The Central Wetland in Gaocheng district is appointed to have an important function in both improving the water quality and retaining water during peak runoff. Analysis of the situation shows two major flows of water crossing in this area. One is the constant flow from Fan Gao river in the west towards Gaocheng river and lake Tai Hu in the east. This water is quite heavily polluted, class V, and the ambition is to improve the quality to class IV. The other flow of water is the net flow from lake Ge Hu in the north through the Yun Ai river towards lake Xijiu and the centre of Yixing in the south. This water is rated class IV, with the ambition to raise quality to class III.
We propose a smart solution in which we organize water to flow through the wetland in two sub-areas, but still be part of the same system. The first wetland sub-area serves as efficient ecological filter to improve Fan Gao river water quality to class IV. In the north eastern corner this water is then combined with the water from lake Ge Hu to either go east as class IV towards lake Tai Hu, or to go south through the other sub-area of the wetland as ecological filter to reach class III and serve as a clean water source for Yixing City.