AHMEDABAD: Sensing the vagaries of nature with rains getting scanty this year in Ahmedabad, officials of Ahmedabad Municipal Corporation (AMC) are chalking out a contingency plan to keep potable water woes away from the city. In the past, Ahmedabad had witnessed water riots over the scarcity of drinking water. To start with, AMC is now constructing 100 percolation wells at AMC premises in six different municipal zones of the civic body within a year. About the construction of wells, a senior AMC official said, "Percolation pits are tried and tested methods to recharge water tables through rainwater harvesting. A single percolation well will cost around Rs 1.50 lakh, the total cost of the project is around Rs 1.50 crore." Explaining about the functioning of well, the official said, "A percolation well is a soak pit with its top covered and the bottom opening into a shallow level permeable strata, having little or no water. The water coming into the well dissipates into the permeable formation (aquifer) through percolation or infiltration from the large surface area of the aquifer that the well intercepts." The depleting water tables in the city remain a concern for authorities, But now, several initiatives have been started by AMC authorities to replenish the water bodies. "There were around 142 borewells in the new west zone and AUDA areas but now we have shut down 70 of them as drawing water from borewells has a major impact on the water table conditions. After Narmada water was made available, situation has improved. But we still have to stop residential units from relying more on private borewells," said an engineer from new west zone of AMC. The civic body has so far converted 35 defunct borewells into percolation wells. In all AMC has constructed 72 percolation wells in city over the years, of which 26 have been built in vacant AMC plots and gardens.