An Integrated Modeling Of Groundwater-Surface Water Interaction In The Kaidu River Basin

Groundwater and surface water are important components of hydrological cycle.It is necessary to consider the interaction in the water transformation and resource management in a basin.GSFLOW model is a coupled Groundwater and Surface water flow model based on the integration of Precipitation-Runoff Modeling System(PRMS)and Geological Survey Modular Groundwater Flow Model 2005(MODFLOW-2005),which can simulate water flow in hill slope,surface water bodies,unsaturated zone,as well as saturated zone.This article briefly introduces the structural framework of GSFLOW,implementing process and its application availability,and comparatively analyzes the impact of temperature,precipitation and hydrological response units(HRU)on the simulation results by GSFLOW modeling.The results show that the different division resolutions of HRU could affect the accuracy of GSFLOW modeling.The output of GSFLOW model is more sensitive to precipitation by comparison to temperature.It is shown that the GSFLOW model can be used to simulate the complicated interaction between groundwater and surface water.This thesis applies GSFLOW model in the source area of Kaidu watershed of Yanqi basin to build the integrated surface water and groundwater model.According to the data of study area from 2000 to 2005 to identify the model,the results show that the Nash coefficient for runoff simulations is over 0.67,the absolute averaged error between the observed and simulated groundwater level is about 1.2 m,indicating that the model achieves satisfying simulation accuracy.According to the data from 2006 to 2011 to predict the results of the simulation using the Yanqi Bridge,Baolangsumu runoff station data,groundwater observation well data,the results show that the Nash coefficient for Yanqi Bridge station runoff is 0.89,Nash coefficient for Baolangsumu runoff station runoff is 0.82,determination coefficient of groundwater observation wells south bank is 0.98,and the determination coefficient North Shore observation wells is 0.99.So the data of observation wells in the study area fit well and get better simulation results.Analyzing relationship of Kaidu river-groundwater shows that the first water diversion hub to Yanqi bridge,Yanqi bridge to Baolangsumu,Baolangsumu to Bosten lake both are river recharge groundwater.The first water diversion hub to Yanqi bridge recharge is large,the other is relatively small.Kaidu river can be divided into four segment.River recharge groundwater in the first water diversion hub to Barunhaermodun segment.River recharge south groundwater and groundwater recharge north river in the Barunhaermodun to Wulasitai river estuary segment.Groundwater recharge river in the Wulasitai river estuary to Wulasitai drainage segment.River recharge groundwater in the Wulasitai drainage to Bosten lake segmentThis thesis shows that the GSFLOW model is a helpful tool for assessing the groundwater-surface water interaction and can be used for integrated management of surface water and groundwater resources in arid watersheds.