INTEGRATED MANAGEMENT OF LANDBASED
ACTIVITIES IN THE SÃO FRANCISCO BASIN PROJECT
ANA/GEF/UNEP/OAS

Subproject 4.7.B - Plan for a Piezometric Monitoring Network
In the Basin of the Rio Verde Grande

Executive Summary of the Final Report

PLAN FOR A PIEZOMETRIC MONITORING NETWORK
IN THE BASIN OF THE RIO VERDE GRANDE

Belo Horizonte - MG

PLAN FOR A PIEZOMETRIC MONITORING NETWORK
IN THE BASIN OF THE RIO VERDE GRANDE

EXECUTIVE SUMMARY

INTRODUCTION
Activity 4.7.B, "Plan for a Piezometric Monitoring Network in the Basin of Rio Verde Grande",
belongs to Component IV (Formulation of the Integrated Management Program) of the Integrated
Management of Land Based Activities in the São Francisco River Basin Project
(GEF/ANA/OAS/UNEP). The Activity views the implementation of the necessary actions for
proposing a piezometric monitoring network, which will provide subsidies and a deeper
knowledge of the availability of groundwater resources in the Basin.
The Basin of the Rio Verde Grande, a right-margin tributary of the São Francisco River, has
approximately 31,000 km², being located in Northwestern Minas Gerais and Southwestern Bahia,
as shown in the map in Figure 1.
In this Sub-basin, there are important sources of groundwater, which have been exhaustively
exploited for urban, irrigation and livestock supplies. In the past years, it has been noticed a
significant increase in the drilling of high-yield wells, for farming activities. In some places,
conflict of uses and over-exploitation has been identified, with interference among wells and
excessive lowering of the water table.
The first chapter of the Final Report contains a description of the methodology and of the
activities carried out. Chapter 2 includes a review of the available documentation, including
studies on a regional level, and current works in the Basin. Based on secondary data, Chapters 3
and 4 describe the physiographic characteristics of the surface water resources and hydrogeologic
aspects of the Sub-basin.
Chapters 5 and 6 present a preliminary definition of the used criteria for selecting control and
monitoring points, culminating with the identification of the target areas, object of the field
surveillance, carried out in the following step. At this stage, a data form was created for
registering the control points and the necessary information for identification of suitable sites for
implantation of the monitoring network, as indicated in Chapter 7.
The proposal of the piezometric monitoring network plan, with objectives, basic procedures,
number of selected points, equipment, data reception and other specifications are included in
Chapter 8. The guidelines for the creation of an information system, including a complementary
hydrologic data collection system, with emphasis on well discharge control, are presented on
Chapter 9. The main conclusions, relating to identified problems and obtained results, are in
Chapter 10.
The presented recommendations include suggestions for completing the study, with the
implementation of three projects, whose preliminary terms of reference are presented.

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1. IMPLEMENTED
ACTIVITIES
The initial stage of the work was carried out in the office, according to the following procedures:
· Gathering and analyzing available documentation on physiographical, hydrological,
geological and hydrogeological aspects of the area.
· Hydrogeologic characterization: identification of aquifer systems, definition of the
hydrogeologic model (recharge areas, flow conditions and discharge areas) of registered
wells' characteristics and yields, of conditions of use and groundwater quality;
· Preliminary definition of selection criteria for control points.
· Identification of target areas for directing field work and defining the network.
· Preparing aquifer system's map.
· Preparing the 1st Partial Report (Main Hydrogeological Aspects of the Rio Verde Grande
Basin), in July of 2002.
The second stage consisted of a field reconnaissance, implemented from July 21st through
August 2nd, 2002, when the wells in the previously selected areas were catalogued, viewing the
identification of suitable sites for the monitoring. Results from this phase were presented in the
2nd Partial Report (August/2002).
The following step consisted of the elaboration and final proposal of the Plan for a Piezometric
Monitoring Network, containing objectives, used criteria, basic procedures and other
specifications (3rd Partial Report).
The last stage comprehended the implementation of activities aimed at the formulation of
guidelines and recommendations for the information and complementary hydrologic data
collection systems. Those systems must be integrated with the one to be developed by ANA, in
the Basin. All results are presented in the 4th Partial Report (September/2002).

2. AVAILABLE DOCUMENTATION PREVIOUS WORKS
The most relevant works in the Basin were analyzed, including those on a regional level and the
ones specific to the area, carried out by CETEC/MG, COPASA, HIDROSISTEMAS/MG,
CPRM, IGAM/MG and CODEVASF. The most remarkable of those were the "Methodology for
Development of Watershed Environmental Management Case Study of the Rio Verde Grande",
by CETC (1995), "Groundwater Resources Availability in the State of minas Gerais", by
COPASA/HIDROSISTEMAS (1995), "Water Resources Director Plan for the Tributary Basins
of the São Francisco in Minas Gerais", by SOAPA/RURALMINAS (1997); "Hydrogeologic
Inventory and Study as Subsidies to the Water Resources Monitoring, Control and Management
System of the Rio Verde Grande Basin", by SEMAD/IGAM/FUNARBE (2000).

