Water Quantity Evaluation Methodology Based On Modified SWAT Hydrological Modeling In Southwest Karst Area

The water resources evaluation of sub-streams in Bare Karst area is the hot topic of present Karst water research. The Karst sub-streams system combined with conduits, caves, fissures, pores and other water-bearing medium widely distributes in South-West of China. The complicated structure leads its high heterogeneity in Hydrology. The sub-streams flow usually constitutes of Darcy flow and non-Darcy flow, so there are many challenges in theory, method and technique toward the traditional Hydrogeology methods that just considered the underground medium structure. Therefore, some new ideals, means and techniques must be developed to solve the problem.The water table discrepancies between sub-streams vary quickly, and there is no uniform groundwater head for an area. As a result, it is hard to distinguish between recharge water resource and storage water resource. The karst sub-streams is similar with the surface river in configuration, runoff dynamic and flow characteristics. So the focus should be put on the simulation of the hydrology process in karst sub-streams basin.There are a number of important limitations to the applicability of the traditional lumped parameters Karst hydrologic model. It is widely recognized that such models can not reflect the heterogeneity of Karst drainage basin structure as well as the rule of water resource variation. Except that, lumped parameters model can not adapt to large climate pattern when applied to large scale basin. This study applies modern hydrology theory and means to evaluate the quantity of karst basin water resources based on the fact that the sub-streams analogous with surface river.One of the overall aims of this study is to develop and demonstrate a new generation of karst sub-streams hydrology modeling, which will improve the present capabilities and accuracies.First, the process of karst sub-streams basin runoff and its characteristics are analyzed, and the conclusion that the sub-streams analogous with surface river is given. The runoff yield mode of karst basin can sum up to runoff yield under saturated storage. The concentration of karst basin flow mainly depends on the medium structure. The karst conduits flow forms the majority quantity of the runoff. The configuration of sub-streams is similar with surface river, they all accord with the Horton's law which is used to describe the river growth, shape and evolution. And the flow characteristic of sub-streams is similar with surface river flow, which is quick and has a big slope. With the karst basin area increasing, the discrepancy area between surface...