Application of in-situ restoration combination technique for eutrophic water in Bailuwan Ecological Wetland Park

Abstract

Abstract Bailuwan Ecological Wetland Park with an area of 200 hm2, has been the first “National Urban Wetland Park” in Chengdu which is divided into A and B two zones. In zone A, as a window and image representative of the city, 50% recharge water in Daxuanhu Lake comes from Xiaoxuanhu Lake. The water eutrophication was serious with water blooms appeared in Xiaoxuanhu Lake in 2017. In order to repair the eutrophic water body, in-situ ecological restoration combination technology was applied. Thirteen kinds of plants, including submerged water, emergent water and floating leaf together with man-made wetland, submerged macrophyte, ecological floating bed and floating leaf plant were selected to construct as restoration system for Xiaoxuanhu Lake. The results showed that Xiaoxuanhu Lake water quality had improved significantly after restoration. The main physical and chemical indexes were up to the standard of III class of surface water from inferior V in one year’s operation. The annual average concentration of CODMn, TP, TN and NH3-N compared with influent decreased 10.4%, 67.7%, 25.1% and 25.6% respectively. The high quality water supply for Daxuanhu Lake was guaranteed in this way. The technique can be used in situ restoration of eutrophic water body in the ecological wetland park and ecological restoration of eutrophic water body in urban rivers and lakes.