Keywords

Introduction

Ground water is essential for human development. In Brazil, it plays an important role in public and private water supply, meeting the most varied needs for water in several cities and communities, as well as in autonomous systems in homes, industries, services, agricultural irrigation and pleasure. Least acknowledged, but equally important is its ecological role, essential for the maintenance of flora, fauna, landscaping and aesthetic purposes in surface bodies of water, since the perpetration of the majority of rivers, lakes and marshes is done through the discharge of aquifers, via the base flow. This same base flow is also important to assist in the dilution of sewages and avoid siltation of rivers caused by the accumulation of sediments and waste in the cities due to the loss of dragging capacity. Preliminary assessments indicate that aquifers supply water to 30–40 % of the country’s population, especially in medium and small cities, but some capitals are also listed, like Natal, Fortaleza, Belém, Maceió, Recife, Porto Velho and São Paulo, where supply is partially done by ground water resource. In the State of São Paulo, 70 % of the urban centers are totally or partially supplied by ground water, including large cities such as Ribeirão Preto, Marília, Bauru and São José do Rio Preto. In the Northeastern semi-arid region, the rural communities have an important watershed in ground water, as does irrigation in the West of the Chapada do Apodi, between the states of Ceará and Rio Grande do Norte. What is also not commented upon is the fact that all mineral water is ground water—yet the opposite is not true. In addition, ground water is responsible for tourism by means of thermal or mineral water in cities like Caldas Novas in Goiás, Araxá and Poços de Caldas in Minas Gerais, Lindoia in São Paulo, aside from being responsible for the supply of the growing market for mineral and bottled water, marketing about US$ 450 million per year. Despite ground water demonstrating its importance in the water matrix, it is still not very exploited. Ground water potential is enormous, especially when one analyzes that, on a global scale, 98 % of fresh water and liquid water reserves are found in aquifers. This tremendous storage capacity and resistance to long periods of droughts, like the ones we currently have due to climatic changes, make ground water resources one of our greatest allies in reducing the water stress which populations have been facing and will continue to face.

Focused on the sustainable management of water resources, Law number 9433/97, of the National Policy on Water Resources, represented the legal framework of a new way of thinking the use of water resources, based on a sustainable vision, considering a decentralized administration and the participation of society. The creation of this law and the progress achieved from its implementation throughout the last 12 years were significant, and its importance has been reinforced by the growing attention society has been attributing to water resources. However, even though the vision of an integrated management of surface and ground water in water basins is made explicit in the law, the assessment of managers and even of users is that it is more of a competition over resources than actually integration. Thus, separately contemplating surface and ground water watersheds represents, aside from a simplification, a limitation in the effective solving of the problem society awaits an answer for (Zoby and Matos 2002). Ground water should not be seen, in this context, as an adjunct to the water supply of cities, communities and even businesses. It should in fact be considered an equally important alternative as a watershed and important in an economic point of view.

The objective of this article is to discuss these issues, showing the uses and potentials of ground water resources in the country, indicating alternatives for an integrated and optimized exploitation, benefitting the environment, society and economy.

Ground Water in Brazil

Renewable reserves of ground water in Brazil, in other words, their effective discharge, reach 42,289 m3 s−1 (1334 km2 a−1) and correspond to 24 % of the runoff of rivers in the country (average annual flow of 179,433 m3 s−1) and 49 % of the drought flow (considered as a drought flow with a 95 % permanence). Twenty seven of the main sedimentary aquifers alone, which occupy 32 % of the country, totalize 20,473 m3 s−1. This gigantic flow of water is distributed, in a simplified way, into two large groups: rock and sedimentary aquifers, and fractured rock aquifers (ANA 2005a, b; Hirata et al. 2006).

