Thursday, 1 May 2014

Dead Borewell can Spring Back to Life

Dead Borewell can Spring Back to Life

Bangalore may have at the conservative estimate, around 4 lakh borewells.
Cost of each borewell is around Rs 1 lakh (drilling + installing a pumping set).
Total investment on borewells in Bangalore is around 40,000 Million Rupees.
At least half of the borewells in Bangalore are dead (not yielding water or low yielding).
Can we bring back life in to these 2 lakh borewells and put back to use the investment of around 20,000 Million Rupees of hard earned money by individuals?

Underground water is one of the important sources of water in urban areas. With increasing urbanization, underground water has been indiscriminately exploited causing depletion in water table and water availability. It is very evident from the number of failing bore wells / open wells that it is unsustainable to pump out water from wells without recharging the same from the rainwater. To reverse the trend or to reduce the effect of over exploitation, ground water recharge needs to be taken up in large scale at residential and institutional buildings. 
There are many methods of ground water recharge, direct recharge through borewells or tubewells (only for low yielding or failed borewells) is one of the method for recharging ground water using rainwater from rooftops of buildings.

Rainwater from the roof may be allowed to flow through PopUp filter and recharge ground water from an existing borewell. Filtered rainwater from PopUp filter enters the storage tank and the overflow from the storage tank with clear and stabilized water should be diverted to the Casing Pipe of Bore well. It is advised not to allow the filtered rainwater from the PopUp filters in to the bore well (Low yielding or failed). Fine silt or dust from the roof may pass through the filter and block the micro pores or aquifers in the bore well causing permanent damage to the bore well. To avoid this, rainwater from the filters may be allowed to stabilize in a storage tank specially designed to inject rainwater in to the bore well.
Clean and safe rainwater recharges the borewell aquifers to increase the yield and availability. It is advised to consult a professional before attempting to inject rainwater into bore wells.

If the roof top rainwater is contaminated with bacteria (may be from bird droppings etc.), the borewell water will also get contaminated. If the contaminated water is injected to borewell, many borewells in the neighborhood may also get contaminated. Care should be taken to address this before attempting for borewell recharge.