Before
taking up any artificial recharge project, it
is a basic pre - requisite to ascertain the
availability of source water for the purpose
of rechargeing ground water aquifers. For determining
the source water availability for artificial
rechage, hydrological investigations are requiredto
be carried out in the watershed / sub basin
/ basin, where artificial recharge schemes are
envasaged. The different types of source water
that are available for artificial recharge are
:
i. The situ precipitation on the watershed
ii. Surface (Canal) supplies from large reservoirs
locating in the basin
iii. Surface supplies through trans - basin
water transfer
iv. Treated municipal and industrial waste waters
Further
the following information are necessary for
designing any artificial recharge structures
:
a.
The quantity that may be diverted for artificial
recharge
b. The time for which the source waater will
be available
c. The quality of source water and the pre treatment,
if any, required
d. Conveyance system required to bring the water
to the recharge site
Hydrological
studies are undertaken to work out surplus monsoon
run off which can be harnessed as source water
for artificial recharge.
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SOIL
INFILTRATION STUDIES
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In
case of artificial recharge through water spreading
methods, Soil and Land use conditions which
control the rate of infiltration and downward
percolation of water applied on the surface
of the soil assume special importance.
The
maximum rate at which water can enter the soil
at a particular point under a given set of conditions,
is called the infiltration capacity. Infiltration
capacity depends on many factors such as soil
type, moisture content, organic matter, vegetative
cover, season air entrapment, formation of surface
seals or crusts etc.
Assessment
of sub surface potential for Ground Water Recharge
:
Based
on the hydrogeological and geophysical surveys,
the thickness of potential unsaturated zone
for recharge should be worked due to assess
the potential for artificial recharge in terms
of volume of water which can be accommodated
in this zone vis - a - vis source water availability.
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