[cor1]Corresponding author. Tel.: +81-3-5452-6381; Fax: +81-3-5452-6383.
tangqh@iis.u-tokyo.ac.jp
The Tuoshigan-Kumalake River alluvial plain is an oasis located in the Tarimu River Basin of central Asia. Large water consumption reduces the discharge and jeopardizes the ecosystem of the lower reaches of the Tarim River. Therefore a recent regulation is enacted to limit water use in the plain. The objective of this paper is to investigate the hydrological cycle inside the intensively cultivated plain. A conceptual water balance methodology was used for evaluating groundwater movement among riverway, irrigation ditches, irrigation area and non-irrigation area, based on the recorded water diversion. Results show that both irrigation area and non-irrigation area are supported by the water from river way in hyper-arid environment. Irrigation area is supported by surface water through canal system and non-irrigation area is supported by groundwater from canal loss and irrigation area. Nearly half of the water in the non-irrigation area comes from the irrigation area in the form of groundwater. This indicates that water supply of natural plants relies on the water from agricultural ecosystem. Tight water connection between irrigation area and non-irrigation area suggests that natural ecosystem needs to be considered in agricultural management in arid environment.
