气候变化与人类活动背景下城市极端暴雨的水文响应

Hydrological Response of Urban Extreme Rainstorm under Climate Change and Human Activities

摘要: 郑州7•20特大暴雨涉及的水文科学问题是气候变化与人类活动背景下城市极端暴雨的水文响应。本文从气候变化与雨洪的“高置信度”联系、极端暴雨仍遵守降雨径流规律、定义城市极端暴雨重现期的难度、城市设计暴雨分析方法的异同和融合、海绵城市与水文循环和极端暴雨情景下洪涝应急体系的水文应对6个方面论述了城市极端暴雨的形成原因、分析难点和应对关键，并得出如下结论：1) 气候变化是城市极端暴雨的气候尺度背景，是否考虑气候变化，极端暴雨的产汇流原理并无不同之处，城市暴雨灾害涉及的科学问题是水文循环的基本问题，核心是理清直接人类活动背景下不透水面积增大、调蓄场所减少等的产汇流规律。2) 市政排水与水利排涝的面雨量重现期计算方法不一，可通过重现期衔接关系、地区线性矩估计等技术手段进行融合；参照江河防洪标准，选用典型年进行排涝设计也是较实用的选择。3) 从国家水网的高度来重新认识城市洪涝防治，以自然河湖为基础，引调排水工程为通道，调蓄工程为节点，重点要加强水系连通，增加大容量调蓄设施，开发城市水系智慧调度与管理系统，提升应对措施极端暴雨的预报预警能力。

Abstract: The hydrologic problem with respect to the 7•20 torrential rainstorm in Zhengzhou city was the hydro-logic response of urban extreme rainstorm under climate change and human activities. This paper dis-cussed the causes, and analyzed the difficulties and countermeasures of urban extreme rainstorm from the following six aspects, i.e., the “high confidence” relationship between climate change and rainfall and flood, extreme rainstorm still following the law of rainfall runoff, the difficulty of defining the return period of urban extreme rainstorm, the similarities, differences and integration of urban design rainstorm methods, sponge city and hydrological cycle, and hydrological response of flood emergency system under extreme rainstorm. The main conclusions are as follows: 1) climate change is the climate scale background of urban extreme rainstorm. Whether climate change is considered or not, there is no difference in the production and concentration principle of extreme rainstorm. The scientific problems involved in urban rainstorm disaster are the basic problems of hydrological cycle, and the core is to clarify the runoff generation and concentration law with increase of impervious area and decrease of regulating structure under human activities. 2) The calculation methods of areal rainfall return period of municipal department and water conservancy department are different, which can be integrated by technical means such as return period connection relationship, regional linear moment method and so on. It is also a practical choice to select typical year method for drainage design with reference to river flood control standards. 3) From the perspective of the national water network to reconsider the prevention and control of urban flood is necessary. Based on natural rivers and lakes, diversion, drainage, regulation and storage projects as channels and nodes, respectively, it is desired to strengthen the connection of water systems and to increase large-capacity regulation and storage facilities, as well as developing the intelligent operation and management system of urban river network and improving the prediction and early warning ability of extreme rainstorms.