Study on Flood Control Risk Management for Reservoir Earth Dam

The evaluation pattern that risk degree is a product of danger degree and vulnerability were introduced based on natural disasters risk expression recommended by the Humanitarian Affairs Department of United Nations. The transformed values function were put out to transfer overtopping probability into danger degree, which were measured on a scale of 0 to 1. "Property index" and "population index" were used to measure the vulnerability of the dam overtopping, in addition, respective computation methods and corresponding transformed values function. Mathematically, the vulnerability is the square root of weighted average of the two indexes\´ given values, which were also measured on a scale of 0 to 1. The mathematical evaluation rank for overtopping risk degree were established, and their guidelines were explained in detail. A case study of Chengbihe reservoir in Guangxi province of China has been used to demonstrate the procedures of the method,, and the example analysis results indicated that the flood control water level of the reservoir may be raised by 1.0 m maximally, as a result, the water storage of the reservoir would be increased by the end of the flood period.