Key point of desert riparian forest development in the arid area: The response of phreatic water table depth to ecological water supply

Abstract

Desert riparian forest vegetation maintains the fragile balance of ecosystems in extreme arid areas. Raising the phreatic water table through efficient ecological water supply is the key to the desert riparian forests in extreme arid areas. The main objective of this study is to explore an innovative framework in which the response of phreatic water table depth (PWTD) to ecological water supply flow (EWSF) can be effectively reflected. The framework is based on the computationally efficient integrated surface water - groundwater model (ISGWM), through which surface water processes, groundwater recharge and discharge processes, and PWTD changes under different EWSF can be accurately simulated. A large number of simulations were conducted to reflect the response of PWTD to EWSF, and to explore the suitable EWSF and its intra-annual process considering the efficiency of PWTD reduction. The applicability and advantages of ISGWM were evaluated for the Tarim River Basin (TRB), a typical inland river basin, northwest China. The response of PWTD to EWSF was studied in 55 gate control areas in the mainstream of TRB. The formulas of suitable EWSF of 55 gates with different initial PWTDs were fitted. It is more beneficial to concentrate the ecological water supply in flood season (Jun.-Oct.). Overall, the ISGWM can accurately describe the multi-process of surface water and groundwater interactions. This study can provide scientific support for water resources management and allocation in the TRB and other similar inland river basins.