1. Pilot Aquifer Mapping in India
Hydrogeological perspectives and
investigations
Dipankar Saha
Central ground water Board

2. We should have a detailed understanding of the
aquifers to answer everybody's queries and satisfaction
Aquifers are of multifarious use
•Store house of ground water, irrigating croplands, catering
industries
•Conduit of flow from recharge to discharge areas
•Can store a part of runoff water in the event of excessive
rainfall
•Maintain aquatic environment in rivers/wetlands by
contribution as base flow
•Potable, pathogen free drinking water to thousand of
villages
Aquifer-is defined as a formation that contains
sufficient saturated permeable material to yield
significant quantities of water to wells and springs

3. Un-informed and unsustainable uses of aquifer may
render-
•Depletion of resource over time
•Deterioration of chemical quality of ground water
•Sea water intrusion through aquifer in coastal area
•Conflict between the users and geographical boundaries
•Land subsidence
•Anthropogenic pollution of aquifers and may trigger
geogenic pollution
•Adverse effect on aquatic ecology in wet lands and rivers
etc……..

4. We should have a holistic
understanding of the aquifer
1.Aquifer geometry
2.Aquifer-aquitard hydraulic
parameters
3.Aquifer yield potential
4.Ground water flow regime
5.Recharge and discharge
components
6.Hydrogeochemistry

5. India is geologically diverse country,
with wide variation in climate
Accordingly the hydrogeological
domains also vary widely
Six pilot projects has been
taken up in India

6. • Area : 376 sq.km
• Major part is under shallow
weathered pediplain and
valley fill
• General elevation – 850 m (S.part)
– 720 m (N.part)
• Residual hill, Inselbergs,
Pediments ,Valley fills, Plain land
Normal Rainfall of study area- 680
mm
• Located on the surface water
divide of Kaveri and Krishna
basins.
• Major area is under agriculture
Tiptur -Chikkanayakanahalli Taluks,
Tumkur district, Karnataka

7. Drainage map
Major area is under
shallow weathered
pediplain and valley fill

8. Aquifer system
• Phreatic aquifer which exists mostly in
the northern parts remains dry for
most part of the year.
• Semi-confined to locally confined
aquifer system in the deep fractured
formations
Water level behavior
Southern part represents the water
divide between the two basins. Water
levels are as deep as 100 m bgl. A
decades back the level was <20 m bgl
Northern part –water level at
present > 40 mbgl. A decade back <10
m bgl Stage of GW dev-158 %

9. Ground water flow
direction is from SW to
NE
Sharply declining water
levels
Depth to water
level below
ground, May 2013
water level contour ,
above msl

10. Exploratory drilling at 14
locations reveals wide variation
in yield- 0.22-4.36 lps
Water level varies from 13.4 to
80.10 m bgl
Depth of fracture model
However it needs detailed
interpretation of data
considering the heterogeneity of
the fractures
Discharge in lps

11. The top layer remains dry during most of the period and the
second layer act as the principal aquifer .
There is no out flow of water from the water shed.
The flow lines indicates ground water troughs at heavy draft
areas.

12. Findings so far
• The area is over-exploited and water levels are generally in the range of
40 to 60 mbgl. Deeper water levels are also observed in isolated patches.
• Ground water exploration has potential fractures in 60-80 m, 100-120m.
Deeper fractures are also observed at 180 – 200 m depth.
• Shallow fractures at few locations are observed to be dry due to over-
exploitation.
• Water quality is mostly good for both domestic and irrigation purposes.
However at certain isolated tiny areas high concentration of nitrate is noticed
• Surface and ground water resources in the area is being fully utilized.
• There is no surplus run-off in the watershed.

13. Baswa-Bandikui Watershed, Dausa district,
Rajasthan
• Area : ~600 Sq.Km
• Physiography: Part of Eastern
Rajasthan Upland, open undulating
plain; badland topography at places.
• Rainfall: av. – 652 mm/yr.
• Water Resources sector scenario –
Main source – GW
SW – Banganga river & its
tributaries – Sanwan and Palasan
streamsi
• GW - Less to Moderate availability.
Quality suffers from fluoride, salinity.