Sedimentary rock aquifers: sedimentary lands occupy about 4.13 million km2, in other words, 48.5 % of the country, associating to the large sedimentary basins of the Proterozoic, Paleozoic, Proterozoic/Mesozoic and Paleozoic and the smaller Mesozoic and Cenozoic basins (Fig. 9.1, Table 9.1). In these lands, there are 27 systems of intergranular porosity aquifers and subordinately, karst and fractured, with an outcrop or recharge of 2.76 million km2 (32 % of the country). The main Brazilian proterozoic sedimentary basin in the one of the São Francisco River, which comprises two important aquifer systems of regional dimensions, the Bambuí Aquifer System (Neoproterozoic) and the Urucuia-Areado Aquifer System (Cretaceous), totaling 175,000 km2. The largest Brazilian basins are from the Paleozoic age and they are: Paraná Basin (Ordovician to Cretaceous, with 1 million km2 on the Brazilian portion), with emphasis on the aquifer systems Bauru-Caiuá, Guarani, Tubarão, Ponta Grossa and Furnas; Parnaíba Basin (Silurian to Cretaceous, with 600,000 km2), with emphasis on the aquifer systems of Itaperucu, Corda, Motuca, Poti-Piauí, Cabeças and Serra Grande; and Amazonas Basin (Ordoviciano and Terciary, with 1.3 million km2), with the aquifer systems Boa Vista, Solimões and Alter do Chão (Fig. 9.1). The sedimentary basins of the Mesozoic have smaller dimensions than those of the Paleozoic, they are found mainly in the coastal regions or near them, and are in general very wide reaching millions of meters (Fig. 9.1).

Fig. 9.1
figure 1

Brazilian Cratons with folded bands and their boundaries

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Table 9.1 General characterization and productivity of Brazilian sedimentary aquifers (Hirata et al. 2006)
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Fractured Rock Aquifers: the Precambrian crystalline terrain, which behave as typical fractured aquifers, occupy an area of about 4.38 million km2 (approximately 51.5 % of the country) and coincide, largely, with the Amazonas Craton and the Neoproterozoic fold belts, encompassing part of the basement of the São Franciso Craton (Fig. 9.1, Table 9.2). The basement of the fold belts is predominantly constituted by metamorphic rocks (gneiss-migmatite, granite and granulite), with subordinate mafic and ultramafic rocks in addition to remnants of metavolcanosedimentary sequence of low to intermediate metamorphic levels. The fold are intruded by granite composed of metassedimentary rocks (terrigenous and carbonate) or metavolcanosedimentary (volcanic, terrigenous and cabonate) in varied metamorphic facies from green schist to amphibolite. Basalts and diabases from the Serra Geral Formation (Early Cretaceous) of the Paraná Basin constitute, together with the Precambrian rocks, the main fractured aquifers of the country.

Table 9.2 Pre-cambrian and volcanic fractured aquifer systems of the Eocretaceous (Hirata et al. 2006)
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In general, the aquifers of the country present excellent to good quality natural quality of its waters in almost all of its territory. The natural chemistry is basically controlled by the rocks and sediments that compose the aquifer and by the climate in the area of recharge. The hydrogeological units of the North region, for example, where rain is abundant, show waters which are acidic, bicarbonate and low mineralized. Crystalline rocks are characterized by having calcic bicarbonate and calcic magnesium waters. Aquifers near coastal regions are, as opposed to inland waters, rich in chloride ions and sodium (Hirata et al. 2006).

Regionally, it is possible to identify problems associated to the excess of some ions, which could locally limit the use of water of the aquifers. The main chemical anomalies are (Zoby 2008):

  1. 1.

    In areas where limestone occur, local problems of high water hardness and/or total dissolved solids, are observed, as is the case of the aquifer systems of Bambuí and Jandaíra.

  2. 2.

    In aquifer systems located in the most confined parts of some sedimentary basins, under low circulation conditions, the growth of minerals in deep waters can cause restrictions to the use of water due to total salinity, as can be observed in the aquifer systems Guarani (Paraná and Rio Grande do Sul), Açu and Serra Grande.

  3. 3.

    Additionally, there are minerals, whose localized dissolution leads to waters with concentrations above potability standards; as is the case of iron in the aquifer systems Alter do Chão, Missão Velha and Barreiras and the case of fluoride in the aquifer systems Bambuí, Guarani and Serra Geral. Also known, is the case of the occurrence of elevated levels of chromium in the waters of the northeast of the State of São Paulo, in the Aquifer system Bauru-Caiuá.

