Calculation of ecological water replenishment in small coastal watersheds based on environmental capacity constraints: A case study of eastern Xiamen, China

Abstract

In response to the issues of severe coastal pollution and exacerbated eutrophication, it is crucial to consider characteristics such as small flow in small coastal urban watersheds and water of low quality when implementing water replenishment measures. The selection of appropriate constraints and methods for calculating the ecological water replenishment (EWR) is the top priority. Here we present a calculation model appropriate for pin down the range of EWR in small coastal watersheds. Taking four of the eastern regions of Xiamen City as examples, the minimum and maximum EWR are independently computed based on the envelope curve and the restriction of the estuarine area's environmental capacity. Rational results are achieved with the approaches of Tennant as well as landscape water requirement, and it shows that the range of EWR for the four watersheds is 1.77×106 – 12.41×106 m3. The calculation model proposed in this paper has greater environmental feasibility from the perspective of the river channel demand and coastal environmental protection. Additionally, it also can provide a reference for EWR plans for urban rivers in coastal regions.

Keywords

• Ecological water replenishment
• Marine environmental capacity
• Small coastal watersheds