The Optimization Mechanism Of The Water Environment Based On Perspective Of Landscape Pattern

Along with the accelerating urbanization process, the alteration of landscape pattern not only affects the rainfall process of hydrologic cycle but increases degree of rainfall runoff pollution, which causes serious influence on urban ecological environment. Therefore, the analysis of relationship between urban landscape structure and the water quality of rain runoff is more and more significant.Hang Zhou city was taken as the research object along the Grand Canal water system in this paper. City development zone could be divided into the three spheres of different landscape structure. According to current standards, the land use pattern of each sphere includes land for construction, green space, water and other land use. Pollutants’concentration of each sphere was monitored in12selected rainfall of different rainfall intensity. The quality indicators of selected water are:SS, COD, Ammonia Nitrogen, Total Phosphorus.Based on the above work, the paper first discussed the characteristics of landscape pattern in different spheres and analyzed the change rules of landscape pattern. It was found that Number of Plaques and Fragmentation had increased dramatically from rural areas to urban built-up areas. The Largest Patch Index and Plaque Connectivity reduced. The patch area of land for construction increased, and green land decreased. Plus, the thesis discussed and analyzed quantificationally that pollutant concentration of each sphere changed with the time under different Rainfall Intensity. The researches show that the pollutant concentration, under large and moderate Rain Intensity, can be kept stably at the lower level in the rain late. The SS and COD concentration is the highest in urban built-up areas and the lowest in rural areas. Ammonia Nitrogen and Total Phosphorus concentration is the highest in urban-rural fringe and the lowest in urban built-up areas and rural areas. Finally, the correlation between Landscape Pattern Index and Average Concentration of Rainfall Runoff Pollutants were analyzed. The relationship between Landscape Index and Runoff Water Quality Index were explored. Combined with the actual situation, some suggestions on optimizing the landscape pattern in different spheres will be provided to make more scientific and reasonable city planning and construction.