HR: 0800h
AN: H31G-0746    [Abstracts]
TI: A distributed hydrological model for drought and flood forecast in the upper Yangtze River basin
AU: * Jijun, X
EM: xujj07@163.com
AF: Water Resources Department, Changejiang Scientific Research Institute, Hankou Huangpu road 23, Wuhan, Hub 430010, China
AU: Dawen, Y
EM: yangdw@mail.tsinghua.edu.cn
AF: State Key Laboratory of Hydro-science and Engineering, Tsinghua University, Tsinghua University Yuan, Beijing, 100080, China
AU: Zhidong, L
EM: Leizd@mail.tsinghua.edu.cn
AF: State Key Laboratory of Hydro-science and Engineering, Tsinghua University, Tsinghua University Yuan, Beijing, 100080, China
AU: Wei, H
EM: huang_wei@sina.com.cn
AF: Water Resources Department, Changejiang Scientific Research Institute, Hankou Huangpu road 23, Wuhan, Hub 430010, China
AB: The Yangzte River (also called Changjiang in Chinese) is the largest river basin in China, which has frequent flood and drought. Building on the physically-based description of hydrological processes, a distributed model has been established in the upper Yangtze River for drought and flood forecast have been addressed in this study. For assessing water resources and drought, a large scale distributed hydrological model has been chosen for the upper Yangtze River which has about 1 million km2 area. In this model, the whole area is divided into a discrete grid system of 10km size, and each grid is represented by a number of geometrically-symmetrical hillslopes. Hydrological simulation has been carried out during 1961~2000, the simulated river discharges, soil moisture and evapotranspiration provided an inside investigation into water resources in the study basin. Results showed that the ratio of seasonal runoff to annual one has a significant increasing trend in summer in the eastern Sichuan basin and the Three Gorges region in the 1990s, but a decreasing trend in autumn. This implies an increasing flood risk in summer and water shortage in autumn. Based on the results of hydrological simulation, a new monthly drought index, GBHM-PDSI, was proposed based on the Palmer Drought Severity Index. It was found that the new drought index has advantages for describing the temporal change of drought severity and the spatial variation. In order to reduce the uncertainties of real time flood forecast in the Three Gorges region, the radar rainfall data has been used together with the smaller scale (1km grid size) distributed hydrological model. Results showed, by means of distributed model combining with radar rainfall data, it could capture adequately the spatial variation of rainstorm, and provide better flood forecast at real time.
DE: 1812 Drought
DE: 1816 Estimation and forecasting
DE: 1821 Floods
DE: 1847 Modeling
SC: Hydrology [H]
MN: 2007 Fall Meeting