Estimation of Environmental Water Requirements via an Ecological Approach: A Case Study of Yongnian Wetland, Haihe Basin, China

Due to natural change and special human destruction, the area of wetland is greatly decreasing. To recover the wetland ecological system has become an urgent task that must be faced. Water plays an important role in the course of wetland recovery. With Yongnian wetland as a case study, the ecological function method was used, based on structures and functions of the wetland ecological system, the ecological water requirement was divided into four parts: water requirement of wetland vegetation, water requirement of wetland soil, water requirement of wildlife habitats and water requirement of recharging ground water. According to the indexes that were presented in the paper, each part was classified to three grades, respectively. According to the formulas that were given in the paper, all kinds of ecological water requirement of Yongnian wetland were calculated; the results showed that the least ecological water requirement is 1.256 x 10(8) m(3). The proper ecological water requirement is between 3.041 x 10(8) m(3) and 4.301 x 10(8) m(3), and the most ecological water requirement is 6.350 x 10(8) m(3).