The Theories And Applications Study Of Double-excess Runoff Generation Model

Influenced and restricted by precipitation, characteristics of terrain and manydynamical and stochastic factors in air-containing belt, the real precipitation-runoffprocess of a basin is such a much complicated and stochastic physical process with highdamp that the simulation of this process only can be based on scientific abstraction andlogical generalization. Xinanjiang model is suitable to be applied to humid area andShanbei model is suitable to be applied to arid area, interiorly. In semi-arid andsemi-humid area, however, the runoff generation process may be saturation-excess orinfiltration-excess and there is no suitable watershed hydrological model up to now.Accordingly, it is theoretically and practically significant to construct a kind of watershedhydrological model suitable for these areas and to study its application.In Double-excess runoff generation model based on the form and characteristics ofrunoff generation process, water supply degree is regard as a controlling factor andinfiltration model with soil humidity factor of pre-precipitation is used to simulatesurface runoff of a watershed. This model comprises the duration law of infiltrationcapacity of suppositional element, watershed distribution of infiltration capacity, surfacerunoff, subsurface runoff, soil evaporation and soil humidity of pre-precipitation. It is arewarding attempt to simulate precipitation and runoff in these areas.Beizhangdian watershed is selected as a representative of semi-arid and semi-humidareas to verify the structure and parameter of the Double-excess model. As downstreamflood duration graph calculated by the model corresponds to the measured graphapproximately and flood peak discharge and its occurring time fall into limit of errorcriterion, it is proved that this model can be applied to runoff simulation and floodprediction. Sensitivity analysis by disturbing analysis method indicates that SR,JL,α0,KS,b are sensitive parameters, δi less sensitive parameter, c non-sensitive one, and thatsensitivity order is SR>JL>b>α0>KS>δi>c.Based on DEM and Double-excess runoff generation model, the distributedhydrological model of Lanhe watershed, which includes digital watershed, hydrologicalmodel of sub-watershed, river confluence model, was established to solve the problem ofapplications of the double-excess runoff generation model. to watersheds of differentscope. The model is computed by sub-watershed. Combining Double-excess model andunit graph of SCS model integrally, the model can be used to solve confluence problemin semi-arid and semi-humid areas. If surface environment change is taken into accountmore, the model can be applied to study the influence that human activity and naturalenvironment change act on hydrological recycle process of a watershed. As distributedhydrological model has characteristics of reacting complex abundant data, manyparameters, etc., watershed hydrological simulation, which includes data managementmodule, hydrological model module and system operation module, is developed toimprove hydrological simulation efficiency.