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Urban turf and green rainstorm more runoff is a source of water can not be ignored. To understand the mechanisms of urban green space rainwater harvesting water hydrology, full use of the green space rainfall, to establish turf rainwater collection system, to fully tap the potential of Greenland rainwater resources, and rainfall of three on the grass slope (0%, 10% and 20%), Runoff observations, analysis of the the runoff differences in slope and rainfall characteristics change, simultaneous analysis of of different slopes bare ground runoff change and different slopes biomass changes over time. In addition, the lawn Threshold Rainfall is an important parameter in understanding turf rainfall runoff process, but also recognize the turf rainwater harvesting potential design green rainwater collection system parameters. In this paper, in Fengtai District, Beijing, Luyuan Park 2006 rainfall - runoff observation test, the slope of the ground for four kinds of lawn rainfall runoff observation, to determine turf critical rainfall runoff threshold. The main findings are as follows: grass, bare land runoff efficiency increased with the slope increases, significant differences between the different slopes; the bare grass runoff significant differences; the the grass runoff by rainfall intensity (I), the largest 30 min rainfall intensity (I30) and the integrated rainfall index (PI30) significant influence of different factors determine coefficient the influence coefficient order PI30 gt; I30 gt; I. While bare by rainfall (P), I30, and PI30 significantly the influence coefficient order PI30 gt; I30 gt; P With the increase in rainfall, rainfall intensity, maximum 30 min rainfall intensity, rainfall index, etc., the the slope greater the runoff efficiency growth rate of the larger, and bare ground plot runoff efficiency growth rate is significantly higher than the grass. Proposed grass, bare ground runoff model by model analysis of grassland, the bare runoff is mainly influenced by rainfall Composite Index and slope, and runoff efficiency Composite Index and the slope of the rainfall was positively correlated. For grass, runoff influenced by the integrated rainfall index is greater than the slope, bare influenced by the composite index is less than the slope. Slope 0%, 5%, 10% and 20% of the turf, its critical runoff rainfall of 9.5 mm. Lawn ground, below-ground biomass with slope rising lower root to shoot ratio and slope no significant difference. For different Lawn coverage, runoff characteristics under different slope length, before the rain water content and other green space type conditions, as well as different lawn coverage before the rain water content under lawn critical rainfall runoff also need further test analysis study.
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