济南市城市暴雨洪涝灾害致灾机理分析与风险评价

With the rapid development of economics and society in China, urbanization developed very quickly during the past years. On the other hand, the impact of climate change on human society has becoming significant. Disasters resulted from storm floods increased year by year. Urban flooding has becoming a great disaster for the sustainable development of economics and society. Jinan City is located between the low mountains/hills in south/middle of Shandong Province and the alluvial plain in northwest of Shandong Province. It is just sandwiched between the hills in south and the Yellow River in north. Recently, urban floods frequently occurred in Jinan City, which is becoming a great threat for local people and society. On the demand from the construction of “sponge city” in China, and the scientific issues for urban flood generation mechanism, flooding disaster mechanism as well as flood control and disaster reduction, with the combination of regional features in Jinan City, the flood routing model for urban area with complex canopy will be developed in this study. The distributed hydrological and hydraulic model for urban storm simulation considering surface runoff, drainage pipeline, and weir/gate on river and lakes will be finally developed. With the combination of simulation results and risk assessment model, the area with high flooding risk will be identified. On the basis of Low Impact Development (LID) and “sponge city” concept, the innovative urban storm management measures will be proposed, and then the scientific support for the flood control and disaster reduction as well as the construction of “sponge city” in Jinan City will be formulated.

近年来，随着我国经济社会的快速发展，城市化进程不断加快，同时，气候变化影响不断加剧，暴雨洪涝灾害日益频繁，城市洪涝灾害已成为制约城市经济社会可持续发展的重大威胁之一。地处鲁中南低山丘陵与鲁西北冲积平原交界地带，南依群山、北临黄河的济南市更是深受城市暴雨洪涝之灾。本项目拟结合当前全国海绵城市建设的国家重大需求，针对城市产汇流机制、洪涝灾害致灾机理与防洪减灾对策等重大科学问题，以济南市为典型区域，从洪涝灾害的形成过程出发，结合济南市的区域特征，探索适用于城市下垫面特点的产汇流模型，开发能够综合模拟城市地表径流、排水管网、河湖堰闸工程运用的分布式水文水动力学城市暴雨洪水模拟模型。根据洪水模拟结果，基于风险评估方法和技术，识别洪涝灾害高风险区。基于低影响开发（LID）和海绵城市建设理念，结合情景分析技术，探索创新性的城市雨洪管理技术与措施，为济南市海绵城市建设和防洪减灾工作提供科技支撑。

城市化和气候变化背景下，城市暴雨洪涝灾害频发，严重威胁城市可持续健康发展。本项目围绕城市产汇流机制、洪涝灾害致灾机理与防洪减灾对策等重大科学问题，以济南市为典型区域，收集气象水文、排水系统、地理信息等数据，形成城市水文基础数据库；采用统计学方法，深入研究了济南市降雨径流规律；构建了山前平原区暴雨径流模型，定量分析了LIDs措施对洪涝过程的影响；构建了水文水动力多过程耦合的暴雨洪涝模拟与风险评估模型，对城市洪涝过程及其影响因素进行深入分析并评估了洪涝风险，基于海绵城市理念，对洪涝削减方法进行了研究分析。结果显示：①济南市降雨时空分布不均，最大与最小年最小年降水量相差达584.7 mm，夏季降水量约占全年60%，空间上由西南向东北递减，与地形特征关系密切；城市化使降雨形成及产汇流机制发生变化，年降水量和汛期降水量呈上升趋势，黄台桥以上流域径流量呈明显上升趋势。②考虑地形地貌差异引起的汇流方式和有关参数的差异可显著提高模型精度；LIDs措施对较低重现期降雨径流具有较好的控制效果，洪峰流量和径流总量削减率达65.23%和45.52%，而在较高重现期时效果较差。③耦合模型对历史洪涝过程的模拟效果较好；随着降雨重现期的增大，排水系统负荷和地表洪涝淹没增大，雨峰延后会加重这种趋势；不同雨峰系数间的差异随重现期的增大而减小，表明雨峰系数的影响随重现期增大而逐渐减小；物理机制法较好地呈现了示范区洪涝风险，但相关参数和阈值具有不确定性，应结合多种方法综合评估。④LIDs措施能有效控制低重现期降雨引起的洪涝，但重现期较高时效果不佳，LIDs与管网改造协同作用时对各种降雨均具有较好控制效果；上游布设LIDs、下游改造管网的海绵城市布局具有较好的洪涝控制效果，在不同地区应结合区域水循环特征因地制宜。研究成果揭示了济南市降雨径流变化规律，定量分析了城市洪涝过程及其影响因子，评估了城市洪涝风险并深入探究了洪涝削减方法，为济南市乃至全国的防洪减灾工作提供了科技支撑。