Aquifer mapping is a multidisciplinary scientific process wherein a combination of geological, hydrogeological, geophysical, hydrological, and quality data are integrated to characterize the quantity, quality and movement of ground water in aquifers. 

1. Aquifer Mapping
Programme of
India
Prof. A. Balasubramanian
Centre for Advanced Studies in Earth
Science
University of Mysore

2. Occurrence , movement, storage
and availability of ground water
 The occurrence, movement, storage
and availability of ground water in an
aquifer depend mainly on two factors,
viz. the physical framework of the
aquifer systems and the recharge and
discharge of water to and from the
aquifers.
 The physical framework of the aquifer
system is governed mainly by
geological and geomorphological
characteristics of the area.

3. Recharge and discharge of
ground water
 are controlled by the aquifer
characteristics as well as several other
factors such as soils, climate, cropping
pattern, land use, surface water
features, agricultural practices etc.
 A realistic representation of an aquifer
and plan for its sustainable
management needs to take into
account the influence of all these
factors on the aquifer system.

4. Work of aquifer mapping
 The work of aquifer mapping through
ground water surveys, exploration and
monitoring is an on-going activity of
State GWDs/Central Ground Water
Board.
 The entire country has already been
covered under systematic
hydrogeological surveys to generate
basic hydrogeological data.
 Besides, an area of 1.50 lakh km2 area
is being covered every year under
Ground Water Management Studies to
study the changes in the groundwater
regime over a period of time.

5. Basic Idea
 ground water survey,
 investigation and exploration program
supported by
 exploratory drilling,
 geophysical investigations and
 hydro chemical studies.

6. Aquifer mapping
 Aquifer mapping is a multidisciplinary
scientific process wherein a
combination of geological,
hydrogeological, geophysical,
hydrological, and quality data are
integrated to characterize the quantity,
quality and movement of ground water
in aquifers.

8. Objectives
 To define the aquifer geometry, type of
aquifers, ground water regime
behaviors, hydraulic characteristics
and geochemistry of Multi-layered
aquifer systems on 1:50,000
 Intervention of new geophysical
techniques and establishing the utility,
efficacy and suitability of these
techniques in different hydrogeological
setup.

9. Objectives contd..
 Finalizing the approach and
methodology on which National Aquifer
mapping programme of the entire
country can be implemented.
 To develop an Aquifer Information and
Management System for sustainable
management of ground water resources
based on the aquifer maps prepared.
 The experiences gained can be utilized
to upscale the activities to prepare micro
level aquifer mapping.

12. Tumkur

14. Aquifer Mapping
 Aquifer Mapping is an attempt to
combine a combination of geologic,
geophysical, hydrologic and chemical
field and laboratory analyses are
applied to characterize the quantity,
quality and sustainability of ground
water in aquifers.

15. Major objectives of aquifer
mapping
 The major objectives of aquifer mapping are
 Delineation of lateral and vertical disposition
of aquifers and their characterization on 1:
50,000 scale in general and further detailing
up to 1: 10,000 scale in identified priority
areas.
 Quantification of ground water availability and
assessment of its quality to formulate aquifer
management plans to facilitate sustainable
management of ground water resources
 at appropriate scales through participatory
management approach with active
involvement of stakeholders.

16. Aquifer Systems of India
 The National Atlas on Aquifer Systems
of India
 on 1: 250,000 scale,
 will form the base for the current
programme of National Aquifer
Mapping

17. Generate aquifer maps
 It is proposed to generate aquifer maps
 on 1:50 000 scale for the country as a
whole and on 1:10,000 scale in identified
problematic areas.
 This exercise shall result in the
demarcation of several smaller
mappable aquifer units within the
identified Principal/Major Aquifer
Systems.
 It is envisaged to name the aquifers with
local names for easier identification and
understanding by the local stake holders.

18. Approach and Methodology
 National Aquifer Mapping Programme
basically aims at characterizing the
geometry, parameters, behavior of
ground water levels and status of ground
water development in various aquifer
systems to facilitate planning of their
sustainable management.
 The major activities involved in this
process include compilation of existing
data, identification of data gaps,
generation of data for filling data gaps
and preparation of aquifer maps.

