How to prevent water exploitation?

With the continuous increase in urban population, the people living in cities are facing the problem regarding fresh water supply. Underground water is one of the major sources of water in cities. But excess pumping of the groundwater and less recharging is causing imbalance in the water table. If the over-exploitation continues, the water of the reservoirs will get depleted, the wells will go dry and it will be difficult to get them replenished.

To prevent depletion of water reservoirs and reduce over-exploitation, it is very important to effectively recharge groundwater aquifers in large scale at residential, commercial and institutional buildings to percolate rainwater to water table.

Here are a few tips for recharging groundwater aquifers.

Recharging of bore wells: Bore wells can be recharged by directing filtered rainwater collected in filtration tank of the building to the wells. Rainwater is collected on the rooftop of the building and diverted to the filtration tank by drain pipes. In filtration tank water is filtered. First shower of the rain should be flushed out by separators.

Recharge pit:Recharge pits are small pits confined with brick or stone masonry walls with weep holes at regular intervals. These pits can be of any shape square, rectangular or circular. Filter materials should be filled at the bottom of the pit. The pit should be covered with perforated covers at the top. The capacity of the pit should be decided according to the catchment area, the intensity of rainfall and recharge rate of the soil.

Recharge dug wells: Dug wells are also used as recharge structure. Rainwater is diverted to these dug well from the catchment areas after passing it through a filtration bed. To enhance the recharge rate, it is very important to clean and desalt dug wells regularly.

Recharge trenches: Recharge trenches are suitable harvesting surface run-off. It is appropriate for small houses, gardens, playgrounds and roadsides, where the upper impenetrable layer of soil is shallow. The trench is dug in the ground and refilled with filter materials like pebbles, boulders or brickbats etc. The length of the trench depends on the expected run-off.

Percolation tanks: Percolation tanks are artificial recharge technique. In this method, a highly permeable land area is submerged to facilitate percolation to recharge the ground water. These can be built where land and topography are suitable.