Integrated Management of Land Based Activities in the São Francisco River Basin Project Ana/Gef/Unep/Oas
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.
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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 know the dynamics of the weather elements and to understand the concept of the complexity of the river/aquifer system for the structure and to start the establishment of a modeling system for supporting the participative management of the water resources in situations were the irrigation plays a big role on water consumption.
The stimulated activity brought close the Superintendence of Water Resources and the Federal University of Bahia, a very important relation. It resulted in the celebration of an important partnership that allowed the integration, the broadening of the actions and the continuity of the activities of monitoring, modeling and staff training.
A process of mobilization of the water users, public administrators, public companies, private companies, non-governmental organizations and schools was accelerated through the accomplishment of technical meetings, seminars, workshops and training sessions.
It allowed integration and it brought close the local government, the society and the university.
1. PHISIOGRAPHIC CHARACTERIZATION OF VERDE/JACARÉ SUB-BASIN
1.1. Location
The Verde/Jacaré Rivers are tributaries on the right margin of the São Francisco River, their hydrographical basins include all the SanFranscican Depression, the Irecê Plateau and the Diamantina Plateau, its total area corresponds to 18.150 sq.km.
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Taking as a reference the State Capital, Salvador, it can be reached through the Federal Highway BR- untill the city of Feira de Santana and from there it is necessary to continue through the State Highway BA-052 (Beans Highway) until Irecê and/or through the Highway BR-242 (Salvador-Brasília). The Figure 1 shows the location of the Activity 1.5 in the map of the State of Bahia divided in Water Management Regions.
SUB PROJETO .1.5
ÁREA SUBPROJETO 1.5
Figure 1. Map of subdivision of administrative regions of water and hydrographic basins of Bahia state, standing out the area of Sub-project 1.5
1.2. Geomorphologic Characteristics.
The geomorphologic characteristics of the region are marked by the following units: Morro do Chapéu Plateaus, Northern Block Plateaus, Chains of Mountains in the western border and pediplan in the center. The limestone plateau of Irecê is a geomorphologic unit well characterized for its table form softly wavy and with the altitude ranging around 700 meters (GUERRA, 1986).
The valleys usually present themselves asymmetrically, with a plain bottom, well fitted channels and sudden slopes. They are constituted of limestone walls that can reach up to 50
iv meters (BAHIA, 1995). Sudden walls can be observed all along the Jacaré River, the only significant drainage system that exists in the area (GUERRA, 1986).
The Irecê Plateau is constituted a plateau full of discontinuities in which the altitude varies from 600 to 800 meters, being characterized by its topography lightly wavy, with soft elevations and without the formation of cliffs, eventhough it locally presents considerable amplitudes with some altitude variation from the top to the base (BAHIA, 1995).
The Romão Gramacho Path is characterized by an area drained by the Jacaré river in a space formed by cenozoic deposits. In the surface, these deposits are mixed with more recent formed debris, the ones that composed a mixture of water sediments, sands and lumps with the limestone favored by the climate conditions. The declination of the river bed is very small, sometimes even inverted, and it forms ponds where the water accumulates for all the dry season (BAHIA, 1995).
Figure 2 presents an plain-altimetric image that expresses topographically the relief in the water dividers of the basin.
Figure 2. Representation (3D and 2D) of topography, where can be identified, with more clarity, the highest points of Verde/Jacaré Rivers Basin..
1.3. Hydrometeorological Characteristics
The weather of the region is determined partly by the atmosphere general dynamics. These dynamics act sometimes in the direction of reducing the regional variations of the weather elements and sometimes increasing these differences such as temperature and precipitation, these have an enormous influence in the agricultural activities of the basin.
The rain behavior is characterized for presenting a more intense rain period from November to March, rain can happen on the months of April and October, varying between 40 mm and 50 mm per month, in an average.
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From May to September the precipitation rates are insignificant. They vary in the average from 4 mm to 14 mm per month. In August the lower average precipitation value of 4.3 mm is reached. The total precipitated volume is about 700.6 mm.
Due to the importance of the dynamics comprehension of the hydrological cycle and its tendencies, for applications in the studies of recharge, hydrodynamics, and the calibration of the Support System for Decision-Making on Agricultural Matters for the optimized management of the water use by the irrigation users, the spatial and temporal variabilities with the analysis of the consistency of the climate elements obtained a detailed study that is on the Annex I.
The climatologic characterization of the studied area was done based on the data of the Irecê´s Meteorological Station, with the reference of the historical series of 1944/1994 found in the study of BARBOSA (1998). According to the weather classification of Köppen the climate of the region is the Bsw”h’(very hot and semi-arid, steppe kind) (BAHIA,1995).
The significant spatial and temporal variability of the precipitation associated to the low yearly pluviometric rates over the basin is one of the main factors for the occurrence of water shortages in the region. It is characterized by a significant reduction in the precipitation in the periods of May to September in Irecê (central basin part) and from June to September in Xique-Xique (northern basin part).
Eventhough a total seasonal reduction on the basin precipitations can affect the water granting criteria, the management of the water resources and the irrigation handling are much more affected directly by the variations in the inter-seasonal space and time scale, they also affect the society in a much stronger manner.
For example, a year on which the total pluviometric overcomes the average can be a year with severe restrictions for the agriculture and also be an excellent year for water storage. In this way, the intra-seasonal pluviometry has an extreme importance in the scope of these applications (agriculture and water resources management).
Even in years (months) in which the annual pluviometric totals (monthly) are next to the historical average, the time distribution over the rainy season can substantially affect the water resources and also the agriculture. The high variability of the rains observed in the basins of the rivers Verde/Jacaré, during all year long is a determining factor for quantifying the needs for irrigation of the diverse cultures and other needs.
The measures taken for a long period of time in the basins of the rivers Verde/Jacaré show a year average of about 630 mm and standard deviation of 52% characterize this region as a semi-arid one.
The time series analysis of the precipitations (mm) and its tendencies on the years from 1911 to 1983 in the Verde/Jacaré rivers basin show that in all the observation period the precipitations were not below 300 mm and also have not gone above 1200 mm. These cycles represent the climatic behavior on the basin , these cycles seem to be linked to the events of the El Niño/ Southern oscillation, these occur in intervals of four and/or seven years, its intensity is variable.
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Eventhough this phenomenon occur in the Pacific , its consequences are sensed in all the planet. The occurrence of four events of the El Niño considered strong (1918, 1932,1932 and 1882) are indicated in the figure 3. Other events of rain scarcity also appear in this figure. Years with abundant rains are alternated by years that have a minor rain occurrence in a compensatory manner, reaching the average precipitation that characterize the basin climate.
The high dispersion rates of the precipitation correspond to another characteristic of the rains in the semi-arid climate. The yearly average standard deviation has a value of 154 mm being almost 25 % of the yearly average precipitation of 626,9 mm. The tendency line presented in Figure 3 was obtained through the square minima method where X represents the time in years.
The tendency curve describes an oscillation of the precipitations between 1911 and 1983 followed by stabilization in the fifties. This description can obey two interpretations: one corresponds to the long term cycle typical of the El Niño weather system; the other is a manifestation of changes in the precipitations, mainly because of the deforestation of the native vegetation for instance.
Figure 3. Average temporal series of precipitations (mm) and its tendency in the long run within Verde/Jacaré Rivers Basin, between 1911 and 1983. The red line indicates the tendency obtained through the method of minimal squares.
Figure 3 shows the average behavior of the total annual of the precipitations in the basins of the rivers Verde/Jacaré. In this Figure it can be observed average totals above 800 mm, considered rainy areas, the higher regions of the basin close to the water dividers that are the limits of the hydrographical basin. While in all the other sectors of the region these average totals are inferior to 700 mm per year, mainly in its central part where other values will not even overcome 600 mm per year.
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The present evolution of the average precipitation on the basin studied shows a certain definition of the existence of a “rainy season”, that is, in a certain period of the year the rains are abundant and as a consequence of that, there is a well defined “dry season”.
The main rainy season of the basin is included between the months of November and February (NDJF), with a rain peak in December. The second season includes the months from December to March (DJFM), with a peak in March. The permanence of the frontal systems is a main mechanism caused of precipitation.
The study allows the conclusion that the seasonal variations (monthly and yearly) affect all the meteorological variables that generally are mutually dependant. This is valuable information for the strategic planning of the irrigated agriculture allowing the view of a detailed hydrological balance sheet.
The information generated by the historical series serves as a fine adjustment in the understanding of the recharge periods of aquifer and the seasonal variations of the demands and availability of the mathematical modeling of the system river/aquifer and in the calibration of the Support System for Decision-Making on Agricultural Matters – SISDA as a tool for optimum management of the irrigation.
1.4. Geological Characteristics
From an area of about 8,500,000 sq. km. of the Brazilian Territory about 213,006 sq.km. are constituted by outcrops of carbon rocks. From this total the State of Bahia has about 65,163 sq.km. of carbon outcrops, out of its 567,296 sq.km. of its total territory.
It is estimated that the São Francisco River Basin has 150,575 sq.km. of outcrops out of a total area of 645,067 sq.km., reaching about 23.34% of the basin. It is highlighted the fact that mainly the carbon rocks occur in the region of the springs, in the state of Minas Gerais up to the city of Juazeiro in the state of Bahia going all the way to the Vale do Salitre (Saltpeter Valley) and the Microregion of Irecê, it also possible to see the occurrence in other hydrographical basins in the state of Bahia. The carbon sequence in the Bambuí Group, in the Irecê Plateau, Central Bahia region, covers an area of about 15,000 sq.km.
The hydrographical basins of the rivers Verde/Jacaré are inserted in the geological context of the Diamantina Plateau – Central Bahia Region. From the paleographical point of view, three units stand out: the crystal substratum (Caraíba Group), the quartz substratum (Diamantina Plateau Group) and the cover (Bambuí Group), (MARINHO, 1977).
In the microregion of Irecê the lithologies of the Bambuí Group dominate, constituted by old rocks, with the age of about 500-630 million years from the Pre-Cambrian Superior (RIBEIRO, 1985).
According to GUERRA (1986), the denomination Bambuí comes from the city with the same name that is located in the south of Minas Gerais, RIMMAN (1917) named the carbon sequences that outcrop there, writing this name in the Brazilian Geological History. The Bambuí Group defines and characterizes a long sequence of clastic and carbon sediments that occur in the east-center portion of Brazil in the domains of the Hydrographycal Basin of the r São Francisco River .
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The geology of the region is predominantly composed by the Sete Lagoas Formation, constituted by calcite limestone, dark grey finely stratified with milky calcite and quartz dikes.
The mineral composition shows a predominance of calcium carbonate, superior to 90%, followed by a small magnesium quantity (<2%). Low contents of aluminum-silicates (1,5%) and quartz, also 2% of carbon and small quantities of sulfates that along with the organic matter is responsible for the black color of the rock (SILVA,1977).
1.5. Soil Characteristics
Accordingly to BAHIA (1995), eventhough the region presents other kinds of soils, predominantly occur the Latosols and Cambisols.
Picture 1. Cambisol Profile Picture 2. Oxisol Profile (Latosol)
1.6. Plant Cover
The region presents the largest part of the area occupied by the caatinga (savanna), also having transition areas in a smaller scale.
On the margins of the Jacaré River the main physiognomy is the Dense Arboreal Steppe, forming also paths. These are vegetable formations with the presence of grasses and sedges, like the rush and the “taboa” plant, and also common species of the caatinga, like the itapirucu, mulungu and the Carnauba Palm Tree (Copernicia cerifera). These paths are plant formations over alluvial terrains (BAHIA, 1995).
According to studies made by COUTINHO, in sites with the predominance of Cambisols (limestone), it is common to find the following species: “barriguda-lisa” “Barriguda Tree” (Cavanillesia arbórea), “Embiratanha” (Pseudobombax sp.), “Inharé” (Brosimum sp), “Angico” (Anadenanthera macrocarpa) and “Quiabenta” (Quiabentia zehntyeri).
2. SOCIOECONOMICAL CHARACTERIZATION AND AGRICULTURE OF THE SUB-BASIN
2.1. Socioeconomic Characteristics
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According to the last demography census in Bahia State made by the IBGE in the year 2000 the population of the region of Irecê corresponds to a percentage of about 3% of the total state. There are 372,944 inhabitants occupying an area of about 4.6% of the total state territory, 26.155 sq.km., including 19 cities.
The school regional system is structured in four levels: pre-school, elementary school, high school and college, all distributed in schools supported by the state, the cities and private institutions.
