Integrated Management of Land Based Activities in the São Francisco River Basin Project Ana/Gef/Unep/Oas
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INTEGRATED MANAGEMENT OF LAND BASED ACTIVITIES IN THE SÃO FRANCISCO RIVER BASIN PROJECT ANA/GEF/UNEP/OAS Activity 1.5 – The Impact of Agriculture on Groundwater Resources in the Verde/Jacaré River Basin Executive Summary IMPACT OF AGRICULTURE ON GROUNDWATER RESOURCES IN THE VERDE/JACARÉ RIVER BASIN U F B A Salvador - BA INTEGRATED MANAGEMENT OF LAND BASED ACTIVITIES IN THE SÃO FRANCISCO RIVER BASIN PROJECT ANA/GEF/UNEP/OAS Activity 1.5 – The Impact of Agriculture on Groundwater Resources in the Verde/Jacaré River Basin Executive Summary IMPACT OF AGRICULTURE ON GROUNDWATER RESOURCES IN THE VERDE/JACARÉ RIVER BASIN Coordinators Heraldo Peixoto da Silva Agricultural Engineering Department Bahia Federal University Collaborators Heraldo Peixoto da Silva UFBA Everardo Chartuni Mantovani UFVUFS Haroldo Silveira Dória LAVAL José Llamas Universidade Jaune I Ignácio Morell Evangelista Universidade del País Vasco Iñaki Antigüedad SRH/BA Ricardo de Souza Rodrigues UFBA Ari Medeiros Guerra UFBA José Alberto Sampaio UFBA Mário Jorge Gonçalves UFBA Antônio Mário Coutinho UFBA Semara de Morais Andrade UFBA Roberto Bonfim SRH/BA March 2003 IMPACT OF THE AGRICULTURE OVER GROUNDWATER RESOURCES IN THE BASIN OF THE VERDE/JACARÉ - BA - RIVER EXECUTIVE SUMMARY INTRODUCTION The Activity 1.5 is part of the Component 1 – The Analysis of the Basin and the Coastal Zone of the São Francisco River, managed by the Integrated Management of Land Based Activities Developed in the São Francisco Basin. (ANA/GEF/PNUMA/OEA). With the small impact of the agriculture in the hydric groundwater resources in the basin of the river Verde/Jacaré, the activity had as its objectives to make a participative diagnose, with emphasis in the technical and scientific aspects of karstic hydrodynamics that is a characteristic of the region, to define criteria and start the establishment of a model monitoring system in the areas of the hydrographic basin occupied by the irrigated agriculture in order to evaluate the impacts over the quantity and quality of the groundwater and the superficial water and identify the main causes and recommend the relieve measures to be taken. The adopted methodology, the activities already done and the ones that are still being done allow that the presented conclusions and recommendations can be adopted as a contribution and reference information for the elaboration of the Integrated Management Program – IMP of the basin of the São Francisco river by the National Water Agency – ANA and the Water Resources Management Program of Bahia State. This is because this basin, study object of the Activity 1.5 is inserted in the Water Management Region # 6, considered a model by the Water Resources Bureau – SRH of Bahia State The execution of the activity allowed that Bahia Federal University, as an education and research institution, through the association of the post-graduate programs in Geochemistry and Environment of the Geosciences Institute (Hydrogeologic and Environmental Study Nucleus - NEHMA) and in the Agricultural Engineering, identified, defined and prioritize the research lines and training for the generation of the karstic systems, applied to the monitoring and to the management of the quantity and quality of the water resources. It stands out the importance and the need for the development of studies/researches applied to the comprehension of the dynamics of hydrogeologic systems considering the interaction between the aquifer/river and the soil use for the generation of referential information as a support base to the integrated management of the natural resources of water and soil. In this sense, Activity 1.5 brings subsidy for the establishment of the Integrated Management Program – IMG of the São Francisco River Basin, through monitoring systems with adequate methods for the identification of the impact indicators, the main cause and the relieve measures as a management strategic instrument for the sustainable use of the water and soil natural resources, all this considering that farming activity is the biggest user of these resources in the basin It is important to emphasize that the agriculture is a vital and important factor in the generation of jobs, income and hunger fighting. Because of its nature, agricultural activity causes great impact in the use of the water and soil natural resources and inevitably generates i negative impacts, also being able to change significantly the hydrological, hydrogeologic and environmental dynamics in the hydrographical basins where it happens. The implementation of the actions of the Activity 1.5 were accomplished through meetings, seminars, workshops and field campaigns with the local