Modeling of nitrate flux between groundwater and surface water based on a coupled model in Shaying River Basin
In order to quantitatively analyze the nitrate flux process between groundwater and surface water in Shaying River Basin,the coupled model of SWAT,MODFLOW and MT3DMS was constructed.The model was calibrated and verified by the observation data of water quantity and water quality during 2007-2012.The results show that coefficients of the surface water flow,surface water quality and groundwater levels are greater than 0.68,0.9 and 0.9 respectively,and the coefficient of determination for groundwater quality is within 15 ％,which meet the requirements of model accuracy.On this basis,relationship of recharge and discharge,as well as nitrate flux process between surface water and groundwater was explored in Shaying River Basin.The results indicate that groundwater mainly recharges surface water in the research area.The average annual net water recharge is about 318 million m3.The annual water flux in wet years is large,which can reach 1.52 billion m3,and in dry years is small with an annual average value of 0.026 billion m3.Generally,surface water recharges groundwater in the flood season,and the other way around in the dry season.For the upper and middle regions(Sha River,middle of Ying River and Fenquan River watershed),the average annual value is large,which can be up to 253 million m3.The average annual net nitrate recharge is 3800 tons.Nitrate flux from groundwater to surface water can account for 81.6％ of total nitrate flux in autumn and winter.In the space,the net nitrate flux from groundwater to surface water of the upper reaches of the basin is large,accounting for 87.4 ％ of the total net nitrate flux.The net nitrate flux in the middle and lower reaches is small,accounting for 12.6％ of the total net nitrate flux of the basin.
surface water and groundwater modelShaying River Basingroundwatersurface waternitrate
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NSTL
万方数据
维普
