Breach of a naturally embanked dam on Yalong River

Abstract

A huge slide involving 68 × 106 m3 of soils occurred along the right bank of Yalong River in Sichuan Province, China. The sliding materials blocked the river and formed a dam-like structure having a height of 175 m and creating a reservoir with a capacity of approximately 680 × 106 m3. The dam breach which was caused by overtopping lasted 13 h and resulted in an estimated maximum flood discharge of 53 000 m3/s. Based on the hydrograph created by measuring the flows downstream of the dam, the process of dam breach was roughly estimated. Key words: landslide dam, cohesionless material, overtopping, breach, flood, hydrograph, failure process.