In crystalline terrain, the problems of natural quality of ground water are concentrated in the Semi-Arid region of the Northeast (Zoby 2008) and refer to the high level of salinity. The use of desalination of water enables the use of these wells; however, reverse osmosis has been the most widely used process.

Exploitation of Ground Water Resources

An effective management of water resources in a watershed basically requires knowledge about water availability—both with regards to quality as well as with regards to quantity of the demand over water. In addition, it requires a database of users; of the aquifers vulnerability to pollution; and of the potential contamination sources that threaten the quality not only of the surface waters, but also ground water.

With regards to ground water, knowledge about water availability is limited at a national scale, and the few Regional studies are outdated (Zoby and Matos 2002).

The first hydrogeological map of the country was made by the National Department of Mineral Production (DNPM 1983). Rebouças (1988) synthesized the available information on the most important aquifers. Later, the National Water Agency (ANA 2005a, b) presented two publications with a synthesis of regional data on the quality of water, on reserves and productivity of the main aquifer systems of the country. More recently, in 2007, the Geological Service of Brazil (CPRM) presented a map of the hydrogeological domains and subdomains in a geographic system of information, on a scale 1:2.500.000.

With regards to regional studies, the most complete regional characterization of aquifers in Brazil was made in the Northeast, between 1965 and 1975, by the Superintendency for the Development of the Northeast (SUDENE), which is the “basic Hydrogeological Inventory of the Northeast”. Also worth mentioning, within the national context, are the “Studies on the ground waters of the administrative regions of the State of São Paulo” performed by the Department of Water and Electric Energy, during the period of 1972 and 1983.

The chart above shows the lack of public policies for the management of ground water resources. The need for hydrogeological studies in the country also reflects the demographic densities and the levels of surface water scarcity with regards to the demands imposed by the population and by the economic activities. Therefore, the highest levels of information are concentrated within the metropolitan domains (Rebouças 1999).

This aspect becomes evident when one verifies the extensive quantities of studies on a local scale, mainly in some states of the Southeast and South regions. Although still very far from the real needs, the state environmental agencies have demanded investigations to characterize contamination of the soil and of ground water. In São Paulo for example, there are 2514 areas declared contaminated (CETESB 2009), many of which are also in the process of being remedied and a few even have already been finalized. Thus, even if there is a lack of regional public policies which would allow for the determination of priority areas for a detailed study, on the other hand, one can verify that individual cases of contamination are being studied, even if not in a systematic way throughout the country.

With regards to demands over ground water, there is yet uncertainty with regards to the number of wells existent in Brazil. Cardoso et al. (2008) performed, using several studies and data from water resources state management agencies and from the National Water Agency, analysis of each unit of the federation, estimating the existence of about 416 thousand wells drilled in Brazil since 1958, of which 63,000 would no longer be in use (approximately 15 % of the total). The current average of well drilled is of 10,800 per year.

For calculation of percentages and medians of the Semiarid Oriental Shield they were not considered the dry wells.

In the state of São Paulo, two areas had their exploitation restricted due to problems of intense use with no planning or due to overexploitation—the cities of Ribeirão Preto and of São José do Rio Preto. In these two localities, restrictive norms were established for the drilling of new wells or for the exploitation of ground water.

The lack of understanding of the hydrodynamic behavior of aquifers has above all complicated the understanding of the meaning of overexploitation. Studies performed in some location are restricted to describing the decrease of levels of water in a specific aquifer, not taking into consideration that this is an inherent characteristic to the use of ground water watershed. The real characterization of overexploitation should mandatorily take into consideration the assessment of the costs of ecological, social and economic impacts caused by this overexploitation, aside from their input and output balance of water from the aquifer.

With reference to the demand of water, it is also worth mentioning that the lack of knowledge about ground water’s roll in public and private water supply creates an important problem. In the majority of cities the total amount of water that comes from wells exploited by private users, is unknown. Usually, estimates are underestimated and do not reflect the real dimension of the cities dependability on ground water resources.

