Harnessing countermeasures of Cuiping Lake

I. Principles and Objectives of Control The core of water pollution control in Tianjin lies in source control. In order to establish an ecological restoration system, it is necessary to reduce the amount of pollutants in storage, promote the adjustment of industrial structure in the basin, speed up the treatment of pollution sources, carry out sediment dredging and ecological restoration projects, reduce endogenous pollution, improve the self-purification ability of water bodies, further improve and perfect the water source management system, and establish an effective mechanism for the whole people and society to protect water resources. At the same time, take all effective measures to control external sources, reduce internal sources, restore ecology, manage according to law, and innovate management system to ensure normal water supply in cities. Through the treatment of systematic engineering and non-engineering measures, it is ensured that the outbreak of aquatic plants and algae does not occur in Yuqiao Reservoir, and the water supply safety is guaranteed. Second, the engineering measures 1, the discharge of high-pollution incoming water in the upper reaches of the flood season According to the characteristics of the incoming water river of Yuqiao Reservoir and the quality of the incoming water, the scheme of retaining pollution and abandoning pollution at the higher level can be adopted. After the confluence of Shahe River and Lihe River, hydraulic structures were built in the downstream, and the diversion open channel was excavated through Yanshan mouth of Xilonghuyu, which introduced the highly polluted incoming water into Lanquan River, entered the Jiyun Canal through Lanquan River, and finally entered the sea. 2. It is a long-term, active and thorough measure to use the original reservoir project to purify the upstream high-pollution incoming water and establish a wetland purification system. The pollution load in the estuary is concentrated and relatively easy to control. Pre-reservoir technology is an important means to intercept pollution load and control reservoir eutrophication. The pre-reservoir can be built on the east side of Daqiao Reservoir (that is, the river junction of Daqiao Reservoir), and its engineering planning, implementation and management are all within the scope of Tianjin, which can avoid the difficulties of inter-provincial implementation and play a role in flood control, water resources utilization and improvement of reservoir water environment. 3. Construction of estuarine wetland The construction of estuarine wetland is mainly to plant higher aquatic plants. When the upstream water comes, plants directly absorb nutrients such as nitrogen and phosphorus, or as a secondary purification measure of the pre-reservoir, further reducing the concentration of nutrients in the incoming water, reducing the pollution accumulated by sediment in the estuary area for many years, reducing the endogenous pollution of the reservoir, and achieving the purpose of controlling algae outbreaks. Why are the main construction areas the reservoir shoals at the estuaries of Linhe River and Wohe River, with water depths of about 1.5m? Restoration of aquatic ecosystem The restoration of aquatic ecosystem is mainly to restore two large systems, namely aquatic animals and aquatic plants. Aquatic animal system is mainly to protect fish resources, establish a balanced fish population, and use the growth of fish to inhibit the outbreak of grass and algae, thus improving the water quality of the reservoir. The aquatic plant system is mainly to inhibit the overgrowth of POTAMOGETON crispus, realize the balance of multiple species, make a large number of higher aquatic plants grow in the reservoir from June to September every year, and compete with algae for nutrients such as nitrogen and phosphorus and light, thus inhibiting the outbreak of algae.

Yuqiao Reservoir

5. The sewage intercepting ditch around the reservoir and the lakeside zone should be built in the permitted area around the reservoir, so as to control the non-point source pollution around the reservoir and directly intercept the direct pollution of the reservoir caused by the farmland drainage containing a large amount of nutrients around the reservoir, so that the farmland drainage firstly enters the sewage intercepting ditch, and then enters the lakeside zone system for secondary purification after a period of purification, and then enters the reservoir, which greatly reduces the contribution of nutrients such as nitrogen and phosphorus around the reservoir to the eutrophication level of the reservoir. 6. Establish wetland system with flat fish ponds. The fish ponds in the 22 m line of Dagu elevation of Qiaoreservoir have leveled 800 hm2. These fish ponds are characterized by being between the reservoir and the farmland around the reservoir, and the villagers who lost the fish ponds have been compensated. Therefore, the water around the reservoir can be purified by making full use of the water depth of the flat fish pond and the embankment between the fish pond and the reservoir and establishing a wetland system in the abandoned fish pond. 7. Construction of River Wetland Corridor The construction of River Wetland Corridor is mainly between Longmenkou Reservoir of Helin River and the inflow estuary, and between Shuikouping Hydrological Station of Shahe River and the junction of Lihe River. It mainly absorbs nutrients and purifies incoming water by planting higher aquatic plants such as reeds. 8. Residents moving around the reservoir. During the construction of the reservoir, most villages and towns around the reservoir are inhabited by immigrants, and a large amount of domestic garbage generated by them is piled up around the reservoir; In addition, the land is small and there are many people. In order to survive and develop aquaculture, villagers also used illegal means to plunder the fish resources of Daqiao Reservoir and develop industries that pollute the reservoir, such as tourism, which caused certain damage to the aquatic ecosystem of Daqiao Reservoir. Therefore, in order to build the largest eco-environmental park in Jixian County, it is necessary to immigrate residents in a certain range of the reservoir area. 9. Dredging or passivation of sediment Due to years of accumulation, the reservoir has formed some highly polluted areas of sediment, and the adsorption capacity of sediment to pollutants has reached saturation, and some pollutants have begun to be released. In order to remove endogenous sources, pollutants in sediments must be removed or passivated. The project mainly focuses on the river mouth area, and the main pollution layer of the sediment is removed from the warehouse by dredger operation, or the sediment is passivated, which effectively reduces the pollution release of the sediment and enhances the self-purification ability of the reservoir. 10. There is a concrete water retaining network around Qiaoreservoir, and the traffic is developed. Around the reservoir, there are two main highways, namely, Bangxi Highway on the north bank and Shuiku South Road on the south bank. Among them, the Bangxi Highway on the north bank is far from the reservoir line of 22 m due to the small slope on the north bank, and it is between 1~3 km, so it has strong handling ability for transport vehicle emergencies. If the ditches leading to the reservoir are intercepted in time, the threat to the water quality of the reservoir is less. However, the south bank of the reservoir is steep, and the south bank of the reservoir is built near the reservoir. Especially the 22 m line between the highway and the reservoir from Su Zhuangzi Village in Bieshan Town to Qingchi Village in Wubaihu Town is only 3~30 m, and there are few natural barriers. Once a transport vehicle loaded with flammable, explosive and highly toxic chemicals has a traffic accident in this section, it will lead to the leakage of highly toxic and harmful substances. In the current environment of the south bank of the reservoir, it is difficult to prevent harmful substances from entering the reservoir by any emergency measures, so the pollution threat of harmful substances to the reservoir water body always exists. The concrete retaining net is mainly built on the north side of Shuiku South Road. Its main features are durability and long service life. At the same time, the concrete foundation can effectively slow down the speed of toxic and harmful substances leaking into the reservoir in sudden traffic accidents, provide conditions and buy time for emergency rescue work, and effectively prevent the expansion of pollution incidents.