基于生态海绵流域视角的河湖联控方案研究——以湖南省凤凰县为例

Viewpoint of eco-sponge watershed based-study on river-lake system joint-control scheme——a case study of Fenghuang County in Hunan Province

海绵城市建设除了实施一系列低影响开发措施之外,还需通过河湖联控措施调丰济枯,实现保障径流总量控制率以及其他城市排水防涝安全、供水安全、生态安全等一系列涉水控制目标。基于生态海绵流域的视角,提出了海绵城市在建成区外和建成区内的建设思路以及相应的河湖联控策略:建成区外主要是做好城市防洪治涝的顶层设计,构建城市外围水安全保障体系,统筹考虑解决城市外围流域内的防洪安全、水资源、水环境、水生态等问题;建成区内以城市河湖为核心,科学安排、因地制宜进行城市海绵体建设,构建多尺度排水系统,弹性应对不同强度的降雨。以湖南省凤凰县为例进行了应用研究。结果表明,河湖联控方案实施后:(1)结合LID等其他海绵城市建设措施,凤凰县年径流总量控制率预期将达到82.9%,满足80%的目标要求;(2)凤凰县防洪排涝标准可以由目前的10年一遇提高到20年一遇的水平;(3)城乡供水保证率预期将达到98%,满足大于95%的目标要求;(4)雨水收集利用率预期将达到20%,满足大于10%的目标要求。可见,研究制定的凤凰县河湖联控方案在技术上是可行的,有效解决了凤凰县的防洪、水资源短缺和生态用水问题,为凤凰县的海绵城市建设提供了有力支撑和保障。

Except for a series of low impact development measures, it is necessary for sponge city construction to realize the guaranteed total amount of runoff control rate and a series of the other water-related targets, such as the safeties of urban drainage and water-logging control, water supply, ecology, etc. through the relevant measures of regulating the wet to supplement the dry with river-lake system joint-control. Based on the viewpoint of eco-sponge watershed, both the construction ideas of the sponge city for the inside and outside of the built-up area and the corresponding joint-control strategy for the river-lake system are put for- ward herein, i.e. it is mainly to make the top-level design of the urban flood and water-logging control well for the outside of the built-up area, so as to establish the water safety guarantee system for the urban periphery and make an overall consideration on solving the problems from the safety of flood control, water resources, water environment, water ecology, etc. within the water- shed of the urban periphery, while it is necessary to take the urban river-lake system inside of the built-up area as the core, so as to carry out the urban sponge system construction and construct multi-scale drainage system with scientific arrangement accord- ing to the local conditions as well as elastically deal with the rainfalls with various intensities. Therefore, an application study is made by taking Fenghuang County in Hunan Province as the case, from which the result shows that after the implementation of the joint-control scheme for river-lake system ： （ 1 ） combined with the other sponge city construction measures, including low im- pact development, etc. , the total amount of runoff control rate of the county is expectedly to reach to 82. 9%, and then can meet the target requirement of 80% ; （2） the flood control and drainage standard for Fenghuang County can be enhanced from the return period of 10 years to the return period of 20 years ; （3） the urban-rural water supply guarantee rate is expected to reach to 98% , and then can meet the target requirement of 95% ; （4） the rain-water collection and utilization rate is expectedly to reach to 20%, and then can meet the target requirement of over 10%. It is obvious that the river-lake system joint-control scheme of Fenghuang County studied and made herein is technically feasible, thus can effectively solve the problems from flood control, shortage of water resources and eco-water use in the county and then provide powerful support and guarantee for the sponge city construction of the county as well.