Mother river of Xiaoyi, Shanxi Province—Xiao River, was still classified as a polluted area in 2011 due to coal washing. Before this project was launched, 20 surrounding villages were haunted by serious haze pollution and the resulting diseases, and improving local environment was a burning issue.

By strictly adhering to the strategy of “prioritizing ecosystem and water conservancy, protecting the nature with the least human intervention and pursuing sustainable development”, ZEHO ECO took a scientific approach to protect and restore water bodies, landforms, biological resources, history and culture through wetland water dynamics simulation, wetland water treatment, aquatic plant restoration and bank ecological protection.

Flowing and floating landscapes: In wet spell, ponds, cascade springs and ecological islands are linked by water bodies in a continuous and flowing way. In dry spell, wetland ponds form in the rain collection area.

Landscaped water regulating system and water purifying system: The two systems are usually unnoticed in the scenic Shengxi Lake. The former is composed of settling ponds, spillways and Shengxi Lake reservoir, and the latter comprises settling ponds, subsurface flow wetlands and surface flow wetlands. The regulating system ensures the safety of the city in flood peak, and the purifying system works during a usual rainfall.

How the constructed wetlands work: We used mixed rain and sewage firstly processed by settling ponds as the water source, developed ponds in current pits and open space, and linked them with narrow watercourses to simulate a natural wetland habitat where plants and micro-organisms can remove oxygen-consuming and suspended substances, namely Nitrogen, Phosphorus, heavy metals, etc. Planted aquatic flora around wetlands such as Phragmites and Yellow Iris can provide a good habitat for aquatic fauna to reproduce and live and boost the mass reproduction of micro-organisms to decompose COD, BOD and other pollutants.

It is monitored that Shengxi Lake Wetland, a comprehensive water treatment system, can remove NH3-N by 47%, TN by 13%, TP by 15%, SS by 21% and decompose COD by 24% and BOD by 23%.

Ecological restoration and reconstruction

Woodland habitat: We preserved current woodlands for birds (e.g., magpie and sparrow) and terrestrial animals (e.g., pheasant and snake) to reproduce and live.

Stone bank habitat: Shengxi Lake is divided by stone blocks, between which fish and other wild animals can use as a diverse habitat.

Ecological corridor: The pedestrian bridges in Shengxi Lake Wetland Park are supported by hardened concrete pillars, and lawns are laid in the middle of and around the lake as a terrestrial animal corridor so that animals can move across.

Aquatic life habitat: The aquatic flora in Shengxi Lake allows amphibians, fish, birds and aquatic insects to hide and rest. The root systems of aquatic flora provide a living environment for micro-organisms to absorb onto and metabolize in.

After the ecological restoration, there are 189 species of wild animals of 24 orders and 55 families, among which there is a richer variety of birds, including 46 kinds of resident birds, 43 kinds of summer resident birds, 18 kinds of winter resident birds and 36 kinds of migratory birds. There are 4 types of first-class protected animals, namely Black Stork, Golden Eagle, Yellow-legged Buttonquail and Great Bustard, and 16 types of second-class protected animals, such as Whooper Swan and Merlin. We successfully built a wetland park which incorporates water conservancy, urban wetlands, ecological culture and folk tourist attractions. It is acclaimed as “The Kidney of Xiaoyi” and has been awarded the title of AAAA (4A) Tourist Attraction and Shanxi Provincial Tourist Resort.