Thursday, March 22, 2012

World Water Day: Water Water Everywhere ...And Shale Gas

Its World Water Day.

Near my house a big site is being developed. The builder excavated a huge pit about 40-50 feet deep for underground parking only to find he had hit a prolific aquifer.

My rough calculations suggest that the hole contains on the order of 15 -20 million liters of water. That sounds a lot but I was struggling to give it a context. Then this morning I read an article on Fracking, Methane and Food Security. Fracking or hydraulic fracturing is the process of injecting shale rock with a mixture of water, sand and chemicals to pry open the shale and release the tightly bound natural gas.

Here is what the article says about the amount of water used by each well being fracked -

 “Every time a gas well is fracked, 4 to 9 million gallons of water are injected into the ground. A single well can be fracked up to 12 separate times, adding up to over 100 million gallons of freshwater used in the lifetime of a well.” (

4-9 million gallons injected every time a gas well is fracked. That's on the order of 20 odd million liters of water, as much as is contained in that hole near my house.

My neighborhood is not depending on groundwater right now, but may have to in the not so distant future. Shale gas though will be extracted in the future from wells drilled in rural India, which depends a lot on groundwater. Farmers use it for drinking purposes as well as irrigating their fields. The gas will be in sedimentary formations a couple of kilometers below the surface, but the water for fracking will be taken from much shallower aquifers that the farmers rely on for their livelihood.

Each time a gas well is fracked, 20 million liters of water will have to be diverted from aquifers underlying their fields for getting the natural gas out. Over the lifetime of a well over 400 million liters of water may be consumed by one well and in an area few tens of sq km, there may be scores of such shale gas wells.

Its early days in our goal to exploit shale gas from various Indian sedimentary basins. Let us quantitatively assess the state of our aquifers besides exploring for shale gas. Let's educate our farmers on how much water shale gas drilling is likely to use up. The residents of central Pune can afford to pump all of 20 odd million liters of groundwater away and still see water gushing out of their taps.

Farmers in the dusty hinterlands may not afford that luxury.

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