07-24-2014, 02:48 PM
In areas where the surface soil is impervious and large quantities of roof water or surface runoff is available within a very short period of heavy rainfall, the use of trench/ pits is made to store the water in a filter media and subsequently recharge to ground water through specially constructed recharge wells.
This techniques is ideally suited for area where permeable horizon is within 3m below ground level.
Recharge well of 100-300 diameter is constructed to a depth of at least 3 to 5 m below the water level. Based on the lithology of the area well assembly is designed with slotted pipe against the shallow and deeper aquifer.
A lateral trench of 1.5 to 3m width and 10 to 30 m length, depending upon the availability of water is constructed with the recharge well in the centre.
The number of recharge wells in the trench can be decided on the basis of water availability and local vertical permeability of the rocks.
The trench is backfilled with boulders, gravels and coarse sand to act as a filter media for the recharge wells.
If the aquifer is available at greater depth say more than 20 m, a shallow shaft of 2 to 5 m diameter and 3-5 metres deep may be constructed depending upon availability of runoff. Inside the shaft a recharge well of 100-300 mm dia is constructed for recharging the available water to the deeper aquifers. At the bottom of the shaft a filter media is provided to avoid choking of recharge well.
![[Image: harvesting3.png]](http://www.frontdesk.co.in/big/bs/harvesting3.png)
This techniques is ideally suited for area where permeable horizon is within 3m below ground level.
Recharge well of 100-300 diameter is constructed to a depth of at least 3 to 5 m below the water level. Based on the lithology of the area well assembly is designed with slotted pipe against the shallow and deeper aquifer.
A lateral trench of 1.5 to 3m width and 10 to 30 m length, depending upon the availability of water is constructed with the recharge well in the centre.
The number of recharge wells in the trench can be decided on the basis of water availability and local vertical permeability of the rocks.
The trench is backfilled with boulders, gravels and coarse sand to act as a filter media for the recharge wells.
If the aquifer is available at greater depth say more than 20 m, a shallow shaft of 2 to 5 m diameter and 3-5 metres deep may be constructed depending upon availability of runoff. Inside the shaft a recharge well of 100-300 mm dia is constructed for recharging the available water to the deeper aquifers. At the bottom of the shaft a filter media is provided to avoid choking of recharge well.