19. The Outputs of Aquifer mapping
will be both scientific and social
Some of the Scientific Outputs include:
 Disposition of Water Bearing Formations
 Surface outcrops.
 Subsurface continuity in vertical and
horizontal disposition.
 Overlay of different litho-units to form a
group & aquifer system, E.g. - Alluvium -
Gravel, sand, silt & clay in different
percentage underlain by compact
Sandstone,/shale, hard rock etc.

20. Outputs of Aquifer mapping
contd..
Water Bearing Capacity
 Variations with depth
 Changes in space and time
 Demarcation of runoff zones, recharge zones
and discharge zones
 Status of ground water abstraction
Aquifer (formation water) Quality
 In-situ (depositional)
 Anthropogenic
 Vertical zonation
 Blending/Migration of pollutants in aquifers
with time

21. Strategies for Sustainable
Management
Strategies for Sustainable Management
 Quantification of water within different
layers (Aquifers- 1,2 3 etc)
 Quality in each aquifer (group)
 Demand-Supply analysis
 Estimation of prevailing Development
Status
 Precise assessment of functional wells
for agriculture, industries, drinking water
purposes (modified well census as
village wise by public participation to be
translated into aquifer wise & then
administrative unit)

22. Identification of Clusters of
Aquifers (layers)
 Vertical-horizontal flow of recharged
water from source - rainfall, canal,
applied irrigation etc.
 Formation of Aquifer Management
Unit
( clustering of villages & depth units)
 Preparation of Aquifer Management
Plans for sustainable ground water
management.

23. AMPs
 The AMPs need to be prepared in a simplified
manner so that they are easily understood
and implementable by the stakeholders and
ensuring wider acceptability.
 Sustainability necessarily means the
reliability, resilience and the vulnerability of
the resource.
 Reliability is the ability of system to meet
demands; resilience is the measure of the
ability of the system to recover from failure
and vulnerability is the measure of
loss/damage incurred because of failure.

24. Aquifer mapping
 Aquifer mapping is a process wherein
a combination of geologic,
geophysical, hydrologic and chemical
field and laboratory analyses are
applied to characterize the quantity,
quality and sustainability of ground
water in aquifers.
 There has been a paradigm shift from
“groundwater development” to
“groundwater management”.

25. Picture of groundwater
 An accurate and comprehensive
micro-level picture of groundwater in
India through aquifer mapping in
different hydrogeological settings will
enable robust groundwater
management plans at the appropriate
scale to be devised and implemented
for this common-pool resource.

26.  This will help achieving drinking water
security, improved irrigation facility and
sustainability in water resources
development in large parts of rural India,
and many parts of urban India as well.
 The aquifer mapping program is
important for planning suitable
adaptation strategies to meet climate
change also.
 Thus the crux of NAQUIM is not merely
mapping, but reaching the goal – that of
ground water management through
community participation.

27. Objective
 The primary objective of the Aquifer
Mapping Exercise can be summed up
as “Know your Aquifer, Manage your
Aquifer”.
 As per the Report of the Working
Group on Sustainable Ground Water
Management, “It is imperative to
design an aquifer mapping
programme with a clear-cut
groundwater management purpose.

28. Outputs
 The Outputs and of Aquifer mapping will be
both scientific and social.
 Some of the Scientific Outputs include:
I. Disposition of Water Bearing Formations
 Surface outcrop
 Subsurface continuity in vertical and
horizontal disposition
 Overlay of different litho units to form a group
& aquifer system, E.g. – Alluvium – Gravel,
sand, silt & clay in different percentage
underlain by compact Sandstone,/shale, hard
rock etc.

29. II. Water Bearing Capacity
 Variation with depth
 Changes in space & time
 Run off zone, recharge zone,
discharge zone
 Abstraction status

30. III. Aquifer (Formation water) Quality
 In-situ (depositional)
 Anthropogenic
 Vertical zonation
 Blending/Migration of pollutants in
aquifers with time

31. IV. Strategies for Sustainable Management
• Quantification of water within different
layers (Aquifers- 1,2 3 etc)
• Quality in each aquifer (group)
• Demand-Supply analysis
• Estimation of prevailing Development
Status
• Precise assessment of functional wells
for agriculture, industries, drinking water
purposes (modified well census as
village wise by public participation to be
translated into aquifer wise & then
administrative unit)

32. V. Identification of Clusters of Aquifers (layers)
 • Vertical-horizontal flow of recharged water
from source – rainfall, canal, applied irrigation
etc.
 • Formation of Aquifer Management Unit (
clustering of villages & depth defined
 • Preparation of Aquifer Management Plans
for sustainable ground water management.
 The AMPs need to be prepared in a simplified
manner so that they are easily understood
and implementable by the stakeholders and
ensuring wider acceptability.

