Two of the old water reservoirs of the Indian city of Hyderabad, Osmansagar and Himayatsagar, face threat to their very existence given a horde of factors that range from illegal layouts in the catchment area to clandestine fishing.
Of late, illegal commercial fish culture has come as a bane for the water bodies. At the crack of dawn, temporary fish stalls surface all along the stretch from Langar Houz to Kali Temple with the catch of the day and traders also fetch fresh prawns. Few others ferry their catch to various localities in Mehdipatnam on two wheelers.
Fishing has been around in these lakes for a while but it reached an alarming proportions now with a commercial aspect to it, concede officials. Local villagers and leaders are involved in Illegal fishing that has been rampant. FIRs have been registered against those indulging in these activities, says D. Sridhar Babu, General Manager (Engineering), Bhojaguda, Hyderabad Metropolitan Water Supply and Sewerage Board (HMWS&SB).
Overstocking of fish seed or frys by farmers involved in fish culture is rampant in order to buffer the loss of fish and prawns. With fish and prawn numbers in excess to the carrying capacity of the lake, dissolved oxygen in water decreases while biological oxygen demand increases. This leads to death and decay of oxygen-starved prawns and fish, which can change the physico-chemical parameters such as ph, micro and macro element content of water, making it unfit for drinking.
Fishing can be hazardous if not practised under controlled conditions. These reservoirs were built for drinking water supply and not for fishing or other activities, says C. Sreenivasulu, Assistant Professor, Department of Zoology, Osmania University.
Introduction of imported species from China too is cited as causing ecological imbalance by wiping out indigenous fish.
Early this year, trial fishing was conducted by AP Fisheries Department to assess the fish wealth in the two reservoirs after which tenders were floated for cleaning the reservoirs of fish and prawns. Work is in progress. We have started removing prawn. The process will be completed in two months, says Visweswaraiah, CGM (Transmission), HMWS&SB.
Adding to the turbidity of the water is the disposal of untreated sewage by neighbouring villages such as Khanapur, Maharajpet, Janwada and Vattinagulapally.
There is no sewage treatment facility in the 26 surrounding villages.
Also, the conduit or channels that bring water from these reservoirs to the treatment plants have been subjected to encroachments, says Mr.Babu adding that construction activity and manufacture of bricks is rampant in the catchment area obstructing inflows.
A recent report from NEERI recommends setting up of a high level committee for protection of the reservoirs.
The water from the two reservoirs at an aggregate of about 40 million gallons per day is critical for localities such as Charminar, Yakutpura, Azampura, Salarjung Colony, Red Hills, Domalguda, Mallepally, Vijaynagar Colony, Humayun Nagar and also Osmania General Hospital, Andhra Pradesh Legislative Assembly, Secretariat and MLA Quarters.
There is no other source of water for these regions. Else, one has to divert the Krishna water or wait for Krishna Water Phase III, which will be expensive.
Osmansagar is the most economical source as the water is not pumped to a second or third stage.
Here the water flows through the steep gradient along conduits by gravity, adds Mr Babu.
Built under the guidance of M. Visvesvaraya by Nawab Zain Yar Jung during the reign of Osman Ali Pasha, the reservoir has stood the test of time till now.
But now, only a concerted effort to check encroachments in the full tank area, plotting and illegal fishing is what can stop it from becoming another Hussainsagar.
2102 The Hindu