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3. PHYSIOGRAPHIC CHARACTERISTICS OF THE SURFACE WATER
RESOURCES
Most of the Rio Verde Grande Basin is nested in a lower plains, in a zone denominated
Sanfranciscan Depression", with 500 to 600 meters of altitude, in Tertiary-Quarternary colluvial
cover and pelitic and carbonatic metasediment domains of the Bambuí Group. Bordering this
depression, there are relief forms associated to the "São Francisco Plateau", with elevations
between 700 and 1,000 meters, characterized by tablelands with well delineated eroded borders,
developed over cretacic sandstones, of the Urucuia Formation. To East, taking the N-S direction,
with maximum elevation of 1,300 m, the Espinhaço Sierra establishes the limits for the São
Francisco, the Jequitinhonha and the Pardo Rivers Basins.
The predominant climate, according to Köppen's Classification, is the Aw, a humid and warm
tropical climate with a well accentuated dry season, covering the most of the Basin. Also, the Cw,
mesothermal with warm and rainy summers and dry winters with milder temperatures, is also
characteristic of oriental border of the Espinhaço Sierra.
The total annual rainfalls show significant variation, ranging from 630 to 1,700 mm, with an
annual mean precipitation of 1.098 mm, in Montes Claros. These values are lowered towards the
North, reaching 700 to 800 mm, in Monte Azul. The rainy season extends from October to
March, when 90% of rainfalls occur, and the dry season from April to September. Temperatures
are high, with annual mean of 23.5 ºC, with the lowest values (mean of 21 ºC), occurring in the
months of June and July.
The Rio Verde Grande enlarges from South to North, having as main tributaries the Gorutuba and
the Verde Pequeno Rivers, to the right margin, and the Cana Brava, Suçuapara and Jacuí rivers
on the left side.
The available hydrologic data indicate a mean flow of 26.4 m³/s and a relatively low specific
discharge with mean, maximum and minimum of 0.875, 6.83 and 0.32 l/s.km², respectively, for
the station at Boca da Caatinga, with drainage area of 30,180 km².

4. HYDROGEOLOGICAL
CHARACTERISTICS
4.1 GEOLOGY AND AQUIFER SYSTEMS
It is worth highlighting the granular aquifer systems associated to the alluvial and Tertiary-
Quarternary detritic deposits usually with restricted importance in the Sub-basin, and the
sandstone aquifers of the Urucuia Formation, occurring in the Plateau zone. The main aquifers
and with the highest yields are associated with the pelitic (slate and siltstones) and carbonatic
(limestone) rocks, of the Bambuí Group, which is spread over 60% of the Sub-Basin's area.
Eastern of the 43º Meridian, fractured aquifers with low yields are predominant. They are in the
domains of quartizitic, schistose and gneiss-granitic rocks of the Espinhaço Supergroup, of the
Macaúbas Group and of the Pre-Cambrian Crystalline Basement (Figure 2).

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4.2 CHARACTERISTICS OF WELLS
The data regarding the catalogued tubular wells are from different sources and are stored in a
databank with diversified structure and types of information, provided by DNOCS, CODEVASF,
CERB/BA, CETEC/MG, COPASA/MG e IGAM. The most recent series are in IGAM's and
CPRM's databases. The first one includes 3,717 wells, catalogued in 2000. The latter, still under
way, covers the micro-region of Montes Claros.
In a general way, a greater well density is found around urban centers and in areas around
irrigation projects, concentrated in regions of high yield carstic aquifers. The Municipalities with
greater concentration of wells are Montes Claros, Janaúba, Francisco Sá and Jaíba. Well depths
range from 20 to 200 meters, most of them between 50 and 100 meters deep.

4.3 WELL
YIELDS
The higher yield wells, with discharges over 1.0 l/s/m, have greater incidence in the
Municipalities of Montes Claros, Capitão Enéas, Francisco Sá, Janaúba, Verdelândia, Jaíba and
Matias Cardoso, besides certain areas in Glaucilândia, São João da Ponte, Varzelândia,
Porteirinha, Nova Porteirinha, Iuiú (BA) and Urandi (BA).
Zones with lower yields, with discharges lower than 0.1 l/s/m, occur in the Lower Gorutuba and
in the Eastern-Northeastern areas of the Rio Verde Pequeno. Nevertheless, there is a great
dispersion all over the region, with heterogeneity and anisotropy of the aquifer systems (Figure 3)

4.4 WATER
AVAILABILITY
The exploitable or renewable resources were estimated, based on long term fluviometric series, as
220 hm³/ano (CETEC, 1995). These reserves could be lowered to 30 to 40% of the long range
average, years of drought or in critical sequences. These are global estimates, considering all the
area upstream from the stations in Boca da Caatinga and in Colônia da Jaíba, and their spatial
distribution is not well known.