33. Outcomes & benefits
 The Social Outputs and benefits are less tangible but
their significance cannot be undermined.
 • Involvement of community and stakeholders would
enable the State Governments to manage their
resources in an efficient and equitable manner, thereby
contributing to improved overall development.
 • Demystification of science will result in better
understanding of aquifers at community level. The
amalgamation of scientific inputs and traditional wisdom
would ensure sustainable ground water resource
management.
 • Community participation and management would
ensure sustainable cropping pattern, thereby
contributing towards food security.

34. 1A. Review & Compilation of
Existing data, Reports etc.
 Geology
 Landforms (Physiography)
 Sub surface Geology
 Well Census – Aquifer wise
 Dug well, shallow tube well/ filter points
tapping watertable aquifer
 Bore well tapping weathered zones &
fractured zones down to 200m (300m in
select areas)
 Tube wells (300m in general, 600m in
select areas)

35. 2 Preparation of Thematic layers
on 1:50,000 scale
 GIS layers ( Soil, land use, hydrological features,
administrative units, rainfall distribution, water quality
ranges- As, Fe, F, TDS, pesticides etc) required for
characterization of groundwater resources, stress on
resources and identification of management issues.
 Base map depicting observed data points
(Central/State/NGO/Institutions data)
 Water Level & Water Quality Monitoring wells
 Sub surface geology
 Electrical logs of select bore holes –Functional or
abandoned, drilled by Government / Private agencies
 VES data by CGWB/Outsourcing
 Depth to Bed rock maps from CGWB & State agencies
from Hydrogeological surveys & exploration.

36.  Compile all available information on
CGWB
 1:250,000 scale maps already
available with CGWB to bring
uniformity
 Transfer all 1:250,000 thematic layers
on the 1:50,000 scale toposheets

37. 3. Identification & Evaluation of Preliminary
Aquifer Boundaries & Units
 Involves GIS applications for demarcation of
aquifer boundaries and division into smaller
units, using various software for defining
preliminary 3-D disposition of aquifer systems
and thereby defining a conceptual model of
the aquifer units.
3.1 Define Preliminary Aquifer Boundary &
Units
3.2 Preliminary 3-D disposition of aquifers
using different software
3.3 Development of Conceptual
Hydrogeological Model

38.  4. Identification of Data Gaps in PABUs
 Once the smaller Aquifer Units have been
defined on the 1:50,000 scale, the units will
be defined on the data availability and data
gaps in respect of various essential
parameters need to be identified.
4.1 Exploration
4.2 Hydrogeology
4.3 Geophysics
4.4 Water level Monitoring
4.5 Water Quality
4.6 Hydrology/Hydrometeorology

39. Preliminary Aquifer Boundaries &
Units (PABUs)
 5 Prioritisation of PABUs (on the basis
of data gaps/ availability)
 On the basis of data availability and
data gaps, the PABUs will be
prioritised for data collection.
 The units will be classified into various
categories on the basis of extent and
type of data gaps.

40. 7. Preparation of Aquifer
Maps
• 2D – Plan View with thickness as Isopach,,
quality contours, specific yield/Yield Potential
zonations
• 3D – block view of aquifer disposition and
geometry.
• Scale 1:50,000 paper copy & soft copy which
can be used to over lay on 1:10,000 to be
prepared by SoI.
 7.1 Refinement of thematic layers on
1:50,000 & 1:10,000 scale
 7.2 Integration of various thematic layers and
models on GIS platform
 7.3 Preparation of Aquifer Maps, i.e. 3-D
Disposition of aquifers

41. 8. Ground Water Assessment
 Making an assessment and preparation
of various maps indicating Points
suitable for recharge, Area suitable for
protected water supply, Hydrochemical
zonation for development &
Management strategies, etc.
8.1 Ground water modelling
8.2 Ground water resource assessment
8.3 Preparation of Vulnerability map for
aquifer Unit
8.4 Identification of Feasible areas for GW
development and Recharge

42. 9. Preparation of Aquifer
Management Plans
 Preparing Aquifer management plans
which can be implemented through
community participation.
 This might also entail development of
DSS with GW modeling for prediction of
different stress conditions of particular
aquifer or group of aquifers
9.1 Identification of Aquifer Management
Units (AMUs)
9.2 Preparation of Aquifer Management
Plans
9.3 Define the scope of participatory
ground water management.

