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

Study region: The East Juyan Sea (Inner Mongolia, China) Study focus: Maintaining 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 region: The 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.

Automated summary

This study comprehensively considered various factors such as ecology, economy, and water resources to investigate the relationship between the water surface area of the East Juyan Sea and its ecological service value. The optimal water surface area was found to be approximately 40 km2, and the value of ecological services increases infinitely with the expansion of the water surface area up until a certain threshold value, beyond which the value increases at a faster rate. However, the larger water surface area may create competition for water with oasis vegetation, which can be detrimental to the ecological health and stability of the region.