4.5 CONCEPTUAL BASIS FOR THE HYDROGEOLOGIC MODEL
Considering the lithic-structural characteristics, the spatial distribution and the geomorphological
conditions of the aquifer systems, a conceptual hydrogeological model was defined for the Basin
(CETEC, 1995), considering two sectors.
In the Oriental sector, domain of fractured aquifer systems, recharge occurs through the fractures
which control surface drainage or by vertical infiltration through the detritic cover and layers of
alteration. The discharges occur through springs in hillsides and bottoms of valleys, often masked
by the alluvia. These are localized aquifers little hydrogeologic potential.
In the Central-Occidental sector, domain of fissured-carstic aquifers, accumulation and flow of
the water are controlled by the structural features and by the development of rock dissolution
cavities (carstification).

4.6 GROUNDWATER USE CONDITIONS

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Currently exploited volumes of water in the Rio Verde Grande Basin are not precisely known.
Outdated estimates, made by CETEC (1995), indicate an annual total in the order of 124 billion
cubic meters (3,936.5 l/s), from which 108 billion (3,428.5 l/s) correspond top irrigation
consumption.
However, the installed pumpage capacity could reach 218 billion m³/year (6,929.6 l/s), in a
maximum exploitation regime, which would be equivalent to regulating reserves of 220 billion
m³/year (6,984.1 l/s).

4.7 GROUNDWATER
QUALITY
The Basin's groundwater quality presents the following physical-chemical characteristics
(CETEC, 1995):
· Calcic bicarbonate waters, with low concentrations of total dissolved solids (< 100
mg/l), rich in dissolved CO2, low pH and aggressive, are associated with the granular
aquifers of Tertiary-Quarternary cover, to the cretacic sandstones of the Urucuia
Formation and to the quartzites of the Espinhaço Group, in its oriental border.
· In the domain of the aquifers in the Bambuí Group, water classes vary from calcic
bicarbonate to calcic-magnesian, with higher contents of total dissolved solids, electrical
conductivity, hardness, pH and alcalinity. Sulphate concentrations are usually lower than
20 mg/l, and the chloride ones less than 50 mg/l.
· In the domain of the fissurated aquifers associated to gneiss-granites, the water classes
vary from bicarbonate to carbonate-chlorinated. In the schistose rocks of the basement,
the water varies from bicarbonate to calcic-magnesian, with moderate to high salinity,
and a progressive increase in chloride and sulphate, with greater incidence in the
Northeastern and Eastern portions of the Basin.

5. PRELIMINARY DEFINITION OF SELECTION CRITERIA FOR THE
MONITORING AND CONTROPL POINTS.
In the definition of the criteria for establishing a monitoring network, emphasis was given to the
selection of abandoned wells with known construction and hydrogeological characteristics. Also
were considered as important the existence of good well-aquifer hydraulic connections, zones
with greater concentration of water impounding structures, high yields total exploited volumes
(individual well discharges greater than 50 m³/h)
Additionally, preference will be given to wells with legal rights to the water, distributed all along
the river course, from headwaters to the lower stretches, in the direction of the groundwater flow
(from recharge areas to the zones of discharge).

6. SELECTION OF TARGET AREAS
Using the above criteria, 15 target areas were selected for guiding field work, aiming the final
definition of the network and of the control points. The following areas were selected:
Glaucilândia, Montes Claros, Vila Nova de Minas, Santa Rosa de Lima, Capitão Enéas,

v

Caçarema, Simão Campos, Floresta, Janaúba, Riacho Catingão, Gorutuba, Jaíba, Verde Grande
downstream from Jaíba, Gado Bravo/Boca da Catinga and Riacho do Aurélio/Córrego Olhos
d´Água (Figure 4).

7. IDENTIFICAÇÃO E SELEÇÃO DOS LOCAIS FAVORÁVEIS À IMPLANTAÇÃO
DA REDE DE MONITORAMENTO
7.1 PLANNING AND ORGANIZATION OF FIELD WORK
Activities regarding the planning and organization of field work consisted of obtaining basic
topographic and hydrogeologic maps of the Sub-Basin, in various scales and collecting data
about tubular wells in the area of interest. It also included establishing preliminary contact with
persons and institutions holding large amount of information and knowledge of the area, in order
to optimize the development of the study.

7.2. CREATION OF THE CONTROL POINTS DATA FORM
The field form contains four blocks of information, covering: (1) identification of the
development; (2) general information on the main activity, including number of wells, used level
and discharge controls, conditions for aquifer testing and willingness of the owner, or user, to
cooperate; (3) wells' characteristics and (4) conditions for installing and operating the wells. All
these information will permit considering the wells as monitoring and control stations.

7.3 INSTITUTIONAL
CONTACTS
While carrying out the field work, contacts/meetings were made with local leaders and
institutions/associations, representative of the public powers or of the communities, with the
purpose of spreading information about the Activity and obtaining support for the development of
the investigation.

