| Dongying Guangli River is the only river between Bohai Sea and Yellow River as well as the drainage system going through the center of the city. In revent years,due to rapid development of agriculture and industry along with Guangli River basin, intensive pollution and relative lagging regulation measures, pollution in Guangli River basin is serious. As part of pollution regulation project of Global Environment Facility (GEF), construction of Dongba Road constructed wetland in Huai River basin is a significant engineering measure to realize purification of downstream river way.Numerical simulation method is one of the main methods to studying hydrodynamic and water pollution dispersion and transportation. Result calculated by numerical simulation shall provide basic technical support and data reference for wetland construction and vegetation plantation. Thus, with such numerical simulation, effective and dependable wetland hydrodynamic force model and water quality model shall be established, which is necessary means to accurately simulate actual problem as well as with significant theoretical significance and practical value at the same time. Based on the example of eight constructed wetlands in the east of Dongying River Basin, this paper provides the theoretical basis for the reconstruction of the late stage and the evaluation of water quality monitoring.This Article first studies specific planning and design of Dongying Guangli River constructed wetland drainage system, and put forwards several problems required to solve in every river way of wetland drainage system, such as flow direction, quantity of flow, water level and water quality, according to drainage system design condition of Dongba Road constructed wetland.Secondly, water flow condition in every river way under two quantity of flow working condition of Guangli River constructed wetland drainage system, namely quantity of flow in summer Q1=7.0×104m3/d=2916.7m3/h and quantity of flow in winter Q2=2.5×104m3/d=1041.7m3/h, which are calculated by two-dimension hydrodynamic force simulation established by MIKE model, including water flow direction, quantity of flow, water level through the river and other problems. It is simulated that overall mobility of water body in Dongba Road wetland is good, without large area of dead water region.Thirdly, WASP model is adopted to establish one-dimension water quality simulation, Guangli River Minghaizha water quality monitoring data is used for numerical simulation, removal process of contaminant types in constructed wetland (such as COD, BOD, NH3-N and TP) is monitored, to evaluate reduction of constructed wetland to water contaminants. For example, deduction of TP is relatively high when influent concentration is high while deduction effect of constructed wetland to TP is not obvious when influent concentration is low. Meanwhile, it is simulated that effluent quality of Dongba Road constructed wetland reaches surface water standard V category. According to water quality index values of different schemes, basic data support and basic suggestion are provided to further improve wetland water quality.Aiming at Dongba Road Guangli River constructed wetland drainage system, the Article simulated in detail and analyzes carefully problems of hydrodynamic force and water quality according to practical situation, and gives out corresponding regulation measures of hydrodynamic force engineering. It is feasible in theory, but there are still some problems to solve. For example, verification of physical simulation shall be regarded as further work to give out corresponding constructive opinions more accurately. |
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