14. Badland
topography
Major part- vally-fill with
badland topography along
the Sarwan River course,
Isolated hills in the northern
and north-western part

15. •The major part is covered by Quaternary alluvium. In the northern
border of the project area, hard rocks are exposed.
•In general depth to bedrock varies from 50-60m bgl. Alluvium depth
increases east ward.
•Ground water generally occurs under water table and semi-confined
conditions in Quaternary sediments & weathered and fractured zones
of hard rocks.
•Ground water is
contaminated in some places
with fluoride.
•Drilling by CGWB-Yield
varies from 0.7-14 lps &
drawdown 3-15 m.
•Transmissivity varies from
7-397 m2
/ day.

16. GW Potential Zone-wise
Resources
Net GW
Availability
Draft SOD Category
Majority of the wells show
declining ground water level
trend
Stage of groundwater
development is 173% (Bandikui
Block). WL declining

17. •The water level varies from
about 15 m in west & north-west
to > 60 m in patches along the
axial part of the area
Ground water flow, both
during the pre- and post-
monsoon seasons,
towards east with minor
local variations, controlled
by the topography

18. Isopach map of aquifers-
Alluvial deposits
Isopach map of weathered
and fractured hard rocks
below the allvium deposits
•based on the results of Exploratory drilling of 14 wells
Thickness of the Alluvium –– 40 to 60 m
 Thickness of the Second aquifer (Weathered hard
rock) – 3 to 30 m

19. Conceptual model – present understanding
• Phreatic Alluvial aquifer, below weathered and fractured rocks
followed by hard rock
• Saucer-shaped basin – thickness of alluvium increasing towards
east
Identification of de-saturated/
unsaturated aquifers and suitable
artificial recharge plan
Optimal utilization of water –
water use efficiency measures
Devising pragmatic groundwater
regulation programme
Issues to be addressed

20. Lower Vellar watershed
Cuddalore district, Tamil
Nadu
•Area : 428 km2
•Rainfall annual average-1400
mm
•Drained by Paravanar and
Uppanar rivers
•The terrain ranges from
sedimentary upland to coastal
Plain

21. • Groundwater pumping for mining, irrigation
• Groundwater abstraction by state agencies for drinking water
supplies (for Chennai Metropolitan water supply).
• Sea water Ingress threat along the coast.
• Two to three decades back the area was marked with autoflow
condition, presently the Pz surface has gone down
• Stage of devlopment of the phreatic aquifer is <50%

22. Recent alluvium Sand/sandstones
Mio-pliocene sandstones
Eocene sandstones
Eocene sandstones
(Aquifer 4/Confined)
(Aquifer 3/Confined)
(Aquifer 2/Confined)
(Aquifer 1/unconfined)
clay
clay
lignite
clay
A”
A
Eocene SST (Aquifer III
Four aquifer system has been
identified within a depth of 400 m
The top aquifer is unconfined. The
aquifers below are under semi-
confined to confined condition
Quality is fit for drinking and
agriculture use

23. Regional Conceptualization of Model area (AQTND)
Mio-pliocene
sandstone
Recent alluvium
and sst...
5 – 50 m
40 - 110 m
110 – 210 m
210 – ? m
Depth of
Occurrence
Multi-layered aquifer system
Seven Layer model
Layer – 1 (sand/sandstone)
Layer – 2 (clay- discontinuous)
Layer- 3 (Sandstone)
Layer – 4 (Clay/lignite – discontinuous)
Layer – 5 (Sandstone)
Layer – 6 (Clay – discontinuous)
Layer – 7 (Sandstone)
Depressurization for
mining activity/Abstraction
for drinking to Chennai city
User aquifer for
Irrigation.
Abstraction for
Domestic &
Irrigation
Less pumping
activity
Explored depth : 400 m
Q (10 – 45 lps)
Q (8 – 40 lps)
Q (10 – 40 lps)
Q (5 – 15 lps)