7.4 FIELD TRIP ITINERARY
The itinerary of the field trip, initiated in Montes Claros, in the Southern portion of the Basin,
meant to cover the 15 target areas, identified in the previous stage. It proceeded to the Northern
portion, near the mouth of the São Francisco River, in the area belonging to the State of Bahia.

7.5 DATA COLLECTION AND OBTAINED RESULTS
Field surveys were carried out in 20 sites, covering most part of the target areas. Some of the
selected areas (6/Caçarema, 10/Riacho Catingão and 11/Gorutuba) were not visited, due to the
difficulty of establishing contact with the owners, for obtaining access permission. In these cases,
the data available for their evaluation and inclusion in the monitoring network was used.
In all the visited developments, the pumping sites, well characteristics and conditions for
operation were identified. Additionally, UTM coordinates were calculated using GPS. As
information obtained in the field, about characteristics of wells and installed equipment, are

vi

usually limited, it was tried to identify the wells for which there are information recorded in the
applications for water rights or in the hydrogeological databases of IGAM or COPASA MG.

7.6 MAIN
RESTRICTIONS
The main restrictions identified during the field work were:
· Difficulties in obtaining permission to access the rural properties and the lack of
willingness, from some of the water users in the Sub-Basin.
· The majority of the landowners do not live in the Municipalities where their
developments are located, what makes harder to access the available data.
· Defiance of the users, in general, towards ANA, whose actions are associated to water
charges. This problem is extended to IGAM, regarding the costs (considered high) of the
processes for granting water rights.
· Many of the information providers living in the location of the developments do not
have precise data on the characteristics of the wells or operational regimes. Final reports
on the drilling of wells, whenever existing, are not available.
· Even though some of the owners are concerned with the preservation and maintenance
of the groundwater resources, and periodically control water levels and yields for
production, most of them do not have control over the operation of the system or the
condition of the wells.

7.7 SUITABLE SITES FOR IMPLANTING THE MONITORING NETWORK
In general, the results from the field reconnaissance and survey allowed the definition of the most
suitable sites for implanting the piezometric monitoring network. Twenty one control points were
proposed, as shown in Chart 1 and Figure 1. It is important to emphasize the small number of
impounding structures, abandoned or not in use, which would allow its utilization as piezometers.
The majority of wells in this condition present several restrictions, involving insufficient
construction and hydrogeological profiles and wells with limited discharges, indicating poor
hydraulic connections with the aquifer zones of greater yields. Giving these conditions, it is
evident the need to drill piezometric wells specifically for the monitoring activities. Of the 21
selected sites, only seven correspond to available wells, considering the willingness of the
owners.

8. PLAN FOR THE PIEZOMETRIC MONITORING AND CONTROL
8.1 OBJECTIVES
The monitoring plan aims at obtaining information on evolution of water table levels, as a
function of the demands and of the current and future exploitation conditions, viewing a better
understanding of the aquifer systems in the Sub-Basin. It is an effort to identify, based on
collected data, the equilibrium conditions, in terms of piezometric evolution, for the major

vii

aquifers and the relationship between exploitation and capacity of recharge in the most intensely
exploited áreas, in the rainy seasons.

8.2 CRITERIA FOR SELECTING CONTROL POINTS
Some limitations are noticed among the criteria for selecting control points, such as:
· Small number of idle wells with well defined construction and hydrogeological
characteristics, with conditions for use as a control point.
· Small number of wells with legal authorization for using the water (water rights).
· Non-willingness of some users to cooperate with the monitoring program and to permit
the access to the properties. The limitation imposed by the lack of idle wells determines
the need to install piezometric wells specifically for the network.

8.3 BASIC
PROCEDURES
The installation of the monitoring network must observe the following procedures:
· Identification of available wells and of the sites for drilling and installing piezometers
(site and technical specifications), where there are no idle wells.
· Legal procedures for obtaining authorization for installing measuring devices in private
properties.
· Contracting drilling services and installation of piezometers, or the testing and cleaning
of available idle wells.
· Supervision of the drilling, cleaning and equipping the wells.
· Technical specification of the equipment, based on the data obtained in the drilling or
cleaning of wells, with respect to water table depth e position of the recording sensors.
· Installation of equipment, under supervision of representative, to assure ideal operational
conditions. Installation for demonstrative purposes may be required.

viii

Chart 1. Selected sites for the monitoring network and general characteristics of the piezometers.

