The Naval divers undertook the challenging task of winching down from the helo and recording of depth using a handheld echo sounder (depth measuring equipment) in the near freezing waters. Throughout the evolution, the IAF pilots maintained accurate positioning in the difficult terrain, the Navy said. The data will help scientists determine the pressure on the mud wall of the dam. Â The temporary water body was formed after sediments that the catastrophic flash flood earlier this month brought down, blocking the mouth of a stream that joins the Rishiganga river. According to the Central Water Commission, the lake is 400 metres in length, 25 metres wide and 60 metres deep.