VIJAYAPURA: The Almatti reservoir, one of the largest dams in Karnataka with a designed storage capacity of 123.081 tmcft, has lost 7.556 tmcft of capacity owing to silt deposit over the past two decades. The current water storage capacity now stands at 115.552 tmcft, according to a study conducted by the Karnataka Engineering Research Centre (KERS) in 2023.
The final report of the backwater silt study, which covered several reservoirs in Karnataka, including Almatti, has been submitted to the State Government as well as to the chief engineers of the respective reservoirs. The findings highlight the gradual decline in water storage due to silt accumulation since the Almatti reservoir became operational in 2001.
KERS Director KG Mahesh, based at Krishnarajasagar, Mandya district, said that the survey was carried out over three months, covering 487 sqkm from the backwaters of the Almatti reservoir to the Hipparagi reservoir. “An advanced echo-sound system installed in boats was used for the study. Sound waves were released into the water and the returning echoes were captured to measure depth. Based on this data, specialised software calculated the silt content. The analysis was completely scientific, and a comprehensive report has been submitted to the government,” Mahesh explained.
Despite the silt in reservoir, no water shortage
The report notes that in the 22 years since its commissioning, Almatti has accumulated 7.556 tmcft of silt. However, officials from the Krishna Bhagya Jala Nigam Limited (KBJNL) clarified that despite the reduction in capacity, there will be no shortage of water for irrigation or drinking purposes in the command areas.
The study also compared siltation levels across major reservoirs in Karnataka. The Narayanpur reservoir, which was surveyed in 2022, has recorded the highest silt deposition in the state. The study revealed that Narayanpur has accumulated 10.550 tmcft of silt, resulting in a loss of 27.292 tcmft of water storage capacity. Tungabhadra reservoir ranks second in terms of storage loss due to siltation.