Characteristics of piezometers
Note
Point
Area / Location
County
UTM Coordinates Depth
drilling (mm)/
casing(mm) -
NE
ND
on well
Nr.
(m)
depth (m)
depth (m)
(m)
(m)
PZ-1
Area 1 Faz. Rio das Pedras
Glaucilândia 639.632 8.133.932
60
200---20 / 150---60
150---20
10
15
To be drilled
PZ-2
Area 2 Montes Claros - Unimontes
Montes
619.780 8.150.990
80
200---20 / 150---80
150---20
1,0
4,0
To be drilled
Claros
PZ-3
Area 2 Montes Claros Cristo Rei
Montes
621.640 8.147.365
100
200---20 / 150---100
150---20
1,5
27
Existing
Claros
(COPASA)
PZ-4
Area 2 Montes Claros
Montes

70
300---31 / 150---78
200---31
3,0
4,0
Existing
Rebentão dos Ferros
Claros
(COPASA)
PZ-5
Area 4 - Santa Rosa de Lima
Montes
610.550 8.192.250
60
200---30 / 150---60
150---30
10,0
-
To be drilled
Claros
PZ-6
Area 5 Capitão Enéas
Capitão
634.100 8.195.700
64
250---10 / 200---64
200---10
5,0
20,0
Existing
Enéas
(COPASA)
ix
PZ-7
Area 5 Faz. Araçatuba
Capitão
631.128 8.197.012
70
200---30 / 150---70
150---30
2,0
2,8
To be drilled
Enéas
PZ-8
Area 6 Caçarema/ Quem-quem
Janúba
653.478 8.223.625
100
200---44 / 150---100
150---44
29,0
55,0
To be drilled
PZ-9
Area 6 - Caçarema
Janaúba
665.244 8.228.452
70
200---10 / 150---70
150---10
9,0
14,0
To be drilled
PZ-10 Area 7Suçuapara/Ribeirão do Ouro
Montes
615.120 8.220.050
80
200---20 / 150---80
150---20
10,0
45,0
To be drilled
Claros
PZ-11 Area 8 Floresta Faz. Boa Vista
Janaúba
655.566 8.269.636
100
200---30 / 150---100
150---30
17,0
-
To be drilled
PZ-12 Area 8 - Verdelândia
Verdelândia
650.059 8.274.927
60
200---10 / 150---60
150---10
7,0
30,0
To be drilled
PZ-13 Area 9 Janaúba Poço COPASA
Janaúba

To be selected
PZ-14 [Area 9 Faz. Baixa da Colônia
Janaúba
678.628 8.243.692
60
200---8 / 150---60
150---8
16,0
-
To be drilled
PZ-15 Area 10 riacho Furado Novo
Verdelândia
673.866 8.286.481
80
200---20 / 150---80
150---20
9,0
27
To be drilled
PZ-16 Area 12 - Jaíba
Jaíba
641.813 8.302.707
96
250---12 / 200---84
200---12 11,0
50,0
Existing

150---120
(COPASA)
PZ-17 Area 12 Lageado, Faz. Agrovema
Verdelândia
636.980 8.298.637
27

150
10,0
13
Existing
PZ-18 Faz. Agropema Poço Velho
Varzelândia
630.153 8.297.230
51
200---42 / 150---51
200---15
9,5
10,5
Existing
PZ-19 Area 13Faz. Santo Antônio
Jaíba
643.084 8.321.268
50
200---30 / 150---50
150---30
12,0
14,0
To be drilled
PZ-20 Area 14 Faz. Santa Laura, Gado
Matias
657.580 8.351.150
60
200---30 / 150---60
150---30
12,0
14,0
To be drilled
Bravo
Cardoso
PZ-21 Area 15 Faz. Olho d´água
Iuiú
653.012 8.389.954
70
200---10 / 150---70
150---10
2,0
4,0
To be drilled

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8.4 PIEZOMETRIC MONITORING AND CONTROL SPECIFICATIONS
8.4.1 Number of Control Points
Twenty one water table monitoring and control points were selected, as represented in the map in
Figure 2. Their location, County and UTM coordinates, as well as general characteristics of their
wells and piezometers are included in Chart 1.
8.4.2 Characteristics of the Control Points
The characteristics of the Control Points, indicated in Chart 2, are related to the available wells,
to the actual identified situation and to the specifications of the piezometers to be drilled, defined
according to the nearby wells.
In the 14 piezometers to be installed, the following model was used as standard:
· 200 mm (8") diameter well drilling, for unconsolidated or altered material, reduced to
150 mm (6") diameter, in solid rock.
· 150 mm galvanized steel casing (DIN 2440), in the unconsolidated rock part. In the solid
rock, with support, free walls without linings and no prevision for filters.
In the available and idle wells (seven), cleaning will be done with an air compressor or a
submersed pump, mounted on a mobile unit, for a 24-hour period, with regular measurements of
discharge and water table fluctuations, during the pumping and recovery, after the first one stops.
8.4.3 Frequency of Measurements
It is recommendable to record water elevations in 1-hour intervals, for all piezometers, in order to
permit a higher accuracy in the operating periods of nearby wells.
8.4.4 Equipment
There are two kinds of automatic water table level recorders available in the market: the floating
type (with floater and cable) and pressure sensors, which measure the water head above the
device. This proposal considers that equipment selection, by ANA, will meet the following
conditions:
· High mechanic and corrosion resistance of the materials and installation flexibility;
· Maintenance and repair warranty, in case of damages;
· Adjustment of time periods of water levels measurement and recording;
· Greater flexibility in remote long distance transmission of data, via radio or satellite.
8.4.5 Installation and Maintenance Processes
The installation process of the water levels measurement equipment in the piezometer network
must include direct technical assistance from the supplier/representative, to ensure perfect
operational conditions. This warranty must be considered in the bidding conditions and in the
purchase contract, which must include a clause of maintenance and eventual repairs of the
installed equipment.
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By occasion of the installation, adequate providences must be taken, viewing the safety and
protection of the equipment, in order to prevent damages caused by animals, vandalism or
robbery.
8.4.6 Data Collection and Control
Inspection visits must be made periodically, by ANA's maintenance team, to check and verify the
equipment and change batteries, in order to assure the seamless operation of the control stations.
This proposal gives priority to implementation of a transmission and reception system, by
telemetry or via satellite, to achieve a greater efficiency.
If preference is given to recovering and transferring data directly from the equipment, the
collection must be made on a 6-month basis, using notebooks and specific software, for creating
tables and generating graphs of the piezometric fluctuations.
8.4.7 Periodic
Assessments
The results of the water levels monitoring must be evaluated at every six months, or annually, by
decision of ANA, in charge of the network operation. The water table fluctuations, its
relationship with pluviometry, the equilibrium conditions of the exploited aquifer systems, their
capacity of periods of recharge in the rainy season must be evaluated, to permit the identification
of critical areas regarding depletions and exhaustion trends of the underground storages.