43. 10. Development of Aquifer Information
& Management System (AIMS)
 An Aquifer Information & Management
will be developed which will be for
public domain as well as for domain
experts where information, maps, data
can be easily accessed.
 10.1 Development of AIMS

44. Methodology of Map preparation
1. Base map
 Digitization of base map, depicting
administrative boundaries up to block
level, locations of important towns, major
drainage and transport network.
2. Geomorphology map
 Reinterpretation of available maps with
value addition from Remote Sensing
data and re-grouping of geomorphic
units as per Natural Resources
Information System (NRIS) codes.

45. 3. Land Use / Land Cover
 To be prepared from Remote Sensing
data using NRIS coding scheme.
4. Canal network and Canal command
area map
 Digitization of canal network and
canal command area maps and
demarcation of command and non-
command area as per standard
norms.

46. 5. Distribution of Rain gauge stations
 Digitization of locations of rain-gauge
stations of IMD/State agencies
6. Distribution of River Gauge/Discharge
Stations
 Digitization of river gauge sites for
monitoring discharge and water quality
with appropriate symbols
7. Distribution of springs
 Digitization of locations of springs

47. 8. Distribution of rainfall (Isohyetal maps)
 Preparation of Isohyetal maps depicting
distribution of normal/annual/seasonal
rainfall over the area.
9. Geology and Structure
 Maps prepared by Geological Survey of
India depicting surface geology to be
updated with information available from
field investigations, re-interpreted and re-
grouped into hydrogeological units.

48. 10. Integrated map of exploratory tube/bore
wells of Central Ground Water Board and
other agencies
 Digitization of maps showing locations
exploratory wells of CGWB and other
agencies using appropriate symbols and
attribute tables.
11. Integrated map of locations of Vertical
Electrical Sounding (VES) and Electrical Log
 Digitization of maps showing locations of
VES and Electrical Logs of CGWB and other
agencies using appropriate symbols and
attribute tables.

49. 13. Integrated map of ground water observation
wells of Central Ground Water Board and other
agencies
 Digitization of maps showing locations of ground
water observation wells of CGWB and other
agencies using appropriate symbols and attribute
tables.
14. Integrated map of ground water observation
wells of Central Ground Water Board and other
agencies
 Digitization of maps showing locations of ground
water quality monitoring wells of CGWB and
other agencies using appropriate symbols and
attribute tables.

50. 14. Spatial distribution of aquifer
parameters (T,K,S, Sy)
 Preparation of maps showing distribution
of aquifer parameters for each aquifer
units as per standard norms & attribute
tables.
15. Depth to water /piezometric surface
maps
 Preparation of maps showing the spatial
distribution of ground water levels
(decadal pre- and post-monsoon) in
each aquifer unit, as per standard norms.

51. 16. Water Table/ Piezometric surface elevation
maps
 Preparation of maps showing elevation of water
table / piezometric surface in each aquifer unit
with reference to mean sea level as per standard
norms.
17. Spatial distribution of water quality parameters
Preparation of maps showing distribution of
important chemical constituents / parameters
relevant to the area as per standard norms.
18. Spatial distribution of ground water recharge
and draft
 Preparation of maps showing spatial distribution
of ground water recharge and draft for each
aquifer unit.

52. Processing of data

57. Compilation of Existing Data
for Mapping
Exploratory Data Availability (Map-2):
 The existing wells (EW, OW, PZ, SH) of CGWB and other
agencies should be plotted on the base map with
 different symbols representing source of data and type of well
on Map-2.
 Lithologs and electrical logs to be plotted on the map.
 Details of each well including the Reduced Level point data
(mamsl) should be tabulated separately.
Geophysical Information (Map-3):
 The existing VES, profiling and other geophysical
investigation data generated by CGWB and other agencies
should be plotted on the base map with different symbols
representing source of data and type of investigation.

58. Ground Water Level Monitoring of Regime/Aquifer
(Map-4):
 Water level monitoring wells/piezometers should be
plotted on the base map with different symbols
 representing their source and type of well.
 Details of each well including the Reduced Level
point data (m.amsl) should be tabulated separately.
Ground Water Quality Monitoring of Regime/Aquifer
(Map-5):
 The water quality monitoring wells/ piezometers and
water quality data should be plotted on the base map
showing source of water samples (Map-5).
 Water quality data network needs to be tabulated
showing location along with Latitude/Longitude and
depth Range.

