Overtopping Loss Assessment Of Earth Dam Using The Technology Of Gis

Water resources are unevenly distributed in China, with significant difference in precipitation along with seasonal changes. Although reservoirs have played important roles in water resources management, many of the dams are under the risk of collapse. So it is of great importance to undertake research of risk assessment of earth dam overtopping. One essential important link of earth dam overtopping risk assessment is the estimation of flood damage of the reservoir downstream, which is an important factor in determining risk and also an important criterion to judge the severity of different risk dam. The estimation of downstream losses involves topographic data, population distribution, economic development and so on, which brings difficulty to the estimation of downstream losses.In recent years, with the development of geographic information sharing and digital geographic information, many problems can find their effectively solutions. This article discussed how to obtain terrain information data of reservoir downstream with the technology of GIS, to provide basic data for the calculation of the dam break flood. Arc GIS software, with a variety of data storage format, can store geographic information and the corresponding attribute information, was used to estimate overtopping loss.The methodology was applied to the overtopping loss evaluation of Chengbihe Reservior, located in Baise of the Guangxi Zhuang Autonomous Region. Results show that, dam break will do serious effects on the downstream areas, in particular, the Baise urban areas also have some impact, the provincial capital city of Nanning is also under risk of flood safety. Dam safety management should be strengthened to avoid such incidents.