9. FORMULATION OF A HYDROGEOLOGIC INFORMATION SYSTEM
9.1 ANTECEDENTS
In 1995, Technological Center Foundation of Minas Gerais (CETEC) prepared a document
entitled "Guidelines for a Monitoring, Control and Management of Groundwater Resources". The
document presents a synthesis hydrogeological diagnostic, based on 1,270 catalogued wells, the
guidelines for the monitoring and control program and general suggestions for the groundwater
resources management.
Still in 1995, COPASA MG concluded the work "Groundwater Resources Availability in the
State of Minas Gerais" (COPASA/Hidrosistemas), with the implantation of a hydrogeologic
database covering the entire State.
In 1999, IGAM initiated the implementation of a hydrogeological information database
specifically for the Rio Verde Grande Basin. The database was created from secondary data,
updated by field surveys, in areas of greater concentration of wells.
Beginning in 2001, CPRM began a detailed hydrogeologic inventory of the Municipalities in the
Planning Micro-Region of Montes Claros, in the context of the Basic Hydrogeological Surveys
Program, of the São Francisco Project (MME/SMM/CPRM- State Government of Minas
Gerais/SEMM/COMIG).
A document prepared by ANA's Superintendence of Hydrologic Information ("Proposed Actions
for Implementation in the Rio Verde Grande Basin" Brasília, May of 2001) includes a series of
actions to be carried out by the Agency, includes, among other actions, the implantation of an
information system.
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9.2
AVAILABLE INFORMATION AND DATABASE
IGAM's and CPRM' hydrologic databases stand out among the existing or under construction
ones and the first one has already been incorporated to the latter. The available information
covers all the main aspects related to the "water points" (tubular wells, digged wells, springs and
emergences of groundwater), construction, hydrogeology, water use, complete pumping tests and
physical/chemical/bacteriological analyses.

9.3
GUIDELINES FOR IMPLEMENTING AN INFORMATION SYSTEM
ANA's "Proposed Actions for the Rio Verde Grande Basin" (2001) presents a series of
specifications and guidelines for implanting a Water Resources Georeferenced Information
System. It is, according to the proposed items, an ample, comprehensive and integrated system,
involving 11 sectors. The mentioned document emphasizes that the information system must be
used as a tool for supporting water resources management.
With respect to computational support, the following recommendations are made:
· The system must be georeferenced (GIS), in order to store the geographic location and
topological characteristics object of investigations and analyses. Additionally, it must
include data in diversified formats, to permit presentation in form of maps, graphs,
charts and texts.
· It must allow incorporation of existing data bases from other institutions (easy
integration with other systems).
· It must allow verification of data and cross-referencing information, in relational
databases.
· It must be usable in microcomputers, without loss of performance or efficiency.
· It must be user-friendly.
· It must present referential data integrity built in data input inconsistency check.

Especially in the case of groundwater resources information, it is noticed a great dispersion of the
data among several State and federal institutions (ANA, CODEVASF, DNPM, CPRM, IGAM
and COPASA). These data are often stored in distinct computational environments, usually non-
compatible, resulting in a duplicity of efforts that could be avoided. This enforces the second
recommendation above, which was to allow incorporation of existing databases.

