"Quack quack ......" in the center of Fengxi New Town green corridor flocks of ducks are happily playing in the pond, the pond around the grass and trees verdant, the terrain undulating and scattered, a beautiful ecological picture is refreshing, here is not only a good place for citizens to relax and entertain, but also a huge "sponge".
"Heavy rain does not waterlog, light rain does not wet shoes. It is the personal feeling of every Fengxi resident. In April 2015, Fengxi New Town became the first batch of sponge city construction pilots in the country and the only one in Northwest China, and innovatively implemented the "four-level rainwater collection and utilization system" to effectively alleviate urban waterlogging, reduce urban runoff pollution load, save water resources, and make the city "breathe".
Walking on the streets of Fengxi New Town, the original large square and hard pavement have been broken down into pieces of "small sponges", the rainwater inlet has been transformed into a sinking mud well, the grass and trees planted in the concave green space are lush, and the green belts on both sides are undulating and meandering, which is quite wild.
"We have laid ecological grass ditches lower than the road surface in the green belt on both sides of the road, bypassing the trees in an S-shape, and collecting 85% of the road surface rainwater to the green belt on both sides for filtration, detention and infiltration. When it rains, the rainwater is discharged into the municipal pipe network through an overflow well in the ecological grass ditch. Even if there is heavy rainfall, it can also rely on the storage pond outside the red line of the road to carry out the storage and staggered peak to alleviate the water on the road. Zhang Zhe, director of the engineering department of the Sponge City Technology Center of Fengxi New Town, is quite proud of this.
In the construction of sponge city, Fengxi New Town has innovatively proposed methods such as "building plots to ensure that rainwater is collected, municipal roads to strengthen water collection functions, landscape green spaces to optimize vertical design, central stormwater system to form a storage hub, and river restoration to increase natural waters", and to treat rainwater in a variety of ways, such as "infiltration, detention, storage, purification, use, and discharge".
Zhang Zhe said that Fengxi New Town has also built different types of small sponge facilities, replacing the traditional underground drainage pipe network with grass planting ditches, water storage gardens, concave green spaces, green roofs, etc., and paving park roads with permeable bricks made of construction waste, forming a four-level rainwater collection and utilization system of building communities, landscape green spaces, municipal roads and central green corridors. Among them, the building community solves the problem of rainwater source absorption, the landscape green space is used as a regional-level rainwater storage hub space, the municipal road solves the process control and the transmission function of rich rainwater, and the central green corridor collects and stores excess rainwater in the whole area, effectively realizing the "source reduction, process control, end control, and three-water integration" of rainwater, and minimizing the impact of urban development and construction on the natural and ecological environment.
After several years of research and practice, the sponge city construction of Fengxi New Town has formed a set of systematic, replicable and promotable models, and has more than 40 intellectual property rights. The sponge city pilot passed the national acceptance, and the construction experience was selected into the national propaganda film and unveiled at the Paris Climate Conference.
At present, Fengxi New Town has built 3.9 million square meters of sponge parks, more than 110 kilometers of roads, 3.8 million square meters of parks and green spaces, with a cumulative promotion area of more than 20 million square meters, the rainwater runoff control rate has reached 86.5%, the rainwater resource utilization rate has reached 12.64%, and the underground diving level has risen by 3.43 meters. During the same period, the average temperature in the pilot area of the sponge city construction in Fengxi New Town was about 2°C lower than that in the adjacent areas, and the goal of "no water accumulation in light rain, no waterlogging in heavy rain, and alleviation of heat island" has become a reality.