Inland river terminal lake preservation: determining basin scale and the ecological water requirement

Abstract

Inland lakes are a major water resource for arid regions. Determining basin scale is therefore an important indicator of variability for water resources in such regions. The goal of this study was to ascertain the appropriate Juyan Lake basin scale and its minimum ecological water requirement for the lake’s continued preservation. This was accomplished in three parts. First, an analysis was carried out on the inflow of the lower reach of Heihe River and any subsequent water surface area change to Juyan Lake. Second, an optimum Juyan Lake basin scale was determined by establishing existing relationships between reservoir capacity and lake area, water level and lake area, and variation in lake area during different times of the year. Third, the ecological water requirement of the lake was determined. Results showed that the decrease in surface runoff and ceased flow of the channel resulted in the drying up of the terminal lake of Heihe River. It was determined that 35.6 km2 is the most stable Juyan Lake surface area, and 0.55 × 108 m3 is the minimum replenishment quantity in which to maintain Juyan Lake throughout the year without it drying up.