The public health system is characterized by two basic services, hospitals and clinical, distributed in 23 hospital units with 944 beds, 14 of them are supported by the cities, 8 of them are private and one of them is liked to the Federal Government. The clinical service is structured in a network of 108 units, distributed in all the cities, with “health clinic posts”, “health centers” and policlinics.
The infra-structure of the region of Irecê does not give a complete support for the economical activities, it is specially noted the limitations of the water resources and other basic systems that allow the overcoming of the natural restrictions that affect the production process.
The average energy consumption is about 149,147 thousands of kWH, 20% of these are consumed by the agriculture, mainly the irrigation.
It is estimated that 65% of the population has access to the water supply systems. The region has available water supply systems managed by the Water and Sanitation Bahia State Company – EMBASA, the Autonomous Water and Sanitation System – SAAE, the National Health Fund – FNS, a body of the Health Ministry and also various simplified systems (fountains of water supplied by tubular wells), maintained in the rural areas by the City Halls, these occur in an isolated way, or in a participative one, in a partnership with associations of small rural producers or workers.
The environmental sanitation involving the collection of sewage and solid waste is precarious, it can be concluded that it almost does not exist the rain water collection network in the cities neither systems for proper technical destination of the solid urban waste. In all cities, the cleaning of the urban trash is done by sweeping, collection and the use of various transportation kinds: dumpcart, truck, tractor or coach.
The transportation net is characterized by the predominance of the roads, the hydroways are non significant, there are only a few number of paved airplane landing sites and there are no railroads. The main road axis is the BA-052, it crosses the region in the direction east-west, allowing the national integration through the highway BR 116.
The integration in the regional scope is done by secondary roads paved and concreted, connecting the cities in the grain producer’s area. The tertiary road network is very precarious, but it still plays an important role connecting small rural villages and also allowing the access of the equipments in the urban zone.
The telecommunication services available in the region are the ones made available by TELEMAR; they have 7,433 phones and communications via internet. It also stands out as communication vehicles the TV, the radio, newspapers, the postal services and telegraphs.
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2.2. Production Activities
All productive activities responsible for the generation of jobs and income are centered in the agricultural and livestock, specially the irrigated agriculture, and also the induced commercial activities.
The Microregion of Irecê constitutes the economical region # 11 of the Bahia State, its agricultural structures are going through significant changes, specially in the last decades, where there has been a passage from a traditional economy basically constituted by the extraction of natural resources to an agriculture much more technical. There are from the most traditional farming up to modern and technical agricultural practices, such as the use of irrigation equipments, machines, implements and inputs.
The main economical activity of the region is the agriculture and as a consequence of that it is the one that absorbs most of the working force and generating the most significant values of income. The vast majority of the areas that are cultivated is used with the dry agriculture, taking advantage of the rainy season, the irrigation is expanding in a fast way with the use of the groundwater on the Irecê Plateau and also the superficial waters of the rivers Verde and Jacaré (CODEVASF, 1993).
After the eighties an intense and growing process of implementation of the vegetable (legume) irrigation crops, centered in the plantation of carrots, onions and beet took this region to the first place of the production of the Northeast of Brazil and also the biggest continuous production area of carrots in Latin America. There is also a small explored area with fruit plantation.
Regarding the use of the water resources, considering the soil potential and the agricultural tradition of the region there has been a significant raise in the water demand for irrigation. This can critically compromise the water availability on the basin (CODEVASF, 1993) in case the support capacity of the aquifer is not respected and/or the recharge dynamics is affected by the negative impacts over the water flows in the saturated and in the unsaturated zones.
According to studies made in the region, on the Irecê Plateau there are approximately 320,000 hectares of soils available for the irrigation, however the potential of the underground water for exploration is only able to irrigate 26,000 hectares (BAHIA, 1995). Data of the Superintendence of Irrigation of the Secretary of Agriculture of the State of Bahia – SEAGRI estimate the existence of more than 6,083 irrigated hectares and 10,000 drilled wells in the Microregion of Irecê.
It was made a careful evaluation of the efficiency of the irrigation through the use of the Support System for Decision-Making on Agricultural Matters- SISDA , a computer tool with resources to assess and guide about the water demands and to generate technical recommendations to avoid the indiscriminate use of water and energy. The complete study is in Annex 2. The areas evaluated are under exploitation through intensive irrigated agriculture, using the center-pivot irrigation method and localized irrigation, with a low efficiency on the water use.
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Picture 3. Implantation and training for Picture 4. Evaluation of the efficiency of the use of the support system water use and of irrigations of decision-making- SISDA handling
Picture 5 Installation of structure of data collect to feed SISDA for the optimized management of hydric demands in pilot area
3. HYDROGEOLOGIC ASPECTS OF VERDE/JACARÉ SUB-BASIN
3.1. Hydrogeologic and Hydrodynamic Characteristics
The hydrogeologic and hydrodynamic characteristics of the water formations define their capacity for water storage and transmission. Appropriated for each lithological kind or aquifer formation, the storage capacity (porosity) and water transmission (permeability) is the result of the relation of geological factors of a rocky body, from its formation.
The hydrogeology of the karstic water bed of the Bambuí group is characterized by karstic sediments that form inter-grain porosity ways or continuous ways, in an opposite way the crystal rocks form porosity ways through the cracks or the discontinuity. In the karstic the porosity is called primary, in the other ones it is called secondary or acquired porosity. Still in this formal division in two great groups, it stands out because of its unique behaviors the extrusive rocks and the limestones.
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Its main characteristics, however, the dominating presence of secondary porosity in the processes of carstification. These processes, associated with the crack porosity whenever it is present, make this group the one with the most special and complex behavior for the development and validation of the modeling.
The karstic water beds represent many peculiarities and the characterization of the hydraulic system of this kind of water bed is one of great complexity, considering its hydrological/hydrogeological parameter, where the storage and the flow of the underground waters are related to de dissolution or the fracture of the carbon rocks.
From the hydrogeological point of view the karstic system can be represented as an underground network of tubes (karst network) and a very high hydraulic conductivity (K>10-1 m/s) built in a rocky matrix of low permeability (cracked limestone) with K values ranging from 10-3 m/s to 10-7 m/s, depending on the cracking and stratification degree.
The storage in the karstic system is low because of the low permeability cracked limestone. The logic of underground flows in the karstic network is, usually, always linked to the exits (springs) of the system (GRASSO & JEANNIN, 2002).
The biggest hydrogeological challenge is the characterization of the hydrodynamic underground flow laws that rule the different kinds of porosity that happen in the karstic water beds for the dynamical recharge modeling (diffuse or concentrated), storage and underground flow (channel or dispersed).
The management of the water resources in the karstic areas requires specific studies and special proper planning, in the specific case of Irecê, the semi-arid conditions and the exploration pressure that the aquifer is under. The method of the natural and artificial tracers, the use of the rain simulator are the most efficient resources among other experimental resources to make possible the knowledge or estimate hydrodynamic parameters for the modeling of the karstic system.
NEGRÃO, 1987, established boundary conditions for the study of the aquifer, defined flow lines and isolines of the aquifer level considering the exploitation level and the available information on that moment.
GUERRA, 1986 presents and discusses the data of a piezometric campaign made in the period of 1980-1982, with a monthly frequency in some wells placed in the plateau of Irecê. Considering the exploitation conditions and the hydrodynamics of the aquifer, in the studied period it was observed a yearly variation from 8 meters in some wells to 2 meters in others, resulting in an yearly average of 3.3 meters.
These information are valuable as a reference data, starting data, for the adjustment in the development process of the concept model and as a comparison basis with the present exploitation conditions of the groundwater, to assess and quantify the lowering tendency.
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Jussara 600 BA - 052 600 787 Central 662 725
725 787 600 São Gabriel 816 Presidente Dutra 662 Irecê Joao Dourado
América 725 Dourada
Ibitá 787 725
Ibipebá
725 Cafarnaum Canarana 725 Barra do Mendes Barro Alto
Rio Jacaré 787
818
787 Linhas de fluxo
Isolinhas do nivel Souto Soares freático (m.s.n.m.) 725
662
Iraquara
30 Km
Cochó do Moleiro
Figure 4. Phreatic level’s isolines and flow lines. Source: Negrão, 1987.
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3.2. Well Inventory – Largest Concentration Areas
BACIA HIDROGRÁFICA DOS RIOS VERDE E JACARÉ - BA.
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11o 11 o ITAGUAÇU DA BAHIA JUSSARA
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h h c c ~ a a CENTRAL SAO GABRIEL m m a a r r
G G PRESIDENTE DUTRA ~ o
^ JOAO DOURADO a
E E m ~ IRECE ~ D D o FAZ. CURRAL VELHO ' R R R UIBAI GENTIO E E o V V FAZ. BAIXA d FAZ. ÁGUA FRIA DO OURO LAPAO~ Barrage m DA PEDRA ' de Miroros AMERICA'' da DOURADA ere O IBITITA ' V I ou R ' R re c ca h. Ja Gr ande IBIPEBA CAFARNAUM Rio CANARANA BARRA DO MENDES BARRO ALTO
a a d d l l o o S S a MULUNGU d DO MORRO
. . h h c c o R R 12 12 o
41o
LEGENDA o
LIMITE DA BACIA BAHIA SALVADOR
RIO PERMANENTE
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15Km 0 15 30 Km
ESCALA 1:1 500.000
Figure 5. Location of the major concentration of wells exploited in the Verde/Jacaré River Basin.
According to information of local companies, NGOs and users, it is estimated that a number close to 10,000 drilled wells are exploiting the aquifer, most of them were drilled without any licensing, without any study of the interference radius between wells by the management government body, the Superintendence of Water Resources – SRH, with all the conflict risks and the compromising of water quality.
During the development of the Activity 1,5, it was possible to make a preliminary inventory of wells investigating the registers of the Rural Electricity of Bahia – CERB, the Superintendence of Water Resources -SRH and local companies of well-drilling. The biggest concentration of wells is in the municipality of Lapão, where there are concentrated 60 % of
xv the wells, followed by América Dourado in second place, João Dourado in third and Irecê in fourth.
In an universe of approximately 5,000 registered identified wells, the vast majority presents only information about the drilling (profile or lithological description, pumping test and some parameters in the water quality such as nitrates, chlorides and phosphates) they are not georeferenced and even those which present the coordinates have low precision on them.
All the gathered information of the well inventory with coordinates, representing an amount of 807 wells, were organized and put in the system in a chronological growing order by drilling year in the period of 1962 to 1999, a scenery of 37 years, to observe the signals of contamination risks of nitrates, chlorides and the lowering tendency. The inventory of the wells can be found in Annex 6.
3.3. River/Aquifer system and the Availability of Underground Water and Superficial Water
The recharge of the aquifer is basically done by the precipitation; however, it should also be considered the contribution of the irrigation, due to the extension of the irrigated area and the frequency and intensity of the irrigations. Another possible contribution hypothesis is the vertical upward recharge made by the cracked lower water bed.
The global water availability for the system river/aquifer can be estimated around 200-250 cubic hectometers per year, considered the uncertainty because it was determined from the available elements of existing the water balance. In the year of 1976 it was exploited 1 cubic hectometer, this value passed to 12,8 in 1986 and 22.6 in 1991.
The discharge of the aquifer is also significant, in the direction of Jacaré River, but the possibility of the occurrence of deeper flows in the north direction with no relation to Jacaré riiverbed in the direction of the Verde river is not discarded, according to previous affirmation and also because of pumping.
The study of the surface water availability defined reference criteria to guide the granting of the surface water and the development of a model to help the decision for the management of surface waters on the basin.
As an estimate base for availability of water resources, it was mainly used the available data of fluvial historical series. In Annex 1 it is described all the methodology for analysis and treatment of the resulted information, considering a period long enough (22 years).
The most important contribution of this part of the study was the definition of a model of administration of the surface waters, based on a balance function among the water total availability, considering the relationship rain-flow. The model can serve as base in the decisions for granting, for as it can quantify the acceptable risk and the maximum flows that they can be granted, with a certain warranty, depending on the established priorities for the manager body or committee of the basin.
In this first stage a monthly scale of availability was considered, however it would be more necessary and appropriate to reduce this period to ten days or one week, above all, in the
xvi critical periods where the demands are more urgent and necessary and the availability even more reduced.
