Study On Water Sensitive Urban Planning Based On The Protection Of Water Quality In Hanfeng Lake

After the impoundment of the Three Gorges Reservoir, the water variation of this reservoir lead to water level fluctuating between 145 m and175 m bands, due to the use of "storing clear muddy" mode of operation,in order toensure environmental safety is located in the hinterland of the Three Gorges Reservoir Kaixian county new ecological, the local government built new dam downstream above 3 km water level regulation Yangcun black, normal water level is 170.28 m. When the new dam is completed, the water level above of the dam, fluctuating water level rose by 22.5 m level down to 4.72 m, forming a unique "city in the Lake"- Hanfeng Lake. In winter, during the high water level in the Three Gorges reservoir area, Hanfeng Lake water level is maintained at 175 m high; in summer, when the Three Gorges reservoir decrease to 145 m, due to the dam’s water level regulator role, Han Feng water level is maintained at 170.28 m. Kai Xian new town and Hanfeng Lake harmony, water is an important factor for urban development, the city due to water and health, but also may be due to bad water.As a medium-sized city with a population of about 300000, Kaixian waterfront and city population, production and living activities, as well as the city land use and spatial layout pattern, Hanfeng lake water quality of city construction closely, The water quality of Hanfeng Lake is directly related to the safety of water environment of Three Gorges Reservoir,so the protection, restoration, construction of the Hanfeng lake and urban landscape ecological construction integrate synergistic symbiosis of great significance.In this paper, water-sensitive urban design philosophy is based on the Hanfeng lake water quality and pollution load to evaluate the status;with the apply of Warren Weddell and Dillon model to assess the capacity of the lake environment; and we also use remote sensing data of 2002 and 2012 years, application data ERDAS after correction for changes in land use structure 10 years of the Han Feng Lake basin, and analyzed the transfer of land-use change; combined 2012 water quality monitoring data, applications GIS, binary linear correlation analysis method, the land use pattern and water quality to do a detailed analysis of the correlation. Secondly, the water-sensitive urban planning principles and system proposed Kaixian Han Feng Lake City spatial pattern of development mode " Mountain, water, forestry, paddy field lake and cityCity – Lake " community of life; and water-sensitive urban ecological projects was carried out. The main results of the paper is mainly reflected in:① The water quality of the Hanfeng Lake in W2,W3,W5,W8 section watershed is evaluated IV category, and the other section is III. Chemical oxygen demand, total phosphorus, fecal coliform, ammonia, total nitrogen are the main pollutants in the river Han Feng lake water quality. In the 2020, total pollution load of the Han Feng Lake watershed is COD 8135.74 t/a,NH3-N 1752.18 t/a,TN 2940.82 t/a,TP 213.03 t/a. Han Feng water environmental capacity for COD 2191.79 t,TN 1646.34 t,TP111.28 t,NH3-H 1748.96 t. Therefore, Hanfeng Lake watershed total pollution load is heavy, beyond the self- purification ability of Hanfeng lake.② The water quality of the Han feng lake is closely related to land use change. 1) 2002 ~ 2012 years watershed land use structure is changed significantly, mainly in the construction land, the rapid increase in the area of bare ground, and the area of forest and grassland continues to decline. From the number of changes, the urban construction land area increased significantly from 3118.01 hm2 to 4533.11 hm2 between 2002 and 2012, with a rise from 7.65% to 11.13%; bare ground is increased from 2002 to 3681.52 hm2 2013 5444.72 hm2. 2) 2002 ~ 2012 years, the construction land mainly in the Han Feng Lake, South River, East River, etc. along the river, the largest concentration of Mikawa Interchange, which is Kaixian Metro. 3) watershed land use transfer occurs mainly in the bare ground and among other types, but the more significant shift for the conversion of forest and grassland, and other types of inter among other types. 4) COD, NH3-H, TN, TP and four water pollution indexes of construction land, farmland was positive correlation with the size of arable land and the construction land, was negatively correlated with forest and grassland.③ Through the elaboration of water-sensitive urban design principles, this paper identified the water sensitive urban planning key area, proposed the water sensitive urban planning conceptual framework based on the water quality protection of Han feng Lake: " Mountain, water, forestry, paddy field lake and city- City – Lake " urban spatial pattern; through water-sensitive urban planning systems analysis, we put forward water sensitivity key space in the design of city planning, including the lakeside buffer, the small watershed ecological corridor etc.④ In order to explore water-sensitive urban ecological project, this article wants to optimize land use spatial pattern of the Hanfeng Lake, with " Mountain, water, forestry, paddy field lake and city- City – Lake " pattern of urban space as a fundamental base proposed urban landscape pond system, Fluctuating Zone Linzey systems, biological depression, rain gardens, and more Tong buffer strips and other ecological projects is proposed, in order to reply the key regional of the city water sensitivity, so that the urban hydrologic environment and water environment management was optimized, and the quality of the Hanfeng lake is ensured.