A Study On Time-space Series Change Of Ecological Factors Of Ecological Restoration Project Within Ziyang Lake

The pollution of lakes and reserviors is becoming more and more serious since the rapid development of economic, rapid growth of population and the accelerating pace of urbanization. Most city park lakes were polluted severely and eutrophication due to its speciality of environment and region. Hence its recreational value of landscape and ecology has been lost. As a new technology, ecosystem restoration is applied broadly. It reflected the philosophic thinking of harmony between human and nature that treated the polluted water through strengthening the self-purification capability of lakes.An ecological restoration project was carried on within Ziyang Lake, which is a small urban lake in Wuhan City. The lake was investigated from March 2008 to September 2009 and the relationship between environmental indicators and phytoplankton was discussed in this thesis. Although ranked at level I as one of the protection lakes in Wuhan, the monitoring results of Ziyang Lake showed that the water quality was ranged V grade and hypereutrophication before 2007. In order to improve the water quality, relevant departments launched ecological restoration in Ziyang Lake, mainly including pulltion preventation, aquatic vegetation planting and artificial wetland construction, etc. The objective of this article was to analyzed time sequence changes of water quality using physiochemical indexes and biological indicators throughout the period of the ecological restoration project. Based on the eutrophication assessment of Ziyang Lake, this paper focused on the indicators and its sensitivity responsed to the effects of the ecological restoration. Combined with the current eutrophication evaluation system, this study proposed a new water quality index for the assessment and diagnosis of shallow eutrophic lake ecosystem.The research results indicated that water quality of Ziyang Lake has been improved and the good basic stability belong to IV class standards of the surface water was obtained along with the ecological restoration project implementation. The dominant species of phytoplankton changed from large group algae into small individual algae, the state of eutrophication was improved as well. Follow the study on the effect of monitoring indexes of ecological restoration, a new method was proposed to diagnosis and evaluate the eutrophication state of shallow eutrophication lakes after the ecological restoration. The water quality index of lakes (LQI), as the major index of our assessment method, would be useful in diagnosis the effect of ecological restoration and management implementation for the shallow eutrophic lakes.