Reservoir Landslides and Its Hazard Effects for the Hydropower Station: A Case Study

Abstract

Reservoir landslide is a typical geological disaster in the hydropower reservoir, which poses a great threat to bank infrastructures and human lives. In this paper, one hydropower reservoir is taken as an example to study the distribution characteristics, formation mechanism and hazard effects of hydropower reservoir landslides. In this hydropower reservoir, different scales of landslides are distributed along the both banks of the reservoir. These landslides are formed in different time and related with the history of the reservoir water level variation. Most of the reservoir landslides are neared to the water surface line with small volume, and happened in the shallow deposits. Favorable geological conditions (steep slope, broken rock, widespread deposits and others) provide the susceptibility of the landslide, and the shocking of the 2008 Wenchuan earthquake and occasional rainfall provide some contributions for the reservoir landslides. Water fluctuation is the key triggering factor for the reservoir landslides, especially by the act of rapid drawdown of water level. These reservoir landslides pose several effects for the Hydropower Station, bank infrastructures and human lives, include uplift of the riverbed elevation and cause the decreasing of reservoir capacity, roadbed settlement and destroy of road and tunnel, threat for the human lives and properties, and others. For the hazard prevention of reservoir landslides, firstly, the traffic route should be changed and moved to higher elevations, and should be stay away from the reservoir bank; secondly, resident live near the reservoir bank can be relocated in advance, preferably not in the reservoir area; thirdly, to develop a reasonable operation scheme for the water level of reservoir, the large and frequent fluctuation of water level should be avoided, especially for the rapid drawdown of water level.