Coupled GSI-SVAT Model with Groundwater-Surface Water Interaction in the Riparian Zone of Tarim River

Abstract

The Tarim River is located in the arid areas of northwestern China, where groundwater (GW) and surface water (SW) in different landscape units have undergone regular and duplicate transformation processes, greatly improving the utilization of water resources. Investigation of the interaction between groundwater and surface water is critical to determine proper water resources planning and management in the Tarim River region. A new approach of coupling the soil-vegetation-atmosphere transport model (SVAT) with the groundwater-surface water interaction model (GSI) is presented in this paper. Usually, the surface water recharges to groundwater and groundwater-soil water exchange are not considered in the SVAT model. However, in reality, the soil water content profiles and soil heat profiles are intensely affected by shallow groundwater table, especially in arid riparian zones where groundwater levels fluctuate substantially. A new method linking the SVAT model with the GSI model is proposed in this paper to approach this issue. The groundwater-soil water exchange and groundwater evaporation can be effectively simulated using GW-SW interface in the coupled GSI-SVAT model. The coupled model is validated in the riparian zone of the upper reaches of the Tarim River with the simulation of heat and water transfer between groundwater level and soil surface, evapotranspiration, root water uptake, and groundwater-soil water exchange. The simulation results show good consistency with experimental data, indicating that the use of this coupled model could improve the accuracy of simulation of ecological water consumption in the riparian zone. The coupled GSI-SVAT model could be used for better planning and management of water resources in arid areas.