.e. the ones not explicitly recognized as belonging to the Nation.

We should admit that determining the quantum of this new power delegation in favour of the Nation * is not an easy task. (*To be understood as the passing of the so-called "environmental minimum budget laws").

In that sense the regulation included in Article 124 of the National Constitution should also be highlighted. It states that the provinces enjoy the primary control over their natural resources. Thus, taking into consideration both Article 41- 3rd paragraph and Article 124 "in fine", the conclusion is that the delegation has been made on condition that the exercise of that delegated power does not involve the domain depletion.

This issue needs supplementing with the "Environment General Law" – Law 25675 - that states the Environmental Federal System, the objective of which is to coordinate the environmental policy at regional and local levels in order to achieve sustainable development. It is within this frame that the Water Environmental Management Regime  -included in Law 25688- must be analyzed. We understand that this regulation creates the "watershed committee" entity, without prejudice of the pre-existing ones. In that sense, the future regulation of the above mentioned law will have to include the basic aspects of those watershed committees all over the country. Despite what has been mentioned above, the constituency of the new specific watershed committees corresponds to all the intervening jurisdictions, namely the Nation, the Provinces and/or the Autonomous City of Buenos Aires. To reach that aim we suggest applying the legal figure of the inter-province treaty - Article 124 of the National Constitution-, and, at the same time, we consider it a good opportunity to include community representatives and citizen participation mechanisms in these bodies so as to meet the general principles of the environmental law.

DIFFICULTIES AND POSSIBILITIES OF THE MANAGEMENT OF THE HYDRIC RESOURCES IN THE VALLEYS OF TULUM AND ULLUM-ZONDA (SAN JUAN, ARGENTINA)

M. C. González Martín

Departamento de Geografía – Instituto de Geografía Aplicada (F.F.H.A. – U.N.S.J.) Centenario 794 (Oeste)- C.P.5413 Chimbas-San Juan-Argentina - mcleogm@uolsinectis.com.ar

The basin of San Juan river, developed between -30° 15’ and -32° 30’ of latitude and -67° 18’ and -70° 25’ of longitude, is the most abundant of the Desaguadero System. By the amount and quality of the hydric resource and its resulting space organization the greater number of the socioeconómic activities of the provincial space is the one of greater relevance when containing.

It is characterized by being of the dendrítica type, irregular regime with alternations of times of swelling and low water, in summer and winter, due to his glacio-nival feeding, with a 66 module of m3/s. Their hydric resources are taken advantage of in their superior and inferior river basin, giving origin to oasis of crops of diverse magnitude.

The inferior course is located when leaving the Precordillera atmosphere and to go into in the tectonic valleys Ullum-Zonda and Tulum until the Bermejo-Desaguadero river, presents unification of takings through diverse docks that allow the use of the hydric resource for diverse uses: irrigation, population and industrial provision, generation of energy and recreation.

This work must as objective individualize the difficulties and possibilities of management of the superficial and subsuperficial hydric resources in valleys of Tulum and Ullum-Zonda.

The methodologic aspects were centered in the processing of auxiliary materials of bibliographical, cartographic, photographic and satellite type that allowed to make diachronic analysis of the advantage of both valleys, with the consideration of the operation of the systems natural, modified and urban, and their verification in field.

Both oases of irrigated land are consequence direct of the natural conditions of the site, of the soil availability, the superficial and underground hydric advantage, and of the actions and infrastructures of services that have organized it, in special throughout century XX.

The control of the contamination of the hydric resource by the responsible institutions is very little. There are natural and artificial channels contaminated by industrial and sewage spills, that deteriorate, in tuin, the quality of underground waters. This worsens by the shortage of sewage network of Great San Juan, located this in the average and apical zone of the alluvial fan of the San Juan river; it forms this of great permeability and easy contamination. This situation still more worsens by the presence of numerous cemeteries covered with grass with minimal burying measures and clandestine waste baskets located in the channels of piedemontes.

The demand of the water increased notoriously, in the last decade of the century 20 ^th, with the new economic enterprises of outstanding space magnitude with pressurized irrigation (dripping, microsprinkling, of pivot) that have contributed to the degree of density of the zones of existing crops, renewing others and to expand them towards before non propitious zones. Some of these systems of irrigation enter conflict with the Water Code reason why uses are considered clandestine.

All this leads, to serious disadvantages in the handling and management of the hydric resources of the province, due to the changes produced in the quality and amount of water altering the aquatic ecosystems of the area and disturbing the future demands and their rational handling.

MONTHLY RAINFALL IN BUENOS AIRES CITY (1861-2000) ANALYSED BY THE GAMMA DISTRIBUTION FUNCTION

L. Serio¹ and P. Martin²

1. Cátedra de Climatología y Fenología Agrícolas, Facultad de Agronomía, UBA Av. San Martín 4453, (1417) Buenos Aires, Argentina - serio@agro.uba.ar

2. CONICET / Depto. de Ciencias de la Atmósfera y los Océanos, FCEyN, UBA

The historical monthly rainfall record (1861-2000) of Buenos Aires City, Argentina, was analysed by fitting the gamma distribution function. The whole record was shifted in 30-years periods, overlapped each 10 years. The shape and scale parameters of gamma function were fitted to the observed monthly frequency distributions. We found a good agreement between theoretical and empirical distribution functions, as confirmed the non-parametric Kolmogorov-Smirnov test. In order to identify possible changes in precipitation regime, a trend analysis (Mann-Kendall test) was applied to the median (50-percentile) of monthly theoretical distribution. We found significant positive trends in summer months (4.1 mm/decade in January and 5.8 in February) and spring months (2.8 mm/decade in October and 2.5 in November). The probability of extremely high monthly precipitation has increased too, as result of trend analysis applied to the 90-percentiles of gamma distributions. Its maximum increment has occurred to a mean reason of 7.8 mm/decade in January, although significant increments were found in other months during the warm season. In addition to these changes in median and extreme monthly rainfall, we observed an increment in their interannual variability.

LEVEL BASIN IRRIGATED RICE WATER USE EFFICIENCY IN A SANDY-LOAM SOIL, MORADA NOVA IRRIGATION DISTRICT, CEARÁ - BRAZIL.

R. Sonsol Gondim¹, R. N. Távora Costa² and D. Santana Colares³

EMBRAPA Agroindustria Tropical

1. rubens@cnpat.embrapa.br; 2. rntcosta@ufc.br; 3. dsantanacolares@yahoo.com.br

Morada Nova Irrigation District, state of Ceará, Brazil has an irrigatable area of 3.737 ha, and only 28% of it is low infiltration level type soil units (clay and clay loam). The total area of rice crop in the region is greater than the suitable soil type available for level basin irrigated rice, in order to have an acceptable water use efficiency. The main objective of this study was to determine the water use efficiency, for level basin rice irrigation (Oryza sativa, L.) in a sandy-loam soil unit at the Morada Nova Irrigation District, state of Ceará, Brazil, from July to December, 2003. EPAGRI 109 rice cultivar was cropped. Parshall flumes and siphon tubes were used to measure and apply water to the field basins. Twelve irrigation procedures were done during the grown crop cycle. The crop water needs was estimated by Penmman-Monteith (FAO) ETo and crop coefficient adapted from Doorembos & Kassan (1979) for each crop development stages I (1.10), II (1.15), III (1.20) e IV (1.,00). The crop water needs, in the period, ranged from 39.6 mm to 93.7 mm each irrigation in a crop cycle of 121 days (average of 10.1 days between irrigation intervals). The irrigated bulk water ranged from 82.9 mm to 264.8 mm and the irrigation water application efficiency for the sandy-loam soil unit was no greater than 59%, considering, irrigation without deficit, resulting water losses up to 80% of the whole water volume.

