Development And Application Of Grid-and-Topography-Based Distributed Hydrological Model

With the development of Information Technology and Remote Sensing Technology, Distributed Hydrological Models are becoming the trend of Hydrological Models due to their abilities to incarnate the spatial variation of hydrological factors and parameters. According to the current study status and needs, the Grid-and-TOPography-based physically distributed hydrological MODEL (GTOPMODEL) is developed.Firstly, the methods to extract basin information are summarized, studied and formulated, including the extraction of river system, the division of sub basins, the creation of drainage networks, the extraction of the distance-accumulated-area curve and so on in the article. Secondly, the Unit Confluence Strap is defined. Based on it, the basic equations for runoff-yield are gained by the Darcy's law and the assumptions that the saturated hydraulic conductivity of the soil follows a negative exponential law versus depth and that the water table is parallel to the soil surface. Meantime, two models of flow routing and confluence are established, including the Grid-Based Muskingum Flow Routing Method and the Sub-basin-Based Isochrone Method. By integrating the runoff-yield model and the models for confluence, two hydrological models, GTOPMODEL-A and GTOPMODEL-B, are developed. Meantime, the second model for confluence is also used to improve the TOPMODEL model and Xinanjiang Model. Finally, the four models are applied for flood simulation to the Upper Lushi basin in Luohe River, one tributary of the Yellow River. The calibration and optimization of the parameters are also studied.The results show that the four models can do well in this basin and that the two GTOPMODEL models usually perform better, which proves the rationality and reliability of the GTOPMODEL model.