Study On Joint Dispatching Of Gate&Dam In The Landscape Environmental Water Of Riverine Wetland

In recent years people pay more and more attentions on the functions of landscape environment in riverine wetland, however, the shortage of water resources and water pollution problems seriously affect the landscape environment function. In this study, the Pu River in northern area was taken as an example, and the joint scheduling of gate and dam for landscape environment water demand is studied combined with the characteristics of riverine wetland to make the water demand for social economy and landscape environment satisfied to the most extent as ensuring safety of river course flooding by the unified dispatching of water conservancy projects, and the water quality can also be improved effectively. The main contents and results of research are as follows:1.The composition of riverine wetland system was defined, and the characteristics of riverine wetland in northern area were analyzed, including water resources, channel morphology, water source composition, hydrology, water quality pollution and ecological characteristics, showing that the characteristics of riverine wetland in different periods in the northern area vary greatly, and the characteristics of artificial control are obvious.2.The content and composition of landscape environment water demand for riverine wetland in the northern area were analyzed, and according to the difference among river function, hydrographic features and water composition in different periods, the stage calculation method of landscape environment water demand which is suitable for the riverine wetland in the northern area was put forward. The landscape environment water demand in Pu River was calculated block by block with the stage calculation method monthly. The results show that the seasonal characteristics of landscape environment water demand in Pu River are obvious, and non-consumptive environmental water demand is greater than landscape water demand. As long as the environmental water demand is satisfied, the landscape water demand is automatically satisfied, proving that landscape water has not been used excessively by the ecological construction in Pu River.3.The joint scheduling model of gate and dam based on landscape environment water demand was established with the controlled gate and dam and other water diversion projects and the consideration of the difference among reclaimed water, surface water, diverted water and other water resource, in water amount, water price, engineering corollary. The effectiveness of scheduling model was analyzed by optimal scheduling results in current years, and through the model solution, the scheduling scheme set in the planning year with 50% and 75% annual water inflows condition was obtained respectively; three programs were selected as the recommended scheduling scheme with the consideration of the original Qipanshan Reservoir's demand for landscape water level.4.The SWAT model was used to simulate the runoff of Pu River for each recommended scheduling scheme in 50% and 75% annual water inflows condition and the current situation respectively, and the satisfaction of each control section's river flow to landscape environment demand was analyzed. Besides, by selecting these four water quality indexes, total nitrogen, total phosphorus, ammonia nitrogen and COD, we simulated the water quality of each recommended schemes in planning year and in current year separately, analyzed the influence and reasons that each scheduling scheme makes on water quality of river's each section, and provided information for the optimization of scheduling scheme. The results show that after the implementation of scheduling scheme under 50% annual water inflows condition, landscape environmental water demand of each control sections of river can be satisfied. After the implementation of scheduling scheme under 75% annual water inflows condition, in the case that the damage depth of agricultural water is less than 25%, ecological water requirement of each control sections of river can also be satisfied. After the implementation of simultaneous scheduling scheme, water quality of each control sections can also be improved to a certain degree.5.The landscape environment and agricultural irrigation water supply function of Pu River was considered comprehensively, combined with the landscape environment functional objectives of different river sections and different time periods, as well as the influence of the water shortage at different growth stages that makes on crop yield taken into account fully, in this paper the identification index system of scheduling scheme was established. By applying AHP-Fuzzy method, each recommended scheduling scheme was performed to identify the superior degree in planning year, in 50% and 75% annual water inflows condition respectively, thereby a best optimal scheduling scheme was obtained, from which this paper made the dispatching rules of each gate dam, optimal transferable water volume, and water transfer duration of each water transfer project.