24. Maner Khagaul area, Bihar
•Located in Sone-Ganga
interfluve area.
•In Middle Gangetic plains,
fringe area of Sone fan
•Thick (~500 m) Quaternary
deposit overlying
Precambrine crystalline and
Sedimentaries
NIR Image
•Area 521 km2
•Terrain- Flat
•Mean annual rainfall – 1100 mm
•Elevation- 46 to 62 m above msl

25. Geology of the area
The area belongs to Flood
plain in the interfluve of
Kosi and Ganga, marked
with flood plain, natural
levee, paleo channel

26. Hydrogeology of the area
•Multilayered aquifer system within the Quaternary
sediments.
•Aquifers are potential, catering the entire demand for
irrigation, domestic and industries.
•Water level is shallow, < 7m bgl, with pre- and post-
monsoon fluctuation as 2 to 3 m.
•No water quality problem is reported except arsenic
contamination of in the northern part of the area.
• Western part of Patna urban area covers the north
eastern part of the pilot area, experiencing heavy ground
water extraction from deeper aquifer.
•Stage of Development 61%

27. From South to North in
western part
From SW to NE
PANEL
DIAGRAM
Two aquifer system
identified in the area

28. May-13
AQUIFER-I
May-13
AQUIFER-II
Water level is shallow, and flow direction for both
the aquifers is towards ENE

29. A three aquifer system exists beneath the top
aquitard layer, within 300 m bgl. The lateral
extension of 3rd
aquifer yet to be ascertained. The
clay layers between 1st
and 2nd
is thinner than
between 2nd
and 3rd
.

30. First aquifer is exploited in rural areas whereas the
second aquifer is mainly exploited in urban areas.
The potentiality of the aquifers is considerable, T
value for first aquifer is 4900 to 12,000 m2/day, for
second aquifer, which is thicher than the upper one,
has a T value of 5800- 15000 m2/day.
Findings..
The main recharge of the
first aquifer is from south.
Isotope character and flow
direction indicates recharge
through paleo channels of
Sone.

31. •Area under paleo channels, which is hydraulically
conductive between surface and first aquifer (demarcated)
can be used for recharge
•Arsenic contamination is confined within the Active flood
plain affecting the top part of the first aquifer. The second
aquifer can be exploited for community supply safely.
•No significant decline of water level in spite of heavy
extraction in Patna urban area (<4.0 m in last two
decades)
•In rural areas ground water extraction is limited to 60 m
bgl in general
Findings….

32. Chandrabhaga Watershed
Chandrabhaga watershed,
Nagpur District
Area- 360 Km2
Average normal rainfall- 915 mm
Elevation- 310 to 509 m amsl
Drained by tributary of Chandrabhaga
river
Major land use is agriculture

33. •The major part of the area is occupied by
Deccan trap basalt (313 sq. km), remaining
47 sq.km is occupied by Gondwana
formation.
•Basaltic terrain is underlain by Gondwana
formation almost in entire basin.
•Ground water occurs under phreatic
conditions in the exposed lava flows and in
semi-confined to confined state in the
subsurface flows. The same situation is
observed in Gondwanas
•In basalt, the thickness of phreatic aquifer
ranges from 6-21 mbgl., while in Gondwanas
is between 8 -19 m bgl.
•Stage of ground water development is 89%
but the long term water level trend is
marginally rising leading to safe category

34. • Long dry spells during monsoon season
• Limited thickness of unconfined aquifer
• Drying up of aquifer particularly in basalt
• Failure of dugwells/borewells due to
unscientific selection of sites
• Industrial & Agriculture Pollution
CHALLENGES IN TERMS OF AQUIFER GEOMETRY
• Delineation of Basalt and Gondwana contacts
• Vertical disposition of deeper fractured aquifers
• Refinement of aquifer geometry including
fracture density
ISSUES

35. Depth of weathering on
the basis of lithologs
the entire area of watershed comes under plateau with
sporadic denudational hills located in the northern part
of the watershed.

