老城区因建筑密度高等特点，是内涝的高发地带。针对这一问题，基于SWMM模型中的LID（低影响开发Low Impact Development）模块，研究选取渗渠、渗透铺装、雨水桶和生物滞留网格4种措施，在不同重现期设计暴雨情景下，对不同布设比例（0.1%~15%）的LID措施进行模拟分析，寻找最佳布设比例。最后将几种最佳比例组合，对组合优化进行初步探索。模拟结果表明，几种LID措施布设在达到某一比例后，对不同重现期设计暴雨的削减作用会减缓，此时的布设比例即为所求最佳比例；而组合方案由于受到措施间的相互作用等因素影响，不能直接套用单项措施最佳比例，其优化仍有待研究。

The urban water logging takes place in the old city area frequently because of its high density of buildings and other characteristics of construction. Responding to this problem, this study used the LID module in SWMM model and chose Infiltration Trench, Permeable Pavement, Rain Barrel, and Bio-Retention Cell for simulation and analysis. We placed different proportions of LID measures (0.1%-15%) on the study area in design storm conditions with different return periods, so as to find the optimal proportions. At last, we combined these proportions to tentatively explore combination optimization. The results showed that the LID measures’ effect on design storms would diminish after their layout reached a certain proportion, which should be the optimal proportion. But the optimal proportions of individual measures cannot be directly applied to the combination scheme because of the interaction between individual measures. The combination optimization still needs further study.

中国工程院重大咨询研究项目（2015-ZD-07）；国家自然科学基金资助项目（41471015）