Through the purple river is flowing through the city of Changde City, a thousand years old canal, the total length of 17.3 kilometers, the watershed area of 27.97 square kilometers. 1952, through the purple river due to water diversion was forced to cut off the water supply, into a self-cleaning "cut-off river". With the acceleration of urbanization, the river has been divided into several water bodies due to urban expansion, and the excessive discharge of domestic garbage and wastewater produced by the surrounding residential areas, farms and factories has aggravated the pollution of the water body of the river, deteriorated the ecological environment of the basin, and had a serious impact on the urban living environment. 2006, in order to manage the deteriorating ecological environment of the river, improve the ecological supply capacity of the basin, and promote the virtuous cycle of urban economic development and ecological protection, a project has been carried out to improve the ecological environment of the river. In 2006, in order to control the deteriorating ecological environment of the river, improve the supply capacity of ecological products in the river basin, and promote the benign cycle of urban economic development and ecological protection, Changde Municipal Government initiated the ecological restoration and management of Dengzhi River, and carried out the five-in-one construction of sponge city of Dengzhi River Basin, which is based on the cooperation between China and Europe, namely, water ecology, water safety, water environment, water culture and water resources. Through unremitting efforts, the river has been transformed from a "stinking ditch" to a "cultural river", "commercial river" and "tourist river". "in one of the urban ecosystem and ecological value realization platform, for the whole city and residents to bring a steady stream of ecological products and comprehensive benefits, has become a veritable city of "golden belt".

(2) Specific practices

First, the preparation of governance planning, sponge city construction. 2006 March, Changde Municipal Government, in cooperation with the government of Hannover, Germany, the German Hanover Water Association, the Dutch government of Utrecht, started the ecological management project through the purple river, compiled and completed the "" Water City Changde" "" - Jiangbei District of Changde City, the water is the most important part of the city. --Changde City Jiangbei District Water Sensitive City Development and Sustainable Water Resources Utilization Master Plan", put forward the concept of "sponge city", and urban rainwater, sewage, groundwater, etc. for integrated planning, with ecological and sustainable concepts for urban water system The concept of "sponge city" was put forward in the Master Plan. Since 2009, under the guidance of the master plan, Changde City has carried out the interception of sewage, lowering of embankments and repair of gates, reconstruction of rainwater pumping stations, storage ponds, ecological filters, ecological shoreline of the river, etc., and has successively launched the reconstruction of neighborhoods, roads, plazas, drainage networks, and construction of ancillary facilities within the catchment area of the river. 2011 and 2015, Changde City adopted and implemented the "Through the purple river two compartments (Soap River)" concept respectively. Through the Purple River two compartments (soap fruit road to Changde Avenue) urban design planning program" and "through the purple river scenery belt construction detailed planning", etc., further promote the through the purple river on both sides of the scenic belt of the supporting facilities construction work.

The second is to carry out systematic management to improve the ecological environment. Intercepting the pollution net pollution, realize the source of emission reduction. Through the repair of groundwater damaged pipe network, upgrading and renovation of eight pumping stations and pumping station storage tanks, construction and renovation of sedimentation tanks and water storage type ecological filter, etc., to enhance the mixed flow of rainwater sewage precipitation and purification capacity, to provide a clean water source through the Purple River. Siltation and dredging, revitalization of water body internal source. The dredging project is carried out by dredging boats, and 370,000 cubic meters of silt is cleared from the 8.4-kilometer-long river channel, which is used as planting soil after secondary treatment; and a willow leaf gate is built to connect the river with the Yuanjiang River and the city's inner lake, Willow Leaf Lake, which revitalizes the water source of the river and realizes the renewal of the water body. Construction of ecological barges to enhance biodiversity. Instead of traditional piers, ecological barges are used to form a vegetation buffer zone in the barge area to filter sediments from surface runoff; ecological floating islands are set up in the areas of river bays with low water flow rates and in the areas near the drainage outlets of the drainage pumping stations to enhance the purification function of the water body; filter-feeding fishes, carnivorous fishes and benthic organisms are stocked, and 58,000 tails of fishes, such as local white chub, bighead carp and bighead carp are put in the area; 58,000 kg of snails and mussels are put in the area to establish a new water body. fish, insects and water birds ecosphere, optimize the biological population structure and enhance the stability of the natural ecosystem.

The third is to promote the comprehensive development, promote the realization of the value of ecological products. Relying on the restoration and management of through the purple river scenery belt, to promote the combination of natural landscape and human landscape, help ecological product value realization. In the north bank to build German style street and Mayang Street, Xiaohe Street, Dahe Street and other characteristics of the street, the formation of catering, clothing and other characteristics of the commercial district, to enhance the economic value of ecological products. Using the pedestrian bridge to connect the north and south banks of the river, a 5.5-kilometer waterfront trestle on both sides of the river and five riverbank viewing platforms have been built, and musical live performances such as Changde Silk String, Folding Opera, and Liu Hai Chopping Woodcutting have been laid out at various points along the river to form a historical and humanistic landscape, publicize the local cultural characteristics, and realize the cultural value. To open up the river water system, connecting the river with Lake Baima and Lake Liuye, opening up 45 kilometers of round-trip waterways, 14 piers, opening up "water buses", and constructing the first water tourism line in Changde City, promoting the development of eco-tourism. Relying on the good ecological environment after remediation and restoration, it attracts business enterprises to move in and builds a number of residential districts and business-housing complexes, realizing the value spillover of ecological products. In the development of "business, tourism, residence" industry at the same time, the planning and construction of the wedding industry park, to explore the value of ecological products industrialization, diversified ways to achieve.

(C) the main results

First, the ecological environment continues to improve. After comprehensive management, through the purple river basin flood storage capacity significantly enhanced, in July 2016 and July 2017, in the 24-hour cumulative rainfall are greater than 177.8 millimeters extreme value of the situation, Changde City, urban areas without large areas of water, through the purple river basin without waterlogging occurs. At the same time, through the purple river water quality, water environment, water ecology, water safety and other comprehensive enhancement, biodiversity and ecosystem stability increased significantly, through the purple river ecological filter pool water outlet at the chemical oxygen demand concentration than the water inlet fell by 59.6%, the river water quality from inferior V gradually restored to Ⅲ.

Second, the value of ecological products gradually highlighted. Along with through the purple river ecological restoration and management of the effectiveness of the emergence of the "water bus" project, the development of commercial industries along the river, through the purple river as the center of the Changde characteristics of the gradual formation of tourism routes, interruptions of nearly 40 years of through the purple river channel can be restored through the purple river on both sides of the river, culture, tourism, entertainment and other related industries to achieve an annual income of more than 30 million yuan. The annual income of cultural, tourism, entertainment and other related industries on both sides of the river is more than 30 million yuan. Relying on the good ecological environment of through the purple river, drive the comprehensive development of the coastal business district and high-grade residential, realize the ecological benefits and economic benefits of **** win.

The third is to improve the living environment, residents' sense of well-being continues to improve. Through the purple river from the stink of the "stink ditch" into a public walk, relaxation and recreation of the "city center green park", the optimization of water quality, climate improvement in Changde City, the quality of urban habitat has been significantly improved. City residents have good ecological products at the same time, you can also enjoy the "water culture", "water industry" produced by the ecological dividend, the formation of a green development and livability of the harmonious pattern of mutual integration.