LEVEL BASIN IRRIGATED RICE WATER USE EFFICIENCY IN A CLAY-LOAM SOIL, MORADA NOVA IRRIGATION DISTRICT, CEARÁ - BRAZIL.

D. Santana Colares¹, R. N. Távora Costa² and R. Sonsol Gondim³

EMBRAPA Agroindustria Tropical

1. dsantanacolares@yahoo.com.br; 2. rntcosta@ufc.br; 3. rubens@cnpat.embrapa.br

Morada Nova Irrigation District, state of Ceará, Brazil has an irrigatable area of 3.737 ha, and only 28% of it is low infiltration level type soil units (clay and clay loam). The main objective of this study was to determine the water use efficiency, for level basin rice irrigation (Oryza sativa, L.) in two clay-loam soil units at the Morada Nova Irrigation District, state of Ceará, Brazil, from July to December, 2003. EPAGRI 109 cultivar was cropped in two fields. Parshall flumes and siphon tubes were used to measure and apply water to the field basins. Ten and fourteen irrigation procedures were done during the grown crop cycle in each field. The crop water needs was estimated by Penmman-Monteith (FAO) ETo and crop coefficients adapted from Doorembos & Kassan (1979) for different crop development stages I (1.10), II (1.15), III (1.20) e IV (1.00). The crop water needs, in the period, ranged from 46.4 mm to 153.6 mm and the crop cycle lasted 125 and 127 days (average of 12.5 and 8.7 days between irrigation intervals for each field). The irrigated bulk water applied ranged from 68.8 mm to 249.7 mm. The average of the water application efficiency for clay-loam soil unit was around 77%, considering, irrigation without deficit. In the lowest efficient event resulted on water losses of less than 40% of the whole water volume applied.

STATE OF WATER RESOURCES AND THE INSTRUMENTS OF THEIR ENVIRONMENTAL MANAGEMENT IN MONTEVIDEO

C. Anido

Faculty of Engineering - J.H. y Reissig 565, Montevideo, Uruguay, canido@fing.edu.uy, http://www.fing.edu.uy,

Synthesis

The administrative division of coastal capital city Montevideo, Uruguay (34º 50´ S – 56º 0´W) west) has about 560 km², 60% rural, a good streams network, with some groundwaters exploited for rural and industrial uses.

The political frames shows advances lately, establishing new democracy models and assigning budget to environment and city equipment. The burocracy and conceptual tools in use are not following enough the trend. New organizational administrative structures respond to negative impacts from 90’ neoliberal model's application. General sustainability actions improves (Agenda 21, -www.gam.org.uy-, Land management of uses plan, citizens’ monitoring of Natural resources, -www.monitoreoambiental.org.uy-) but strong pressures came nevertheless from social exclusion generated with people that lives off the garbage in irregular dwellings; this, together with urban and Metropolitan expansion, port, coastal and transport routes, urban flow and sanitary water not enough treated disposed with an underwater pipe, and non reducing-recycling consumers culture, are resting and future problems.

Building of a New project local, national and global of fair and democratic cities need to be continued, to prepare a different Sustainable Civilization model.

Objectives

To analyze state of water resources and which tools of environmental administration are used for the pressures, impacts and city sustainability on rivers, coast and groundwater.

To identify the main causes of pressure, tools associated to achievements, lacking tools and attitudes unappropiated for positives effects on quality and sustainability

Methodology

To revise the state in urban and rural Montevideo looking to social, economic, ecological and political aspects of processes and natural and constructed environment, overlooks the technical and political tools established, alike the technical and political instruments not used

To analyze the net of relationships, previous history and actual commitments between all aspects

Results

The pluvial and sanitary city waters are poured in the Plate estuary, which incoming flow carries also the diluted waste water from cities and activities in all the amont basin. The local state of the waters bodies are affected by a 100 year-old up-and-downs process of urban and industrial growing and pouring as well as waste dumping without technical and sustainability concepts. Streams are born in rural area and go through city. Two rivers with wetlands limit the zone east and west, suffering severe urban pressure

Much of loss of quality problems come from administrative boundaries dividing water basins between departments (like provinces but with less autonomy).

The urban expansion presses the rural area. The city has a center in the port and inhabitants density diminishes in circular mode toward rural countryside

Economics of the 1990 diminish industry and associated waste waters momentarily. After 2002 crisis and devaluation enterprises grow again with potential to increase pollution loads being poured. The main concern now to water quality is social inequality effects created by the phenomena of impoverishment followed by exclusion associated to the dominating model of free market, making garbage collecting a way of life in shantytowns.

CAPTURE AND STORAGE OF PLUVIAL WATER: AN ALTERNATIVE PRACTICE FOR ARID-SEMIARID ZONE OF LA PAMPA PROVINCE (ARGENTINA)

A. M. Umazano¹ and E. O. Adema²

1. CONICET-Facultad de Ciencias Exactas y Naturales (UNLPam), Avda. Uruguay 151, 6300 Santa Rosa, La Pampa (Argentina) - amumazano@yahoo.com.ar

2. INTA EEA Anguil “Ing. Agr. Guillermo Covas”, CC 11, 6326 Anguil, La Pampa (Argentina) eadema@anguil.inta.gov.ar

La Pampa is a mediterranean province localized between 35º S to 39º 20’ S and 63º 23’ W to 68º 17’ W. Water availability in west and south La Pampa strongly limits range production. Alternative strategies for a rational water survey and management are needed due to the arid-semiarid climate and scarcity of underground and surface aqueous resources of acceptable quality and amount. A possible solution for the problem is the harvest and storage of pluvial or meteoric water in dirt-tanks. The purpose of this project was to evaluate the potential to capture and storage of pluvial water (aptitude), as well as to asses the necessity of this alternative practice. The study was carried out in different geomorphic regions from west and south La Pampa with an annual mean precipitation bellow 500 mm. Isohyetal lines map was actualized until 2000 year, considering the pluviometric records of 36 localities with series longer than 20 years. This map established the northeast limit of study zone. Seven geomorphic regions were mapped using topographic, geologic and geomorphologic charts (Scale 1:100.000 to 1:250.000) considering direction and magnitude of slopes, absolute and relative altitudes and hydrography. Climatic (B1: annual mean precipitation), geomorphic (B2: topographic mean gradient, B3: soil permeability, B4: drainage, B5: surface material, B6: caudal of lotic waters and B7: salinity of lotic waters) and hydrogeologic (B8: caudal of aquifers and B9: salinity of aquifers) factors were used to classify the regions. In decreasing order of aptitude and necessity of capture and storage of pluvial water, the factors were qualified from 5 to 1. Using a matrix (rows: geomorphic regions, columns: factors), both aptitude and necessity were evaluated. For each region, arithmetic mean () summarizes the possibilities of capture and storage of pluvial water and scarcity of conventional water resources. These means, called mean conditions, were classified as follow: very good (> of 4), good (4 to 3), fair (3 to 2) and bad (2 to 1). B1 values were taken from isohyetal lines map, B2 values were calculated from topographic charts, B3 and B4 values were defined from test-pits, B5 values were taken from geological charts, and B6 to B9 values were calculated from data of various authors. Finally, these regions were classified in decreasing order of aptitude and necessity of capture and storage of pluvial water, as follow: I) Lihuel Calel peneplain (good), II) modern floodplain (fair), III) sandy plain (fair), IV) mesas and depressions (fair), V) Colorado river fossil alluvial fan (fair), VI) Chical-Có plain (fair) and VII) basaltic plain (bad). This work found help for future research toward productivity increase for the zone with small environmental effect, intended a sustainable development.