59. Pre-processing of data
Exploratory Data (Map-6, 7 & 8)
A. Alluvial Area
 Based on the lithological logs, electrical logs and other
relevant information gathered from the exploratory
 data, aquifer geometry should be deciphered and plotted on
the Map-2.
 The aquifer geometry should clearly define the disposition
of the various aquifer groups and should be
 depicted through fence diagrams and cross sections in
different directions (at least four numbers).
 The cross sections must be prepared using the RL values.
 Using these plots, top, bottom and isopachs of different
aquifer layers should be identified and drawn. (Map
 6 &7).
 Quadrant-wise and Aquiferwise parameter such as T &
S/Sy should be tabulated.

60. B. Hard rock area
 Isopachs of weathered zone/ fractured zones should be
drawn (Map 6 &7).
 Available information on fracture density, yields, quality
variations etc. should be represented pictorially (Map-8).
 Ground Water Levels (Map- 9 & 10)
 The depth to water level (DTWL)/ piezometric contour
maps for the pre- and post-monsoon period should
 be prepared aquifer-wiseto depict the general depth of
occurrence of water level (Map-9).
 Using RL values, water table elevation contour maps
should be prepared specially to depict flow directions
 and gentle/ steep ground water gradient areas (Map-10).
 Ground Water Quality (Map-11):
 Preparation of aquifer wise water quality contours (EC)
and Region-specific relevant parameters and Stiff
 diagram for each monitoring station (Map-11).
 Water quality trends.

62. Tumkur

65. Contents of Format of Data
Compilation & Computerisation
1 Litholog
2 Aquifer Parameters
3 Aquifer Wise/Zone wise Water Quality Data
4 Minor Irrigation Data
5 Major, Medium and Bigger Minor Irrigation Data
6 Water Conservation structures
7 Soil Conservation structures
8 Cropping Pattern Data
9 Hydrogeoogical Data
10 WaterLevel Monitoring Data
11 Rainfall Data
12 Geophysical Data

66. Methodology
Hydrogeological studies Remote Sensing
 Remote sensing is an important tool in the study of natural
resources.
 CGWB has used this technological tool for more than three
decades for identifying and demarcating aquifer systems.
 Aerial photos and satellite images, in visual and infra-red
spectral ranges, are utilized in regular ground water
investigation programs of CGWB.
 In some of the R&D activities, colour infra-red and Radar
products are also used in hydrogeological studies.
 The existing thematic layers of geomorphology and ground
water related information on 1:50,000 scale, compiled by the
National Remote Sensing Centre (NRSC), are used in the
aquifer mapping pilot study.
 The information from the layers is refined with additional
detailed field observations and data.

67. Satellite images
 Satellite images, LISS III, covering the pilot project
areas are studied to refine the existing information on
geomorphology (massive hilly regions, intruded high
relief dykes, weathered zones, valley-fill deposits,
drainage analysis & anomalies, abandoned / paleo
drainage, sand dunes), geology, geological structures
(fractures, faults, strike & dip directions), agricultural
activity, hydrological features, soil conditions, etc. with
the inputs from detailed field studies.
 The information obtained from this study is integrated
with the results of geophysical & hydrochemical studies.
 This spatial information is crucial in delineating areas of
potential and non-potential aquifer zones.
 The information derived from remote sensing is also
integrated with field data on irrigation, soil salinity,
ground water stress areas and is finally useful in aquifer
modeling studies.

68. Hydrogeological studies
Hydrometeorology & Hydrology
 Rainfall is the main source for surface and
ground water resources.
 Detailed analysis of daily rainfall data and its
distribution in time and space is studied based on
the data recorded within & from surrounding area
of study.
 Additional raingauge stations are planned for
data gap areas.
 Hydrological studies are conducted to determine
infiltration characteristics, base flow, etc.
 Surface hydrological data is taken into account to
estimate the surface water distribution as outflow,
storage, evaporation and infiltration into sub-
surface.

