The Combined Model Of Surface Water And Groundwater Is Constructed In The Ziya River Watershed

The study area belongs to the Ziya river watershed in Huabeibasin, with the Taihang mountain as the western boundary and Bohaisea as the eastern boundary, joins with Shijiazhuang to the north. Thetotal area is about 3.9×104m2 , including Handan city and Xingtai city.Huabei plain region is one of the water shortage regions in our country,with the quantity of water per person and per unit of area the least ofthe whole country. Especially in Jing-Jin-Tang region, Cangzhou andHandan cities and so on, the confliction of water supply and waterdemand is crucial, where the groundwater yield is close or exceeds thepermit exploitation yield. The ratio of groundwater yield and the totalamount of water resource in this region exceeds 70 percent. Ziya riverlocates at the middle of the Huabei plain, and the activities ofgroundwater development in this region is the dominate factor thateffect on the water circulation system in Ziya river watershed.The combined model of surface water and groundwater isconstructed in the Ziya river watershed. The SWAT model system isused to deal with the precipitation recharge and surface water runoff,and the groundwater model in the piedmont alluvial plain with porouswater is built too, and then the coupling model of surface water andgroundwater is constructed with dissymmetry characters in spatial.Around the recharge boundary, the seepage recharge from themountainous surface is accepted as the side flux of the groundwatersystem. The amount of precipitation varies obviously according to thespatial location and time. Based on the watershed unit combined withthe surface lithologic characters,the parameter distributing zones isdivided in this study. In another word, firstly to carry on the waterquantity monitoring in the specific watershed unit, then to calculate thewater balance in each region, and at last to calculate the precipitationamount for using in the groundwater numerical modeling model.In the model, the western boundary is a boundary with specificflux, the east-northern boundary is a boundary with specific waterhead, and the eastern and the northern boundaries are boundaries withzero flux. The groundwater recharge is mainly composed ofprecipitation seepage recharge and piedmont side recharge; and thedischarge items are mainly evaporation discharge and artificialdevelopment discharge. According to the formation location of theobservation boreholes and pumping wells, the multi-layers aquifersystem is generalized as a heterogeneous homogeneous threedimensions unsteady-state flow aquifer system with leakage. TheGMS software is used in the paper. The simulation region is dividedinto 150×150 grids using the MODFLOW module, the calculate timeis specified from the first day of January to the thirty-first day ofDecember in 1979, and this period of time is divided into 12 timeintervals with one month as an interval. According to the water levelsof the observation boreholes with long period and other observationpoints, the constraint conditions of the model are determined, and thenthe three dimensions groundwater simulation is carried on combinedwith the mathematical model.The hydrogeologic parameters gained by the model are ideal after...