NEW DELHI, July 20 ? The Tsatichhu Lake in neighbouring Bhutan which was breached leading to devastating floods downstream in Assam was cleared by an expert team from India a month earlier in June. The Royal Government of Bhutan, however, has denied that the worsening flood situation in Assam was due to breaching of the Tsatichhu Lake, about 30 km upstream of the Kurichhu Hydro Power Project. The lake in question was breached around 3.30 pm on July 10. The Tsatichhu is a tributary of the Kurichhu river on which the Kurichhu Hydro Power Project is situated. The lake was formed by a massive landslide, which occurred on September 10, 2003, blocking the whole ravine and thereby forming a dam.
A number of expert teams had visited the Tsatichhu Lake to assess the possibility of breaching it. The most recent visit was by an expert team from India on June 5. All the expert groups had concluded that it was not possible to manually breach the dam. To reduce the possible impact in the event of a breach, an overflow channel was created to maintain the water level in the dam. At the same time, early warning systems were enhanced so that warning is passed immediately downstream to India in the event of a breach, official sources of Royal Bhutanese Embassy said. The Kurichhu Hydro Power Project is a run-of-the-river scheme, which diverts the river through penstock pipes to produce electricity and then join the main river course via the tailrace channel. As the Kurichhu Project is not a storage scheme, there are no large volumes of water stored and hence opening of the gates does not increase the flow to create floods downstream.
Meanwhile, the Royal Government of Bhutan has reacted to reports in the media that Assam Chief Minister Tarun Gogoi approached the Prime Minister pleading that Bhutan Government be asked to ensure ?adequate measures to safeguard the dam?. Bhutan and India have a comprehensive scheme of flood warning that has been in place since the 1960s. This has been instrumental in providing timely information to India thereby allowing Indian authorities to issue early warning to its people who live along the flood zones, a statement issued by the Royal Bhutan Embassy here said.
While the present spate of floods in Assam is not related to the breach in the Tsatichhu Lake, information on the breach was conveyed immediately to the Indian authorities, based on which a high alert was issued by the Central Water Commission (CWC). Therefore, reports linking the breach in the lake to the floods in Assam are totally incorrect, the embassy said. The first wave reached Kurizampa near Kurichhu Hydro Power Project around 6 PM and by 7.30 pm the water level had progressively decreased. The maximum discharge recorded at Kurizampa was 5,764 cubic meter per second around 6.30 pm. Because of prior information of the breach, an increase in water level of the Manas river of about four cm per hour was noticed between 3 am and 5 am on July 11.
At that time there were no reports of flooding, the Royal Bhutan Government claimed. The embassy also denied reports that floods in North Bengal were made worse due to ?indiscriminate extraction of boulders in Bhutan?. While there is minimal mining in Bhutan, it is being strictly monitored by Royal Government?s National Environment Commission and Department of Geology and Mines and therefore there is no indiscriminate mining in the country. Royal Government of Bhutan attaches the highest importance to the preservation and protection of its environment and would never undermine the safety and security of friendly Indian neighbours by carrying out any indiscriminate acts of mining, the Royal Bhutan Embassy said.