Emergency rescue and disposal technology for Baige Barrier Lake on the Jinsha River, China

Abstract

<p indent="0mm">When a landslide blocks the river and forms a barrier lake, the need for emergency rescue is urgent, the environment is hazardous, environmental conditions are harsh, transportation is inconvenient, and disposal is difficult. Once the lake is out of control and released, it will endanger people’s lives, property, and the safety of cascade hydropower stations safety downstream. Based on the analysis of the characteristics and causes of “10·11” and “11·03” Baige barrier lakes in the upper reach of Jinsha River, a hyperbolic dam erosion model is used to predict the peak discharge of the two Baige barrier lakes to be 10000 and <sc>44370 m³/s,</sc> respectively, to investigate emergency disposal technology and explain the process of landslide dam failure and rescue. Therefore, it is proposed that the emergency disposal of the “11·03” barrier lake should be a series of emergency measures for manual excavation of drainage channel, destruction of the cofferdam for the Suwalong Station under construction, and discharge of the reservoir of Liyuan Station in operation. The results show that for the “11·03” barrier lake, (1) the excavation of the 13.5-m deep drainage channel reduced the peak discharge to <sc>33900 m³/s,</sc> which is the same as the predicted <sc>34400 m³/s;</sc> (2) the destruction of the cofferdam for the Suwalong Station under construction avoids superimposition and magnification of the flood peak, and if the cofferdam is not destructed, the peak discharge may be increased from 19800 to <sc>32200 m³/s;</sc> (3) the water discharge of the Liyuan reservoir successfully reduced the peak discharge from 7190 to <sc>4500 m³/s,</sc> reducing the flood control pressure of downstream cascade stations and minimizing the coastal disaster loss through the joint dispatch of the cascade reservoirs. This study provides a systematic back analysis of the rescue process and key technologies and emergency measures of the Baige barrier lakes and a reference for the emergency rescue of similar landslide dams and the risk prevention and control of cascade hydropower stations in the basin.