Bhubaneswar, June 19: The state government is chalking out ways to conserve water, with a senior minister saying that rainwater harvesting structures would soon be made mandatory in all buildings irrespective of their shape and size.

The statement of environment and forest minister Debi Prasad Mishra on Sunday came in the wake of experts saying that the city had already experienced a one-metre fall in the ground water table since 1992.

This project will be carried out by the housing and urban development, revenue and water resources departments because the city’s water table is set to face tremendous pressure because of the rapid urbanisation.

“Though the dip in the water table is not alarming, both the civic and urban development authorities should take this as a wake up call and take steps. Else, things could go out of control in the next four or five years,” said a scientist of the Central Ground Water Board (CGWB), Bhubaneswar.

Eminent geologist and former professor of geology at Utkal University Manmohan Mohanty said: “Urbanisation has shrunk the area of open land because of concrete structures in the city and this has lessened the percolation of rainwater into the ground. In some places in the city, open areas have gone down to 10 per cent of the geographical area. Since by 2050, more than 50 per cent land of the city is likely going to be covered by concrete structures, we should take note and act now.”

Speaking on the occasion of the world day to combat desertification and drought – 2012 on May 17, the minister said according to the report of the Public Health Engineering Organisation (PHEO), 45 per cent water was getting wasted while being transported by pipeline from the origin to the destination. Also, PHEO’s dependency on groundwater was a cause of concern. He also admitted that unless an efficient sewerage system was implemented in the city, groundwater would cease to remain potable in many areas in the capital within 12 years.

Interestingly, the Bhubaneswar Development Authority (BDA) has a rain-water harvesting clause only for bigger structures, but for thousands of individual households, there is no plan or action to implement the clause.

The CGWB has six shallow wells and two deep wells in Bhubaneswar as reference wells. Between 1992 and 2011, the data with the shallow wells pointed out a dip of one metre in the water level. As the data concerning the deep wells are not available for a longer period, scientists said that the water level goes down drastically between 8am and 3pm when the pumping of ground water is maximum near the Governor’s House area.

The city has two layers of geological plates. The Athgarh formation, which constitutes about 75 to 80 per cent of the BDA area and where water collects in the shale and sandstone layer. The remaining 20 to 25 per cent area is the alluvial soil of the Kuakhai basin. Interestingly, though the Kuakhai basin’s alluvial soil contains more ground water, the city draws most groundwater from the Athgarh formation.

The groundwater table is naturally recharged through the northern part of the city constituting Chandaka, Andharua and Chandrasekharpur. But baring Chandaka and some portions of Andharua, Chandrasekharpur has become a thickly populated concrete jungle which is not good news for the city’s groundwater table.

Urban management practitioner Piyush Ranjan Rout said: “The geologists’ findings and the urban development pattern as designed by the BDA seems to have no correlation. If Chandrasekhrpur and Andharua are the natural recharge areas, they should be conserved. It seems the planners have no idea on the geological data which is very vital in terms of urban settlement planning with a focus on the future.”

The CGWB scientist added that all drainage channels should have a 100m buffer zone on both sides to ensure better water drainage and recharge. All the ancient lakes in Old Town could also be renovated and used as water sources.