Study On The Hydrological Response Characteristics Of The Change Of Forest Cover In Watershed

As the largest ecosystem on land,forests have a significant impact on human life.In order to make the forest system better serve for human society development,it is imperative to analyze its hydraulic features to scientifically guide the construction of ecological protection.Meanwhile,the research have certain significance for the development of eco-hydrology and other disciplines.This paper firstly summarizes the hydraulic value of forest cover.Xiaoxi Watershed was then taken as a typical district and the distributed hydrological model was established using MIKE SHE software.The classic parameters of the model were calibrated and verified by measured hydrological data.A combination of parameters suitable for Xiaoxi River Basin was obtained and its applicability was also evaluated.The model after validation was applied to simulate the river watershed runoff under different forest coverage.The results showed that with the increase of forest coverage and vegetation transpiration,the watershed evapotranspiration was reduced,which means water resources were stored.With more water resource,the annual total runoff showed a certain increase inclination.Besides,a fitting formula for the change of water production in Xiaoxi Watershed with rainfall and forest coverage is obtained.The simulation results of flood process under different forest coverage indicated that changing the forest coverage rates has a great impact on the flood characteristics of Xiaoxi watershed.Importantly,the greater forest coverage rate,the more obvious the effect.Compared with zero forest coverage condition,the forest coverage reaching the maximum can reduce the flood peak flow by about 13.2%,delay the arrival of the flood peak by about 4 hours,and extend the flood duration by about 13 hours.Besides,when the forest coverage rate is below than 40%,it has a very limited reduction effect on the flood peak flow;when the forest coverage rate is more than 40%,the average 10%increase in forest coverage can lead to 2%reduction of flood peak flow.