69. Hydrogeological studies
 Hydrogeology- Well Inventory
 Under the hydrogeological component of the
programme, wells are inventoried.
 Different types of wells are studied for recording their
yielding capacities, main aquifers contributing to yield,
etc.
 The nature and period of their use and sustainability are
also recorded.
 The hydrostatic heads of the aquifers are monitored on
a monthly basis through shallow dugwells (monitoring
stations), piezometers, deep wells, etc, in the areas.
 Water samples are collected from selected wells and
analysed to determine the variation of water quality over
time and space.

70. Aquifer Tests
 Hydrogeological studies include determination of aquifer parameters by
conducting pumping tests on dug / bore / tube wells and analysis of pumping test
data. Important aquifer parameters are:
 Porosity : measure of void space in the rock formations. It is defined in
percentage as the ratio of the void pore space to the total volume of the rock
formation sampled.
 Hydraulic conductivity : rate of flow under a unit hydraulic gradient through a
unit cross-sectional area of aquifer. The unit is in m/ day.
 Transmissivity : rate of flow of groundwater under a unit hydraulic gradient
through an aquifer of unit width and unit thickness. That is, transmissivity is the
product of hydraulic conductivity and thickness of the aquifer. The unit is in
m2/day.
 Storativity or storage coefficient, applicable for confined aquifers : volume of
water released from storage per unit surface area of a confined aquifer per unit
decline in hydraulic head. It is dimensionless.
 Specific yield, applicable for unconfined aquifers : volume of water released
from storage under gravity by an unconfined aquifer per unit surface area of
aquifer per unit decline of the water table. Specific yield is dimensionless or can
be given in %.
 Specific capacity of a well : ratio of discharge of the well to the drawdown, in
m3/hour/m.

71. Hydrogeological input
 Hydrogeological input also comprises
the study of unsaturated zone.
 This includes micro-level studies at
selected sites and areas as well as
utilizing the information on
unsaturated zone obtained from
remote sensing study and geophysical
measurements.

72. Ground Water Monitoring
 Monitoring of depth to water in phreatic aquifer and piezometric
head in the deeper confined aquifers, in time and space, is a very
important activity in the estimation of ground water resources and
their change with time.
 Study of pressure heads in each individual aquifer of the multi-
layered aquifer system is very important to understand the ground
water movement across the system.
 From the well inventory, representative wells tapping the phreatic
aquifer are selected at a close interval for monitoring.
 Piezometric heads are measured from existing / purpose-built
piezometers.
 Some of the monitoring wells are fitted with pressure transducers to
record continuous change in the pressure heads.
 The differences in the phreatic and piezometric heads and their
variation are analyzed to understand the ground water flow pattern
along and across the aquifer units.
 Based on the processing of data from well inventory, monitoring and
the field observations, ground water high stress areas and
vulnerable areas are identified.

73. Example of a tentative
hydrogeological map, Tumkur
district

74. Hydrogeological studies
 Groundwater Quality
 Monitoring of ground water quality is an effort to obtain
information on chemical quality and its variation through
representative samples.The existing chemical quality
data of the aquifers in the project areas is compiled by
CGWB.
 In addition to regular groundwater sampling during
groundwater level measurement at the National Ground
water Monitoring Stations, an aquifer specific
groundwater quality sampling network is developed.
Collected samples are analysed in CGWB and other
chemical laboratories. In addition to normal chemical
constituents, information on the heavy metals and
organic compounds in ground water is also generated.
This leads to the preparation of aquifer water quality
maps.

75. Contaminations
 Besides, specific studies are launched on geogenic
contaminations like arsenic and fluoride in selected
project areas.
 Groundwater is in general of good quality in the pilot
project areas.
 However, there are occurrences of saline groundwater
in the desert of Jaisalmer district, Rajasthan, in Dausa
district, Rajasthan and in the coastal tract of Vellar
basin, Cuddalore district, Tamil Nadu.
 Occurrences of arsenic contamination, in excess of the
limits prescribed for drinking water use, are reported in
the western part of the project area in Bihar.
 The other main geogenic contaminants are fluoride and
iron.
 There are also anthropogenic contaminants, such as
nitrates, phosphates, heavy metals, etc, in some places
due to various human activities.

76. Electrical
conductivit
y of
groundwate
r in India.

77. Geophysical Studies
 The role of geophysics in
groundwater exploration is vital to
understand subsurface conditions
accurately and adequately.
Geophysical investigations help
assess the presence of aquifers in
geologic formations, estimate
weathered zone thickness or bed rock
topography and fractures, and assess
quality (in terms of salinity) of
groundwater.