technicians' involvement, professors/researchers, consultants, users, associations of producers, public organisms, public companies, private companies and Non-Governmental Organizations, resulting in a participative diagnosis. There were identified negative impacts caused by the intensive irrigated farming in the water resources of the basin, with the increase and the systemization of every available information on geoenvironmental aspects, characterization of the water and soil natural resources uses and the risks of contamination. The analysis and treatment of the data obtained allowed the identification of the impacts and its causes; relieve measures and the need for generating of specific information about the unsaturated and saturated zone of the water bed. Through researches it was possible the definition of parameters that regulate the hydrogeologic dynamics (recharge, discharge, reserves, vulnerability) of the karstic water bed, considering the exploration regime that it is submitted to allow the calibration of the flow and transport model(s) as a support tool for decision-making on the management of the demands and for the water quality protection. The area of the object of study of the Activity 1,5 is located in the mesoregion Center-north on the territory of the State of Bahia, the micro-region is named Irecê, with a code number 135. It is inserted in the Northern Diamantina Plateau on the right border of the lake formed by the Sobradinho Hydroelectric Power Plant. The georeferenced location defines the embracing area of the Activity in the central part of the State of Bahia, between the coordinates 9o56´ and 12o28´ of latitude South and 40o47´and 42o53´of West longitude, the area includes the cities of América Dourada, Barra do Mendes, Brotas de Macaúbas, Gentio do Ouro, Ibipeba, Ibititá, Ipupiara, Itaguaçu da Bahia, João Dourado, Jussara, Lapão, São Gabriel, Xique-Xique, Barro Alto, Cafarnaun, Canarana, Central, Irecê, Presidente Dutra, e Uibaí. These cities are totally or partially on the basin of the Verde/Jacaré Rivers. Under the coordination of the professor/researcher Dr. Heraldo Peixoto da Silva of the Federal University of Bahia, the actions, studies and researches supported by the Project GEF São Francisco were made by a multidisciplinary team with Brazilian, Spanish and Canadian specialists with various universities of their countries involved. The Superintendence of Water Resources of the State of Bahia was also involved. The results are presented in 9 chapters and 9 annexes. The chapters are about the characterization physiographical, social, economical and also the agriculture of the area studied. It is enclosed the hydrogeologic aspects, identifies impact indicators of the agricultural activity over the quality and quantity of the water resources, defines criteria and technical method procedures to guide the establishment of a water quality monitoring system. Reference information is presented to guide the establishment and development of a hydrogeologic concept model to be validated as a decision support tool for the management of the demands. ii Considering the great demand of consumptive use of water by irrigation, it was introduced a Support System Decision-making on Agricultural Matters – SISDA as a computer tool with enough resources to guide the optimized management of water demands and also gauging the volume of water to be extracted from the aquifer, all this considering its location and the seasonal demand pressure. It was defined the location of a network of reference wells and it was started the measurement of the piezometric levels for the evaluation of the recharge volume, lowering levels and the definition of the influence area between the wells. These are basic information for the mathematical modeling to be used to support for the decision of technical analysis of the water use licenses and the risk of conflicts between the users. The applied methodology in the development of the studies and researches allowed, from careful analysis results, to diagnose, make conclusions and suggest recommendations to be implemented and broadened, defining the procedures and the costs. Method procedures were defined by the consultants and professors/researchers of the Federal University of Bahia, with the effective participation of the technicians from the responsible government body for water resources management of the state, the SRH-BA, and also post- graduate students participated. Field researches for collecting data were done and are still being developed for the formation of the data bank necessary to make possible the calibration and validation of the modeling procedures. The activities developed and the resulting products of the consults were put in the system and integrated. They made possible to identify the impact indicators of the agriculture in the hydrographical basin, to