3.4. Surface Water and Underground Resources Use
The pressure of the uses over the rare surface and underground water resources available in the Verde/Jacaré Rivers is characterized by the strong demand of intensive irrigated agriculture, already approached in previous chapters, followed by the human supply of some municipal districts that do not have access to the supply through the Mirorós reservoir water line that supplies most of the cities on the Microregion of Irecê.
The lack of precise knowledge of the hydrodynamics of the waterbed and consequently the criteria for the analysis and granting considering the interaction between the river/aquifer and the inexistence of a effective governing body on the basin, are all risk factors of a possible overexploitation and lowering of the quality of the water resources in the basin, what is being confirmed through statements of water users about existing conflicts.
Because it is an experimental basin, defined reference by the policies of the Water Resources Management Program – PGRH of the State of Bahia, the studies, the participative troubleshooting, the seminar, the workshop and the technical meetings confirmed the need of strategic actions/inteventions instigated by its management body and participation of the water users, the public bodies and the university, to structure colectively a model of sustainable management and water quality protection on the hydrographical basin, these bases were defined in the Activity 1.5.
4. DIAGNOSIS SYNTHESIS AND INDICATIVE OF IMPACTS OF THE INTENSIVE AGRICULTURE OVER THE QUANTITY AND QUALITY OF GROUNDWATER AND SUPERFICIAL WATER
According to the experimental methodology developed for the Activity 1.5 it was made possible to make the diagnosis through the quantifiable indicators (infiltration, piezometric level measurement, analysis of water samples) to identify the physical degradation signs of the soil and the analysis of the landscape.
The synthesis diagnosis was centered in the perception of the provoked modifications by the human activity over the natural resources, soil, water, vegetation, that are part of the physical environment of the hydrographical basin, in consequence of the conventional agricultural model that is traditionally used in the basins of the Verde/Jacaré Rivers.
The users of the water resources of the region, in statements, affirm that the most perceptive impacts, in which the main cause can be associated to the implementation of the intensive irrigated agriculture on the basin is the reduction of water quantity and the degradation of water quality.
This evidence is a consequence of the land occupation process, the appropriation and the use of the natural resources, soil, water and vegetation, that transformed the natural environment of the region (caatinga) to an agrosystem characterized by the dry agriculture, livestock and later the irrigated cultivations of vegetables, most of the times the management system is not proper and there is no adoption of water or soil conservation.
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The withdrawal with no orientation of the plant cover in regions close to water springs and also aquifer recharge and the margin of the rivers associated to the effects of the degradation of the physical-chemical soil characteristics as a consequence of the intensive mechanization without considering the management of the water and soil principles, the water dynamics of the system the intensive and abusive use of pesticides, fertilizers and herbicides and the lack of sanitation are the main causes of the impacts known by the community, diagnosed and measured by Activity 1.5.
As a continuation it is presented images that show some signs of degradation observed in the of the Verde/Jacaré River Hydrographical Basin and details of some activities developed in the field.
Picture 6. Soil degradation and instability Picture 7. Soil mechanization and soil use of the aquifer structure. up to the river shore, causing Compression of the “dolina” as sedimentation and degradation consequence of over- of the basin. exploitation.
Picture 8. Pesticide recipients discarded in Picture 9. Waste of water due to the environment besides a open unefficient irrigation and soil well. management.
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Picture 10. Intensive mechanization Picture 11. Evaluation of physic and causing physical-hydrical soil chemical degradation process degradation in the aquifer unsaturated area (irrigated soil)
5. EXPERIMENTAL SYSTEM OF CONTROL AND MONITORING
Analysis studies of the degradation risks of water quality in the rural zones or basins where the activity of agricultural production is intense consider as a main causes of pollution/diffuse contamination the use of chemical products such as pesticides, fertilizers and the lack of basic sanitation.
It is evident the need to discipline, reduce and monitor the use of such products, the release of the sewages and the disposal of solid waste for the reduction of the natural resources contamination of water and soil.
The intense and not careful use of these chemical products, its mass production, the ease of getting them with no prescription or inspection and also the careless in the use and knowledge of the persistency of it in the soil and in the water after its application is an unquestionable risk for the environment and the public health.
This problem turns even bigger when it deals with short term crops (vegetables,) and the ones with a great susceptibility, for instance the tomato culture. Due to this particularity, the irrigated agriculture practiced in the hydrographical basin of the Verde/Jacaré Rivers and the sub-basins of the São Francisco River, require special attention because traditionally it has been practiced a traditional agriculture model with great use of herbicides, pesticides and chemical fertilizers, in the majority of the time it is used not obeying the use limits as established by the laws and it is not used any prescription for the product.
The results of this stage of the completed diagnose and the object of Activity 1.5 in a partnership with the Federal University of Bahia and the Superintendency of Water Resources – SRH of the Bahia State, about the study of environmental impacts of the agriculture in the water resources of the basins of the Verde/Jacaré Rivers allows the conclusion that the Microregion of Irecê can be considered a diffuse contamination risk zone of the water and the soil.
According to the Superintendence of Water Resources (1995), the diagnosis made through the Direction Plan indicates that the zone named Plateau of Irecê uses about 10% of its water reserves to supply water for humans and animals, and even with the risks of contamination by
xix the massive use of chemical products (pesticides, fertilizers and herbicides) there is no monitoring and using criteria established.
Considering the present condition and the increase of the irrigated agriculture in the basin of Verde/Jacaré Rivers, with a continuous and growing application of fertilizers and pesticides, it has been made necessary the implantation and systematic use of a monitoring and controlling program of diffuse contamination risks of the toxic waste in the environment, determining its effects and pollution risks of the water bed, of the surface waters and the population;
The diagnosed situation recommends the continuity of the mapping of the risks, the implementation of proper public strategic policies for the decrease of the identified impacts through the mobilization and education of the communities, the participation of research institutions and the systematic presence of the public body responsible for the management and conservation of the natural resources of water and soil.
The environmental meaning of the presence of these chemical wastes in the region is almost unknown since little is known of its nature, effects, composition, biodegradability, how toxic it is and the cumulative nature of the used products, also how difficult it is the detection by the conventional methods, that can underestimate the total load of pesticides in the waters, soils and foods.
Research results conclude that the greates part of the majority of the applied products in the agriculture remains in the soil, a percentage from 50% to 70% approximately can hit the water. What represents a loss of pesticides and also the fertilizers for the agriculture engineers it represents a real risk of the toxic waste to reach the water bodies, with all the known consequences for the public health and animals when the body of water is used for the supply of the animals.
With the objective of characterizing the use of pesticides in the agricultural production system in the Microregion of Irecê and the water contamination risks, it was applied a questionnaire and field campaigns were made to study the pesticide diffusion dynamics in the saturated zones of the aquifer and also the analysis of the presence of toxic waste in water samples from wells and the river.
Among the gathered information through the questionnaires, in an universe of participants of about 350 rural producers, more that 100 answered the questions made about the use and the management of the soil, use of fertilizers, pesticides, herbicides and a management system for the irrigation. It was made the identification of the chemical group, the active principle, composition, formulation, concentration and toxicology of the pesticides more used by the rural producers.
Collections of the water samples in the unsaturated zone were made. This stage has as an objective the withdrawal of the infiltration/percolation, these are the waters that come from precipitation or irrigation and they move in the surface flows and/or it is found between the pores of the soil.
Besides tracking pesticides listed by the rural producers, it was made an option of increasing the research with the objective of tracking the waste of non listed products. The pesticide tracked groups are in the consultant report – Annex 2.
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A second step in the risk analysis consisted in taking water samples from the saturates zones in the aquifer and the river to define the risk indicators of the presence of pesticide waste in the aquifer to serve as support parameters to the decision and guidance of strategic actions of interventions with measures to protect water quality and public health.
The diagnosed situation recommends the realization of a sample planning that is more detailed and that monitors not only the waters of wells and river but also the ones that are in the houses of the population that use the river and the aquifer of the region, other environmental compartments such as the soil and sediments and also the food that is found in the commerce.
The diagnosis made with the actions of Activity 1.5 supported by the GEF and completed with the studies and researches that are being developed by the Federal University of Bahia, funde by the Superintendence of Water Resources – SRH of the state, created a package of basic reference information that allowed the development of the structure and the design of a monitoring and information system proper to the exploration conditions of the natural resources of the water and soil, oriented by a mathematical model of flow and transport that allows the simulation with an acceptable degree of precision of the hydrodynamics of the system river/water bed.
5.2. Selection of the Points for the Establishment of the Underground Water Monitoring System
Chart 1. Definition of the observation well and piezometer network
CITY NUMBER OF WELLS Jussara 08 Central 15 Presidente Dutra 15 São Gabriel 12 Irecê 15 Lapão 15 João Dourado 15 América Dourada 15 Ibititá 12 Ibipeba 06 Barra do Mendes** 04 Canarana** 03 Carfanaum** 02 Uibai 12 Barro Alto** 04 Morro do Chapéu** 06 ** Wells close to the river, on their margins.
Considered criteria in the definition of the well and piezometric network of monitoring. • Integrated management of the surface water and the underground recharge (quantity) and contamination (quality); • Agricultural activity as the biggest user of water and soil natural resources (irrigated agriculture in the semi-arid);
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• Knowledge and registration of the network of water wells, the intensity and forms of use demanded by the agricultural activity; • Establishment of piezometers and water level readers ranging three depths for the sampling and determination of the water level.; • Hydrodynamical characterization of recharge and discharge; • Determination of the direction of the water flows in the system river/aquifer; • Identification of the homogeneous and heterogeneous hydrodynamical behavior zones; • Identification of the situations of overexploitation of the influence areas between the wells to avoid conflicts; • Definition of volumes in the recharge season; • Well that is not under exploration situated at a range of about 400 meters of an exploration well; • To have the known coordinates and depths; • To make the data annotation weekly during the recharge season and monthly during the dry season.
Areas that have a priority for exploitation and higher density of wells: Lapão, João Dourado, América Dourado, Irecê, São Gabriel, where the observation network can be more dense. It is also necessary to extend it for the regions/cities that do not have an intense exploitation of the underground water.
The non existence of accumulated piezometric data, measured in a systematic form, of quality parameters for the classification and a georeferenced register of the wells under exploration are limitations that make it hard the modeling of the aquifer.
As a strategy to obtain reference information in a manner that is more immediate, for a preliminary evaluation of the tendency of the situation of exploitation that it has been submitted the aquifer, it was identified wells that were monitored systematically through a period and are part of the network observed by GUERRA (1987).
Monitoring campaigns were re-started with systematical water level measurements in the wells from the beginning of the rainy season (referent of the recharge volume) of the year 2002, these recently collected data are in Annex 6.
Once concluded the already started works in the inventorying of the wells (registration), which is a crucial information to visualize the space distribution and the distance between the wells, boundary conditions will be defined and the well net monitored will have its number broadened, that is when the piezometers will be installed in some essential points, considering the criteria previously presented in the definition of the monitoring net.
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Variação de nível estático de poço (Avaliação Preliminar)
50.000 )
40.000 SALOBRO 30.000 UMBURANINHA 20.000 ALTURA 10.000 ACHADO PIEZOMÉTRICA(mm 0 AMÉRICA DOURADA 1981/122002/1 2003/0 ANO/MÊS
Figure 6. Variation of the static level of wells in the regions of Salobro, Umburaninha, Achado and América Dourada.
6. HYDROGEOLOGICAL MODEL
The simulation or modeling of the dynamics of piezometric variations is a complex procedure that involves the multi-variation model resources, it requires a number of specific information about parameters that regulate the flow dynamics and the saturated and the unsaturated zone in the hydrogeological system.
To avoid conflicts and guarantee the sustainable exploration and the rational management of the demands of the water resources of the karstic formations, it is absolutely essential the characterization of the hydrodynamical laws that rule the different kinds of porosities that occur in the karstic water beds. Various approaches and methods are used in the quantitative study of a karstic system.
6.1. Unsaturated Zone Characterization
The evaluation of impacts in the unsaturated zone was made through the characterization physical, chemical and also of the flow water dynamics and the diffusion of pollutants, always comparing the intensive zone of cultivations with zones that were never used as a plantation.
The physical properties more affected with the intensive use of the irrigated soils were the porosity, the density, the hydraulic conductivity, the infiltration rates and the water retention capacity in the soils.
The negative effect of the culture in the porosity of the irrigated soils occurred with a higher intensity in the soil layer of depth between 10 and 30 centimeters, in which there was a significant reduction in the macroporosity and in the total porosity, confirmed by the presence of the compacted layer in this depth.
