DAMS AND THE ENVIRONMENT: THE BRAZILIAN EXPERIENCE (pp. 127-140)
aDepartment of Hydraulic and Sanitary Engineer, Escola Politécnica da USP, São Paulo, SP, Brazil; bDEBE, Universidade Federal de São Carlos, SP, Brazil; cCRHEA, Universidade Federal de São Paulo, São Carlos, SP, Brazil
Abstract: Water resources development requires basically two types of action: structural and non-structural. The developed world, since early times, has been using the structural approach (dams, reservoirs, canals, etc.) in order to provide the infrastructure for development. Non-structural alternatives are now in great evidence in the developed countries. They include, in the case of flood control, among others, laws, regulations, insurance and flood warning systems. These measures can significantly reduce damages in flood control management, but, in general, they do not reduce the risk of a flood. Conservation of energy is a typical non-structural measure to increase energy supplies in the developed world. On the other hand, the developing world is at a level of energy generation such that structural measures are necessary for development. This paper discusses this issue in a Brazilian case study. It presents the energy matrix of the country showing that hydropower is the only feasible alternative for electrical energy generation. Since the largest potential of the country is located in the Amazon basin the paper points out the importance of careful economic, social and environmental analysis before implementing any water resources project in the area. Another case study, the state of São Paulo, is presented. Here are shown techniques of lake and reservoir environmental management that can be implemented in a situation when all the hydropower has been developed and important pollutant loads are discharged into the reservoirs.
RESERVOIR MANAGEMENT IN SOUTH AMERICA (pp. 141-155)
aCRHEA, Universidade de São Paulo, S. Carlos, SP, Brazil; bDEBE, Universidade Federal de São Carlos, SP, Brazil; cDepto. de Hidráulica e Sanitária, Escola Politécnica da Universidade de USP, São Paulo, SP, Brazil
Abstract: There has been a rapid increase in the number and size of reservoirs in all continents. In South America some hydrographicbasins such as the la Plata are almost completely exploited whereas others such as the Amazon are just starting to be exploited for hydropower energy. Ecological studies at the newly created artificial lakes were carried out from the filling phase and extending some years after, in order to understand the functioning of the lakes, the problems arising from the impoundment and to explore the possibilities of applying cheap ecotechnology as corrective measures. The studies in the Amazonian reservoirs have shown that oxygen depletion and nutrient accumulation are a serious problem in lakes with dendritic shape and long residence time. Clearing biomass prior to impoundment and new engineering designs for water oxygenation must bc developed. Results from la Plata basin reservoirs show that eutrophication, toxic contamination and siltation are widespread problems which must be corrected by pollution and erosion control.
ENVIRONMENTAL ISSUES IN THE LA PLATA BASIN (pp. 157-173)
Abstract: The la Plata River basin is one of the largest in the world, with an area of about 3 million km2. It includes parts of five countries (Argentina, Bolivia, Brazil, Paraguay and Uruguay) and the water resources of the la Plata basin are essential for their economic development . The main tributaries are the rivers Parana, Paraguay and Uruguay. Some of the main developmentshaving environmental impacts that influence the basin have been the following: (1) developments of many hydropower reservoirs in the Upper Parana River, in Brazil, from 1960-90; (2) deforestation in the Parana, Uruguay and Paraguay basins from 1950-90; (3) introduction of intensive agricultural practice after 1970; (4) urban developments with change to flood regimes; and (5) navigation and conservation of the Upper Paraguay River. Since 1970, flow increases have been observed which may have been caused by changes in vegetation cover, or by climate variation. The changes have raised important issues for both water resource development and environmental conservation. This paper discusses the water management and environmental issues, taking account of climate patterns and the development of the five count ries sharing the basin.
THE BRAZILIAN WATER LAW: A NEW LEVEL OF PARTICIPATION AND DECISION MAKING (pp. 175-182)
Abstract: Brazil has a new water law and is now implementing an innovative system to manage its waters. The Brazilian Federal Water Resources System Law was signed by the President of Brazil on 8 January 1997. To implement such a system, all institutional framework is now in the process of important changes, seeking achievements which it will be quite hard to meet. It is an arduous task to overcome obstacles such as effectively directing the decision-making process towards its lowest appropriate level. This paper will briefly present the new management system and the respective institutional framework. It will also discuss the implementation of River Basin Committees as the participatory approach adopted to decentralize management.As a case study, it will show the experience of the Piracicaba River Basin Committee, the first to be established under this new and modern vision in 1993.
