HYDERABAD: It is shocking but true. Massive intervention by way of obstructions and diversions of water inflows are main reasons for the Osmansagar (Gandipet) and Himayatsagar reservoirs getting dried up gradually.Construction of a whopping number of 29,000-30 000 check dams, rock-filled dams, percolation tanks, contour bunding, farm ponds and major water harvesting structures in the entire catchment areas are making the reservoirs dry up. No wonder, two reservoirs have ever reached their full tank level (FTL) in the past two decades.
The total catchment area of the two reservoirs is about 584 sq km ie, 58,400 hectares or 1,44,248 acres which implies that for every 5 acres of the catchment there is some intervention or the other by way of check dams, percolation tanks, contour trenching, etc. This proves that the catchments of these two reservoirs are the most exploited, mostly by builders and developers.
“How can water inflows be ensured with more than 29,000 major water-harvesting structures blocking the water flows even in heavy rains or floods in nearby areas? Even the Environment Protection Training and Research Institute (EPTRI) report has expressed grave concern at the reduced inflows into the drinking water sources,’’ former HMDA director (planning) Vishwanath Sista told Express. Shamshabad, Chevella, Shabad and Moinabad mandals, which fall in the Himayatsagar reservoir catchment, have about 9,100 rock-filled dams, 9,500 contour bunds, 978 check-dams, 7,500 sunken ponds, 169 percolation tanks, 180 mini percolation tanks, 1,450 long trenches and 150 farm ponds. Shankarpally, Vikarabad and Navabet mandals falling in Osmansagar reservoir catchment have nearly 4,400 rock- filled dams, 3,950 contour bunds, 450 check-dams, 3,600 sunken ponds, 60 percolation tanks, 170 mini percolation tanks.
If reservoirs are to be restored and the inflows to the lakes increased, obstructions like check-dams are to be removed, the water bodies and channels should be desilted, encroachments in the water spread (FTL) need to be dismantled and the green cover increased by taking up massive block afforestation in the vicinity, Vishwanath said.
Raising the hackles over unauthorised constructions is not going to solve the problem. The state government should focus on the root cause that is impeding the inflows into the two lakes which are being killed by over 29,000 check-dams and other water-harvesting structures just as the way two reservoirs killed Musi river, he remarked.
Apart from this, no major industries that discharge pollution should be allowed. But as a corollary, those habitations that ensure that pollutants were not discharged into the lakes. IT-enabled services should be allowed to set up office in the area if they undertake that they won’t cause pollution of the lakes. In case of area development or layouts permitted, 60 percent should be common areas and only 40 percent ‘developable areas’. The Himayatsagar has an afforestation belt of about 1 km around the lake and a similar plan should be devised for the Osmansagar too.