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Chart 2 . Reduction in the hydraulical conductivity (cm per hour) of the non-saturated zone due to the agricultural mechanization effect.
Hydraulic Coductivity Depth (cm) 0 – 10 10 – 20 20 – 30 30 – 40 Irrigated Area 25,73 a 6,92 b 2,89 b 6,85 b Reference Àrea 13,10 b 15,80 a 18,85 a 22,31 a OBS: In each coli\umn, the averages followed by the same letter do not differ among themselves through the SNK test at 5% of probability.
6.2. Recharge Areas
The karsts, because of its special recharge forms, circulation and storage are distinguished from the other water system being, probably, the most complex of them.
According to LLADÓ, (1970) mentioned by GUERRA, (1986) the karstic forms of absorption depending on how the water penetrates can be classified in open or closed forms. Some denominations were adapted from the Spanish because there were no corresponding words in Portuguese.
Between the closed forms these stand out: the lapiás that are embrionary forms, the dolinas, úvalas, poljés and the blind valleys. The dolina is the most classical form of a karst and results in the settlement of the rocky mass caused by the dissolution of the limestone. Its most internal and external form varies according to climatic and geological factors. The blind valleys are valleys that interrupt suddenly the karstic landscape. Generally it indicates ground drainage.
The open forms are those that allow the free penetration of the water, passing from the surface to underground suddenly. Among these are the tops and the drains.
The Figure below exempifies the structural forms of drainage/recharge.
Figure 7. Evolution of absorption forms Source: Lladó (1970)
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6.3. Flow conditions
As consequences of the decrease on the size of the macropores due to the compactation, it can be observed and quantified significant alterations in the physical-hydrical properties of the soil, mainly in the water flows, with the decrease in the hydraulic conductivity and the infiltration rate of water in the soil being able to compromise and/or limit the aquifer recharge, because it changes the natural hydrogram, i.e., the relation between rain, infiltration and runoff is changed, also there are risks of erosion and silt depositing causing it to decrease its depth and make is wider.
The hydraulical conductivity decreased critically in the irrigated areas, the observed values indicated reductions of 56%; 84% and 69% in the hydraulic conductivity in the respective irrigated areas.
Figures 8 and 9 show the behavior and the modifications in the flow dynamics of the unsaturated zone.
Taxas de Infiltração M édia e Instantânea
Média (cm/h) Instantânea (cm /h)
300
250
200
150
VIm = 215,02T-0,2828 R 2 = 0,8786 100 Taxas de infiltração em cm/h 50
VI = 154,21T-0,2828
0 0 50 100 150 200 250 300 350 Tempo em minutos
Figure 8. Behavior and modifications in the dynamics of water flow
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Taxas de Infiltração M édia e Instantânea
M édia (cm/h) Instantânea (cm/h)
350
300
250
200
150
100 -0,4925 Taxas de infiltração em cm/h VIm = 231,33T VI = 117,4T -0,4925 R 2 = 0,8998 50
0 0 50 100 150 200 250 300 350 400 450 500 Tempo em minutos
Figure 9. Behavior and modifications in the dynamics of water flow
The studies and researches allow the conclusion that the dynamics of the macrodrainage of the karstic areas result of the active geomorphologic and hydrogeological processes, it stands out the presence of the extensive nude areas (without vegetation) without currents of surface waters, the occurrence of depressions with underground drainage; the existence of conduits and cavities in the underground by them the currents of groundwater circle and there is a very reduced superficial drainage.
These geomorphologic units allow the classification different stages of the karstification starting with a fluvial landscape and finishing in a landscape fluviokarstic with no superficial drainage. The fluvial landscape is marked by composed depressions. Like this the geomorphologic process of the genesis of a karstic basin is characterized starting from a drainage basin that drains in areas of carbonatic rocks. (Illustraton 10).
There are a great heterogeneity and vertical and horizontal structural differences; it leads to a great variability in the permeability that favors a punctual and zonal infiltration of the currents of surface waters. The direction of the underground flow is determined by the tectonic structure of the karstic forms, regulated by the areas where the recharge and discharge occur.
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Figure 10. Conceptual model of the flow in the conduits of karstic aquifers Source: Leibundgut et. al., 1997.
6.4. Discharge Areas
The sources of great punctual discharges are common. A special kind is the one that works with a siphon; they work in an intermittent way.
Through studies GUERRA (1986), evaluating the hydrodynamic of the karstic watery of Irecê, observed the variation of the hydrostatical levels in the observation wells and it was verified that the fall of the levels, because of the effect caused by the underground drainage, in the dry period, is approximately linear. It should be considered that the even during the rainy months, when there is a relative ascent of the levels because of the effect of the recharge, there would be a relative fall to a corresponding rate to the one observed in the dry period.
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7. SUPPORT SYSTEM TO DECISION-MAKING ON AGRICULTURAL MATTERS – SISDA APPLIED TO THE OPTIMIZED MANAGEMENT OF HYDRIC DEMANDS FOR IRRIGATION USES
SISDA is a software, an useful tool to give subsidies demands for the use of water in irrigation on the basis of simulations of the hydric needs of the exploited crops, making available indicators of technical efficiency, adapted to edaphic and climatic conditions of the region, an experience that have been being used successfully in different irrigated regions of Brazil.
As a computer resource, SISDA (Support System to Decision-Making on Agricultural Matters) is an alternative that allows the systematic monitoring of reasonable use of water by irrigation users. It integrates a larger package of software named IRRIGA, aiming at integrating activities handling with equipment handling (AVALIA).
Starting from climatic information, the program calculates the present demand of water for crops, supplying reports, graphics and standards as well as personalized orientations. Considering a historical basis of climatic data available in the program, the system allows building a historical climatic data basis available in the program, the system allows making rain forecasts and it guides users about the moment to irrigate and the water sheet to be applied, decreasing, thus, chances for waste of water by unnecessary applications.
The system generates a data base corresponding to the consumption of water, hydric deficit throughout crops cycle, which is an important information for management of demands. Utilizes daily meteorological data base of about 700 stations belonging to National Meteorology Institute, allows studies of viabilities (various levels of probability).
Knowing accurately the volume of hydric demands on a monthly and daily scale is fundamental and must be considered in the balance of entrances and exits of water in the procedure of modeling of the aquifer, as well as evaluating the dimensions of wasteful use of water and decisions on demands for granting. The general methodology of work and the results obtained can be found in the consultant’s complete report in Annex 3.
It is worth emphasizing that having defined the strategies and programs of ordering of the use of hydric resources it is important to have instruments that guarantee its applicability. If, in the one hand, it is important to create systems of supervision and control, in the other hand, it is fundamental that irrigation users (small, medium and large) dispose of a management tool applied to hydro-agricultural projects, so that they can optimize the use of water in their production unities.
7.1. Pilot Unities of Consumption Monitoring of Water by Irrigation
The following pilot areas, were set up: Nova Esperança Ranch, Jota 5 Ranch and Estância do Curral Velho Ranch, located in the region of the project’s encompassment. In each of the unities it was installed a meteorological station, composed of a meteorological shelter, thermometer of maximum and minimum and a pluviometer. Each of the irrigation systems was evaluated in order to determine the uniformity of water application, losses by evaporation and wind dragging (aspersion).
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Figure 11 shows a basic exit of the program that accurately indicates the moment for irrigating and the quantity of water to be applied in each field parcels.
Figure 11. Basic Exit of the program SISDA to one of the Pilot Unities. It informs a water deficit on the ground, efficiency of irrigation, time of irrigation and color scale to indicate smaller or greater urgency of irrigation (blue, yellow and red).
Various indicators are necessary for planning the reasonable use of hydric resources in irrigative agriculture, activity that is responsible for the consumption of approximately 80% of freshwater.
The net and gross irrigation sheets are among the most important technical indicators from the point of view of dimensioning of the irrigation system.
By using SISDA, were carried out simulations for two boarder-line situations of hydric needs, involving a region of larger demand, Irecê, in the altitude of 722m, and another of smaller demand, Morro do Chapéu, altitude 1012, utilizing for this SISDA/IRRIGA’s climatic data bank, with historic climatic series of minimum 15 years of daily data.
For the city of Irecê, it was obtained values of gross sheet of project varying 7,6 to 9.6 mm/day, depending on the culture, irrigation equipment, time of planting and probability of rain. It can be observed that the hydric demand of the atmosphere, represented by ETo, showed values quite close to the two studied times of planting, with differences of the order of
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6%; These results indicate stability in the consumption of water throughout the year for Irecê’s region.
As for the city of Morro do Chapéu, also located in the region of encompassment of Sub- project 1.5, under distinct climate conditions, it could be observed that it is a region of smaller hydric demand, claiming smaller sheets of project (mm) and applications of water in smaller quantity. These differences show once more the importance of implanting control systems to obtain reliable levels of control of grants concession.
The simulated results of water consumption for crops of carrot, onion and beet can be used to guide studies of water granting, from the point of view of those who request, as well as from the point of view of those who manage the process of water granting.
Studies on the documentation on the region and visits in the irrigated area indicate that there is not any system of technical management of irrigation, making difficult any conclusion on the efficient use or not of hydric resources on the part of irrigation users. The lowering of the water level in various wells is an indicator of a lack of organization in the process of wells- drilling and use of groundwater.
The simulated values such as gross sheet of dimensioning (mm/day) for crops of carrot, onion and beet varied from 7,5 to 9,6 for Irecê’s county (high demand), and from 4,6 to 6,7 mm/day, in Morro do Chapéu, are technical indicators to subsidize the planning of hydric resources in irrigation projects.
Determining the uniformity of application of water at field level, for the irrigation systems, indicated CUC (CCU)(Christiansen Coefficient of Uniformity) values of 77,6% per center- pivot and 77,9% for leaking. These values are quite bellow those recommended for this systems, which are of 85 to 90% for center-pivot and 90 to 95% for leaking.
Once defined suitable sceneries it is feasible the utilization of SISDA for simulation of hydric need and water granting. The simulated results for water consumption for crops of carrot, onion and beet are subsidies to guide decision-making on the quantity of water to be granted. It is necessary a continued program of training to make available the information, methodologies and implemented products.
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8. CONCLUSIONS
8.1. General Conclusions
• The adopted methodologies, the accomplished and ongoing activities allowed that the conclusions hereby presented serve as subsidy and reference information for the elaboration of the Integrated Management Program –PGI of the São Francisco river by the Brazilian National Water Agency – ANA, for the Program of Management of Hydric Resources –PGRH of Bahia State and for the post-graduation program in Geochemistry and Environment of the Institute of Geosciences of Bahia Federal University, define and prioritize lines of research applied for the Nucleus of Hydrogeologic and Environmental Studies – NEHMA;
• The analysis and treatment of colleted data indicated the need for generating specific information about the unsaturated and saturated area, through research, for the definition of parameters that regulate the hydrogeologic dynamics (recharge, discharge, reserve, vulnerability) of the karstic aquifer, considering the exploitation regime to which it is submitted, to allow the calibration of the model (s) of flow and transport as a support tool to decision-making for the management of the demands and protection of the quality of the water;
• Allowed the evaluation, identification and measuring of the risks of contamination of the water by pesticides and fertilizers residues, of the compromised mechanisms of the hydraulic dynamics and flows of transmission of water in the unsaturated area in large areas where is practiced intensive irrigated agriculture in the basin;
• The activities developed and the outcomes from systematized and integrated consultancies, allowed diagnosing and identifying the indicators of impacts in the agriculture in the river basin; knowing the dynamics of the elements of the climate and conceptually understanding the complexity of the river/aquifer system for structuring and implementing a system of support to decision-making for the participative management of the water resources, in situations where the irrigation has been established as a large user;
• The Subproject stimulated and catalyzed important partnership with the State Managing Organism SRH-BA and with Bahia Federal University, resulting in the celebration of an important agreement that allowed integrating , amplifying actions, continuing monitoring activities, modeling and personnel training;
• Data collecting and systemization of existing and generated information through field campaigns, allowed building up a body of knowledge on specific aspects of the hydrogeologic dynamics characteristic of the karstic systems, to guide the structuring of a monitoring program and the evaluation of the impacts of irrigated agriculture on the quality and quantity of superficial water resources and groundwater in the Verde/Jacaré River Hydrographic Basin, applicable to similar situations on the São Francisco River Basin;
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• Allowed catalyzing a process of mobilization of users, state’s power, public and private companies, NGOs and schools by having technical meetings, seminars, workshops and training;
• Allowed the integration and the strengthening of the relationship university/civil society as well as the one with local state power.