9.4
CONCEPT OF COMPLEMENTARY DATA COLLETION SYSTEM
Data collecting for incorporation in the system ANA intends to create and the permanent
updating of groundwater related information should take into account the following topics:
· Information on newly drilled wells - permanent incorporation of data on newly drilled
wells in the Sub-Basin should be a routine task of the institution in charge of the
information system. Actually, the data should be provided by the water rights concession
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system, under the responsibility of IGAM. The greatest drawback is that the majority of
users have not been requesting the authorization, either for drilling or for use. The fact
demands providences.
· Water use conditions discharges for production and pumping regimes, constitute
important information for the integrated analysis of the piezometric monitoring, to allow
assessment of the groundwater resources availability. They are also the most critical to
establish a routine of continuous collection and incorporation to the system. Putting
aside the non-willingness of many of the owners to cooperate in the process, the options
for controlling the discharges would be:

Creation of a specific form for distribution among users, for monthly records,
indicating type of use, duration of pumping and well discharges.

Installation of timers, to estimate duration of pumping. Part of the stations lacks this
type of device, which is recommended.

Installation of hydrometers in the wells these devices imply in a series of
restrictions, regarding purchase and maintenance costs, besides adjustment and
measurement problems.

Indirect estimates of monthly exploited volumes, based on electric energy
consumption.

Estimates of irrigated areas, based on maps on proper scales.

10.
CONCLUSIONS
Regarding the physiographic and surface water resources aspects:
The main data and available documentation on the Rio Verde Grande Basin were analyzed. The
analysis covered regional and specific data, upon which the physiographic, hydrologic and
hydrogeological aspects were assessed.
The predominant type of relief is the "Sanfranciscan Depression", with altitudes of 500 to 600
meters. The São Francisco Plateau is at the borders of the depression, with elevations of 800 to
1,000 meters. The Espinhaço Sierra, to the East, with elevations up to 1,300 meters, serves as
limits to the Basins of the Jequitinhonha, the Pardo and the São Francisco Rivers.
The Aw, warm and humid tropical climate, predominates in the Sub-Basin, but the Cwa,
mesothermal of altitude, characteristic of the Espinhaço Sierra, also occurs in the oriental border.
Total annual precipitation varies from 630 to 1,700 mm, in Montes Claros, decreasing to the
North, where they vary from 700 to 800 mm. Temperature are high, with annual mean of 23.5ºC.
The Rio Verde Grande runs from South to North, draining pelitic and carbonatic soils of the
Bambuí Group, as well as Tertiary-Quarternary eluvia and colluvial sediment covers.
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The available hydrologic data point to a mean flow of 26.4 m³/s and mean specific surface flow
of 0.875 l/s/km² (maximum values of 6.83 and 0.32 l/s/km²0, verified in the downstream station
of Boca da Caatinga, for a drainage area of 30,180 km²).
Regarding the hydrogeological Characterization:
Most part of the Sub-Basin is occupied by pelitic and calcic rocks of the Bambuí Group of the
Precambrian Superior. In the Eastern part, the granite-gneissic, schistoze and quartizitic rocks of
the inferior and medium Precambrian predominate. In the Plateau, the Tertiary-Quarternary
detritic covers and the cretacic sandstones of the Urucuia Formation.
The main groundwater reservoirs are associated to the rocks of the Bambuí Group, forming the
carstic and fissured-carstic aquifers of great heterogeneity and anisotropy. In this area, there is the
greater concentration drilled wells in the Sub-Basin, with high production capacities, which may,
in some places, achieve discharges exceeding the 250 m³/h. Current estimates indicate a total of
6,000 tubular wells in the area. The depths of these wells vary between 27 and 200 meters, most
of them being between 50 and 100 meters deep.
The wells with the greatest yields, with specific discharges exceeding a 1,0 l/s/m, have higher
incidence in the Municipalities of Montes Claros, Capitão Enéas, Francisco Sá, Janaúba,
Verdelândia, Jaíba e Matias Cardoso. Mean specific discharge in the area is of 1.87 l/s/m, with a
maximum of 94 l/s/m.
The Sub-Basin's storage capacity, representing the exploitable resources or renewable reserves,
has been estimated in 220 million m3/year. This value corresponds to the long term average and
was estimated based on the fluviometric series from the stations in Colônia da Jaíba and Boca da
Caatinga, in the periods of 1939-1989 (CETEC, 1995).
Most part of the groundwater is used for agricultural and livestock raising purposes,
corresponding to 73% of a sample constituted of 672 wells inventoried by IGAM, in the year
2000.
The total exploited volume of groundwater in the wells inventoried by IGAM was estimated as
65,870,000 m³/year (2,091.1 l/s). For the entire Basin, it is estimated a total consumption in the
order of 135,500,000 de m³/year, equivalent to 4,301.5 l/s.
Most part of the water analyses available in the Sub-Basin correspond to samples collected in the
Bambuí Aquifer, involving the carbonatic and pelitic-carbonatic facies. Around 60% of the water
present electric conductivities lower than 750 µS/cm and 80 % present values less than 1.000
µS/cm.

