tangqh@iis.u-tokyo.ac.jp [cor1]Corresponding author. Tel.: +81-3-5452-6381; Fax: +81-3-5452-6383.

Abstract:

Groundwater recharge and discharge were estimated from a water balance method in the Akesu alluvial plain. The Akesu alluvial plain (4842 km²) is an oasis located in the hyperarid Tarim River Basin of central Asia. Along the Akesu River, this land has long history of agriculture development and the irrigation area highly depends on water withdraws from the river. A water balance methodology is represented to describe water interaction between surface water and groundwater, and groundwater interaction between irrigation area and non-irrigation area. Groundwater is recharged from irrigation system and discharged in non-irrigation area. Wild plants and wetland are supplied from groundwater in hyperarid environment. The results show that about 90% groundwater recharge comes from canal loss and field infiltration. The groundwater from irrigation area to non-irrigation area is about 70% of non-irrigation area recharge and acts as subsurface drainage for irrigation area. It desalinates the irrigation area and supplies water to non-irrigation area. The salt is moved to non-irrigation area following subsurface drainage. The flooding of the Akesu River is a supplemental groundwater replenishment mechanism. The river desalinates the alluvial plain by recharging fresh water in summer and drainage saline regeneration water in winter.