Suitable water surface area of the tail lake under the constraint of water diversion scheme in arid areas based on emergy theory

Abstract

Study regionThe East Juyan Sea (Inner Mongolia, China) Study focusMaintaining a certain water surface area in the East Juyan Sea is the main sign of the success of the Heihe River water diversion. However, under the realistic constraint of limited water resources, the maintenance of the lake's water surface area and the oasis ecological water are in conflict. Through comprehensively considering various factors such as ecology, economy, and water resources, this study focused on the relationship between the East Juyan Sea's ecological service value and water surface area, which was investigated with emergy theory. Meanwhile, based on the status of local water resources and the principle of water diversion, the suitable water surface area of the East Juyan Sea's was given. New hydrological insights for the regionThe results indicated the optimal water surface area of the East Juyan Sea is approximately 40 km2. In addition, we can observe that the value of ecological services of a specified area increases infinitely with the expansion of its water surface area. But, within a certain threshold value, the amount of its value will become stabilize. Below or beyond this threshold, the value of regional ecological services will increase at a faster rate. However, the larger is not always better. The larger the water surface area, the easier it is to create competition for water with the oasis vegetation, which will be detrimental to the ecological health and stability of this region. Thus, the appropriate water surface area needs to be determined comprehensively by considering various factors such as ecology, economy, and water resources.