KURNOOL: With Krishna river management being taken over by the Union government, a hydrographic survey was commissioned at Srisailam reservoir to assess the extent of its storage capacity. A team of hydrologists, along with oceanography engineers, began the survey on Sunday. The reservoir depth has been shrinking consistently in the past 45 years, particularly after Srisailam was made operational. While AP engineers said that the present capacity is no more than 175 tmc ft (thousand million cubic feet), the recorded capacity since 10 years hover around 215.6120 tmc ft.
Srisailam dam chief engineer Muralinath Reddy said there was a steady depletion of depths in the reservoir due to sedimentation and other environmental causes. Recalling the history of the storage as revealed by successive hydrographic surveys, Reddy said that the shrinking of storage capacity in Srisailam reservoir from 308.60 tmc ft in 1977 to 215.6120 tmc ft, a loss of almost 93 tmcs has become a cause of concern between Telangana and Andhra Pradesh, the two contending states over sharing of Krishna waters.
He said that hydrographic surveys were conducted in 1997, 2006 and 2011. When the first hydrographic survey was conducted after a gap of 20 years, it was noticed that the Srisailam reservoir storage capacity has fallen to 263.601 tmc ft. By the 2006 survey, it had lost a further 73.818 tmc ft of original storage capacity and recorded 234.242 tmc ft. And the 2011 survey showed a loss of 92.253 tmc ft at 215.807 tmc ft.
Muralinath Reddy said “our estimate of present storage capacity is 175 tmc ft or less. As the Krishna river management is with the Centre, it has commissioned the survey to dispel doubts over the actual storage capacity. The team is conducting the depth of the reservoir and the inflow levels to arrive at the displacement of water finally leading to measuring the storage capacity accurately,” he said.
A hydrologist at the dam site said the survey includes recording of soundings at an interval of 5m, along with the predetermined ranges. He said the average speed of the boat for accurate data collection is usually 3.5 to 4.5 knots. The hydrographic survey will be conducted to the extent of maximum water level (MWL), the balance from MWL to FRL is supplemented by remote sensing techniques.