78. Three -dimensional geometry
 Geophysically, it is possible to precise
the three-dimensional geometry and
disposition of aquifers.
 Application of geophysical methods for
aquifer characterization has been in
practice in India since the 1930s,
mostly through electrical resistivity
sounding and profiling and
geophysical logging of boreholes.

79. Apply geophysical
methodologies
 In view of mapping the entire aquifer systems in India
within a short period of time, it is necessary to apply
geophysical methodologies comprising a combination of
techniques that give fast coverage and yield the desired
information as precisely and adequately as possible.
 With this objective, NGRI, the agency in charge of
geophysical investigations, applies both airborne and
ground based (surface and borehole) state of the art
techniques in the pilot project areas.
 All of these play a significant role in aquifer
characterization at various scales in different
hydrogeological terrains.
 The most appropriate geophysical methodologies are
then identified for the National Aquifer Mapping
Programme.

80. In the pilot study, the following
methods are used:
 Airborne: heliborne time-domain electromagnetic
and magnetic
 Ground-based: resistivity and induced
polarization sounding and resistivity profiling,
resistivity imaging, time-domain electromagnetic
sounding, and
 Geophysical logging of boreholes
 The aquifer geometry mapping by these
geophysical methods and techniques helps
identify the aquifers, their lateral extents and
vertical grouping through generation of cross-
sections and contour maps.
 The hydrogeological studies in conjunction with
geophysical parameters also help identify the
areas for artificial recharge or areas requiring
aquifer protection.

81. The flow chart below shows the approach
adopted for geophysical investigations under
the pilot study

82. Outcomes of geophysical
investigations in the pilot
study In six pilot areas :
 Aquifer-geometry maps up to 200 m depth in hard rocks
and 300 m depth in sedimentary areas.
 Establishment of the efficacy of various geophysical
techniques under different hydrogeological conditions.
 Establishment of a methodology for geophysical
investigations to be up scaled up for the entire country.
 Besides these, geophysical investigations will give
information on the suitability of near surface layers for
artificial recharge as well as help identify recharge
zones.
 Also, geophysical investigations bring out the aquifer
boundaries required for mathematical modeling.

83. Surface Geophysical Methods
 Surface geophysical methods include
electrical, electromagnetic, magnetic,
seismic and gravity.
 The most commonly used method is
electrical, followed by electromagnetic,
as they directly give information on the
quantity and quality of water present in
the primary and secondary pore spaces
of the formations.
 Therefore these two methods are used in
the pilot project areas.

86. Borehole Logging
 Geophysical borehole logging or well logging,
also known as borehole geophysics, involves
insitu measurements within a borehole or well
to determine the physical property
characteristics of the geological formations
immediately surrounding the borehole wall
and the salinity of interstitial pore fluid.
 The aim of logging is to obtain precise depth-
wise aquifer and confining aquitard
information which may not be obtained in
general through surface geophysical methods
and to refine the lithological information
obtained from drilling.

89. Integration and
Standardization
 Geophysical methods and techniques are
based on measuring certain physical
properties of the subsurface, which are
translated into hydrogeological conditions.
 They are not all equally responsive to the
hydrogeological conditions and have their
inherent limitations and ambiguities.
 Therefore, a combination of methods and
techniques is preferred. It is then critical to
integrate and standardize the results
obtained through the different geophysical
methods to arrive at the least ambiguous
positive anomaly.

90. Hydrogeological Interpretation
 Once the geophysical parameters are
standardized through information on
lithology and groundwater conditions
from boreholes, the observed
variations in geophysical parameters
are interpreted to reflect the
hydrogeological variations.
 Thus, the geometry of the aquifers,
the quality of water in them, and the
potentiality of the aquifers are inferred
for each area.

91. Aquifer-geometry maps
 Aquifer-geometry maps of the areas
are then produced, with information up
to 200 m depth in hard rocks and 300
m depth in the sedimentary areas.
 Information is also provided on the
suitability of near surface layers for
artificial recharge and on recharge
zones, and possibly as well on aquifer
boundaries for mathematical
modeling.

