PURIFICATION-EFFICIENT-BASED HYDROECOREGION IN A LAKE OF IRRIGATION RETURN WATER, CHINA

摘要

Based on environmental monitoring data in 2012-2013, this paper analyzed the reduction processes of nutrients from inlet to outlet at the Ulansuhai Lake. A Purification Efficiency (PE) index was constructed to regionalize different lake zones. Results indicate that nutrients in the water body displayed an obvious decreasing trend from northwest to southeast and the PE index was varied in different regions around the lake. According to the results of the cluster analysis on PE indices, the entire lake area could be classified into three zones including high-efficiency zone (Zone I, PE ranges from 0.4-1.0 mg(Lkm)(-1)), mid-efficiency zone (Zone II, PE ranges from 0.2-0.4mg(Lkm)(-1)), and low-efficiency zone (Zone III, PE ranges from 00.2mg(Lkm)(-1)). In terms of management, for Zone I, bottom sediments dredging is necessary to maintain the high purification efficient of this zone.; for Zone II, biological cleaning is the primary treat due to the advantage from the dissolving function of the emerged plants to improve the purification efficiency; for Zone III, more work should be emphasized on the cleaning of submerged plants to create good ecological habitats for fishery industry. This work is significant to provide scientific evidence for the environmental assessment and management in terms of the lake eutrophication issue in the Ulansuhai Lake.