Hydrological Response On Land Use Change In Luoyugou Watershed

This thesis took the Luoyugou watershed in the third subplot of loess plateau hilly and gully region as study area, used the land use change model CLUE_S and distributed hydrological model SWAT to build a new coupled model, and discussed the effect of economy and policy on the land use change and hydrologic response. This can provide support of decision-making for the government to adjust the development strategy. The results were as follows:1. The thesis analyzed the land use change between 1986,1995,2001 and 2008. Because of the impacts of increasing population, policy and economy, the land use had changed a lot, especially in the early 90's,73% of slope farmland had changed to terrace, and the area of forest had increased 26%.The comprehensive index of land use degree is 0.7054 in 1986. After the 90's, the comprehensive index of land use degree had decreased, then increased to 0.7061 in 2008, the land use had entered development period.2. The research took the topographical factors, such as slope, aspect and attitude, and the distance to road and river, as well as the location of settlements as driving factors, based on the current economy and policy of Luoyugou watershed, used the CLUE_S model to forecast the land use condition in 2020.3. The SWAT model was used to simulate the hydrological process of Luoyugou watershed. After calibration and verification, the related coefficient exceed 0.92, certainty factor exceed 0.78, which showed a good simulated result in runoff simulation by SWAT.4. Analysising the effect of meteorology and land use on the hydrological change, the result displayed the contribution rate of land use on hydrological change is 73%, and the contribution rate of meteorology is 27%.5. To analyze the hydrological response on the basis of the prognostic land use map of 2020, the result showed that the mean annual runoff depth decreased 51%, comparing the mean annual runoff depth from 1986 to 2004.