|
|
|
|
The main source of groundwater is
precipitation. The rate of replenishment of the groundwater
varies with the pattern of precipitation, surface runoff along
with the intrinsic permeability of the soil and other
materials through which the water must percolate to reach the
zone of saturation. Now a days due to overexploitation of
ground water for irrigation purposes, the water table is
falling by about 20-25 cm per year in regions of Punjab,
Haryana and Gujrat. Therefore, there is urgent need for ground
water recharging.
|
|
Method of
Artificial recharge |
|
Ground water
recharge may be increased by soil conservation measures and
artificial recharge procedures. The amount of water
infiltrated into the soil varies with the condition of soil
surface and the moisture content of the soil at the time of
rainfall. The total amount of water infiltered depends on the
infiltration opportunity time, which depends mainly on the
slope of the land and the field structures like contour bunds,
terraces and other structures, which tend to hold the runoff
water over long periods on the land surface.
|
|
Water spreading |
|
This method is similar to that of
surface irrigation, with the difference that in recharge
operation the water is allowed to stand on the field for a
much longer period. This method may be further classified into
(i) basin method, and (ii) furrow or ditch method depending
upon the topographical conditions of the soil.
|
|
Ground water
recharge through wells and pits |
|
Depending upon
the depth of the impermeable layer, ground water recharge can
be done by large pits or wells, former being used where the
impermeable layer is encountered at large depths. In this
method water is allowed to infiltrate into the soil from large
pits filled with water. Sometimes water is recharged into the
soil directly through the tube-wells. The excess surface water
is directly feed into ground through wells/tube-wells. Mostly
this method of recharge used where sufficient land is not
available for water spreading. The volume of water recharged
by the well or pit method is, however, low and the method is
not practised where surface methods are feasible.
|
|
|
|
|
