Nepal earthquake tests dam safety

 

Major cracks in the Kulekhani dam crest, now repaired © Ratan Bhandari

 After the devastating Gorkha earthquake of April 25, which killed thousands and left many more homeless, details are slowly emerging that power plants and dam projects were extensively damaged across the country. The national grid lost 150 megawatts of grid power.

On May 10, my colleague DP Upadhyaya and I visited the Kulekhani Dam site. A two-hour drive on motorbike from Kathmandu we arrived at the site to observe the serious damages incurred to the civil structures. A national daily had earlier reported that the project had been stopped and a 100-meter stretch of the 406-meter long dam crest had been cracked and damaged.

When we reached at the dam site, we saw landslides nearby the Indra Sarobar reservoir of Kulekhani Hydropower Project and found many cracks in the crest of the rock filled dam. However, the Nepal Electricity Authority (NEA) has been quick to cover up the damage and pack the cracks. The project has resumed operation. I tried to take some photographs of the cracks, but security personnel did not allow me. Nonetheless, I did manage to take some photographs while they were distracted.

 During our day trip we talked with local junior officers of the NEA. The officials said that the dam subsided 3 meters and Nippon Koi, the project consultant from Japan, has conducted a preliminary assessment. A National daily reported a more realistic subsidence of approximately 10cm.  The junior officers claim that the crest cracks won’t make any impact because the cracks are above the water level. However the water level will go up during the monsoon, which is a standing concern.

We also talked with army personnel who were on duty during the quake. According to them, there was huge wave of water that moved from several kilometers upstream and crashed against the dam. As a result the waves washed in and out some of the mud and soil from the rock fill dam, questioning the long-term safety of the structure.

En route to the dam site we met quake victims looking for relief. People living downstream also shared their experiences of the quake (and ensuing after shocks) and said that none of the villagers have been able to sleep properly given the fear of another quake and possible outburst of the dam.


The dam supports two power stations of 60 MW and 32 MW, and a third yet to be commissioned power station of 14 MW. The 114 meter high dam is the only storage project in Nepal, located in Markhu and Kulekhani Village Development Committees (VDCs) of Makawanpur district. However, more than 29 storage high dam projects are being planned in Nepal. This list including the 315 meter high Pancheshwar, 270 meter Karnali-Chisapani, 220 meter West Seti, 269 meter Saptakoshi, the 263 meter Budhi Gandaki project, among others. The Gorkha earthquake and its impacts on the Kulekhani dam raises serious questions on the issue of dam safety in the fragile Himalayas.


Ratan Bhandari is a water resources activist based in Kathmandu, Nepal.


Source : International rivers