36. Depth to Water Level Pre (May 2013)
Electrical Conductivity (Nov.2012)
Lithological Cross Sections Shallow
Aquifer using Rockworks

37. Parameters Layer-I Layer-II
Formation Zone-I
Basalt (Deccan Trap)
Zone-II
Sandstone (Gondwana)
Zone-III
Basalt (Deccan Trap) and
parts Sandstone
(Gondwana)
Zone-I
Basalt (Deccan Trap)
Zone-II
Sandstone (Gondwana)
Zone-III
Basalt (Deccan Trap)
covered Sandstone
(Gondwana)
Zone-IV
Basalt (Deccan Trap)
underlain by Gneisses
(Archaean)
Layer Type Unconfined, Type-1 Semi-confined to Confined,
Type-2
Layer thickness (m) 20 (GL to 20 m bgl) 180 (20 mbgl to 200 m bgl)

38. Findings
•Considering the elevation, above the msl, the water level ranges from 294 m
to 510 m above msl. The ground water flows towards ENE following the
topography.
•The drilling data indicates that the thickness (other than areas where
Gondwanas are exposed) of basalt varies from 27 m to 200 m and more.
•3-5 flows has been identified in Basalt area, thickness of each flow ranges
from 15-40.
•The vesicular zones at deeper level are not found to be very potential.
However when they are fractured they are of good potentiality.
•Sustainability of aquifers in basaltic terrain is challenging because of its low
storage potential
•Aquifer parameters;
1.Gondwanas- Shallow , yield, 2-5lps, T-4-12 m2/day
Deep, 1.37-10 lps, T- 122m2/day
2. Basalt- Shallow, yield 1-14 lps, The- 1-72 m2/day. Deep 2-14 lps, T- 6-226

39. Ramgarh area, Jaisalmir Dist,
Rajasthan
• Study area - 675 sq.km, around
Ramgarh town
• Lies in arid tract of Thar desert
characterised by extremes of hot and
cold weather
• Rainfall - less than 200 mm,
occurrence of frequent drought
• Major part of the study area is
predominantly covered with flat,
limestone terrain.
• Sand dunes are observed about 10
km north of Ramgarh town
• IGNP branch canal flows north of
Ramgarh town.

40. Age Formation and Lithology
Quaternary
(Pl. to Recent)
Aeolian sand & alluvium, gravel sand , silt,
kankar & clay
Tertiary Sanu sandstone, Bandha and Khuiala
limestone
Mesozoic Lathi, Jaisalmer, Baisakhi, Bhadesar,
Parewar, Abur formation - Sandstone,
shales with intercalated limestone,
siltstone, clay stone
Proterozoic
(Post Delhi)
Granite

41. HYDROGEOLOGY
•Aquifers zones - 45 to 70 m ; 125 to
160 m
•Unconfined to semi-confined
conditions
•ground water is fresh to saline – EC
-1500-9500 µmhos/cm
•fresh-Saline water interface (based on
Geophysical studies) - 80 to 270 m bgl
•Ground water level : around Ramgarh
area ~ 30 to 40 m bgl; south of
Ramgarh - beyond 100 m bgl at
places.
Stage of Ground water development
for the Sam Block, in which the study
area falls is 60%

42. The long term trend of water level
in the area does not show any
significant rise and decline

43. •Mesozoic formations (Pariwar sandstone) upper part- compact and
fine to medium grained, lower part- partly consolidated and fine to
coarse grained. The yield of tubewells ranges from 330 to 500
litre/min. EC varies from 2000 to 6000 microsiemens/cm.
•Tertiary group of sedimentary rocks are calcerous-argillaceous-
arenaceous assemblage. The yield varies from 500 to 1000
litre/min. However, quality of water is saline.
• Alluvial formations occurring at the northern part exhibits yield of
4-5 lps the quality is fresh to brackish
GROUND WATER LEVEL
•Ground water level around Ramgarh area is about 30 to 40 m bgl.
However, in the area lying south of Ramgarh, water level goes
deeper even goes beyond 100 m bgl at places..
•Water level trend both rising and falling

44. GROUND WATER MANAGEMENT OPTIONS
Identification of fresh water zones/ pockets and their
sustainable use
Estimation of fresh water resources in different formations
Conjunctive use of surface and ground water in canal
command area
 Identification of de-saturated/ unsaturated aquifers and
suitable artificial recharge plan

45. THANK YOU