Chronology of Tsho Rolpa GLOF Hazard Response

Despite the earlier consensus that disruption of the moraine was unwise as a first step, the hazard mitigation project involves precisely that: in 1998 HMG budgeted a plan to cut a notch right through the moraine. In 1999, a "coffer dam" (a large watertight chamber used for construction under water) and a sluice-gated notch was being constructed by Nepal Hydro and General Construction in conjunction with Bhutwal Energy and the Department of Hydrology and Meteorology. The engineering was designed by Bruce O'Neill, a Canadian engineer; the project was supervised by Adarsha Pokharel but financed by the Dutch government.

At the time the site was visited by our Bridges team, in November 1999, most of the first phase of the notch in the moraine had been cut, and the sluice gate was erect. Water was seeping slowly into the cut area, but the flow had not been initiated. According to the designer, the cut would be stabilized with special high-tech "cloth." A release was scheduled for Spring 2000: over 12 days, enough water would be released to reduce the water level three meters. The next step would be to cut another parallel notch, to a deeper level. As the water level dropped the notches would be joined and further down-cut to produce a single and much deeper notch. This step, which would have increased the spillway depth from three meters to twenty, was never implemented, due, according to our sources, to a shortfall in funding.

(above and below:) The Tsho Rolpa project camp, autumn 1999

The Tsho Rolpa project camp

The Tsho Rolpa project team in 1999, with Empar Alos (second from left)