USING SIMGRO MODEL FOR THE ANALYSIS OF WATER USE IN THE MENDOZA IRRIGATED AREA

J.A. Morábito¹, E.P. Querner² and D. Tozzi¹

1. INA & UNCuyo, Belgrano Oeste 210, 5500, Mendoza, Argentina - jmorabito@lanet.com.ar

2. Alterra, P.O. Box 47, 6700 AA Wageningen, The Netherlands

The Province of Mendoza has more than twenty percent of the total irrigated land in Argentina. As the average annual rainfall is approximately 200 mm, irrigation is critical for agriculture. A storage dam was recently constructed in the Mendoza River to control the fluctuating inflow and to guarantee meeting water demand through the year. The dam will have an impact on the hydrology. The groundwater system will be also influenced and this, in turn, could have a crucial effect on parts of the irrigation area where groundwater levels are already high and salinization occurs. For the evaluation of these changes and possible mitigation measures, there is a need for performance indicators at a river basin scale that take into consideration groundwater and surface water use efficiency. The SIMGRO model was used for the assessment as it simulates water flow in the saturated zone, in the unsaturated zones and in surface water in an integrated manner. The objective was to use the SIMGRO model as a tool to evaluate the effect of hydrological changes in the irrigated area due to the construction of the storage dam. Scenarios are presented on estimated irrigation water losses and on their effect on agricultural production, by using a set of performance indicators for surface and groundwater.

ENVIRONMENTAL CONFLICTS IN IRRIGATED AREAS: IMPACT ASSESMENT IN THE TUNUYÁN RIVER BASIN, MENDOZA, ARGENTINA,

J. Chambouleyron, S. Salatino, A. Drovandi, R. Medina, M. Zimmermann, M. Marre, R. Bustos, E. Antoniolli, M. Filippini, N. Nacif, S. Campos, C. Dediol, A. Camargo, and D. Genovese

Instituto Nacional del Agua – Universidad Nacional de Cuyo Belgrano 210 Oeste (5500) Mendoza, Argentina –Telefax: (54) (261) 4286993 cra_riego@lanet.com.ar

With an average flow of 30 m³/s, the Tunuyán River has contributed to the development of the central oasis in the Province of Mendoza, Argentina. It is divided into lower and upper sub-basins --54,000 and 81,000 ha respectively ^[1] with registered irrigation rights. In the early 1990s, there was a boom in agricultural development in the command area of the Upper Tunuyán River. Important investments in the planting of quality grapevines for winemaking brought about a rapid growth of the cultivated area with considerable use of groundwater due to the requirements of pressurized irrigation systems. As groundwater withdrawal intensifies, the flows of the brooks and streams leaving the upper area will diminish and salinity will rise affecting the water quality of the Lower Tunuyán River and, consequently, crop yields in one of the most important agricultural areas of the province.

The objective of this paper is to assess the environmental impact of current and potential development in the upper sub-basin on the lower sub-basin of the Tunuyán River. The scenario considered envisages an expansion by 20,000 ha of the area cultivated with quality grapevines and irrigated solely with groundwater. This will lower the water table, deplete brooks and streams –which are tributaries to the river downstream from the Valle de Uco diversion canal– and transform them into drainage collectors, with the ensuing degradation of the quality of the water used to irrigate crops such as peach trees and vineyards (“sensitive” and “moderately sensitive” to salinity). Reduced irrigation water supply in the lower oasis and increased water salinity levels will lead to soil salinization and crop yield drops.

A transdisciplinary research group studied the physical-natural and socio-economic-cultural environments: physical characteristics of the area, calculation of the salt-water balance, irrigation water pollution, socio-economic description of the area, administrative and management aspects, economic aspects, and characterization of production models. Water quality samples were taken regularly at four inlets to the upper area and at four outlets upstream from the dam where irrigation water flows into the lower basin. In order to collect information on the socio-economic-cultural environment, the cultivated area of the upper sub-basin was surveyed. Data was obtained on the conditions and profitability of agribusiness in the area, farmers’ profiling, social aspects, and on irrigation water management. With a view to quantifying environmental impacts, they were identified, linked and qualitatively valued by means of an “importance matrix”.

Results showed that a potential increase of 20,000 ha of vineyard in the upper basin would lead to a salt content increase in irrigation water (currently at 1130 mScm-1) to some 1420 mScm-1. This would diminish the available water supply (200 Hm3), which may suffice to meet the requirements of only one third of the registered area, and would substantially reduce crop yields (grapes and peaches) between 12 and 22%. Unless adequate measures are taken, the current 4500 ha of peach orchards would be lost and grape yields would drop. Estimates show that annual losses may reach some $20 million ($1 = U$S 1) and that the available water supply would suffice to meet the demands of only one third of the registered area.

It is recommended that water management be consolidated at the basin level; that water be distributed in a proportional and equitable manner on the basis of quality and salt content –as is the case of Colorado River (Mendoza) and that groundwater be integrated into water management, with users’ organizations assuming responsibility for water management and pollution control (decentralized administration).

For a modern, sustainable and integrated surface and groundwater management, with no disruption of the basin’s ecosystem balance, it is further recommended that the structural and non-structural factors of the complex mechanism of variables interrelation be taken into account. Users’ organizations should also be involved in the process, attain economies of scale and become financially self-sufficient.

THE WATERS OF THE LUJAN RIVER –LUJÁN - PROVINCE BUENOS AIRES

M. Vasconi

Centro de Investigación y Capacitación Empresaria - Agüero 2232 Piso 3 Dpto A movasco2002@yahoo.com.ar

In the religious, historical and recreational space of the Lujan river, its waters observe the different grades of value, ranks, grades of quality and types of contamination according to days and hours in relation to the trilogy of its generation: the local population, the local and external business and the religious excursionists.

5.000.000 of pilgrims a year come to Lujan, but none can swim in the river. Some people throw liquid and solid residues. The bed of the river shows during the descend of the waters: sailor ropes, glass bottles, plastic objects, cans of beer or soda, batteries... In addition to this plastic residues very difficult to degrade are plentiful in the banks and the concessionaires of the recreation places produce the reduction of the bed with speculative purposes. The limit of the threshold of the charge is widely surpassed.

The local inhabitants who live upstream also throw the organic and chemical liquid. There aren’t plants for your treatment in the citys and villages of the superior valley of the river.

The external and industrial investment contaminates with some toxic residues, and including it inject them into the subterranean watercourses.