A good example is that which occurs in the Upper Tietê Water Basin (BAT), where the metropolitan region of São Paulo is located. Supply by means of public network, with waters from surface origins that cover almost the total needs of the population, add up to 64 m3 s−1, whereas the 10,000 wells in operation meet the needs of an additional 10 m3 s−1 and, together cover the needs of the total demand of 74 m3 s−1. The problem is that the facilities of the sanitation company do not possess the capacity of supplying additional water. If the private well (of which 70 % are illegal) stop their exploitation, whether due to its overexploitation or due to contamination, the public supply system would collapse; despite only supplying 15 % of the demand, there is no more water available unless a long term investment is made (Hirata et al. 2002). Another example is the paradox which occurs in the metropolitan region of Belém, located in a region with abundant water availability that has about 30 % of public water supply provided by ground water, aside from millions of private wells. Many of these private wells are poorly built, facilitating the occurrence of contamination, especially by domestic sewage. In fact, the lack of sewage collecting networks in this region results in the pollution of several of the rivers which cross the city, increasing the pressure for the use of ground water.

The country’s current situation reveals that knowledge about hydrodynamic and about hydrochemistry of the aquifer systems is also extremely limited with regards to the monitoring systems available, contrary to what is observed with regards to surface waters, which have an extensive network of fluviometric monitoring, with about 5800 plants in operation. Only a few states have monitoring networks of quality and quantity, within their water resources and environmental management agencies. Some few examples of these networks are in operation in the states of São Paulo, Minas Gerais and Rio Grande do Norte and in the Federal District.

Aside from these agencies, the sanitation companies, which have ground water in the water matrix, also possess quality monitoring networks, even though these agencies are far more interested in verifying potability of the waters in their wells than they are in assessing the conditions of the aquifer as a whole.

São Paulo was the pioneer state in regional monitoring, having initiated its activities in 1990. Currently, the network has 180 public supply wells spread throughout the state, including the BAT, which are monitored biannually by means of 40 physical, chemical and microbiological characteristics, and even includes organic compounds (Dias et al. 2008). In the state of Minas Gerais, in the Verde Grande Basin, affluent of the São Francisco, a pilot water quality monitoring network was implemented, in 2004. In the Federal District, regional biannual quality monitoring was initiated in the second semester of 2006 in 150 operating wells by CAESB and includes 27 physical, chemical and bacteriologic characteristics. The monitoring of quantity started in 2007 and involves the measuring of the static level of 27 wells, some of which are exclusive for observation and others which are in use (Moraes et al. 2008). More recently, the Guarani Aquifer Project implemented a monitoring network in the four countries of its extension, nominating people in charge in each Brazilian state.

Through this report, it is obvious that the monitoring network does not meet the minimum requirements to understand the aquifers or its behavior throughout time and throughout use and the threat of contamination. In addition, it is worth mentioning that the monitoring wells are “blind”, in other words they can monitor only one area of a few square meters located around it. Therefore, either we establish a strategy that focuses on monitoring networks, where they are most needed (with very clear objectives), or we increase the density of the wells and the frequency of monitoring samples. This lack of basic information about drilled wells results in the scarcity of trustworthy data on the actual water potential of the aquifer system and about the actual state of exploitation. Thus, we are lacking, for an effective planning of water management, the most basic information on hydrogeology that would allow for the making of decisions by competent water resources and health authorities.

The gap in the systematic knowledge of the situation of ground water in the country does not allow for the identification and the specification of the extension of the problems that affect the aquifers and its users. Anthropogenic contamination and the overexploitation of aquifers are occasionally identified by the territory, but without a systematization that would allow for the extrapolation of its real dimensions or for the identification of other areas of equal potential. It is true however that the problems are still few in contrast to the volumes and extension of aquifers, but it is also true that based on the information available, that these issues are rapidly increasing in number and in complexity, increasingly impacting underground watersheds.

