‘Appropriate time for rain water harvesting with onset of monsoon’

“Rain water harvesting has become a necessary aspect in Nagpur city in view of reduced seepage area due to concrete roads, choked trees and felling of trees. In fact, it is essential for every home to promote rain water harvesting to recharge groundwater to cater to the increasing requirements.” This view was expressed by Nandu Kanoje, Acting Senior Geologist, Groundwater Survey & Development Agency (GSDA), Nagpur, while talking to ‘The Hitavada’ here on Monday.

However, he lamented that due to lack of proper awareness among the public about importance of rain water harvesting much amount of rain water was washed away. The groundwater level depletes to an alarming situation due to excess pumping out of groundwater during summer, he added. The underground water table will rise during monsoon but the percolation area has dwindled due to concrete roads, tiles laid on ground and choked spots.

Therefore, arresting the otherwise flowing rain water and percolating it underground is the only way to overcome the possible problems in the future, Kanoje said. Depletion of water level from one to two metres is manageable but from two metres onwards it is severe. At present, the water level in Nagpur district has gone up to one metre and it is manageable. Now, monsoon is fast approaching and hence there is a need for promoting rain water harvesting to utilise water in a proper way. If the people fail to adopt this method then the history will repeat, he added. There are two types of rain water harvesting - roof top and roof tiles. In roof top system, rain water is collected on terrace and channelised it through pipe to filter chamber for onward well or bore-well recharge.

The measurement of filter chamber is 2 mt x 2 mt x 2 mt and it is filled with gravels, pebbles and fine sand. The filtered water goes underground. Water is not used for first two rains and then water is arrested. The water stored in the tank can be used to avoid scarcity. In the old houses with roof tiles, rain water is channelised through pipe to well for recharge purpose, Kanoje said. As per the provision in Maharashtra Groundwater, Development and Management Act, 2009, in urban areas falling in notified areas, the State authority will issue directives to concerned authorities for ensuring construction of appropriate rain water harvesting structures in favourable or technically suitable residential, commercial, industrial and other premises having 100 sq mt or more. Failing to which, the urban local bodies may get such rain water harvesting structure constructed and recover the cost incurred along with a penalty from the occupants in the prescribe ed manner.

Not with standing anything contained in the relevant laws, the urban local bodies may impose necessary conditions for providing rooftop rain water harvesting structure in the building plan before cording approval for construction and permanent water and electricity connections shall be extended only after compliance of the directions. There is provision in the Act that the authority or through other agencies shall take steps for promotion of mass awareness and training programme for watershed water resources committee and stakeholders on rain water harvesting and artificial recharge to groundwater through government agencies, NGOs, voluntary organisations, educational institutions, industries or individuals. Creating awareness about importance of this method is the need of hour for water management.