There is inadequate use of the resources that play as the support of the activity, therefore the river and your environment generate: “the senses of the forgotten places”, “the senses of the contaminated places” and “the senses of the reject places” in the actuel stage.

The mitigation of these impacts would contribute in the territorial ordaining and the supported development.

SOIL WATER STORAGE IN PAMPEAN FLATLANDS (ARGENTINA) WITH SPECIALL ANALISYS TO SAN PEDRO AREA

O. E. Scarpati^1,2, J. Forte Lay¹ and A. Capriolo¹

1. National Council of Scientific and Technical Research

2. Geography Department, Humanities and Education Sciences Faculty, La Plata National University

Av. Rivadavia 5485 (1424) Buenos Aires, Argentinae - olgascarpati@yahoo.com.ar

In the present paper, values of daily soil water storages were calculated for the period 1965-2004 by soil water balance according to Thornthwaite method using the daily precipitation and daily normal potential evapotranspiration calculated by Penman´s formula. ENSO events were separated according to El Niño or warm phase and La Niña or cold phase, with the remaining cases being Neutral condition.

The paper allows a geographic visualisation of ENSO influence over summer soil water storage and autumn soil water surplus.

The scheme used for determining different ENSO phases followed the Wolter classification by employing terciles of the ranked MEI values. So during the period 1961 – 2004 there are 16 cases of El Niño, 14 cases of La Niña and the rest are Neutral.

It can be said that El Niño years contribute with higher soil water storage than La Niña years.

The area involving San Pedro (Buenos Aires province) presents a mean autumn soil water surplus of 75mm which changes to 125 – 150mm for warm phases and to 50mm in cold phases.

FLOOD RISK IN THE GRAN LA PLATA, (BUENOS AIRES PROVINCE, ARGENTINA) CONSIDERING THE AVAILABLE INFORMATION AND MANAGEMENT OF THE AREA

M. I. Andrade^{1, 2} and O. E. Scarpati ^{2, 3}

1. Depto. de Geografía. Fac. de Filosofía y Letras, UBA

2. Depto. de Geografía. Fac. de Humanidades y Ciencias de la Educación UNLP

3. CONICET

The present paper presents the causes of occurrence of flood in the Gran La Plata, (Buenos Aires province, Argentina).

The studied area has 1,160 km² and 640,000 habitants and includes the districts of Berisso (135 km²), Ensenada (101 km²) and La Plata (924 km²).

The characteristics of use and management of the water resources is deficient because there are

- lack of actualized information about the risk of flood,

- lack of urban building organization and

- the total physical features of the studied are not taken into account.

All the difficulties founded during the realization of the present study are presented, and too, the ways which some of them have been solved.

All the information used is evaluated with the objective to obtain a model inside the Social Theory Risk.

The use of a Geographic Information System and satellite images is discussed to evaluate the factors affecting the area and producing inundations.

A map of flood occurrence is obtained and so a map with the areas more vulnerable of the Gran La Plata.

The authors propose to analyse the map of flood risk from the point of view of the human social vulnerability.

THE ROLE OF ATMOSPHERIC WATER VAPOR FLUX ON MONTHLY PRECIPITATION EXTREMES OVER THE LITORAL REGION OF ARGENTINA

W. Reimers¹, G. Almeira² and B.Scian¹

1. Dpto. de Agronomía, UNS. - wreimers@criba.edu.ar

2. Instituto Nacional del Agua, Argentina

In this paper it is analysed the relationship among anomalies in the water vapor flux and extreme monthly rainfall computed with reference to the stream flow of several sections of the main Litoral Region rivers, Uruguay and Paraná. A quantification of the terms in the atmospheric water balance equation is performed for a Box centred in the study region. It covers the Argentine basin portion of the La Plata basin and it is enclosed between 20-35º South and 52-60º West. Series of monthly precipitation anomalies, in the form of Standardized Precipitation Index (SPI) at 3 month time scale, from 1960 to 2000 posses a good correlation with stream flow differences of both rivers (Almeira, 2005) and they are employed to select extreme hydrologic conditions (monthly rainfall deficits and excess). The integrated (from surface to 300hPa) water vapor flux is computed based on NCEP-NOAA database. Composite maps of anomalous fluxes are analyzed under two conditions: neutral and ENSO months. In agreement with previous results for the Pampa region, composite maps for the Litoral Region presents an anomalous meridional flux component from the South when rainfall deficit months are considered, while the opposite occurs with rainfall excess: anomalous flux shows a strong North-South component. A box over the Region helps to calculate the mean vapor flux anomalies through the respective walls and the contribution of each term of the water balance equation to the atmospheric water flux under two different atmospheric conditions.

ASSESSMENT OF WATER AVAILABILITY EN CLOSED BASINS OF SEMIDESERTIC ENVIRONMENTS IN PATAGONIA

E. Mazzoni, M. Vazquez, D. Grima and F. Cola

Universidad Nacional de la Patagonia Austral - Fundación Ecopasur - gis@uarg.unpa.edu.ar

In the extensive area of Patagonian plateau, which lies east of the Patagonian Andes, between 37 and 52º south latitude, there’s a large number of depressions on the ground called “bajos sin salida”. They are the most important source of water, apart from the few aloctons rivers that cross the area.

This landforms are closed basins towards which precipitations (snow and rain) drain off. The characteristics of this area are dry and windy weather, heterogeneous distribution of surface sather and low vegetation cover. The ponds that fill these depressions are temporary and show big level fluctuations. They may dry completely and show salt concentrations in their base in year or cycles of low precipitations.

This research work evaluates the changes registered in surface water availability in depression the southern part of Santa Cruz, Argentina, in order to provide information that would allow to plan the use of this resource. The years 1986, 1999, 2002 and 2004 were taken into account, in which the rain has been very changing, fluctuating between 160 and 416 mm per year.

The methodology used is based in the visual analysis and digital processing of satellite images and their integration in a G.I.S. The area studied is 15.000 km², included in the Landsat image 228-96. It lies between parallels 50º50’ and 52º south, and the Atlantic coast on the East and meridian 70º40’ on the West. Within these limits 106 depressions, whit a diameter bigger than or equal to 1 km were identified.

Water availability in these basins showed important changes in the analysed periods, corresponding with the differences in rain measurements registered in the area (weather station Río Gallegos).

The amount of water available in all the depressions together varied between 12.000 and 30.000 hectares, with important depth variations. This parameter was inferred from the spectral behaviour of the ponds, although it must be said that the sediment in the water may modify ther spectral signature.

The quality of the water resource has started to be evaluated, having up to this date, data that show great heterogeneity.

The results obtained up to now show the importance of closed basins as water gatherers in the semiarid region of Patagonia, as they temporarily store precipitations, avoiding in this way the quick surface runoff.