Regarding total hardness, 25% (55 analyses) present CaCO3values under 200 mg/l, 15 of them
with values lower than 100 mg/l (soft to slightly hard waters) and 40 with values between 100 e
200 mg/l (moderately hard waters). The great majority, corresponding to 165 analyses (75 % of
the sample), fits in the category of very hard water, with values above 200 mg/l of CaCO3.
Usually, there is no restriction for their use for agriculture or livestock consumption. For human
consumption, however, hardness represents the greatest restriction in some áreas.

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Regarding the criteria for selecting piezometric control points and defining target areas:
Based on the hydrogeological characteristics, a series of criteria were defined to aid in the
identification of target áreas. Among these it is worth emphasize the following:
· Areas with greater concentration of wells for agricultural purposes and production
discharges over 50 m³/h;
· distribution and coverage from the áreas of recharge to the points of discharge;
· wells not in use, with well defined construction and hydrogeological characteristics;
· good aquifer-well hydraulic connection;
· wells with legal authorization for using the water; and
· permission and willingness of the owners, to participate and cooperate with the
monitoring program.
Based on the above criteria, the following 15 target areas were selected: Glaucilândia; Montes
Claros; Vila Nova de Minas; Santa Rosa de Lima; Capitão Enéas. Caçarema; Simão Campos;
Floresta; Janaúba; Riacho do Catingão (Furado Novo); Gorutuba; Jaíba; Verde Grande, jusante
Jaíba; Gado Bravo and Riacho do Aurélio/Córrego Olhos d´Água.
Regarding the identification and selection of suitable monitoring and control points:
In order to collect basic information during the field surveys in the selected areas, a data form
was created for cataloguing the points. The field form contains 4 blocks of information, as
follows:
1) user identification;
2) general information on the main activity, number of wells, kind of water level and/or
discharge control, aquifer testing conditions and willingness of owner to cooperate,
among other details;
3) wells' characteristics; and
4) installation and operational conditions, to allow assessment of possibility of using the
wells as monitoring and control stations.
Field surveys were carried out in 20 locations, covering most of the selected target areas.
Analysis of the collected data permitted defining the monitoring network, constituted by 21
points.
Regarding the difficulties in the work:
Two of the main obstacles to the field activities were related to the difficulty in obtaining
permission to access the rural properties and to retrieving information from some water users in
the Sub-Basin. This difficulty, in part, is due to problems in establishing previous contact with
the users, as most of the landowners do not live in the same Municipality of the operation.
Besides, it should be added that the work program did not include an earlier campaign to make
public the objectives of the program, which happened only during the work in the field.
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The greatest difficulty, however, was the resistance of the users, in general, in dealing with ANA,
whose actions are associated with water taxing and charges. The same situation is extensive to
IGAM, regarding the considered high costs of the processes to authorize the use of the water.

Regarding the piezometric monitoring and control plan:
The proposal for the Piezometric Monitoring Plan for the Rio Verde Grande Sub-Basin was
based on the following parameters:
· Number of control points: 21 (7 wells not being used and 14 wells to be drilled).
· Frequency of recording: hourly.
· Equipment: automatic recorders, to be defined based on the recommended
characteristics.
· Estimated costs:
R$ 357.000,00 (US$ 119.000)
After the evaluation of the obtained information, the general guidelines for an information system
model were defined, with a structure, flowcharts and the required tables of hydrogeological data.

11. RECOMMENDATIONS
The outcome of Activity consists of the Plan for a Piezometric Monitoring Network of the Rio
Verde Grande Sub-Basin, which includes the proposed strategic actions described ahead, with
total estimated costs of U$ 182,980.
It is essential to carry out a campaign for making clear and known to the users the objectives and
the relevance of a program of piezometric monitoring and control of discharges, viewing the
preservation and maintenance of the groundwater resources. The final product will be a
informative manual for the water users, which must be distributed in the entire Sub-Basin. The
total duration of the activity is of three months, at a total cost of US$23,300
A program of aquifer testing must be implemented, using observation wells in previously
selected locations, with conditions for assessment of the hydraulic characteristics of the aquifers
(transmissivity and effective porosity, or storage coefficient). The corresponding activities
(identifying observation wells, testing and interpretation of results) are to executed in a 3-month
period, at a total cost of U$ 40,680.
The piezometric monitoring network must be implemented in compliance with the procedures
and guidelines defined in this Activity. The objective is to improve the level of hydrogeological
knowledge about the Sub-Basin. Among the necessary activities to accomplish this are the
location, design and installation of piezometers and water level recording devices, as well as the
implementation of data transmission and reception systems. The total estimated cost is of U$
119.000, for a 6-month duration.
A cost summary for the proposed actions is as follows:

Diffusion and public awareness campaign: US$ 23.300
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Aquifer testing program:
US$ 40.680
Implementation of monitoring network:
US$ 119.000
Total:
US$
182.980

At the end, it becomes evident that it is important to collect supplementary data and to further
improve the level of information passed to the users and to those in charge of the data generating
activities, including the well drilling enterprises working in the Sub-Basin. Additionally, it is
highly recommendable the creation of instruments which will contribute to a permanent feeding
and updating of the information system.
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