SHILLONG, Apr 11: According to a study, dredging of Umiam reservior to eliminate the silt deposits and enhance the storage capacity does not appear to be an attractive proposition the Meghalaya Assembly was informed on Wednesday.
State Power Minister, James K Sangma while informing this during the Question Hour said that the study was carried out by M/s Tojo Vikas, International Pvt Ltd, New Delhi in 2004.
Sangma stated that as per the report, the dredging is proposed for 2.17 Million Cubic Metre which is only 1.53 percent of the live storage capacity of the Reservior.
“The cost of dredging even this insignificant volume of 1.53 percent of the live storage will involve a cost of about Rs 41 crore at the rate of Rs 189 per Cubic Metre (2004) which is not economically viable,” the Power Minister said.
According to Sangma, with the object of assessing the siltation of the Umiam Lake after its construction in 1965, studies were conducted by M/s WAPCOS in 1990 and M/s Tojo Vikas, International Pvt Ltd, New Delhi in 2004.
The state Power Minister informed the House that the siltation studies acrried out by M/s Tojo Vikas (India) Pvt Ltd, New Delhi were much more elaborate and involved both hydrographic and as well as topographic studies of the Umiam Reservior by using state of the art high-tech instruments Differential Global Positioning System, Digital Echo-Sounder, Analogue Echo Sounder.
As per studies carried out by M/s Tojo Vikas (India) Pvt Ltd, New Delhi, the volume of sediment collected in the Umiam Reservior over the past 39 years (1965-2004) works out to be 20.551 Million Cubic Metre which corresponds to a sedimentation rate of 23.79 hectare metre/100 sq. Km/year.
“The overall rate of sedimentation as on 2004 in both live and dead storages of the Reservior was 0.527 Million Cubic Metre/year which corresponds to sedimentation of 23.79 hectare metre/100sq.km/year,” Sangma said.
Earlier, Umroi legislator George B Lyngdoh said that the drawing of water by the Umroi Cantonment from the Umiam Lake was directly affecting the live storage of the dam and as well power generation.