8.2. Specific Conclusions
8.2.1. Hydrogeologic aspects characteristic of the Verde/Jacaré River Sub-basin.
• Defined criteria and hydrogeologic points adequate for the implantation of a monitoring net of dams and the beginning of systematic campaigns of data collect in order to study the recharge ;
• Defined and started specific researches to generate the characteristic hydrogram (rain x infiltration x drainage) and valuation of the hydraulic parameters, hydrologic, hydrogeologic and physical-hydric that regulate the dynamics of water flows, in the system aquifer/river, which is a fundamental information for modeling the hydrogeologic system being studied;
• It was estimated a referential hydric availability as hydric storage available in the aquifer of the order of 200-250 H3/year, this information will have to be accurately gauged, starting from the quantification of recharge and the full annual hydric balance, considering historical series of rain data, flows, piezometric levels and extracted volumes to meet crop demands;
• The compiled information on the evolution of hydric demands reveal that during the periods 1976, 1986 and 1991 it was exploited approximately 1Hm3/year, 12,8Hm3/year and 22,6Hm3/year, respectively, this information will have to be up dated and gauged for the present scenario of exploitation of the aquifer;
• It was executed a study about the regime of pluviometric precipitation in the Verde/Jacaré River Hydrographic Basin, starting from the historical significant series that allowed, to a detailed level, the identification of the spatial and temporal dynamics variation of the distribution of precipitations identifying rainy and dry periods;
• The temporal distribution of rains, corresponding to the monthly average totals, highlights the existence of two pluviometric regimes, with the smallest variability observed in the months of November and December, as well as, in February and March;
• The main rainy season in the basin is between the months of November and February, with a pick in December; and the second rainy period is between the months of December and March, with a pick in March;
• The months from April to September are less rainy. The months from May to October are considered transitory;
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• It can be observed in the basin high levels of rain dispersion, characterizing it as a semi- arid region, with a Standard deviation of 29% of the annual average value of the total of precipitation, which is approximately 734 mm;
• While analyzing the pluviometric totals, it was verified the existence of different cyclic movements, that obey two interpretations: one corresponding to the very specific climate system (El Niño/La Niña) and the other a manifestation that can be related to the effects of the evolution of deforestation in the basin;
• It can be observed that the distribution of rain in the basin does not diverge, in complexity, to the other semi-arid areas of the North-East of Brazil, presenting discrepancies as far as the general tendency of decrease of the pluviometric heights, with values higher than 800 mm in the highest regions and values lower than 700 mm in the other areas of the basin;
• The contribution for the recharge of the basin springs is more significant in the highest regions, where pluviometric totals reach easily above 800 mm;
• The detailed study of the spatial-temporal dynamics of distribution of regime of rains in the basin is a valuable information to establish the conditions of contour of the conceptual model of entrances of water in the system, as well as to guide the installation and suitability of the hydrometric reference network to build a data bank that will be utilized in the study of recharge moments and hydric deficit, to subsidize hydrologic/ hydrogeologic modeling to support decision-making for the management of the hydric demands;
• The interdependent meteorological variables (rain, temperature, evaporation and relative humidity) experience seasonal variations that are co-related. The variations demonstrate changes of direction in the dry season (in the middle of the year) and of the rain (at the end and beginning of the year). There is a strong joining among the meteorological phenomena in the region, with interdependence of tendencies and variations in the long run, mainly, in the case of precipitations and temperatures, and the continued increase of evaporation observed in the period between 1961 and 1970;
• It was carried out an analysis of consistency of the pluviometric and fluviometric information, starting from existing historical, developed and guidance model of support for decision-making in the management of demands of superficial waters, on the basis of a function of balance between hydric availabilities and granting availabilities, considering the risks. The model developed also will be able to serve as a reference when deciding about dimensioning of works of regularization of the rivers flows.
8.2.2. Impacts of the Intensive Agriculture Irrigated on the Quantity and Quality of the Water in the Basin.
• The general absence of riparian woods as well as in important drainage sectors of the hydrographic basin, which were identified as important recharge areas or as producing flowing, is a key factor to be taken into consideration as responsible for the reduction of hydric availabilities because of damaged recharge and silt depositing of the rivers;
• The degradation of the physic and hydric characteristics of the ground was diagnosed and measured through the increase in the apparent and porosity reduction, as indicators of
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generalized compacting in large areas submitted to intensive irrigated agriculture, without the adoption of suitable flow techniques or ground and water preservation;
• The degradation of the physic and hydric characteristics of the ground in the unsaturated area is reflected in the hydraulic conductivity and the rates of water infiltration in the unsaturated area of the aquifer, reaching a reduction of the order of 84%, thus contributing to the damage of the recharge area of the aquifer and of its irrigation efficiency;
• The results of wells and river water analysis detected residues of pesticides organochlorated and/or piretroids in concentrations above acceptable limits, which put at risk people’s and animal’s health, in case spring water will be used for thirst-quenching;
• According to Brazilian legislation, the waters of the three sampled springs have concentration values above what is allowed for potability purposes for aldrin and endosulfan. The values for aldrin are 84 times higher than what is allowed in the samples of América Dourada, meanwhile Endosulfan shows values 20 to 26 times higher than what is allowed in the samples of water of the three counties where it was sampled;
• Among all the spectrum of pesticides traced in the samples of water extracted from the profile of ground for the study of diffusion of pesticides in the unsaturated area, only carbendazir was detected in increasing concentration, expressed in the order 0,40 µg/L for the depth of 15cm, increasing in an increment of 130% in the depth of 35cm reaching the concentration of 0,92µg/L;
• The persistency and mobility of carbendazir in the samples of water and the increase in the concentration in depth is and indicator of contamination risk for the saturated area of the aquifer;
• It was also proceeded to the evaluation of the evolution of nitrate concentrations in wells water in the area by observing an increasing augmentation, throughout time, reaching concentrations above limits, which put a risk public health, in case that water will be used for human consumption.
8.2.3. Pilot System of Controlling and Monitoring
• Were identified, by municipalities, the areas submitted to a larger pressure of use of the natural resources water and ground by irrigated agriculture, as a criteria for finding wells of observation, piezometers and points of water collect for analysis of the parameters of framing and presence of pesticide residues;
• On the basis of the information obtained on the conceptual model of the hydrogeologic framework of the aquifer and in an estimation of spatial distribution of the density of wells under a regime of exploitation, were previously defined the criteria for establishing network for monitoring the wells and the installation of piezometers, to be ratified in the period after the wells were registered, when it will be amplified and defined the permanent collect network of information that will feed the data bank for modeling of recharge purposes, evaluation of the lowering, ray of interference and quality of groundwater;
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• As a strategy, in the short run, to generate information to allow preliminary interferences over recharge and lowering, was identified a network of wells for observation that were monitored from 1980 to1981, georeferenced and taken again systematic campaigns of level measuring, as from the rainy season of 2002;
• Comparing the levels or piezometric heights measured in the same wells in December 1981, December 2002 and January 2003, it can be observed signs of lowering of the order 13 meters, 11 meters and 6,0 meters respectively for three studied points;
• The preliminary detected results, knowing that organophosphorated pesticides have been being used in the region, recommend that it should be carried out a more detailed sampling plan in order to get a more complete and funded diagnostic, monitoring not only wells and river waters, that serve for human supplying, but also waters that are at homes;
• The identified situation of existing rural communities supplied with wells, suggests urgency and priority in the execution of a more detailed study, with a longer monitoring time and more rigorous control over environmental parameters, evaluating co-relations between the latter and illnesses that attack the population;
• Considering the high vulnerability to contamination risks, characteristic of karstic aquifers, it is prudent that tracking should be amplified including other possible sources of contamination, such as effluents, accumulated garbage and gasoline stations, besides pesticides, considering all the parameters of the resolution CONAMA 20/86 as well as the presence of hydro-carburets for wells used for human supplying.
• 8.2.4. Hydrogeological Model
• From a hydrogeologic point of view, karstic system can be understood as a waterground net of conduits with a very high hydraulic conductivity (K > 10-1 m/s), characteristic of a low permeability rocky matrix (fissured calcarium) with K values in the range 10-3 m/s to 10-7 m/s, depending on the degree of fracturing and stratifications. The storage capacity in the karstic conduit system is low and because of the fractured calcarium is also of low permeability. The karstic net is, generally, always connected to the exiting springs of the system;
• According to the interpretation of hydrogeologists, Dr. Iñaki Antiguedad and Dr Ignácio Morell Evangelista, the possible vertical hydraulic relations existing between the hydrogeologic system of Irecê´s Plateau are not well known, and this justifies the lack of clarity reflected on the available information in the executed studies. However, it allows to affirm that the aquifer system drains to both borders of Irecê’s Plateau, with discharge to Verde River West bound and to Jacaré River East bound. The latter characterized direction flow is the most important discharge area of the Plateau;
• The recharge of the aquifer is fed, fundamentally, by precipitation waters; however, it must be considered the possible contribution of irrigation, given the extension of irrigated area and the frequency and intensity of irrigations. Another possible hypothesis for the contribution of the recharge is the vertical ascending feeding from the fissured lower aquifer.
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• Aquifer’s discharge is significant, mainly in Jacaré River, though, it cannot be rejected the hypothesis of occurring deeper flows North bound in relation to Jacaré river’s bed and also by pumping effects.
• 8.2.5. Support to Decision-making on Agricultural Matters – SISDA Applied to the Optimized Management of Hydric Demands for Use in Irrigation
• SISDA has proven to be a useful tool to estimate, with an accurate degree, volumes of demands for the use of water on the basis of simulations of annual hydric needs for the main exploited crops in the region, making available technical indicators of deficiency, adapted to edaphic and climate conditions of the region. This information is fundamental and must be taken into consideration in the balance of entrances and exits of water in the modeling proceeding of the aquifer, as well as to evaluate the dimension of the wasteful use of water;
• As a computer resource, SISDA (Support to decision-making on agricultural matters) is an alternative that allows the systematical monitoring of the reasonable use of water by irrigation users;
• Considering a historical climatic data basis available in the program, SISDA allows the forecast of rain and guides users about the moment to irrigate and about the water sheet to be applied, decreasing chances of water wasting because of unnecessary applications;
• There was a significant manifestation of interest, involvement and demand of training on the application and use of the SISDA software on the part of irrigation users of the region;
• The events that were carried out: seminars, workshops, training, through statements, allow to conclude on the existence of risk already installed of conflicts among users, recommending the definition of strategies and programs of ordering the use and participative management of demands of hydric resources, making available tools that ensure its applicability;
• It can be observed that to equationate or mitigate the risks of eminent conflicts in the region, on the one hand, it is important to create inspection and control systems, on the other hand, it is fundamental that irrigation users (small, medium and large) have access to information as well as to technical and management training in order to promote culture- change regarding the wasteful use of water and wells-drilling in their producing units;
• A program of activities was developed aiming at avoiding, in the medium to the long run, conflicts between the availability of water and the needs for irrigation in Irecê’s region, through the popularization, organization and implantation of a managing system, referenced in technical indicators gauged on a level of irrigation users’ properties
• The simulated results of water consumption for the crops of carrot, onion and beet will be used to estimate the volume of hydric demands extracted annually from the aquifer. This information will be integrated to the data/information bank and will be used as a reference in the proceedings of modeling, as well as to guide decisions on the granting of water;
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• With SISDA resources, values of gross dimensioning sheet (mm/day) for irrigated crops were generated and made available as technical indicators to subsidize the planning of the use of hydric resources in the irrigation projects;
• Determinations of the uniformity of application of water at field-level, for the irrigation systems, indicated CUC values (Christiansen’s Coefficient of Uniformity) of 77,6% for center-pivot and 77,9% for leaking. These values are much lower than the recommended values for these systems, which are from 85 to 90% to central pivot and 90 to 95% to leaking.
9. RECCOMENDATIONS
9.1. Recommendations of Structuring Character for the Use and Conservation of the Natural Resources Water and Ground in the Sub-basin.