There is no systematized assessment on contamination or on anthropogenic degradation of aquifers in the country. The state of São Paulo is one of the pioneers in these studies (Hirata et al. 1997), but it lacks a systemized update of their researches.

The knowledge available in the country indicated that the main contaminants are: nitrate, products derived from petroleum (especially gasoline and chlorinated solvents), heavy metals, viruses and bacteria. Nitrate is the individual contaminating substance most found in Brazilian aquifers.

In urban areas, it is a result of the lack of sanitary sewage systems, which in the country affects over 50 % of the population, and in areas where such sewage networks exists it is due to the lack of maintenance. Some studies have revealed that the loss of sewage of São Paulo networks has been above 40 %, with a significant volume recharging aquifers. Up until now, there are very few studies about the issue, aside from those described in the Barreiras Aquifer System for the cities of São Luís, Fortaleza, Belém and Natal (Zoby 2008); those for the cenozoic aquifers of the capital of São Paulo (Viviani et al. 2004); and some for the several cities of the interior of São Paulo (Cagnon and Hirata 2004), indicating that it is in fact an extensive problem throughout the country. In agricultural areas, nitrate originates from the excessive use of nitrogen fertilizers. Up until now, there are no studies about this in Brazil and the assessments are based on cases reported abroad.

Other contaminations of ground water by compounds in urban areas are the liquid fuels derived from petroleum. Based on the statistics of the state of São Paulo (CETESB 2009), the most common occasional contamination comes from service stations, by means of leakage of fuel from storage tanks, from underground pipes or from operation itself.

Heavy metals and chlorinated solvents are quite common products of industries, and are responsible for the largest and most complex contaminant plumes in aquifers. A recent study was requested by the Department of Water and Power to the Servmar Environmental Company, in the southeast region of the city of São Paulo. This study indicated that, in the area of Jurubatuba, an old industrial area, there are several plumes of contamination by halogenated solvents and that several of them overlap, even reaching the fractured aquifer underlying the sedimentary deposits with free phase chlorinated solvents denser than water. This area was the first in the country to suffer restriction in exploitation through a legal measure due to contamination. In this area, no new wells can be drilled and, where the contamination is detected, the well is sealed and the neighboring area is prohibited to drill new wells.

Heavy metals and several chlorinated solvents are also present in several aquifers due to the inadequate deposition of solid wastes in landfills. Based on statistics of other countries and on studies held in Brazil, it is believed that this activity might be the cause of the second greatest group of soil and aquifer contaminant in the country, proportionate to the number of activities in operation or abandoned.

The mining activity causes great alterations to the local hydrological cycle, reducing the vulnerability of aquifers due to the removal of the non-saturated area and the protective layers of the soil. One of the few areas where there is reasonable knowledge about this is in the State of Santa Catarina, where coal mining affects the quality of surface and ground water. In the state of Minas Gerais, studies about the hydraulic impacts of the mining of iron in rivers and in the aquifer itself are well conducted in several establishments, with a good monitoring network of aquifers by the companies responsible for extracting the mineral.

Additionally, saline intrusion is a problem that affects the aquifers in coastal areas, a result of an imbalance of ground water extraction close to coasts and the underground discharge, needed in order to avoid the invasion of salt water onto the continent. This problem has been identified in some urban aquifers, in coastal capitals, especially in the Northeast. Some examples can be found in the Barreiras Aquifer System, in the cities of São Luís, Maceió, Fortaleza and in areas of the state of Rio de Janeiro (Zoby 2008). The induction of low quality water by excessive pumping is also another issue that affects the aquifers, such as those observed in the Beberibe Aquifer in Recife, where the uncontrolled extraction is inducing the movement of saline waters from the Boa Viagem Aquifer in poorly build wells (Costa Filho et al. 1998). The same problem has also been observed in some aquifers located in urban areas in the state of São Paulo where the upper portion is contaminated by nitrate and the pumping of wells induce the plumes to its lower portions, compromising, in some cases, even the sources of mineral waters.

