Estimation of ecological flow requirement in Zoige Alpine Wetland of southwest China

In many vulnerable wetlands, water is the most crucial factor for sustaining human development, economic growth, as well as existence and evolution of various indigenous ecosystems. This has led to intensive competitions against limited water resources and caused a number of potentially adverse effects on local ecosystems and human society. As water demand by human activities is increasing, balancing water demands between human society and ecosystems is desired to improve economic development without causing too much disturbance on the environment and ecosystems within a wetland. In this study, a computationally efficient quantitative method was developed to calculate the ecological flow requirement (i.e., water demand by ecosystems) in an alpine wetland of western China. The proposed method was also carried out by means of remote sensing images interpretation. Through this method, variations in water demands by human beings and ecosystems could be reflected and analyzed, which would be useful in helping formulate water allocation strategies under multiple objectives such as environmental protection, economic development, and ecological conservation. The method was then applied to assess ecological flow requirements in Zoige Wetland of western China. The results indicated that to maintain the basic ecological structure and integrity of the wetlands, the minimum reserve of 6.218 billion m³/a and a suitable reserve of 6.639 billion m³/a of water would be required. Also, the application results indicated that the method is applicable and can be expanded to other similar wetlands for balancing water demands between ecosystems and human beings.