Study On Flood Response Of Small Mountainous Watersheds Based On Different Land Use Scenarios

This paper takes Xinxian,Henan province as the study area.According to the characteristics of the study area,which is located in a hilly area with complex terrain and is prone to flash floods,a HEC-HMS hydrological model is constructed for flood simulation in the study area.Based on the analysis of the evolution characteristics and driving forces of land use in the study area in different periods,a prediction model of land use change in the area is established.The flood processes under different land use scenarios are simulated by the HEC-HMS model,and the flood response of the study area under different land use development scenarios is explored.The main research contents are as follows.(1)The HEC-HMS hydrological model of the study area is established by calculating rainfall loss,direct runoff,baseflow and river confluence using the SCS curve method,Snyder unit line method,exponential decay method and Maskingen method,respectively,and the model is parameterized and optimized by selecting five typical field flood data,and the adaptability of the established hydrological model is studied based on the simulation results of two field floods.The adaptability of the model is investigated based on the simulation results of two floods.;(2)The quantitative analysis of the quantitative structure and spatial and temporal change characteristics of land use types in the area is carried out by integrating land use shift theory,comprehensive land use index and land use dynamic attitude,and the driving mechanism of driving factors on land use shift in the study area is investigated by logistic regression,and the prediction model of land use change in the study area is established by using this transformation rule,and the validity of the model is tested;(3)Three future land use development scenarios are set with 2000 as the base period,considering natural development scenarios and land planning in the area,and land use changes in the study area in 2040 are predicted.The flood processes under different scenarios are simulated by the HEC-HMS model,and the responses of hydrological elements such as flood peaks and flood volumes in time and space are analyzed.The disaster prevention capacity level of the disaster prevention objects in the study area is evaluated under different land development scenarios.