ESTIMATING SOIL HYDROLOGICAL PARAMETERS IN A RURAL BASIN OF NORTHWEST BUENOS AIRES, ARGENTINA

WITH PEDOTRANSFER FUNCTIONS

R.A. Díaz¹, M.M. Puricelli¹ and R.E. Godagnone²

1. Instituto de Clima y Agua, Centro Nacional de Recursos Naturales, I.N.T.A., Las Cabañas y Los Reseros s/n, 1712 Hurlingham, Bs. As., Argentina. rdiaz@cnia.inta.gov.ar; mpuricelli@cnia.inta.gov.ar

2. Instituto de Suelos, Centro Nacional de Recursos Naturales, I.N.T.A., Las Cabañas y Los Reseros s/n, 1712 Hurlingham, Bs. As., Argentina. rgodagno@cirn.inta.gov.ar

Assessing the water dynamics of a rural watershed demands the knowledge of key hydrological parameters of arable lands. Both the characterization of sustainable water use and the application of models to better understand the hydrological functioning in rural areas are but two areas where the information is needed. Soil classification and mapping of Argentina made by the National Institute for Agriculture and Livestock Technology (INTA) yielded a national database with the physical and chemical properties of hundreds of soil profiles. However soil hydrological parameters are not available. Since 2004 INTA, the National Institute of Water (INA) and Alterra Inc., The Netherlands, joined strengths to survey surface and groundwater levels in a rural area of about 250.000 ha near Pehuajó, Buenos Aires, Argentina. The area is subject to frequent flooding episodes, and soil water storage capacity partially controls the rate of groundwater raise. One of the main objectives of this research is the simulation of the water budget of different land uses, for which purpose data on soil field capacity and wilting point are required. It is the aim of the study to estimate the mentioned parameters taking advantage of recent progress in low cost and quick methods from commonly available soil data. A recent release of SOILPAR program provides a simple tool to compare most of well known pedotransfer functions. This software uses as input soil variables available in the SOTER database (Global and National Soil and Terrain Digital Database) of the Soils Institute of INTA such as depth, texture and organic matter content of layered profile as well as unavailable bulk density. SOTER database evolved from a UNEP (United Nations Environmental Program) project on gathering soil and terrain information worldwide at 1:1M scale. Our strategy is based upon measurements of hydrological parameters and unavailable soil bulk density in the most widespread mapping units of the basin coupled to properties in SOTER database. A comparison of measured and estimated parameters will enable an objective selection of the function of best fit. Thereafter estimates will be extended to the remaining soil units. As a result the representation of the spatial coverage of hydrological parameters for the Pehuajó basin will be provided.

APPLICATION OF SATELLITE MONITORING AND GEOGRAPHIC INFORMATION SYSTEM FOR A WATER-EXCESS WARNING SYSTEM FOR THE RURAL AREA IN THE NORTH-WEST OF BUENOS AIRES PROVINCE

B. Matossian¹, G. M. Barría ², D. Goniadzki ³ and R. Díaz⁴

1. Becaria del proyecto PICTO 07:12932 Sistema de alerta de excesos hídricos para el sector rural del noroeste de la Provincia de Buenos Aires. bmatossian@yahoo.com.ar. 2. Becario del Sistema de Información y Alerta Hidrológico del Instituto Nacional del Agua. gbarria@ina.gov.ar. 3. Directora del Sistema de Información y Alerta Hidrológico del Instituto Nacional del Agua. dgonia@ina.gov.ar. 4. Director del proyecto PICTO 07:12932 “Sistema de alerta de excesos hídricos para el sector rural del noroeste de la Provincia de Buenos Aires”. Instituto de Clima y Agua, Centro Nacional de Investigaciones Agropecuarias, Instituto de Nacional de Tecnología Agropecuaria. rdiaz@cnia.inta.gov.ar

The agricultural activity in the center of the Pampeana region, Argentina’s main productive area, is currently threatened by the risk and uncertainty associated to flood, drowning and drought events. The presence of shifts, hemicycles or climate phases has a substantive influence on both the regional productive capacity and its economic and environmental sustainability. Different scientific and technological researchers and institutions focus on this problem; one of these efforts is the project “North-west Buenos Aires water-excess warning system”. This project aims at integrating different disciplines related to this topic, through the interdisciplinary work of researchers from the participant institutions (INTA/INA). Within the frame of this project, the National Water Institute (INA) Hydrologic Information and Warning System has developed a satellite monitoring tool for assessing the regional hydrological condition and a Geographic Information System integrating the spatial information of interest.

The objective of this paper is to describe the methodology and the resulting products within the mentioned two activities. The monitoring has been made with satellite information from remote sensor, in this case, the TM sensor from Landsat 5, and its aim is to study the swamping and superficial water amount and spatial distribution.

The purpose is to exert a permanent hydrological control of the area under study. This monitoring is also useful to analyze the hydrological dynamics. This study is based on satellite-image analysis, which contributes to a better understanding of the soil response to observed meteorological extreme events.

In this paper the results of a superficial-water change-detection study from the southern-hemisphere winter of 2004 are presented. The use of a Geographic Information System (GIS) allows the integration of data obtained from different sources as vector layers, fieldwork and satellite. The GIS also allows the utilization of spatial-analysis functions makes product elaboration simpler and supports other activities as hydrological modelling. This project has made a good progress in the production and analysis of geographical and spatial information required for the implementation of the hydrological excess or deficit warning system.

FLOODING WARNING SYSTEM TO THE RURAL SECTOR OF WESTERN BUENOS AIRES PROVINCE

J. C. Gramicci¹ and M. M. Puricelli²

1. INTA Agencia de Extensión Rural Pehuajó, Pehuajó, Buenos Aires, Argentina, inta@speedy.com.ar

2. INTA Instituto de Clima y Agua, Las Cabañas y Los Reseros, 1712 Hurlingham, Buenos Aires, Argentina, mpuricelli@cnia.inta.gov.ar

Argentina is much impacted by flood events. Economic losses exceed 1% of national GNP. The rural sector is one of the most affected. After the excess water in 2000-2001, as a result of large spring precipitation totals, direct losses of 600 million US$ were reported to which another 300 million were added because of damages to infrastructure and related industry. Four INTA (National Institute for Agriculture and Livestock Technology) Experiment stations from north central Buenos Aires Province joined forces in a Project “Pampa Húmeda” to have farmers informed during the mentioned flooding. Road conditions, field management recommendations according to moisture condition and weekly reports on rainfall amounts and groundwater levels from 152 sites were among the information disseminated across the area. Since 2004 the Water National Institute (INA) and INTA cooperates in monitoring the surface and subsurface waters in a region nearby Pehuajó, chosen because: 1) is representative of a larger closed watershed; 2) has a long term measured weather record; 3) artificial drains such as Mercante channel are present; 4) a recorded historical field management farm from the center of the study area is available. This 24.000 km² area is further subdivided into more manageable units. First a 3.200 km² area was identified from available information, which allowed identification of hydrological units. Because the flat relief of the region and the large variability in flooded areas in different events, an accurate split of basin subdivisions is highly uncertain. Therefore remote sensing information was used to improve these boundaries. A Landsat image at the end of the anomalous 2002 rainy season was used. A recent field survey confirmed that the initial assessment of hydrological units was proper. At present a third more detailed analysis is being carried out at a 97 km² zone where daily rainfall and weekly ground water are measured. Here, in the “El Tostado” farm phreatic levels are measured at eight sites representative of the landscape variation. The elevation above sea level and situation for each of these sites were determined. This activity yielded 1100 points with known altitude and position, which will be used to compare with STRM sensor estimates. The activity performed by the Rural Extension Agency of INTA at Pehuajó should increase by the addition of weather measurements from an automatic weather station and recording of groundwater levels in one of the sites at “El Tostado”. As a result continuous monitoring of field conditions representing both the boundary and the core of the basin will be achieved aiming at further advancing the knowledge upon the dynamics of regional water by coupling field measurements to detailed remote sensing information.

