Constructed Wetlands In Spatial Planning And Urban Stream Repair

Nowdays more and more people have recognized the value of wetlands in China. Meanwhile the constructed wetlands (CWs) have boomed up since the year 2000. These projects roughly fall into two categories-1) the subsurface flow CWs that target the water quality improvement and are funded and implemented by environment or water sectors;2)the wetland parks that pay most regards to educational, landscaping and recreational values rather than specific water quality standards, most of which are designed by landscape architects.However, neither of the two categories of CWs are aimed at the flood control and stormwater management. This thesis proposes a system of CWs and step by step planning process, which aimes at urban stream repair and stormwater management. 9 types of CWs were summarized and classified by analyzing the CW strengths among the techniques in urban stream repair. More types are to be generated if 2 or 3 types are combined in usage, which are encouraged in application due to a better treatment performance. 4 CW cases were presented in terms of land requirement, flow path, layout, treatment performance and etc., through which urban planners are able to acquire a common sense of CWs in a short time and cooperate with specialists from relevant fields. In sizing the stormwater wetland, a curve showing the relationship between annual pollutant load reduction and stormwater wetland surface area was obtained by using computer simulation. Simulation results were finally applied into urban design at the lower reaches of River Hai. The application results show that CWs can well be incorporated into urban open spaces and shall be planned with the urban planning process at its related level.