93. Exploratory Well Drilling &
Aquifer Parameter
Characterization Groundwater exploration forms the
background of scientific evaluation of the
water bearing properties of various rock
formations.
 Under this programme, 120 boreholes are
drilled at selected sites in the pilot project
areas, using rotary as well as DTH drilling rig
machines.
 These sites are selected based on the
compilation of existing data and identification
of data gaps, as well as on hydrogeological
and geophysical studies.
 Drilled boreholes are geophysically logged to
accurately delineate the aquifers and

94. Aquifer performance tests
 Aquifer performance tests required for the
characterization of each aquifer unit, inter-aquifer
hydraulic relation within the multi-aquifer system and
corroboration with existing information are carried out.
 Aquifer characterization is the overall output of
groundwater exploration.
 It includes studying the subsurface lithologic variations
and water bearing properties and map the three-
dimensional disposition of different aquifer systems up
to the desired depth, spatial & vertical variation in
pressure heads and hydraulic gradients, assessing their
storage and transmissivity, their recharge potential as
well as determine their ground water quality.

95. Aquifer geometry

96. Aquifer Maps
 The hydrogeological, geophysical and geochemical
components of the pilot study are integrated to provide
information on the aquifers in each pilot area.
 This includes in particular the geometry of aquifers and
hydrogeological information on these aquifers.
 Also, aquifer characterization helps estimate the water
budget and the aquifer resource availability.
 A major output is 1:50,000 scale multiple-layer digital
maps of the areas; in selected areas the scale of the
maps is 1:10,000 scale.
 These maps are given both under 2-D and 3-
D.Technical maps are produced to support modeling
and aquifer-based groundwater management.
 Besides these, descriptive maps are also produced at
the block level or watershed level.

97. These maps integrate the
different thematic layers,
including:Background maps, i.e. on lineaments, soil types, surficial geology,
hydrogeology, fence-diagrams / cross-sections, etcAquifer maps:
•Aquifer geometry maps,
•Contour maps for water table and hydrostatic heads of different
aquifers,
•Groundwater flow maps,
•Maps on aquifer depths, saturated/total thickness and estimated yield,
•Maps on spatial variation of hydraulic parameters,
•Maps on quality of groundwater in different aquifers,
•Hydrogeological cross sections and 3-dimensional aquifer disposition
diagrams,
•Depth of drilling, discharge, well spacing and the limits,
•Level of exploitation of aquifers and annual recharge, vulnerable
aquifers, their protection and sites for their monitoring,
•Dynamic and static resource and aquifer wise water budget, and
•Areas for artificial recharge.

98. Thematic layer of an aquifer
map

100. Mathematical modeling
 Mathematical modeling is a powerful tool in
groundwater resource management.
 Once the aquifer geometry and its characteristics
are known, with the available boundary
conditions, CGWB undertakes groundwater
modeling.
 The mathematical modeling is initiated at
different scales to:Project future scenarii and
predict future groundwater conditions based on
the present and projected demand.Understand
surface water - groundwater interactions and
interactions within the aquifer systems under
varied water table/piezometric head and aquitard
conditions.And thus consolidate the aquifer-
related problem for theoretical as well as
management programmes.

101. Aquifer Management
 Based on the results of aquifer mapping and modeling,
CGWB implements a follow up program for aquifer
management, focusing on participatory groundwater
management plans.
 The definition of management plans involves stakeholders
and takes into account local water issues and
socioeconomics characteristics.
 It is done at the village or watershed level to arrive at an
effective solution.
 A clear picture of the aquifers in each area, including aquifer-
wise water budgeting and water availability and quality in pre-
and post-monsoon periods, is provided to the stakeholders.
 Aquifer management plans include for example:
 Provisions on groundwater abstraction for improving the
water balance in the watershed,Identification of areas for
artificial recharge,
 Identification of alternative sources for water supply, in
particular in geogenically contaminated areas where
contamination-free aquifers identified through aquifer-
mapping could be tapped.

102. Aquifer Data Management
 CGWB is maintaining the Ground Water Information
System (GWIS) in collaboration with the National
Informatics Center.
 It contains limited data pertaining to CGWB only.
 This information system is being rebuilt into a more
robust, web-based tool: the Aquifer Information and
Management System (AIMS).
 This information system integrates all groundwater
related data/ information and management plans.
 It makes data available for the public domain and is a
key management tool for planning and for participatory
groundwater management country-wide.
 Data from the pilot study are integrated to this Aquifer
Information and Management System.

103. GWIS- Ground Water
Information System

104.  Article available in Researchgate
 Thank You