Research On Distributed Hydrological Simulation And Its Application In Xijiang River Basin

At present, the problems of flood disaster, dry and water ecological environment deterioration have become the important factors which restrict the development of Chinese economy and society. Seasonal water quality problem has become the key feature of the water source problems in the downstream of Pearl River, especially the salinity intrusion which has threatened drinking water safety in Zhuhai and Macau. In recent years, water decrease in the upstream in dry season has intensified salinity intrusion, which resulted in water supply situation more severe. In the context of climate change, for the sake of exploring and studying variation characteristics of hydrologic and meteorological elements of Xijiang River basin located in the upstream of Pearl River, this paper firstly carried out distributed hydrological simulation, and then used a variety of statistical methods to full-scale analyze the variation characteristics of hydrologic and meteorological elements, so as to provide scientific reference for water resources exploitation and management and suppressing salinity intrusion and operation in dry season.(1) According to geography, hydrology and meteorology characteristics, based on EasyDHM hydrological simulation platform, this paper constructed the Xijiang River distributed hydrological model, completed calibration and validation of parameters for 15 parameter subareas, and obtained a good simulation result. The result showed EasyDHM has very good applicability in Xijiang River, and the model constructed can describe objectively the inner mechanism of hydrologic processes. Therefore, the model could be used to research and solve practical problems.(2) Based on the Xijiang River distributed hydrological model, the paper adopted many kinds of statistics methods to analyze variation characteristics in temperature, precipitation, evaporation and runoff, and then analyzed the effect of climate change on runoff from the point of view of climate change.a. As for trend change, in the last 55 years, temperature demonstrated a remarkable significant upward trend, evaporation had significant down trend, and there was no significant trend in precipitation, runoff and natural runoff of reservoirs. The trends are likely to continue in future. The sudden change occurred from cold to warm in temperature, from increase to decrease in evaporation, and there was nearly no sudden change in precipitation and runoff. As far as period variation was concerned, temperature, precipitation, evaporation and runoff existed multi-time scale change character, and had different composition of period. In recent years, the lower runoff in dry seaon is close to periodical change of precipitation and runoff.b. From the impact of climate change on runoff perspective, precipitation is the main climate factor affecting on runoff, followed by evaporation, and other climate factors indirectly influence through evaporation and rainfall. Annual and dry season runoff amount are related to the occurrence of El Nino and La Nina. In addition, sunspot number has a good response relationship with runoff.