城市化生态水文效应

Eco-hydrological impacts of urbanization

研究城市化的生态水文效应对于指导河流的保护与生态修复实践具有重要意义。基于河流径流情势在维持河道生态系统完整性方面的重要性,在分析现有生态水文指标体系的特征及可操作性的基础上,建立了以径流历时曲线、洪峰流量频率超出曲线和T0.5(区域径流超出天然状态下重现期为0.5年的降水所产生的洪峰流量的时间占区域有径流总时间的比例)为代表的生态水文指标体系。利用SWMM(Storm Water Management Model)来模拟不同城市化程度下的降雨径流过程,并利用所建立的生态水文指标体系模拟其生态水文效应。结果表明:城市化程度越高,其时段流量幅度及历时越大,洪峰流量及发生的频率越大,T0.5越小。城市化通过改变径流的大小、历时及频率,改变了水域生态系统完整性与多样性,进而对河道生态系统产生了负面影响。

Eco-hydrological impacts caused by urbanization are important issues in protecting and restoring river ecosystem.Given the importance of flow regime in maintaining river ecosystem integrality,an eco-hydrological indicator system including flow duration curve,peak flow frequency exceedance curve and T0.5（The fraction of the simulation period that the peak flow rate exceeds the peak flow of the predevelopment 0.5-year storm） were developed by analyzing characteristics of current indicators and their feasibility in data-lacking area.Urbanization development degrees and their eco-hydrological impacts were simulated in a hydrological model SWMM（Storm Water Management Model）.Results demonstrated that the higher imperviousness,the greater instantaneous flow,peak flow,frequency,duration and smaller T0.5.indicating a negative effect of urbanization on the river in ecology.