Lastly, the presence of bacteria and viruses is also very common in poorly built wells and/or in those that lack maintenance. The construction of wells out of the recommended standards by ABNT is common throughout the country, which increases the fact that the majority become vectors of aquifer contaminations due to the connection created between the surface and the saturated area, or also, between the shallow portions of the aquifers and the deeper portions. This issue is particularly worrisome in areas neighboring cities, where the lack of public water supply networks, results in supply wells being placed nearby cesspits, endangering the population.

Challenges for the Management of Ground Water Resources

The importance of ground water for the social and economic development of the population contrasts with the lack of knowledge about the potentiality and the stage of exploitation of the aquifers, resulting in great challenges for an adequate management of water.

A relevant aspect which needs to be considered is that the dynamics of ground water is different from that of surface waters. The river, from a water management point of view, is the “opposite” of an aquifer. The river has a low capacity for storing water, yet, on the other hand, can deliver a larger instantaneous flow than the aquifers. Additionally, aquifer exploitation is done through wells and springs, which usually have stable flows (which are not influenced by climatic seasonality), but are usually less than those compared to what has been observed in surface catchments. The use of this typical dynamics of both water manifestations is poorly used in the country. Even in cities that do make use of these two watersheds, there is no integrated planning that benefit of the advantages of each resource. In some cities, like Madrid (Spain), for example, the excess of surface water during rainy seasons helps recharge the aquifer after the critical period in which it was most used—during droughts, when the rivers were low in water and ground water supplied the city.

Likewise, exploitation of ground water is characterized by a lower initial financial investment and for allowing gradual solutions (one well after the other) in the implementation of large supply systems, allowing even, independent and atomized systems. Catchment of surface water however, need greater initial investments, and is not as flexible. Furthermore, pumping and electricity costs, render ground water uncompetitive in aquifers where transmissibility (result of the hydraulic conductivity and of the saturated width of the aquifer) is low or where the dynamic levels are deep or even where the demand is high and the productivity of the well is low.

Thus, it is crucial to rethink the water matrix; not only at a municipal level (involving the concessionaire and the local and municipal public authorities) but also at a water basin level (involving the basin committees) and train they based on this point of view, which would result in great economic, social and ecological benefits. Based on this, the National Water Agency is developing an Atlas of Urban Water Supply, which aims at optimizing the choice of the watershed, and proposes technical alternatives for the supply of water in the Brazilian cities by 2015.

The use of these concepts in public or private water supply has not yet been implemented in any part of the country; but a window of opportunity opens in several cities of Brazil. The concessionaires supply water to the population through the public network (both from surface and ground water origins). The population, with their tubular wells, is further supplied by ground water. Though not intentionally, concessionaires end up being benefitted by this additional source of water, for in many cases, it does not have the capacity of supplying the population’s total demand. The real problem is that this is not a planned process and the knowledge about the real dependency on this additional supply, is frequently underestimated.

This lack of planning ends up bringing additional problems which could have been avoided, among them: contamination of waters of wells (whether due to poor catchment construction, or due to contamination in the catchment area of the well) and overexploitation, even affecting the wells of the concessionaries themselves.

The disciplining of the use of ground water through an effective program to license drilling and authorizations, together with billing for sewage services (of which concessionaires are entitled to and which could help pay off part of the investments in infrastructure), and an efficient social communication program aimed at users, could represent the cornerstone for an adequate exploitation of ground water resources. The concessionaires or the association of ground water users could assist the owner of the catchment in obtaining the maximized use of his well, thus reducing costs and environmental impacts, and consequently giving concessionaires a breather, who then would have less problems related to seasonal water demands, or even would be able to reduce their short and medium term investments in implementation of water treatment and reserve systems. At a second stage, municipal public authorities (whether associated or not to the basin committees) should seek to optimize the entire system in an integrated way.

