Ecological Water Requirement For Marsh Wetlands Based On Hydrological Simulating

Zhalong Wetland is located in Songnen Plain of Northeast China, which is the largest ecological National Nature Reserve to protect red-crowned crane and other water birds. Its functioins include regulate regional climate, store flood water, purificate water body and reduce pollution. However, in recent years the shortage of water resources has severely affected the wetland's ecological environmental health and even local economic and social sustainable development. In order to calculate ecological water requirement and supplement of Zhalong wetland and provide reference for other wetland ,the paper provide a method to calculate wetland ecological water requirement based on hydrological simulation and the conclusions are as followings:(1) Developed a wetland hydrological model based on reservoir model concept. The model divided wetland to interconnected weltand units according to topographic features. Each weltand unit was simulated by water balance, and ultimately established a water cycle system simulation model of the wetland. The model application in the Zhalong wetland shows that the model has a high precision in simulating wetland surface area and outflow. The model can provide a key simulation tools to establish ecological water supplement of Zhalong wetland.(2) Provided a method to calculate wetland ecological water requirement based on wetland hydrological model. Using hydrological model,the method developed a series of relationship curves beteewn inflow and hydrological index accoding to different inflow frequency,and used these relationship curves to estimate ecological water requirement in different frequency and different ecological degree. The method can calculate ecological water requirenment for any given year,so it provides a quantitative skill and tool for ecological water resupplement.(3) Provided a method to establish wetland ecological water resupplement strategy. Using wetland hydrological model, the method simulated the hydrological effects of Zhalong wetland under a number of ecological water resupplement scenario, and the simulation results were compared to elect one of the most consistent with wetland natural water cycle characteristic for the optimal scenario. The method was applied to Zhalong wetland and two ecological water resupplement strategy were concluded. (4) The impact of human activities to the natural runoff of Zhalong wetland is below 20%, the impact degree is not very high, but with a constantly ascending trend. The reason why water inflow to Zhalong wetland in dry years is very low is mainly due to the natural hydrological cycle periodicand, and human activities made this situation more serious. To restore Zhalong wetland, providing sufficient ecological water is important, but other measures are also need, such as strengthening pollution management, reducing wetland internal human interference, and improving the management of wetlands and wetland protection awareness of the whole people, only with the active cooperation of these measures, Zhalong wetland can realize ecological restoration and sustainable use.