Assessment of Desertification in Semiarid Intermountain Valleys with Radar and TM images

S. M. Navone, M. Bargiela, R. Introcaso, A. Maggi and D. Laureda

CIAT-Facultad Agronomía Universidad Buenos Aires. Av. San Martín 4453, Buenos Aires, Argentina Tel.(5411)-4524-8092 - Fax: . (5411)-4524-8737 - navone@mail.agro.uba.ar

There was 75 % of arid and semiarid lands in the Argentine Republic. Desertification/ land degradation increases, according to the government 650000 hectares per year. (PNUMA, 1996). The region of the Arid Valleys of the Argentine Northwest has an approximate area of 14,000,000 ha. The Santa María Valley, in Catamarca, Tucumán and Salta provinces is within this system. Rational water use is very important in this basin because agriculture is concentrated in irrigated oases. They produce the best pepper and aromatic species of the country and grapes for wine.

A management plan for this valley should be made on the basis of a proper description and diagnosis of the different levels of desertification present in the basin. The use of preventive measures is very important in the areas not yet affected by degradation processes or showing a minimum degree. The objective of this research was to find an enhancement to discriminate the earlier stages of desertification through radar and Landsat Thematic Mapper images in this valley

A diagnosis of the desertification degree was done in the field through observations and transects aplying FAO (1984) methodology.

We tried on the following methods of combining radar with VIS/IR imagery: RGB to IHS transforms, Principal components transform and Multiplicative

A visual analysis has been done to determine the accuracy level. For that purpose the desertification map done in the field has been overlapped with the enhanced images

Besides, we originated a scale (value) in order to determine the coincidence level.

The image generated aplying Principal Components in an image with 3 bands: radar, near infrared and middle infrared band, Then Fourier transformation and low pass shows the highest coincidence .Radar image adds very important information in the desertification inventory of this valley.

HOW MUCH PEOPLE KNOW ABOUT THE WATER, AND HOW CONSCIOUS IS ABOUT ITS USAGE? TOPIC STUDIED IN SAN MIGUEL DE TUCUMÁN CITY, PROVINCE OF TUCUMÁN, ARGENTINA

P. Sesma^{1 y 2}, P. García de Jacobo², M. Krautman, V. Gil², J. Forgas², A. Lima², A. Ross² and E. Zelaya²

1. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Miguel Lillo 205. (4000) San Miguel de Tucumán. Tucumán, Argentina. sesma@tutopia.com.

2. Colegio María del Rosario. Las Heras 565. (4000) San Miguel de Tucumán. Tucumán, Argentina.

The following task is developed in the context of the Environmental Education Project “Por una mayor calidad de vida” (For a better life quality), and carried out by a group of teachers and students of María del Rosario School, educational institution located in San Miguel de Tucumán city.

The aim of this work is to develop a research of the level of knowledge of the population of San Miguel de Tucumán about water issues, environmental functioning and the level of consciousness that they have about the water usage.

Located a few kilometres from San Javier hills, San Miguel de Tucumán City, capital of Tucumán province, has a population that overcomes the 500.000 inhabitants, which make it one of the most populated city in Argentina. Historically rich of water, the province had been suffering periods of drought more frequent and lasting and they have began to make a show of on the resources and consequently on the normal supply of the water to the inhabitants of the city.

Concerned about this reality, the government has began working in different alternatives, such as new dikes or drillings, so as it could have enough drinkable water for all the inhabitants of the capital and the municipalities. However, all the alternatives are orientated to have more volume of drinkable water to satisfy people’s need, but nobody thought about the damage that it would cause on the environment (erosion, diminution of the underground resources, etc.).

In order to fulfil the outlined objective of the project, from the methodological point of view, an inquiry, with 27 general questions of easy understanding, had been prepared. This inquiry had been taken to 500 people of different ages and social economical levels (students, teachers, housewives, professionals, etc.). Apart from that, a representative of the company that is under the charge of water service in the province and specialists on the theme had been interviewed.

As a result of the interviews and the inquiries, we can mention:

a) That the inhabitants do not know enough about water and its usage.

b) Although all the inhabitants consider that is important to take care of water, only a few people use the water reasonably.

c) There is a complete absence of a global politics about environmental awareness and education, specially about water usages, both of the government and company that is in charge of water service.

As a result, we consider essential that, before some other projects on water supply for the inhabitants of this city would be done, the government should set and carry out a clear politics about environmental education related to the reasonable use of water so as to reduce the level of consumption of water that presents the actual population of San Miguel de Tucumán, which according to the information given by the company that is in charge of water service in the city presents values higher than the recommended by international institutions.

WASTEWATER MANAGEMENT IN MILK PRODUCTION, PROBLEMS ASSOCIATED WITH THE USE OF WATER RESOURCES IN BUENOS AIRES, ARGENTINA

G. M.I. Sardi, L. I. Carbó, M. Flores, S. B. Gil and M. A. Herrero

Facultad de Ciencias Veterinarias – UBA - agricola@fvet.uba.ar

Milk Production demands great water volumes, reaching 10 L.water/L.milk produced. Most of this water along with excessive amounts of nutrients from animal feces and urine will become part of the farm’s wastewaters, which will need to be treated accordingly, to avoid potential water contamination processes. Preliminary studies have shown that 58% of Dairy farm wells have excessive nitrates and 58 to 73% are microbiologically contaminated. Data also shows that, in Buenos Aires, 20% of the farmers throw their wastewaters directly into nearby streams with no prior treatment. The remaining 80% discharges inadequately treated liquids into water courses. The accelerated intensification processes which accompanied technology incorporation in these productive systems have induced increases in nitrogen inputs that not necessarily mean increases in production. Consequently effluent generation increases, which should be accompanied by appropriate treatments to avoid water resource deterioration. The objective is the characterization of wastewater management in relation to the dairy farm’s technological level and with nitrogen surplus that are potentially contaminant of water resources in the milking area. Nineteen producers were surveyed from farms located in the Abasto Norte and Sur Milk Basins (Bs.As.), selected and characterized according to: total and stock destined surface, number of cows in milk (MC), and production (litters/cow/day). Samples were taken from wells and analyzed for nitrates by spectrophotometry. Three indexes were built: Whole Farm Nitrogen Annual Mass (WFN: kg N/ha/year), as an indicator of technological level, Nitrogen Annual Mass/cow in the milking area as an indicator of amount of nitrogen to be treated in manure (NAMC: kg N/CM/year) and Effluent Management system in Use (EM). Variables used for WFN were: off-farm feed, fertilizers, rainfall, and Nitrogen Fixation as nitrogen inputs and Product (L milk) as output. For NAMC nitrogen from all feeds (input) and production (output) were taken into account, in accordance with time spent in the milking area. Variables used for EM were: pre-treatment, transfer, storage, treatment and post-treatment effluent constructions, and their cleaning system and frequency, which built a management indicator, ranging from 1-100, being the optimum, 100. Nitrate contents were 56.42±42.68ppm (Mean ± Standard Deviation). Results, as Median-(Maximum-Minimum), were WFN: 66.68-(135.82-(-52.12)); NAMC: 55.55-(98.81-24.33); EM: 30.60-(82.87-21.25). Spearman Correlation analysis was carried out and results were: WFN and EM r_s=0.065 (p>0.05), and NAMC and EM r_s=0.32 (p>0.05). In both cases the correlation is not significant. In 84.2% of the farms effluent management efficiency was not in accordance to the technological level reached (WFN). The 94.74% does not have an adequate effluent management for the amount of nitrogen that remains in the milking area (NAMC). One of the farms showed a thorough nutrient management, which answers to productive and environmental sustainability requirements needed for organic production certification. Results show an inadequate adjustment of effluent management to productive technological changes and in consequence the potential contamination of water resources. Local deficient regulations and controls help this situation. Therefore, people should be made aware of how improvement in the use of excessive nutrients within the farms, will help attain productive-environmental sustainability in these systems.

