ARTIFICIAL RECHARGE OF GROUNDWATER

ARTIFICIAL RECHARGE OF
GROUNDWATER
Er. Namitha M R
Asst. Prof. (Dept. of IDE)
KCAET, Tavanur

ARTIFICIAL RECHARGE OF GROUNDWATER
 Artificial Recharge:
“augmenting the natural movement of surface
water into underground formations by some
method of construction, by spreading of
water, or by artificially changing natural
conditions”
-(Todd, 1980)

CONTD…
 Recharge method depends on
 local topography
 geologic and soil conditions
 amount of water to be recharged
 the ultimate use of water.
 the value of land
 water quality, or climate

METHODS OF ARTIFICIAL RECHARGE
 Artificial techniques use for groundwater
recharge can be divided in two
groups, i.e. direct method and indirect
method.
 Further, the direct method can be sub
grouped as surface method and sub-surface
method.

ARTIFICIAL RECHARGE METHODS
1. DIRECT METHOD
A. Surface method
1. Percolation tank
2. Flooding
3. Stream augmentation
4. Ditch and furrow
system
5. Contour bund
B. Sub surface method
1. Recharge well
2. Dug well
3. Pits and shafts
2. INDIRECT METHOD:
1. Induced recharge
technique
2. Aquifer modification
technique

DIRECT METHOD
A. SURFACE METHODS
1. Percolation tank
 In this method, series of earthen dams are
constructed on suitable sites for storing of
adequate quantity of surface water.
 Water infiltrates through the bed of the tank and
reaches the groundwater table.
 Very effective in alluvial area as well as in areas
with hard rock.
 This method is very useful in providing
continuous recharge after the monsoon.

2. Flooding
 Suitable for relatively flat region where water
can be spread as a thin layer.
 Water is distributed over the region using a
distribution system.
 This method can achieve higher rate of
infiltration in a region having thin vegetation
cover or sand soil cover.

3. Stream augmentation
 Seepage from natural stream or river is
artificially increased by putting some series of
check dams across the river or stream.
 Placing of check dams spread the water in a
larger area which eventually increases
groundwater recharge.
 The sites for the check dams should have
sufficient thickness of permeable bed to allow
quick recharging the stored water.

4. Ditch and furrow system
 Used for uneven terrain.
 A system of closely spaced flat bottom ditch
or furrow is used to carry the water from the
source.
 Provides more opportunity to percolate the
water into the ground.
 Spacing of the ditch depends on the
permeability of the soil.
 For less permeable soil, more densely spaced
ditch or furrow should be provided.

5. Contour bund
 Contour bund is a small embankment
constructed along the contour in hilly region
to retain the surface runoff for longer time.
 This scheme is adopted for low rainfall area
where internal subsurface drainage is good.

B. SUB-SURFACE METHOD
 1. Recharge well
 Recharge wells are used to recharge water
directly to the aquifer.
 Similar to pumping wells.
 Suitable to recharge single wells or multiple
wells.
 Costlier than the other method as wells are
required to be bored.
 Abandoned tube wells can be used for
recharging water into the aquifer.

2. Dug well
 Dug wells can also be used to artificially
recharge the groundwater.
 Sometime the dug wells dries up in the non-
monsoon period.
 These dug wells can be used for recharging
groundwater.
 Water from various sources can be collected
through a distribution system and can be
discharged at the dug wells.

3. Pits and shafts
 Recharge pit of variable dimensions are used to
recharge water to unconfined aquifer.
 Due to the existence of the less permeable strata,
the surface flooding methods of recharge do not
show satisfactory performance.
 For such type of cases, recharge pit can be
excavated which are sufficiently deep to penetrate
the less permeable strata.

CONTD…
 Recharge shaft is similar to the recharge pits,
but the cross sectional size of the recharge
shaft is much lesser than the recharge pits.
 Recharge shafts are also used to recharge
water to unconfined aquifer whose water
table is deep below the land surface and a
poorly impermeable strata exist at the surface
level.

INDIRECT METHOD
1. Induced recharge
 In this method water is pumped from the
aquifer hydraulically connected to the surface
water sources like stream, river or lake.
 Due to pumping, a reverse gradient is formed
and water from the surface water source enters
into the aquifer and thus the aquifer is
recharged .
 The filtration of surface water through soil
strata removes the impurities of the water.

2. Aquifer modification method
 Some techniques are used to change the
aquifer characteristic so that aquifer can store
more water and also can transmit more water.
 Most commonly used techniques are, bore
blasting method, hydro-fracturing method,
jacket well techniques, fracture seal
cementation and pressure injection grouting,
etc.

a. Bore blasting method
 This method is used to increase the fracture
porosity of an aquifer.
 The bore holes are blasted with the help of
explosive which creates fracture porosity in
the aquifer.

b. Hydro-fracturing method
 Hydro-fracturing is used to improve the yield of
a bore well.
 In this technique, water is injected at a very
high pressure to widening the existing fracture
of the rock.
 As a result of these, the water storing and
transmitting capacity of the strata increases.

c. Jacket well techniques
 Jacket well technique is used to increase the
yield of a dug well.
 In this method, the effective diameter of the
well is increased by drilling small diameter
bores around the well in a circular pattern.

d. Fracture seal cementation and pressure
injection grouting
 This technique is used to control the outflow
from an aquifer.
 Cement slurry is injected into the aquifer using
mechanical means or manually near to the
aquifer outlet like spring, etc.
 The injection of cement slurry helps in
reducing the fracture porosity of the aquifer
near the outlet which will eventually reduce the
outflow from the aquifer.

“WATER IS VALUABLE IN TWO SITUATIONS:
BEFORE GETTING IT AND AFTER LOSING IT”

ARTIFICIAL RECHARGE OF GROUNDWATER

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