• Generation of digital cartographic basis in scale 1:25:000 including the Verde and Jacaré River Hydrographic Basin and contour of the aquifer with all the wells, main springs, recharge and discharge georeferenced areas;
• With the cartographic basis on scale 1:25.000, to build equipotentials, lines of flows, to define conditions of contour for modeling and shaping an information system to support decision-making on the control of granting through management of demand, in the precise definition of monitoring points for the generation of a data bank to accumulate historical series of the dynamics of seasonal and spatial variation of the quantity and quality of water throughout a hydrologic year;
• Acquisition of automatic mediators of wells-level, linygraphs and meteorological stations with datalog to enable the assembling of a daily collecting information net on a static basis, river flows and element of the climate to enable the definition of the ray of influence between wells and the full hydric balance, considering all the entries and exits of water in the system (rain, evaporation, evapotranspiration, extractions and applications by irrigation) ;
• Acquisition of a special probe to measure parameter of monitoring of water quality for monitoring and framing purposes;
• Installation, in the municipality that exercise the greatest pressure of exploitation in the aquifer, of a support basis of data geoprocessing and processing with server in net to systematize all information, calibrate and validate hydrogeologic model and make available information to irrigation users, associations, basin’s committee, universities, companies and anyone interested;
• Amplification of the pilot areas to implant the bases and training for optimizing the efficiency of water use in the irrigated agriculture by using SISDA - (Support to decision- making on agricultural matters) as a tool to support the strategic management of irrigation;
• To define and validate optimal levels of hydric demands for irrigated cultivations as reference information for the efficient use and/or non conflictive management of the demands for hydric resources as a subsidy for users, basin’s organisms and public managers;
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• It is necessary a continued program of training to make available information, methodologies and resources of optimized management of water use in the irrigated agriculture as the main demand for water in the basin;
• It is recommended to carry out training for technicians and mobilizing region’s users to demonstrate and disseminate the economic and environmental advantages of the efficient water use in irrigation ;
• Some aspects were perceived as priorities, such as the need for detailing and/or fine adjusting in the comprehension of the hydrologic year in Verde/Jacaré River Hydrographic Basin, consistently and accurately defining the significant moments of entries and exits of water, the shortage periods, considering spatial-temporal dimensions and the possibility of amplifying the study up to the passage of the São Francisco Basin that is inserted in the territory of the Bahia State;
• The follow up of climatic variations is an activity that depends on the availability of information collected in networks of meteorological observations. The absence of reliable historical series and the insufficiency in meteorological stations, in number and in uniformity in the periods of operation, do not allow the evaluation of climate variations and, thus, the evaluation of the regional hydrology;
• To increase the number of automatic meteorological stations of long autonomy and install linygraphs;
• The collecting network of hydrometeorological data must be coherently installed and operated according to the World Meteorological Organization – OMM standards, such as:
− Maximum spacing between the stations must be approximately 100 Km, allowing the efficient use of information such as initial conditions for global and regional models of whether and climate forecast; − The distribution of stations must comply with the different regional climatic behaviors, as well as the variations of relief and vegetation along the basin; − The choice of locals that present a certain degree of security should be a requirement to designate the location of the data collecting station.
• Making use of the above criteria and taking into consideration infra-structure, road access conditions and the homogeneous regions of the São Francisco Basin, were identified 20 (twenty) places within the basin to compose the net of automatic Data Collecting Platform (PCD). However, due to the high costs of PCD’s it was chosen to install only 11 (eleven) Platforms;
• Each station must be provided with, at least, sensors of atmospheric pressure, precipitation, wind direction and speed, solar radiation, air temperature and humidity. Other sensors can be added to the stations to complement the observations, destined to assist sectors such as agrometeorology, climatology and others;
• The implantation of this PCDs net will allow the monitoring of climatic and hydrologic conditions, besides to contributing for maintain the Hydrometeorological Data Bank of
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Bahia state - BDRH, which shall serve as the base in the management of hydric resources, in the granting processes, electric power sector, sectors linked to agriculture, to the environment, civil defense, leisure and tourism, scientific research and others;
• Amongst the main products that can be available, stand out: 1) weather forecast emission with forecasts up to five days and tendency of the climatic behavior three months beforehand; 2) emission of alert bulletins of severe whether and of occurrences of climatic adversities; 3) agrometeorogical zoning for the main cultivations of the Basin, 4) system of hydric availability for the agriculture and hydrologic data gathering of the hydrographic micro-basins for the agriculture in the São Francisco River Basin;
• To establish interactions on the global and regional level, as well as to evaluate the consequences of global climatic changes and the use of hydric resources in the basin;
• That the developed methodology and the recommendations of Sub-project 1.5 be applied in the whole course of the São Francisco River in the territory of Bahia state, wherever be practiced intensive irrigated agriculture and wherever it exists evidences of a narrow interaction between superficial water and groundwater;
• Mobilization for spreading out all the information obtained by Sub-project 1.5 , by the agreement SRH/UFBA and to form the basis’s committee.
9.2. Recommendations of Specific Character
• The stages of fundamental basic necessary studies on the system aquifer/river of the Verde/Jacaré Rivers Basin, so that the hydrogeological model is used as support tool to the decision-making, they are the following ones:
• Estimate and validate the volumes of hydric storages of the karstic aquifer;
• To carry out and interpret results of experiments with natural and artificial trackers;
• Proceed to the analysis of hydrograms in springs exits (analysis of the recession and separation of its components);
• To carry out whole hydric balances characterizing the hydrologic year;
• Statistic analysis between dependent variable in function of the independent variables of entries and exits (auto-correlation and crossed correlation);
• Study of the mechanism of infiltration and recharge concentrated in drains and diffuse in the fissured calcareous area;
• Collecting water from rain, wells and rivers for isotopic analysis with oxygen 18, deuterium, other markers and building up-to-date maps with equi-potentials and resulting lines of direction of the flow is necessary to validate the hypothesis;
• To define and implement an environmental monitoring program for controlling the risks of contamination and use of pesticides through a sampling plan, defining frequency and
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number of samples, starting from data carefully gathered and according to the availability of resources, interests on the part of society and on the public organ in charge of the management and preservation of the hydric resources of the state;
• To increase the number of pesticides to be analyzed, going up to 20 composts. Thus, besides those which were already traced, it must be imported patterns of pesticides that have a significance on national and international legislation, but, mainly those pesticides that are important for the studied region, such as: methamidophos, mancozeb, benomil (carbendazim e thiabendazole), linuron, dieldrin, DDT, endrin, 2,4D, lindano and permetrina ;
• For the 20 points to be established, as initial hypothesis, the minimal number of samplings to be collected during each period (6 months) for water, ground and sediment is of 120 samplings. For reliability and results, samplings will be duplicated;
• Sampling points must be in number enough to allow the interpretation of the results. To take out at least 6 samples for appropriate characterization of a cycle of fluctuation or a period of high or low concentration of residues;
• To determine residues of pesticides in food, mainly carrot, with field samples, which have been being traded;
• The desirable time for the study to characterize the quality of food as far as the presence of pesticides is concerned is of 2 years. During this period, it can be done a monthly sampling plan, collecting samples from products traded and/or consumed;
• To carry out rehearsals with ground columns in laboratory, establishing a bank prove and increasing the doses of the most used pesticides, considering persistency and mobility. To proceed to the analysis and study of the correlation among applied doses, time and detection level on the ground and in the water, evaluating risks of residues transference to the aquifer, trough diffusion or vertical percolation of water;
• To establish experimental parcels, in the field, with suction lisymeters for the collect of samples of water in different depths, until reaching the aquifer’s saturated area.
9.3. Proposals of Terms of Reference and Associated Costs
The adopted methodologies and the activities accomplished by Subproject 1.5 allow that the conclusions and presented recommendations serve as subsidies and reference information for the elaboration of the Integrated Management Program – PGI of the São Francisco River Basin. In this sense, the following synthesis of terms of reference are presented:
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Chart 3. Detail of the necessary resources (in US$) to the continuity of the project. Specification Products/Length Value (U$) Digitalization of map of hydrographic basin Cartographic and planialtimetric 20.000 in scale 1:25:000 integrating the system base in scale 1:25:000, digital aquifer/river, georeferencing all the wells and model of the site, map of grounds, points of superficial water capitation to isohyets, uses, hydrometric network establish the condition of contour for the and homogeneous areas/10 months. mathematic modeling. Developing researches using rain simulator, Installation of equipment and 50.000 linygraphs, automatic level measuring, experimental parcels of monitoring isotopes and other markers to determine and control of diffusion of polluting parameters that regulate the hydrodynamics matters, presenting and making a of flows (entrances and exits) and transport of map of the vulnerability and quality polluting matters for calibration and of the waters, calibration of the validation of mathematic model for mudflow and other models as tools management of karstic systems. of management of the waters / 12 months. To implement a program of environmental Map with the specification of the 80.000 monitoring and mitigation of risks on public georeferenced monitoring network health. To install monitoring network, carry and reports with results, conclusion out systematic sampling, and carry out and indication of measures that analysis for tracing pesticide residues in may mitigate risks of waters of sources used for human supply and contamination /2years. agricultural products . Amplification of the hydrometric network Assembling and operation of 250.000 and observation wells in the passage of the hydrometric network during a year. São Francisco River in Bahia State. Presentation of map of hydrometric network and technical report on the implantation and data collected and consisted during a year/2 years. Campains of systematic data collect in the Implantation of pilot unities, 130.000 field, formatting of a system of information, calibration and training for calibration and validation of the irrigating producers using the hydrogeologic model and implantation of the system of support of decision- system to support decision-making on making to optimize the efficiency agricultural matters in the large irrigated and use of water in the irrigation. perimeters in the passage of the São Presentation of reports with Francisco Basin in Bahia State. technical indicators of reference for sustainability of hydroagricultural projects/ 2 years. . Mobilization and training of users, formation Formation of a Committee of the 70.000 of a committee of the basin active in the Verde/Jacaré Rivers Basin /1 year participative and systematized by computers and a half management of the waterground and superficial resources in the basin, starting from sceneries strategically drawn. TOTAL 600.000
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• Terms of Reference - 01
Objectives: Digitalization of cartographic base of the basins of Verde and Jacaré Rrivers in scale 1:25:000 integrating the system river/aquifer georeferencing all drilled wells and points of capitation of superficial water, adding to the maps karstic areas as well as connection areas with the system aquifer/river, of occurrence out of the water divisors of the basins, in order to establish homogeneous areas and conditions of contour for the mathematic modeling.
Value of the Contract: U$20.000
Working Area: Geoprocessing, Geomatic, Hydrogeology, Hydrology and Geostatistics.
Main Specific Activities: Proceed to the vectorial digitalization of the area, area of inclusion defined in the objectives, through the photo-restitution technique using aerial photographs in scale 1:60:00, satellite images, gathering referential network points in the field using a GPS of accuracy and registering wells and grantings conceded in the Verde and Jacaré Rivers. To elaborate thematic maps of grounds, present uses, precipitation regime, hydrometric net.
General methodology of Work: Proceed to the gathering and systemization of all the information (cartographic, data bank of georeferenced wells and hydric resources users, aerial photographs and satellite images) existing on the area. To carry out campaigns in the field to gather referential network points with a GPS and identify occurring types of ground. To use the photo-restitution technique and build up cartographic base in scale 1:25:000 and thematic maps of ground, uses and homogeneous areas.
Products: Planialtimetric cartographic base in the scale 1:25:000, digital model of the site, maps of grounds, isohyets, uses, hydrometrics and homogeneous areas.
Detailed Timetable: The stages of field work and the evaluation and approval of the products will be accomplished under the supervision of the coordination of the sub-project with the participation of teachers/researchers of the Department of Agricultural Engineering - DEA of the School of Agronomy and the Nucleus of Hydro-geologic and Environmental Studies - NEHMA of the Institute of Geosciences of UFBA. The execution of activities/goals will be seized as an opportunity for personnel training as well as involving students of Post-graduation and Graduation in Agronomy, Geography and Geology.
Length and Headquarter: The development of the activities will last eight months. Works will be carried out in the field, in Irecê’s micro-region, in the Nucleus of Hydrogeologic and Environmental - NEHMA and at the company specialized in geoprocessing that will win the bid to carry out the work.
Reports and Payment Conditions: • Payments against products and final payments of 35% of the value of contract after the approval of the final product;
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• Partial and final reports presented in two originals and a disk - Word 6.0 or above (Final Report with executive summary in Portuguese and English, with conclusions and recommendations).
• Terms of Reference - 02
Objectives: Developing researches using rain simulators, linygraphs, automatic level meters, isotopes and other markers to determine parameters that regulate the hydrodynamics of flows (entries and exits) and installation of experimental parcels and executing campaigns to control water quality for purposes of framing and modeling of transport of pollutants for calibration and validation of the mathematic model for management of demands and protection of water quality in karstic systems.