FLOODS AND THE PROCESS OF URBANIZATION IN ARGENTINA: THE CASE OF RESISTENCIA

A. M. Liberali and O. H. Gejo

Tte. Gral. Perón 1333 – 2do piso “24” - C1038ABA – Ciudad Autónoma de Buenos Aires amliberali@yahoo.com.ar

Different natural disasters regularly affect vast regions in Latin America, a continent where their consequences are increasing. In Argentina, the city of Resistencia (Chaco Province) is the clearest example of vulnerability to such disasters among countless other Latin American urban centers. This vulnerability is not only caused by the on-site conditions (location, demographics and infrastructure) but also because of the city’s position with respect to its economic and political relations to the region and the country. The increasing process of urban impoverishment in Argentina is shown in this area in its crudest form and therefore floods only reflect and worsen the prior social, economic, political and territorial inequalities. Dominant economic activities, social actors, the land situation, macro regional management and technical solutions are but some aspects which deserve in-depth study. Urbanization and industrialization have been the principal factors in this subject. In other words, the form of the market subordinates all others and provides for sub-spaces which are reduced and given potential in an interregional division of work.

OBSERVED ATMOSPHERIC HUMIDITY DISTRIBUTION OVER SOUTHERN SOUTH AMERICA EAST ANDES: ANALYSIS FROM RADIOSONDE DATA

A. E. Fernández and M. E. González

Sea and Atmospheric Research Center – CONICET - Department of Atmospheric and Oceanic Sciences – University of Buenos Aires - 2º piso, Pabellón 2, Ciudad Universitaria , 1428, Ciudad Autónoma de Buenos Aires, Argentina - aefernandez@fibertel.com.ar

This paper analyses the annual evolution of total humidity transports over southern South America. A daily time series of specific humidity and wind data were obtained from the Argentinean radiosonde observations network (National Meteorological Service) during 1958 – 1982 period. Total (meridional and zonal) monthly mean transport of humidity were calculated, integrating the humidity fluxes at atmospheric fixed pressure levels. Statistics were based only on observations at fixed pressure levels greater than 400 hPa.

Zonal transport from East are only observed in the Northwestern subtropical Argentina during February. In the Northeastern subtropical Argentina strong zonal transports from the West occur during the whole year, except during summer time. In this season similar intensities to those in the central subtropical Argentina are observed. Zonal transports from the West are observed in the Western Argentina (e.g. Mendoza location) during the whole year. Values are close to 300 g/cm seg with relative minimum values during March, April, September and October. A similar behaviour presents the transports near the Andes at approximately 38º South (Neuquén location), presenting humidity transports from East during the above mentioned months. Absolute maximum humidity zonal transport values are observed at Comandante Espora and Neuquén from May to December. During March and April the maximum values are shifted Southward (reported at Comodoro Rivadavia). During the mentioned months, the meridional humidity transports from North reach deep in the South.

In the Central – Northern Argentina from May to November the annual evolution of the zonal transports present similar values at Santa Rosa and Ezeiza. During the remaining months of the year, Santa Rosa presents greater transports than Ezeiza. In general in the central Argentina relative minimum transports occur in autumn and spring, mainly during March - April and September – October. This may be indicative of a diminution the West fluxes and a greater frequency of humidity contribution from the East, as has been before mentioned for Neuquén location.

The total meridional vapor transport present in the region a marked annual variation: The subtropical and central Northern Argentina are influenced by transport from North throughout the whole year. Maximum absolute values are reported by Resistencia station, except at the beginning and at the end of the summer. At this time Córdoba station reports strongest Northerly transports.

Transports from north and from south converge in a region limited approximately by 36º and 38º South parallels to the East of central Argentina. Winter mean conditions in the central – Eastern Argentina are southerly. Meanwhile the latitudinal variation of northerly transports is notably intensified in subtropical – East Argentina.

IRRIGATION WATER MANAGEMENT AS A TOOL TO IMPROVE WATER USE EFFICIENCY IN BLUEBERRY CROPS

A. Pannunzio¹, F. Vilella², D. Pérez³, P. Texeira Soria⁴

Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453 (C1417DSE) Buenos Aires Argentina 0054-11-4524-8000. 1. Cátedra de Riego y Drenaje, pannunzi@agro.uba.ar - 2. Cátedra de Producción Vegetal, vilella@agro.uba.ar - 3. Cátedra de Topografía, UBA. dperez@agro.uba.ar - 4. Cátedra de Riego y Drenaje, texeira@agro.uba.ar .

The experiment was developed in Zarate, Buenos Aires province, in a blueberry (Vaccinium corymbosum L.) orchard examines the effects of different drip irrigation systems in an O´Neal variety. There have been different reports on yields increase for different crops, thanks to the use of localized irrigating systems. A uniform and adequate supply of moisture and fertilization is essential for optimum growth. The soil of the region is a heavy texture, composed by 13.5 % of sand, 69 % of limo and 17.5 % of clay. A considerable amount of organic matter is added, compound mostly of pine bark, different sorts of chips, etc., which recreates an acid environment similar to their soil of origin, airy and filled with organic matter. Water source used, is in this case, of the Puelche aquifer, containing 800 micromhos/cm of salts, and a ph of 7.4. The plants of the experiment were implanted in august of 2001, after one year in nursery. The first harvest was in October 2003 and the second in October and November of 2004. The research field area receives 1000 mm annual rainfall irregularly distributed, with resulting water deficit for the shallow-rooted blueberries. Managing soil moisture is critical to achieve high yields, being 10 centibars the ideal water potential in the soil. Either deficit or excessive water supply has a negative effect on blueberry plants. The goal of the experiment was to find the relation between water irrigated and yield obtained per cubic meter of water. Two water management strategies were evaluated, comparing different surfaces of irrigate soil. The irrigated percentage of wetted soil increases in the second treatment, in which we use two parallel drip irrigation lines, separated 30 cm each other, compared with the first treatment in which we used only one line of drippers per blueberry row. Each treatment plot contained completely randomized blocks, each one with 5 plants and 5 replications. During the harvest of October and November 2003 and 2004, higher yields were found, in treatments which irrigate a higher surface of soil. Therefore, we can assert that in this environment, with three years old plants of O´Neal varieties of blueberries; with can obtain higher yields, increasing the wetted area of beds, reaching 2436 kg. ha^-1 for the first treatment and 4335 kg. ha^-1 for the second one in 2003, and 3.950 kg. ha^-1 and 4.750 kg. ha^-1 in 2004 respectively.

