The Model Research Of "Four Waters" Conversion On Plain Areas

A "four waters"(Precipitation, Soil moisture, Surface water and Groundwater) conversion model has been established on the basis of water cycling and the law of water balance as well as hydrological runoff theory. Model structure, calculation procedure and the calibration of each parameter also have been presented.The model is a physical model based on hydrodynamics. It also takes account of the smooth slopes, which are typical topographies in plain areas. With these two considerations, soil moisture in vadose zone has been focused on. A hydrological model derived from a coupled LSM-MM5 model is used to simulate the temporal variations of soil water content. The model not only comprises the continuous conversion of "four waters" but also follows time scale water balance. An omnibus model is used to calculate runoff yield. It consists of two runoff yield patterns. One is SWB model, which means the runoff yields at the time when the rainfall intensity exceeds the infiltration intensity. The other is that the runoff yields when the water content in aeration zone reached up to the field moisture capacity. The model is adapted to be used in semiarid regions.This article presents Wudaogou Test Site to carry on modeling simulations. Based on the results of "four waters" conversion at Wudaogou Test Station, groundwater evaporation and infiltration have been evaluated furthermore. It is demonstrated that the calculation methods in this article are efficient and are satisfied with the analysis of "four waters" conversion in plain regions. It can be used as a tool to evaluate water resources in plain areas.