Dynamics model to simulate water and salt balance of Bosten Lake in Xinjiang, China

Abstract

Bosten Lake, the largest inland freshwater lake in China, is similar to other lakes in arid regions in that it faces shrinkage of its area and a decrease in environmental quality due to climate change and anthropogenic pressures. A water and salt balance model, developed using system dynamics approach, was used to estimate potential contributions of natural and socio-economic factors to variations in the lake’s level and salinity. Calibration of the model provided new estimates of conversion coefficients for the actual evaporation and dissolved salt from the lake bed. The sensitivity analysis indicated that the lake’s level and average salinity have significant and high correlation with the water exchange rate and evaporation of surface water. Analysis showed that (1) increasing water exchange of the lake promoted a decreasing average salinity of the lake and an increasing water supply to the downstream area of the lake; (2) the average unproductive water lost was larger than half of the average surface water inflow; (3) enlarging the agricultural area in the Konqi River basin instead of the Kaidu River basin promoted a decrease in the lake’s salinity as well as a decrease in the total amount of salt in the lake. This study implies that increasingly efficient water management practices and greater conservation of water resources are required to save Bosten Lake and its ecosystem.