建筑小区尺度下LID措施前期条件对径流调控效果影响模拟

以西咸新区天福和园住宅小区为研究对象，采用暴雨洪水管理模型（Storm Water Management Model，SWMM）构建含低影响开发（LID）措施调控作用的城市雨洪过程数值模型，模拟分析了不同重现期降雨下LID措施和传统开发情况在不同前期条件下的径流控制及峰值削减效果。结果表明:① LID措施自然状态、半饱和与饱和状态在不同重现期降雨下径流控制率分别为64.3%~83.2%、56.3%~76.5%和48.7~68.1%，与自然状态相比，半饱和与饱和情况径流控制率分别减少了6.7%~9.1%和15.1%~15.8%，且皆随重现期增大径流控制率减少值先增大后减小。②径流峰值分别为23.3~189.4 L/s、25.9~198.4 L/s和28.8~290.7 L/s，与自然状态相比，半饱和与饱和状态径流峰值分别增加了4.5%~20.9%和22.9%~53.4%，表明LID措施在饱和状态下的调控效果远不如自然状态。③相较于传统开发，LID条件下自然状态和半饱和状态对径流峰值削减显著，但饱和情况在降雨重现期20年时径流峰值反而升高，表明LID措施饱和状态在大暴雨情况对下游管网造成更大压力。④在相同前期条件下有LID措施对径流控制率有明显提升。

Effects of initial conditions of LID measures on runoff control at residential community scale

Low Impact Development (LID) measure is a type of sustainable engineering measure to solve the urban water problems. The runoff-control rate is considerably affected by the initial hydrological conditions. Through using Storm Water Management Model (SWMM) for Tianfuheyuan Residential Community in Xixian New Area,this work simulates the runoff control and flood peak reduction under different initial conditions for LID and traditional-development measures,respectively for a set of storms with different return periods. The results indicate that:① The runoff-control rates of natural,semi-saturated and saturated LID measures are 64.3%—83.2%,56.3%—76.5% and 48.7%—68.1%,respectively. Compared to the natural condition,the runoff-control rates in the semi-saturated and saturated conditions are reduced by 6.7%—9.1% and 15.1%—15.8%,respectively. As the rainfall return period increases,the reduction value of runoff-control rate increases at the beginning but then decreases. ② The runoff peaks are 23.3—189.4 L/s,25.9—198.4 L/s and 28.8—290.7 L/s,respectively for natural,semi-saturated and saturated LID measures. In contrast with natural condition,the runoff peaks of semi-saturated and saturated conditions increase by 4.5%—20.9% and 22.9%—53.4%,respectively,indicating that the runoff-control effect of LID measures in saturated condition is far lower than that of nature condition. ③ Compared to the traditional development,LID has significant improvement for runoff control rate. The natural and semi-saturated LID measures could significantly reduce the peak runoff,but it increases under the saturated condition with the rainfall return period of 20 years,showing that the saturated LID measures may lead to higher discharge in the sewer networks downstream for heavy storms. ④ Under the same initial conditions,LID measures are able to effectively improve runoff-control rate. The research can help investigate the practical effects of LID measures.