以北京北护城河周边区域为例,探讨了降雨和土地利用对地表径流的影响.选取了2011-2012年4-11月的15场降雨,分别代表小雨、中雨、大雨、暴雨、大暴雨和特大暴雨这6个雨量级.利用校准的雨洪管理模型(Storm Water Management Model,SWMM)分别模拟每次降雨事件下研究区7个控制断面的地表径流深度.结果表明,地表径流深度随降雨量的增加显著线性增加.当降雨量在不同量级之间变化时,地表径流深度的变化幅度不尽相同.在不同的降雨事件中,降雨量和地表径流深度随时间的动态变化趋势可能有很大的差异,但地表径流深度在某一时刻的值的高低均决定于之前1～2 h的降雨量,而地表径流深度的总体上升或下降趋势均决定于前期累积的降雨量.地表径流深度随渗透面积比例的增加显著下降,且变化曲线存在临界阈值(为15％～20％).在暴雨、大暴雨和特大暴雨时,渗透面积比例对地表径流的影响更大.研究结果可为控制汛期城市地表径流量和洪峰流量、减少城市内涝提供土地利用和管理方面的理论依据和决策建议.
Impacts of Rainfall and Land Use on Urban Surface Runoff: A Case Study of Area Surrounding the North Moat in Beijing, China
The study explored the impacts of rainfall and land use on surface runoff,taking the area surrounding the North Moat in Beijing,China,as an example.We selected 15 rainfall events occurring from April to November in 2011 and 2012,representing six rainfall levels,which were light rain,moderate rain,heavy rain,rainstorm,heavy rainstorm,and torrential rainstorm,respectively.Surface runoff depths during each rainfall event in the seven control sections were simulated using the calibrated SWMM (Storm Water Management Model).The simulated results showed that the modeled runoff depth significantly linearly increased with increasing rainfall.There were distinct variations in runoff depth when rainfall varied between different rainfall levels.Although rainfall and runoff depth might exhibit different dynamics over time during different rainfall events,runoff depth at each time was determined by rainfall in the previous 1-2 h,and the overall variation in runoff depth depended on the early cumulative rainfall.Runoff depth significantly declined with increasing permeability area ratio (PARO),occurring a critical threshold of 15％-20％ at control section scale.PARO had greater impacts on the runoff in rainstorm,heavy rainstorm,and torrential rainstorm events.The result can provide important theoretical basis and implications for catchment management and urban planning to reduce surface runoff and flood peak and avoid waterlogging disasters,which are very common in current China.
North Moat of Beijingrainfallsurface runoff depthpermeability area ratio
NETL
NSTL
万方数据
维普