Activity Costs: U$50.000
Working Area : Hydrogeochemistry and Hydrology
Main Specific activities: Acquisition of automatic level meters, linygraphs, TDR, extractor of solution of the soil, collects of the soil and column assembly for simulation of transport of pollutants. Collecting water and carrying out isotopic analyses. Simulation of the dynamics of transport of pollutants in the unsaturated area with use of the rains simulator.
Metodologia Geral do Trabalho: Acquisition and installation of equipments, monthly collections of water of wells and of the rivers to analyze parameters of quality of water, accomplishment of rehearsals of diffusion of pollutants in field conditions with use of the simulator of rains, installation of experimental portions for systematic monitoring and validation of the dynamics of diffusion of pollutants. Calibration of the modflow and framing of aquifer and superficial waters.
Products: Installation of equipments and experimental portions of monitoring and control of diffusion of pollutants, making and presentation of vulnerability map and quality of the waters, calibration of the modflow as a tool of management of water quality . Detailed timetable: The accomplishment of the activities is foreseen for a period of two years The stages of field work and the evaluation and approval of the products will be accomplished under the supervision of the coordination of the sub-project with participation of the teachers/researchers of Department of Agricultural Engineering - DEA of the School of Agronomy and the Nucleus of Hydro-geologic and Environmental Studies - NEHMA of the Institute of Geosciences of UFBA. The execution of activities/goals will be seized as an opportunity for personnel training as well as involving students of Post-graduation and Graduation in Agronomy, Geography and Geology.
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Length and Headquarter: The length of work will be monitoring at least two complete hydrologic years, ideally three. Works will be carried out in the field, in Irecê’s micro-region, in the Nucleus of Hydrogeologic and Environmental - NEHMA , at the laboratory of nuclear physic of UFBA.
Reports and Payment Conditions: • Payments against products and final payments of 35% of the value of contract after the approval of the final product; • Partial and final reports presented in two originals and a disk - Word 6.0 or above (Final Report with executive summary in Portuguese and English, with conclusions and recommendations).
• Terms of Reference - 03
Objectives: To implement a program of environmental monitoring and mitigation of risks about public health through the contamination of the water and foods by pesticides residues, nitrates, chlorates and metals. To install monitoring network and to carry out systematic samplings, and execution of analyses for tracking of pesticides residues in spring waters used for human storage and also to analyze residues of pesticides in agricultural products
Cost: U$80.000
Working Area : Chromatography and Statistics.
Main Specific activities: To carry out systematic collects of samples of water during one complete hydrologic year and chromatographic analysis to proceed to tracking residues of pesticides, concentrations of nitrate, chlorates and elements lines, in the water of wells and rivers. To collect sampling of food and carry out analysis of pesticides residues.
General Methology of Work: To apply statistical analysis to define points, frequency and number of water samples to be collected. Proceed to collecting samples with adequate techniques, packaging at low temperature and chromatographic analysis for residues of pesticides. Analysis of water samples, collected in wells and in the residences, used for human storage. Tracking of pesticides residues in samples of carrot, onion and beet.
Products: Map with specification of the georeferenced monitoring network and reports with results, conclusions and indication of mitigating measures of risks of contamination.
Detailed Timetable: The stages of field work, the evaluation and approval of the products will be accomplished under the supervision of the coordination of the sub-project with participation of the teachers/researchers of Department of Agricultural Engineering - DEA of the School of Agronomy and the Nucleus of Hydro-geologic and Environmental Studies - NEHMA of the
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Institute of Geosciences of UFBA.. The execution of activities/goals will be seized as an opportunity for personnel training as well as involving students of Post-graduation and Graduation in Agronomy, Geography and Geology.
Length and Headquarter: Works will be carried out in the field, in Irecê’s micro-region, in the Nucleus of Chromatography of Sergipe Federal University during a whole hydrologic year.
Reports and Payment Conditions: • Payments against products and final payments of 35% of the value of contract after the approval of the final product; • Partial and final reports presented in two originals and a disk - Word 6.0 or above (Final Report with executive summary in Portuguese and English, with conclusions and recommendations).
• Terms of Reference - 04
Objectives: Amplification of the hydrometric network, including observation of wells, in the passage of the São Francisco Basin in Bahia state, to feed data bank for modeling of the basin hydro dynamics.
Cost: U$250.000
Working Area : Hydrometrics and Meteorology
Main Specific Activities: To define adequate points and install hydrometric network with meteorological stations and linygraphs.
General Methodology of Work: Starting from the defined criteria for the World Organization of Meteorology (OMM) to define the number and place of installation of meteorological stations and according to hydrologic criteria to define the number and place of the linygraphs installation for the collection of data for the calibration of hydrological modeling of the basin.
Products: Assemblage and operation of a hydrometric network during a year. Presentation of map the hydrometric network and technical report of implantation and data collected and consisted during a year.
Detailed timetable : It is estimated a period of two years for the acquisition of the equipments, installation of the net and operation during a period of one hydrologic year. The stages of field work, the evaluation and approval of the products will be accomplished under the supervision of the coordination of the sub-project with participation of the teachers/researchers of Department of Agricultural Engineering - DEA of the School of Agronomy and the Nucleus of Hydro- geologic and Environmental Studies - NEHMA of the Institute of Geosciences of UFBA.. The execution of activities/goals will be seized as an opportunity for personnel training as
xlv well as involving students of Post-graduation and Graduation in Agronomy, Geography and Geology.
Length and Headquarter: Works will be carried out during a period of one and a half year, in the field, in the region defined on the objectives.
Reports and Payment Conditions: • Payments against products and final payments of 35% of the value of contract after the approval of the final product; • Partial and final reports presented in two originals and a disk - Word 6.0 or above (Final Report with executive summary in Portuguese and English, with conclusions and recommendations).
• Term of Reference - 05
Objectives: Campaigns of systematic collects of data in the field, formatting an information system, calibration and implantation of a system of support to decision-making on agricultural matters in the large irrigated perimeters of the São Francisco Basin in the passage in Bahia State.
Cost: U$130.000
Work Area : Agricultural Engineering and Hydrocomputer studies.
Main Specific Activities: Evaluation and efficiency of the irrigation systems of the main irrigated perimeters in Bahia, inserted in the São Francisco river’s basin.
General Methodology of Work: Technical meetings with irrigating producers and technicians in the main irrigated perimeters of Bahia inserted in the São Francisco Basin, installation of pilot units for calibration trainings of users for application of the System of Support to Decision-making for the management of demands and optimization of the efficiency of application of the water in the irrigated cultivations as the most expressive demand of consumptive use of water.
Products: Implantation of pilot units, calibration and training for irrigating producers using the System of Support to Decision-making to optimize the efficiency of use of water for irrigation. Presentation of reports with technical indicators of reference to sustainability of hydroagricultural projects.
Detailed Timetable: The activities will be accomplished during a period of 2 years. The stages of field work, the evaluation and approval of the products will be accomplished under the supervision of the coordination of the sub-project with participation of the teachers/researchers of Department of Agricultural Engineering - DEA of the School of Agronomy and the Nucleus of Hydro-
xlvi geologic and Environmental Studies - NEHMA of the Institute of Geosciences of UFBA. The execution of activities/goals will be seized as an opportunity for personnel training as well as involving students of Post-graduation and Graduation in Agronomy, Geography and Geology.
Length and Headquarter: The activities will be accomplished during a period of 2 years, in the field, in the region defined on the objectives, in the Department of Agricultural Engineering - DEA of the School of Agronomy and the Nucleus of Hydro-geologic and Environmental Studies - NEHMA of the Institute of Geosciences of UFBA
Reports and Payment Conditions: • Payments against products and final payments of 35% of the value of contract after the approval of the final product; • Partial and final reports presented in two originals and a disk - Word 6.0 or above (Final Report with executive summary in Portuguese and English, with conclusions and recommendations).
• Term of Reference - 06
Objectives: Mobilization and users' training for the formation of the Basin Committee and/or consortium of active irrigation users in the participative management and computerized of the waterground and superficial hydric resources in Verde/Jacaré Rivers Basin.
Cost: U$70.000
Work Area : Sociology, Hydrology, Agronomy, Education.
Main Specific Activities: Execution of diagnostic on the level of existing organization in the basin (associations, cooperatives, unions, NGOs, multiple uses of water, public power actors, and gathering of information on problems related to the management of demands and water quality with identification of the root-causes. Formal constitution of the committee.
General Methodology of Work: Users’ mobilization through meetings, seminars, workshops carried out in all the municipalites that integrate the hydrographic basins of Verde and Jacaré Rivers, the activities will be carried out, coordinated and evaluated together with professors/researchers of UFBA and NGOs.
Products: Formation of the Committee of Verde/Jacaré Rivers Basin
Detailed Timetable: Activities will be carried out during a period of 2 years, with monthly meetings in all the municipalities and quarterly integrative inter-municipalities meetings with the participation of representatives of users of all the municipalities.
Length and Headquarter:
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Works will be carried out during a period of one and a half year, finalizing with the formation of the basin’s committee and the implantation of a model of computerized management as a tool of support to decision-making in the integrated management of superficial and ground water.
Reports and Payment Conditions: • Payments against products and final payments of 35% of the value of contract after the approval of the final product; • Partial and final reports presented in two originals and a disk - Word 6.0 or above (Final Report with executive summary in Portuguese and English, with conclusions and recommendations).
TOTAL COST: U$ 600.000
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IMPACT OF THE AGRICULTURE OVER GROUNDWATER RESOURCES IN THE BASIN OF THE VERDE/JACARÉ RIVER
SUMMARY
INTRODUCTION 1
1. PHISIOGRAPHIC CHARACTERIZATION OF VERDE/JACARÉ SUB- BASIN 3 1.1. Location 3 1.2. Geomorphologic Characteristics 5 1.3. Hydrometeorological Characteristics 6 1.4. Geologic Characteristics 18 1.5. Ground Characteristics 19 1.6. Vegetable Coverage 21
2. SOCIOECONÔMIC CHARACTERIZATION AND AGRICULTURE OF THE SUB-BASIN 22 2.1.Socioeconomic Characteristics 22 2.1.1. Demography 22 2.1.2. Education 22 2.1.3. Health 22 2.1.4. Infra-structure 23 2.2. Productive Activities 24 2.3. Agriculture in the Verde/Jacaré Sub-basin 25 2.4. Existing Irrigation Projects 26
3. HYDROGEOLOGIC ASPECTS OF VERDE/JACARÉ SUB-BASIN 29 3.1. Hydrogeologic and Hydrodynamic Characteristics 29 3.2. Inventory of Wells – Areas of Major Concentration 33 3.3. System Aquifer/River and Waterground and Superficial Water 34 Availability 3.4. Use of Hydric Waterground and Superficial Resources 41 3.5. Preliminary Estimation of the Average Production Capacity of the 42 Explored Wells 3.6. Waterground Quality 43 3.7. Analysis Results 53
4. DIAGNOSTIC SINTHESIS AND INDICATORS OF IMPACT OF 60 INTENSIVE AGRICULTURE ON THE QUANTITY AND QUALITY OF GROUNDWATER AND SUPERFICIAL WATER
5. PILOT SYSTEM OF CONTROL AND MONITORING 62 5.1. Definition of Criteria and Basic Procedures for the Implantation of a 62 Monitoring System of Impacts of Agriculture on Hydric Resources 5.2. Selection of the Points to the Establishment of a Monitoring System of 63 Waterground
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6. REFERENCIAL INFORMATION FOR THE STRUCTURATION OF A 66 HYDROGEOLOGICAL MODEL FOR THE KARSTIC AQUIFER OF IRECÊ-BA. 6.1. Characterization of the Unsaturated Area 66 6.2. Recharge Areas 67 6.3. Flow Conditions 69 6.4. Discharge Areas 72
7. SUPPORT SYSTEM TO DECISION-MAKING ON AGRICULTURAL 74 MATTERS– SISDA APPLIED TO THE OPTIMIZED MANAGEMENT OF HYDRIC DEMANDS FOR IRRIGATION USE 7.1. Pilot Unities of Water Consumption Monitoring by Irrigation 74
8. CONCLUSIONS 81 8.1. General Conclusions 81 8.2. Specific Conclusions 82 8.2.1. Hydrogeologic Characteristic Aspects of Verde/Jacaré River Sub-basin 82 8.2.2. Impacts of Intensive Irrigated Agriculture on the Quantity and Quality of 83 Water in the Basin 8.2.3. Pilot System of Controlling and Monitoring 84 8.2.4. Hydrogeologic Model 85 8.2.5. Support System to Decision-Making on Agricultural Matters– SISDA 86 Applied to the Optimized Management of Hydric Demands for Irrigation Use
9. RECCOMENDATIONS 87 9.1.Reccomendations of Structuring Character for the Management of the Use and 87 Conservation of the Natural Resources Water and Ground in the Sub-basin 9.2. Recommendations of Specific Character 89 9.3. Proposals of Terms of Reference and Associated Costs 90 10. BIBLIOGRAPHIC REFERENCES 97 10.1. Specific References on the Sub-basin 97 10.2. General References 97
11. ACTORS 99 11.1. Entities Involved with Waterground in the Sub-basin 99 11.2. Personnel that Participated Directly and Indirectly in the Sub-project 100
ANNEXES
1. ANALYSIS OF THE CONSISTENCY OF FLUVIOMETRIC AND PLUVIOMETRIC DATA AS FROM THE EXISTING HYSTORICAL SERIES IN TWO STATIONS LOCATED IN THE VERDE/JACARÉ RIVER BASIN.
