Artificial recharge

1. ARTIFICIAL RECHARGE
PRESENTED BY
U VAMSHI KRISHNA PRASAD

2. Why Artificial Recharge?
 In most low rainfall areas of country the
availability of utilizable surface water is so low
that people have to depend largely on ground
water for agriculture and domestic use.
 The problem has been further compounded due
to large scale urbanization and growth of
megacities which has drastically reduced open
lands for natural recharge.

3. INTRODUCTION
The artificial recharge to ground water aims at
augmentation of ground water reservoir by
modifying the natural movement of surface water
utilizing suitable civil construction techniques.
Artificial recharge techniques normally address to
following issues:
 (i) To maintain the ground water resources.
 (ii) To store underground
excess surface water.
Fig.1 Water Scarcity

4. (iii) To improve saline
water intrusion in
costal aquifer.
(iv) To remove bacteriological and other impurities from
sewage and waste water so that water is suitable for
re-use.
(v) To minimize the land
subsidence from drawn
of excess ground water.
Fig.2 Saline water
intrusion
Fig.3 Land Subsidence

5. (vi) To improve Physical and Chemical quality
of ground water.
Case study 1
Wailapally , Nalgonda District, T.S
 Fluoride contamination is more
in underground.
 NGRI ( National Geophysical
Research Institute)
 Excess of rain water recharged
to decrease the fluoride
quantity.
Fig.4 Wailapally watershed

6. DEFINITION
Augmentation of ground water reservoir by man made
structures by using rain water.
QUALITY OF SOURCE WATER
Chemicals and salts:
 Problems which arise are mainly related to quality of raw
waters available for recharge which requires treatment
before being used in recharge installation.
 Changes in soil structure and biological phenomena are
also related to it. For source water and ground water the
chemical and bacteriological analysis is essential.
Sediment load:
 The water used in recharge projects should be free from
silt. Silt may be defined as content of undissolved solid
matter measured in mg/L, which do not exceeds 0.1m/hr.

7. SOURCES OF WATER FOR RECHARGE
 Precipitation (rainfall) over the demarcated area.
 Large roof areas from where rainwater can be
collected and diverted for recharge.
 Canals from large reservoirs from which water can be
made available for recharge.
 Natural streams from which surplus water can be
diverted for recharge, without violating the rights of
other users.
 Properly treated municipal and industrial wastewaters.
This water should be used only after ascertaining its
quality.

8. Fig 5 Artificial Recharge technique

9. Factors Affecting the Artificial
Recharge:
1. Topography
2. Water supply
3. Geology
4. Mechanical properties of geological
materials.
5. Cost
6. Social Benefits

10. Advantages of Artificial Recharge
 No large storage structures needed to store water. Structures
required are small and cost effective.
 Evaporation losses are negligible
 Quality improvement by infiltration through the permeable media
 Biological purity is very high
 Negligible losses as compared to losses in surface storages.
 Temperature variations are minimum
 It is environment friendly, controls soil erosion and flood and
provides sufficient soil moisture even during summer months
 Water stored underground is relatively immune to natural and
man-made catastrophes.
 No displacement of local pollution.

11. Implementation of Artificial Recharge
Schemes
Successful implementation of artificial
recharge schemes will essentially involve the
following major components:
 Assessment of source water
 Planning of recharge structures
 Finalisation of specific techniques and designs
 Monitoring and impact assessment
 Financial and economic evaluation
 Operation and maintenance

12. Methods of Artificial Recharge
They can be broadly classified as:
Direct Method Indirect Method
A) Surface Method A) Induced Recharge
i) Flooding B) Aquifer Modification
ii) Basin i) Hydro-Fracturing
iii) Stream augmentation
iv) Ditch & Furrow
v) Contour Bund
B) Subsurface Method
i) Injection wells
ii) Recharge pits

13. A)Surface Method
 Increasing the contact area and resident
time of surface water over the soil to
enhance the infiltration.
 To augment the groundwater storage in
phreatic aquifers.
Fig.6 Surface Method

14. i)Flooding
 It is very useful in selected areas where a favourable
hydro-geological situation exists.
 Flat region where the water can be spread as thin
sheet.
Fig.7 Sheet Spreading

15. ii)Basin
 Excavated or enclosed by dykes or levees.
 Built parallel to ephemeral or intermittent stream
channels.
 Water contact area in this method is quite high.
Fig.8 Basin Method

16. iii)Stream augmentation
 Seepage from natural stream or river is artificially
increased by putting some series of check dams
across the river or stream.
 Site selected should have sufficient thickness of
permeable bed.
Fig.9 Stream
augmentation

17. iv)Ditch and Furrow
 In areas with irregular topography, shallow, flat-
bottomed and closely spaced ditches and furrows.
 Reguires less soil preparation.
Fig.11 Furrow MethodFig.10 Ditch Method

18. B)Subsurface Method
These aim at recharging deeper aquifers that are
overlain by impermeable layers,preventing the
infiltration from surface sources to recharge them
under natural conditions.
i)Injection wells
These structures are similar to a tube well.
 Directly discharge water into deep water-bearing
zones.
 Suitable only in areas where a thick impervious layer
exists between the surface of the soil and the
aquifer that is to be replenished.

19. Fig.12 Injection wells

20. ii)Recharge pits
 Overcome the difficulty of artificial recharge of
phreatic aquifer from surface water sources.
 Similar to recharge basins in principle,with the only
difference being that they are deeper and have
restricted bottom area.
Fig.13 Recharge pit

21. A)Induced Recharge
 Pumping water from aquifer,which is hydraulically
connected with surface water.
 Improves the quality of surface water.
 The filtration of surface water through soil strata
removes the impurities of the water.
Fig.14 Induced Recharge

22. B)Aquifer Modification
 Modify the aquifer characteristics to increase its
capacity to store and transmit water.
 After application of it more recharge take place
under natural as well as artificial condition.
i)Hydro-Fracturing
 It is a process whereby hydraulic pressure is applied
to an isolated zone of bore wells to initiate and
propagate fractures and extend existing fractures.
 The water under high-pressure break up the fissures
cleans away clogging and leads to a better contact
with adjacent water bearing strata.

23. THANK YOU