WATER RESOURCES IN BRAZIL AND THE SUSTAINABLE DEVELOPMENT OF THE SEMI-ARID NORTH EAST (pp. 183-198)
Abstract: This paper is the result and synthesis of several water resources studies carried out by a group of specialists within the ‘ARIDAS Project-A Strategy for the Sustainable Development of North East Brazil’. The paper comprises basically: diagnosis of the water resources situation in the North East; analysis of water sustainability, vulnerability to droughts, current water policies, and implications for the future; and guidelines for the setting up of a new water resources policy taking into account the sustainable development of the region. Deficient or critical areas were identified in terms of quantity, quality and vulnerability. Patterns of sustainability and vulnerability indexes were suggested, as well as a few general lines of action.
A MODEL DESCRIBING PERFORMANCE OF RURAL DRINKING WATE SYSTEMS IN HONDURAS (pp. 199-215)
aSenior Environmental Engineer, Navajo Indian Health Service, Many Farms, Arizona, USA; bUPS Foundation Professor, Department of Civil Engineering, Stanford University, Stanford, California, USA
Abstract: The following factors may influence the performance of drinking water supply systems in rural areas of low-income countries: community motivation; use of technical and local information in system design; community capacity to maintain a new water sup ply system; protection of watersheds and access to water system facilities; and ongoing support from organizations outside the community. Field research in rural communities of Honduras provides a basis for investigating how these factors affect rural water system performance. Results from this research also lay a foundation for a conceptual model of water system performance which integrates all of the aforementioned factors.
POST-PROJECT REVIEW OF ENVIRONMENTAL IMPACT ASSESSMENT FOR SAGULING DAM FOR INVOLUNTARY RESETTLEMENT (pp. 217-229)
Abstract: It is imperative to refine the EIA methodologies applicable to dam construction projects. The aim of this study is to seek clues to this end by carrying out a post-project review of the EIA study conducted for the Saguling Dam in Indonesia. The following aspects were found to have been improperly dealt with either in the EIA study or during the implementation of the project: (a) collapse of the community; (b) improperly conveyed information for resettlers; (c) distrust among residents; (d) employment by construction project; and (e) compensation for resettlers. Recommendations are made on each of these items to improve the methodologies.
MEASURING LAND AND WATER PRODUCTIVITY IN A MEXICAN IRRIGATION DISTRICT (pp. 231-247)
Abstract: Being a water-scarce country, Mexico needs to try to optimize economic returns to irrigated land and irrigation water. This paper discusses a methodology to measure land and water productivity and shows how this methodology was applied to the Alto Rio Lerma irrigation district. Returns to land and water are compared over time as well as across the 11 irrigation modules within the district. The main conclusion of the paper is that although water is the limiting production factor, farmers still try to maximize returns per unit of land cropped, resulting in relatively high returns to consumed water, but very low returns to unit of command and water supplied. It is argued that, prior to trying to increase returns to water supplied, one needs to gain better understanding of the effects of using water ‘more efficiently’ within the district on land and water productivity of other users within the river basin.
SUSTAINABILITY OF A WATER SUPPLY SYSTEM: THE CASE OF HAI WATER PROJECT IN TANZANIA (pp. 249-270)
Abstract: In the developing countries, self-sustaining water supply projects have become critical for the long-term development and well-being of the people. To ensure sustainability, equity, billing collection, cost recovery and beneficiary participation are emphasized. This paper investigates a small rural/urban water supply project in Tanzania in terms of the above attributes and evaluate its potential for further improvement. Equity in public tap distribution is analysed using the Theil information theoretic measure while the performance in monthly water bills collection is evaluated using the Theil forecast error method. The results show that public taps are unevenly distributed among beneficiaries. The performance in bills collections is better for public taps than for house connections and, overall, townships’ performance is better than that of villages. Though the project as a whole recovers 127.4% of its operations and maintenance costs from billings, it has a high potential for further improvement.
Sharing the Ganges, Ben Crow, Alan Lindquist and David Wilson, New Delhi, Sage, 1995