2. SYSTEM OF MONITORING AND ANALYSIS WATER, GROUND AND FOOD CONTAMINATION RISK BY PESTICIDES.
3. APPLICATION OF SUPPORT SYSTEMS TO DECISION-MAKING ON AGRICULTURAL MATTERS FOR THE OPTIMIZED MANAGEMENT OF
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HYDRIC DEMANDS TO USE IN IRRIGATION: IMPLANTATION OF PILOT UNITIES OF MANAGEMENT AND STUDY OF HYDRICAL NEEDS OF THE MAIN CULTIVATIONS.
4. ANALYSIS OF CONSISTENCY OF CLIMATOLOGIC DATA, QUANTIFICATION AND STUDY OF SPATIAL-TEMPORAL VARIABILITY OF THE ELEMENTS OF THE CLIMATE, AS FROM EXISTING HYSTORICAL SERIES. 5. CHARACTERISTICS OF THE FAVORABLE POINTS FOR THE CONTROL OF MONITORING NETWORK OF WELLS. 6. INVENTORY OF WELLS
7. II SEMINÁRY: USE AND MANAGEMENT OF RESOURCES OF THE NATURAL RESOURCES WATER AND GROUND IN THE VERDE/JACARÉ RIVERS BASIN-IRECÊS MICRO-REGION 8. WORKSHOP: INTERINSTITUTIONAL INTEGRATION AND TECHNICAL LEVELING ON THE BASIS OF INFORMATION AND METHODOLOGIES ON GEF-SÃO FRANCISCO PROJECT AND SRH/UFBA AGREEMENT. 9. COURSES: BASICS ON THE USE OF GPS AND PROBES. MONITORING OF GROUND AQUIFERS.
LIST OF FIGURES
1 Map of subdivision of administrative regions of water and hydrographic basins 3 of Bahia state, standing out the area of Sub-project 1.5 2 Map of hydrogeologic domains of Bahia State. 4 3 Map of location of study areas. 5 4 Representation (3D and 2D) of topography, where can be identified, with more 6 clarity, the highest points of Verde/Jacaré Rivers Basin. 5 Extract of the hydric normal balance by Thornthwaite & Mather, (1955). 10 6 Monthly average values and vulnerability of precipitations for the location of Irecê 12 (11°18’ S; 41°52’ W) within the basin being studied. Rainier months and periods show a smaller variability. 7 Monthly average values and variability of precipitations for the location of 12 Xique-Xique (10°50’ S; 42°43’ W) within the basin being studied. Rainier months and periods show a smaller variability. 8 Average temporal series of precipitations (mm) and its tendency in the long run 13 within Verde/Jacaré Rivers Basin, between 1911 and 1983. The red line indicates the tendency obtained through the method of minimal squares. 9 Annual average behavior of rains for the period 1911 to 1983 in the 15 Verde/Jacaré rivers basin. 10 First rainy quarterly of the Basin (November, December, January) within the 16 Verde/Jacaré Rivers Basin. This quarterly is considered the Basin’s main rainy period.
11 Behavior of rains for the quarterly (February, March, April) values between 16 100 and 600 mm. 12 Behavior of rains for the quarterly (May, June, July) values between 30 and 300 mm 17
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13 Behavior of rains for the quarterly (August, September, October) values 17 between 10 and 210 mm 14 Isolines at phreatic level and flow lines 31 15 Location of the greatest concentration of exploited well in the Verde/Jacaré 33 river basin 16 Comparative values of monthly flows in Verde 36 17 Comparative values of monthly flows in Verde 36 18 Volume curve required to guarantee some monthly flow with a pre-defined 37 probability (95%) Verde River – station 47236000 19 Volume curve required to guarantee some monthly flow with a pre-defined 37 probability (95%) Verde River – station 47236000 20 Curves of maximum monthly availability and of maximum monthly flow guaranteed 38 Verde River – station 47236000 21 Expenses curves. Verde River – station 47236000 38 22 Expenses curves. Verde River – station 47249000 39 23 Expenses curves. Verde River – station 47480000 39 24 Monthly average flows Verde River – station 47249000 40 25 Monthly average flows Verde River – station 47480000 40 26 Monthly average flows Verde River – station 47480000 41 27 Variation of the static level in wells drilled in the Verde/Jacaré River Basin 43 28 Evolution of nitrate contents in the waters of Irecê’s karstic aquifer 46 29 Temporal Variation of concentrations of chlorates in Irecê’s karstic aquifer 46 30 Details for the proceedings for extraction of water from the ground 51 31 Evolution of Absorbing Forms 69 32 Behavior and changes in the dynamics of water flows. 70 33 Behavior and changes in the dynamics of water flows. 70 34 Flow Conceptual model in the conduct of karstic aquifers 72 35 Basic Exit of the program SISDA to one of the Pilot Unities. It informs a water 76 deficit on the ground, efficiency of irrigation, time of irrigation and color scale to indicate smaller or greater urgency of irrigation (blue, yellow and red).
LIST OF CHARTS
1 Monthly average value and standard deviation of maximum (a) and minimum (b) 7 temperatures in ºC, to the location of Remanso in the periods between 1961 to 1970. 2 Local climatic indicators – Irecê County – 1944/1994 8 3 Normal Hydric Balance by Thornthwaite & Mather, (1955). Latitude 11º18’ - 9 Longitude 41º52’ - Altitude 747mm. Period 1944/1994
4 Calculation of Effective Precipitation Method SCS\USDA – The USA Service of 10 Conservation of Grounds 5 Annual average rains (mm) in the Verde/Jacaré Rivers Basin, as a whole, for the 13 period of 1912 to 1983. 6 Monthly average and standard deviation (mm) in the Verde/Jacaré rivers basin, as a 15 whole 7 Presents the average percentile of enrollments per teaching level 22 8 Data of variation of piezometric levels of Irecê karstic aquifer (1980-1982). 32 9 More utilized pesticides in de Irecê-BA Micro-region. 47 10 Characteristics of more utilized by rural producers 48 11 Characterization of analysis results 53
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12 Data of field samples. 56 13 Results of the analysis of pesticides in water samples. 57 14 Results of the analysis of pesticides in water samples. 57 15 Results of the analysis of pesticides in water samples. 58 16 Definition of a network of wells of observation and piezometers 63 17 Average values of Cambissolos’ physical properties submitted to an irrigated flow 67 For a period of 15 years, compared to reference profiles, in different depths – Irecê’s - Bahia Micro-region. 18 Summary of the characteristics of pilot areas 75 19 Simulated values of evapotranspiration of reference (Eto) and of crops of carrot, 78 onion and beet (Etc), pluviometric precipitation, net and gross sheet for project of irrigation system, for the two planting periods (first and second semester) and two levels of precipitation probability, 50% (average) and 75% (normal values of the project), for IRECÊ. 20 Simulated values of evapotranspiration of reference (Eto) and of cultivations of 79 carrot, onion and bet (Etc), pluviometric precipitation, net and gross sheet for project of irrigation system, for the two planting periods (first and second semester) and two levels of precipitation probability, 50% (average) and 75% (normal values of the project), for the city of Morro do Chapéu.
LIST OF PICTURES
1 Cambissolo’s profile 19 2 Latossolo´s profile 19 3 Implantation and training for the use of the support system of decision-making- 27 SISDA 4 Evaluation of the efficiency of water use and of the flow handling 27 5 Installation of structure of data collect to feed SISDA for the optimized management 27 of hydric demands in pilot area. 6 Opening of trenches for soil collect 49 7 Detail of Field Sample Collect 49 8 Detail of soil sample storage in a Refrigerated Chamber 49 9 Manual Driller 50 10 Trado Stainless steel 50 11 Suction Lysimeter 50 12 Solution Extractor 50 13 Application of suction with mini-pump in vacuum of syringe type 51 14 Application of suction with mini-pump in vacuum of syringe type 51 15 Amber type flask 52 16 Storage in Refrigerated Chamber 52 17 Evidences of soil degradation and destabilization of the aquifer’s structure. 61 Washout of dolina because of overexploitation 18 Mechanization and soil use up to the margins of the river, implicating in silt 61 depositing and degradation of the hydrographic basin. 19 Discarded packing of pesticides in the environment beside an open well. 61 20 Wasteful use of water due to the low efficiency in the application and handling 61 of irrigation and ground. 21 Intensive mechanization provoking physical-hydric degradation of the soil 61 22 Evaluation of process of physic and chemical degradation in the aquifer unsaturated 61 area (irrigated ground) 23 Characteristics of the meteorological station installed in the Pilit Areas, 75
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meteorological shelters with thermometers of maximum and minimum (A) and detail of pluviometer (B). 24 General view of the irrigated area with carrot cultivation by center-pivot (A) and by 75 leaking-sprinkler (A).
LIST OF ACRYNOMS AND ABREVIATTIONS
ANA - Agência Nacional de Águas/Brazilian National Water Agency CEE - Comunidade Econômica Européia/European Economic Community CETESB - Companhia de Tecnologia de Saneamento Ambiental de São Paulo/ Company of Technology of Environmental Sanitation of São Paulo CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico National Council of Scientific and Technological Development CONAMA - Conselho Nacional do Meio Ambiente/ National Council of the Environment DL50 - Dose Letal 50/Lethal Dose 50 EPA - Agência de Proteção Ambiental dos Estados Unidos/ The United States Agency of Environmental Protection FAO/OMS - Organização Mundial para Alimentação /World Food Organization Organização Mundial de Saúde/World Health Organization GC/MS - Cromatografia m Fase Gasosa acoplada a Espectrometria de Massas/ Chromatography m Gaseous Phase joined to Masses Spectrometry GEF - Fundo para o Meio Ambiente Mundial/ Fund for the World Environment LCP - Laboratório de Análise de Combustíveis e Poluentes Orgânicos Laboratory of Analysis of Fuels and Organic Pollutant LD - Limite de Detecção/Detection Limit LQ - Limite de Quantificação/Quantification Limit MAA - Ministério da Agricultura e do Abastecimento/ Ministry of the Agriculture and of the Provisioning MS - Ministério da Saúde/Ministry of Health NBR - Norma Brasileira/Brazilian Norm OEA - Organização dos Estados Americanos/ Organization of the American States (OAS) P&D - Pesquisa e Desenvolvimento/Research and Development PNUMA - Programa das Nações Unidas para o Meio Ambiente United Nations Program for the Environment POP - Poluente Orgânico Persistente/ Persistent Organic Pollutant SIM - Monitoramento do Íon Selecionado/Monitoring of Selected Ion SUDENE - Superintendência de Desenvolvimento do Nordeste Superintendency of Development of the Northeast USGS - United States Geological Survery” ANP - Anomalias da Precipitação Normalizadas/ Anomalies of the Normalized Precipitation TSM – Temperatura da Superfície do Mar/ Temperature of the Surface of the Sea VCAS – Vórtices Ciclônicos de Ar Superior/ Cyclonic vortexes of Superior Air ZCAS – Zona de Convergência do Atlântico Sul/ Area of Convergence of South Atlantic Ocean ENSO – El Niño/Oscilação Sul / El Niño/ South oscillation
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OMM – Organização Mundial de Meteorologia/ World Meteorology Organization BDRH – Banco de Dados de Recursos Hídricos/ Database of Hydric Resources PCD – Plataforma de Coleta de Dados/ Platform of Data Collection INPE – Instituto Nacional de Pesquisas Espaciais / National institute of Space Researches SRH – Superintendência de Recursos Hídricos/ Superintendency of Hydric Resources
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