Research On The Large Scale Distributed Hydrologic Model

On the basis of studying the classical distributed model (such as SWAT), this paper advances the Distributed Time Variant Gain Model (DTVGM) and set up a large scale Distributed Time Variant Gain Model. There are many new sub modules in this model, such as land use module, land cover module, human activity module, water and soil conservation project module, reservoir dispatching module. The main function of this model is to analyse the human activity impact on water circulation of a basin. This model is applied in the Yellow River 79.5km2 basin, the research results indicate that the application of the model is successful in some sense, which can satisfy the requirement of water resources management.The groundwork of this paper and content studied are as follows:1, Give a method, which can gain the river net and divide the sub catchments only passing the DEM of a basin. The advantage of that method is which can make each grid connected in a basin and gains a directed acycline graph. The method of computing the flow direction of each grid is traversing graph, which study the idea of D8 method. The river net can be gotten according to the flow accumulation matrix and the flow direction of each grid. The sub catchments are gained by river net.2, Establish a large-scale distributed model. The runoff is calculated in each sub catchments, and then river nets get river routing. Each of sub catchment must deal some hydro elements, which are precipitation, evaporation, runoff and soil humidity. The precipitation and meteorological data of each sub-catchment are gained by the technology of data assimilating. The influence of the land use and cover change is considered from remote sensing and water and soil conservation project data. The irrigation water is fixed with the type of the crop and the area of the cultivated land. The function of the reservoir is to change the space-time distribution of the water resource. There is a Routine dispatcher's module about reservoir in the distributed model.3 Set up the month distributed model of the Yellow River. It is very violent that the human activity influenced the Yellow River Basin. The paper analyzes the rainfall, flow, the area of irrigation and water and soil conservation project etc. data in yellow river. From yellow river source to seaport, the model simulates 17 flow stations' observer flow. The efficiency coefficient of natural catchment in the upriver is greater then 0.8. The efficiency coefficient is simply not good enough in middle and downstream catchment, because of thehuman activity and not enough observer data.4 Developing visual system and system integration. We developed a visual system about distribute model. There are several types database and several languages in this system. Chapter 5 and chapter 6 give some method of system integration.