FLOODS INCREASING IN BUENOS AIRES SALADO RIVER BASIN

M. H. González and A. E.Fernández

Sea and Atmospheric Research Centre – CONICET - Department of Atmospheric and Oceanic Sciences - University of Buenos Aires - 2° piso, Pabellón 2, Ciudad Universitaria, 1428, Ciudad Autónoma de Buenos Aires, Argentina - gonzalez@cima.fcen.uba.ar

This paper analyses the annual cycle of rainfall and water storage in soils and their interannual variability during the last twenty five years in order to improve the knowledge of principal hydrological variables behaviour in the Salado River basin in Buenos Aires province. The rainfall regime was studied in detail by Gonzalez and Barros (1996, 1998). Monthly rainfall and temperature from stations from the National Meteorological Service (SMN), during the period 1980-2000 were used to apply Thornwaite and Matter method (1955), which provides mean water balance. January is the rainiest month and rainfall decreases from the north (130mm) to the Southwest (40mm). The maximum turns to the Northeast and in May it is a Southwest-Northeast gradient. August is the least rainy month and rainfall increases from the west with less than 30mm to the east with only 50mm next to the coast. However, soil water storage reaches a peak in winter because low temperatures do not let water evaporate. Therefore if rainfall is unusually high in autumn, soils become saturated and can determine a severe flood (Gonzalez and Fernandez, 2005). The water storage in the soil increases from South to North and only a small area is saturated in summer. Alternatively wet and dry periods are observed, as Florentino Ameghino (1954) reported more than a hundred years ago; for example, the wet period beginning in 1860 and ending in 1920 and the present one which began in 1970 and still ongoing. Although short humid periods have been appearing since 1900, the situation seems to be changing in recent times. During the last forty years, rainfall has increased an average of 20% in the plain, yearly rainfall has risen from 600mm to more than 1000mm in the west of Buenos Aires and the agronomic limits have shifted about 200 km towards the west (Castañeda and Barros, 1994, 2001). Flood frequency has considerably increased during the last twenty years in Buenos Aires province. The interannual variability of rainfall and water storage is analysed too performing sequential water balances since 1980 to 2000. More frequent flooding events are detected and corroborated with newspaper information. Therefore, great floods occurred in 1980, since October 1982 to April 1983, since October to December 1985, since June 1991 to June 1992, since January to December 1993, with great severity in Autumn, since August to October 1997, during 1999, since May to December 2000 and from January to September 2001. Sometimes they covered the complete basin and other only an area. In this region, considered one of the richest areas in Argentina, rainfall and soil water storage have to be monitored in order to minimise the negative impacts of the intense floods that have been taking place more frequently since 1980.

GROUP AND PUBLIC POLICY IN THE LOW BASIN OF THE SAUCE CHICO, SOUTH EAST OF THE BUENOS AIRES PROVINCE. STRATEGIES OF ENVIRONMENTAL WORK IN A HORTICULTURAL PERIPHERAL AREA*

M. A. Lorda

Roca 637 - 8.000 Bahía Blanca. Argentina - malorda@criba.edu.ar

The nature-society relationship starts in General Daniel Cerry in 1880. Due to a number of favourable natural conditions, horticultural practice begins to grow in the lowest part of the Sauce Chico, and as a result an urban area begins to develop thanks to two important factories: a meat and a wool processing plant.

There is an important growth in population because of the arrival of immigrants from Italy mainly, which in response to different historical, political and economic reasons find in the area a place to live.

As from the 1990s they witness a series of changes which will bring about a territorial impact of great importance. Bahía Blanca enjoys a time of big economic investment as seen in the consolidation of the Industrial Pole and the creation of new business activities. However, Cerri faces the end of its industrial period and undergoes a serious economic crisis. Horticulture remains though weak. The whole atmosphere changes due to the arrival of Bolivian immigrants and the establishment of supermarket chains which will bring vegetables from distant areas of production.

It's important to pinpoint here that the horticultural activity in the region is carried out by small scale farmers, who respond mainly to family heritage, whose products are closely related to the region's. The activity in the area near the city encounters certain specific problems: its resources, not only water but also land, its commercialisation and its economic viability.

This thesis deals with one of the fundamental problems regarding the issue: the inadequate use of water from the theory - methodology point of view given by the social geography authors (Di Meo, 1985; 1991, 1998; 1999; Raffestin, 1987, 1995). It also gives a complete study of the rural activity, the actors and developing actions from the theories of competent authors (Giddens, 1998), and the structural discourse analysis (Demazière y Dubar, 1999).

The main objective is the interpretation of the society- nature relationship, taking as a starting point the analysis of action-articulation capacity of public policy of development, the role of the extension agents in mediating with local actors in order to create and recreate intervention strategies regarding horticulture. The results make it possible to show that the environmental strategies developed from the local public policy, include the weakest horticultores, try to strengthen practice through learning and relearning their job as regards land use, water administration and subsequently make it possible for them to protect the food to be consumed.

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* The authors express their gratitude to the Ministry of Science, technology and sports of Republic Croatia for financial support. This work has been carried out as part of the contract ICA2- CT- 2002- 10007 (APOPSBAL) between the European Commission, Rudjer Boskovic Institute Zagreb, Geological survey Sarajevo, Institute for public health Maribor and Faculty of science Prishtina.

* The authors express their gratitude to the Ministry of Science, technology and sports of Republic Croatia for financial support. This work has been carried out as part of the contract ICA2- CT- 2002- 10007 (APOPSBAL) between the European Commission, Rudjer Boskovic Institute Zagreb, Geological survey Sarajevo, Institute for public health Maribor and Faculty of science Prishtina.

* The authors express their gratitude to the Ministry of Science, technology and sports of Republic Croatia for financial support. This work has been carried out as part of the contract ICA2- CT- 2002- 10007 (APOPSBAL) between the European Commission, Rudjer Boskovic Institute Zagreb, and Institute of Public Health, Zadar

* Acknowledgments: Funding for this project was provided by the UBACyT G033 and ANPCyT (BID 1201/OC-AR-PICT 15028). We thank Prefectura Naval Argentina for logistic assistance.

* Funding for this project was provided by the UBACyT G033 and ANPCyT (BID 1201/OC-AR-PICT 15028). We thank Prefectura Naval Argentina for logistic assistance.

* Acknowledgement: SECYT-CONICET Project “Evaluación ecotoxicológica del Río Reconquista: Proyección del estado de la calidad del agua del río", directed by Dr. A. Salibián.

* Funding for this research was provided by RFBR (project N 03-05-64306, 04-05-08063–ofi–a)

* Acknowledgement: UBACYT Project "Análisis integrado de la cuenca del Río Matanza-Riachuelo”, directed by Moretton, Iorio & Santanatoglia

* Presentation of the Research Project within the frame of the Project “Risk Management and Climate Change”, PICT 2002, Agencia Nacional de Promoción Científica y Tecnológica –ANPCyT–. Director: Hilda Herzer

* This extract is part of the thesis called "Local development, environmental strategies of the agricultural activity in the area surrounding Bahía Blanca".