The Construction And Validation Of Liugou Distributed Hydrological Model In Caijiachuan

Distributed Hydrological Model, as one of the hot-spots in hydrology research, due to its unique performance, has been proved to be an effective approach to simulate the relationship between land use and hydrological process.This paper established the canopy interception model, litter water storage model, soil infiltration model and surface flow model to simulate their hydrological response to rainfalls. Based on these four hydrological model results, peak flow process model was built. Then the observed data was used to validate the model.This paper aims to build the distributed hydrological model of the research watershed to identify the effect of land form character, land use, forest type on runoff yield and runoff process.The research result indicates that:The average relative errors of canopy interception model, litter water storage model, and surface flow model are 11.85%, 16.65% and 21.11%, respectively. The coefficient of runoff model is 0.831. The average relative errors of peak flows and runoff yield coefficient for each rainfall are 15% and 20%.High forest quality and larger forest area will contribute to lower runoff yield in different extent. Forest will reduce more runoff yield in strong and short term rainfall processes than in small and long ones.The scenario model results reveal that peak flow will be reduced by 13%-30% and runoff yield coefficient will lessened by 13%-30% when the canopy density of young and half-mature forest adds to 30% with mature canopy density unchanged. The peak flow and runoff yield coefficient will increase as the forest land with slope of less than 25 degree (covering an area of 50% of the watershed) are developed to cropland. Hence, forest land with slope of less than 25 degree can reduce peak flow by 60~75% and runoff yield coefficient by 47%~68%.