Another important difference between the two water resources is the difficulty in the decontamination (remediation) of aquifers in comparison to surface water. Although the natural quality of ground water is excellent and meets potability requirements, the reduced speed of water circulation through the pores or through fractures, together with the complex geometry of the pores and its heterogeneity, makes decontamination for some types of compounds, such as free phase chlorinated solvents, practically impossible except by physically removing it from the aquifer. This characteristic, exemplifies why quality control programs should be focused upon prevention, rather than on the recovery of the aquifer.

Controlling use and soil occupation, by means of restrictions and monitoring of anthropic activities is one of the strategies for the protection of ground water, with two main objectives in mind (Foster et al. 2002). The first objective is the general protection of the aquifer, identifying areas most vulnerable to contamination, in order to carry out a regional control over the use of the soil in all its extension, especially on the outcrop areas. The second approach is on specific protection, focused on ground water catchment, which is usually a quite common tool used by concessionaires of water.

In Brazil, studies on the protection and the vulnerability of aquifers are still very limited (Zoby 2008). The state of São Paulo, as a pioneer, proposed technical criteria for the use of protection perimeters of wells (Hirata 1994; Iritani 1998). In some regions of the country which have considerable demands for water, studies to determine the vulnerability and/or the danger of contamination have been done, such as in the Northwestern portion of the metropolitan area of Belém, on the Serra Geral aquifer in Londrina and on the Beberibe Aquifer, in the North part of the Metropolitan Region of Recife; or even in the metropolitan regions of Campinas and São Paulo and in the cities of São José do Rio Preto, Itu and Sorocaba, in the State of São Paulo.

It is important to add that the protection of ground water depends entirely on anthropogenic activities; therefore, it can only be effective if it is implemented within the city’s Master plan for land use.

More recently, ground water has been addressed, by means of Resolution 396/2008 approved in 2008 by the National Council of the Environments (CONAMA), which constitutes a new legal tool, encompassing all of Brazil, to protect ground water. Later, in December of the same year, Resolution number 91/2008 was passed by the National Council of Water Resources (CNRH), addressing general procedures for dealing with surface and ground water this is an invocative norm in the integrated management of water resources. It is also worth mentioning, that until now, ground water was not focused upon or even classified.

Thus, a paradox is formed, where the lack of an ample and systematic assessment of the potentiality of the aquifers is, at the same time, the cause and the effect of the lack of policy within the sector (Hirata et al. 2006). Protection programs, when they exist, are very outdated with regards to their real importance. Therefore, the definition and the implementation of consistent and pragmatic ground water protection policies are of the utmost importance in all Brazilian states. This policy needs to prioritize the definition of critical areas where:

  1. 1.

    The exploitation of ground water is intense.

  2. 2.

    The ground water resource cannot be substituted for any other source of water.

  3. 3.

    There is the evident presence of potential contamination sources that place aquifers at risk. In these critical areas, detailed studies aimed at solving the problem, should be a priority. On the first two cases, knowledge of hydraulics and of the potentiality of the resource and of the demands to which ground water are subject to, will allow one to define the best form of exploitation of the resource, by means of authorizations granted by managing agencies.

In the third case, focus is on the protection of the quality of ground water. In this case, the specification of critical areas should be done by means of maps that determine aquifer contamination vulnerability, in order to protect the aquifer itself, and by means of maps that determine protection perimeter of wells or sources, in order to protect public supply watershed or strategic watersheds. These specifications, together with the database on sources liable to contamination, will allow for the identification of the areas that present the highest risks and that demand the most environmental attention; they would also allow for the implementation of regional monitoring in these areas or for determining priorities for detailed studies.

In addition, also considered of extreme importance, are the economic assessments of the ground water resource and the economic, social and ecological costs involved in its exploitation, including those associated to overexploitation and to the contamination of aquifers.

Environmental education focused on water resources, and in particular on ground water is also a relevant tool for management. It is only by means of education itself that current and future generations will understand the role of ground water resources, and thus place the appropriate value on the water they don’t actually see, but which carries equal importance.

In conclusion, despite ground water resources playing an essential role in human development in the country, its management is not in accordance to its strategic nature. The challenge faced by public management, by society and by those who use water, is to create and articulate actions that reflect a new form of relationship between man, land and water.