news Saturday, July 18, 2015 - 05:30
  The monsoons have arrived but one of Karnataka’s biggest dams, the Tungabhadra Dam, cannot store more than 15 percent of its capacity, due to heavy siltation, and no government appears to have the will to resolve the situation. Located in Ballari district, the Tungabhadra dam irrigates Karnataka and the Rayalseema region of Andhra Pradesh. Karnataka’s farmers have been facing a water scarcity and the current situation does not help matters. The problem is so dire that some media reports say around 66,000 acres of land would be required to deposit the removed silt. Apart from large tracts of land, a lot of money will also be needed for de-siltation. In November 2014 the Tungabhadra Command Area Development Authority (T-CADA) was set up. Its Chairman A Vasanth had assured that the authority would address the problem. (Silt comprises small granular particles of sand and clay that are deposited at the reservoir by running river water, and which directly affects the storage capacity of a reservoir.) However, two months later, irrigation expert and Executive Engineer JB Sajjan said that it was “practically impossible” to remove the silt from the dam due to technical complexities involved. All dams in the country face the same situation and none has ever been de-silted till date, according to a DNA report. Small experiments have been carried out but with little effect.   One attempt however, seems promising at this juncture. A first of its kind de-siltation process was started in Khadakwasala dam near Pune, Maharashtra, by NGO Green Thumb, and real estate developers Amanora and Cummins. In a year, around 60,000 truckloads of silt were removed from the dam in a two-kilometre stretch, freeing up space for 11,000 litres of water. The silt was distributed free of cost to farmers because of its high nutrient value. Col. Suresh Patil of Green Thumb said: “If all the dams in the country are de-silted then the water storage capacity would increase by 50% all together.” The group has said that if Khadakwasala de-siltation process was successful, then they would repeat the process with other dams in and around the city. Every truck of silt removed is one more tanker of water to the city. Patil also added that Bhakra Nangal Dam has around 78 percentage siltation. In February 2013 a Dam Safety Authority team led by the Kerala State Electricity Board Chief Engineer Karuppan Kutty cleared the silt accumulated in the Idukki arch dam as water was leaking through the sluice valves. However, the board ended up polluting the Periyar river by dumping all the removed silt into the river near Cheruthoni town. In 2009, the then Karnataka Water Resources Minister Basavraj Bommai had talked about using Italian made machines to de-silt the dams in the state but it never materialized. Tungabhadra Dam is one of the worst affected dams in the state. The dam has lost around 0.871 tmc of water every year and until 2012 siltation was up to 85 percent.  

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