Application Of SWAT Model In Runoff Simulation Of Watershed In The Northern Slope Of Qinling Mountain,Xi’an, China

As the main water source conservation of Xi’an city, Qinling Mountains occupy an important position in the ecological environment and economic sustainable development.Nevertheless,in recent years, by reason of population growth, rapid economic development,urban, industrial, ecological water consumption increases, supply and demand contradiction of water rave become increasingly prominent. Coupled with the lack of measured hydrological data in most of North Qinling Mountains basin, the total water supply is still unknown. Therefore, to carry out the simulator investigation on ungauged basins based on the similar basin is very necessary.This article selects the typical basin-heiyu at the northern slope of Qinling Mountain to construct the SWAT hydrological model and simulation verification in the study area,exploring the applicability of the model, and this model is applied to the northern slope of Qinling Mountain in Xi’an and then the annual mean runoff is calculated; the development potential is preliminarily analyzed, which will provide a scientific basis for the development and management of water resources in the area. The main findings are as follows:(1) According to the existing DEM, land use, soil and other data, SWAT model is built on the Heihe watershed, and the basin is divided into 25 sub-basins, 54 hydrological response units. Finishing parameter sensitivity analysis and parameter calibration, model validation and uncertainty analysis by the SUFI-2 algorithm of SWAT_CUP software. Using the correlation coefficient(R2) and Nash-Sutcliffe coefficient(Ens) as adaptive evaluation of the model,2005-2010 monthly runoff processes of Heihe watershed is simulated. The results show that the SWAT model has higher simulation precision and better applicability.(2) Due to most Yukou of the northern foot of Qinling Mountain lacking of hydrology observation data, the water resources management, development and evaluation of water disaster have been greatly restricted.Therefore, through extracting the topographic and hydrologic information from each valley basin at the northern foot of Qinling Mountain,establishing four categories and six sub-categories of the main features of the factors affecting the properties of the runoff, on account of the hydrological similarity theory and multiple-indicators comprehensive evaluation method based on rough set and conditionalinformation entropy to divide the likeness basins. With Heiyu, Laoyu, Dayu, Fengyu,Wangchuanyu as a benchmark, the 48 valley basin in xi ’an qinling is divided into five similar basin group; hydrological model parameters of similar watershed will be transplanted.(3) With Heiyu as the reference basin and Wangchuanyu as the proving basin, the model parameters of Heiyu are transferred to Wangchuanyu; the results of parameters transfer test show that the parameters of the model are fine, this demonstates that parameters can be transplanted in the same group. On this basis, to build the SWAT model for ungauged watersheds respectively, with Heiyu, Laoyu, Dayu, Fengyu, Wangchuanyu as the reference basin, using the hydrological similarity calculation as the substitution method to calculate the annual mean runoff of all basins in the northern slope of Qinling Mountain of Xi’an city.(4) According to the condition of Xi’an qinling runoff, the water resources’ development and utilization model of Yukou at the north of Qinling is put forward. Combining the water available(including the water from the reservoir) of all Yukou in qinglin and reasonable exploitation of groundwater, formate water-supply system that two types of water in use at the same time.