北京城市绿地生态系统调蓄雨水径流的时空作用规律及其调控对策研究

In recent years, many cities in China have been suffering from water logging disasters, and how to effectively cope with urban flooding has been paid great attentions. At present, to built more and more rainwater-drainage systems seems to become the best pathway. The major purpose of this research is to investigate the driving mechanism and spatio-temporal characteristics of urban green areas on rainwater runoff storage, subsequently utilize them to reduce urban flooding by the optimization of green spaces. There are three steps will be conducted. Firstly, this project will adopt multi-period TM images and meteorological data to explore the spatial-time patterns of rainwater runoff and green spaces in Beijing, and analyze the relationship between urban flooding risk and urban impervious lands. Secondly, based on the inventory data of urban green spaces, as well as classics ecological filed theory and GIS techniques, we develop an eco-service filed model of urban green area on rainwater regulation, and analyze the change of rainwater storage provided by urban green spaces in a year and theirs spatial characteristics in Beijing built-up area. Finally, the optimization strategies for urban green spaces will be proposed to alleviate rainwater runoff and reduce urban flooding, which including the spatial distribution, community structures and landscape design of urban green spaces. This study will extend the research view of urban water security and ecosystem services research, improve present evaluation method and propose an ecological strategy for water logging alleviation and rainwater resource utilization.

近年来，逢雨必涝已成为我国许多城市的通病，而一味提高排水系统标准似乎成为应对城市内涝问题的最佳途径。本研究应用多时期遥感影像和气象站点数据，研究近十年北京城区绿地景观与雨水径流的时空变化特征，分析绿色空间减少与内涝风险增加的关系；然后基于2010年北京城区园林绿地调查数据，应用生态场理论和GIS空间分析技术，构建绿地调蓄雨水功能场模型，定量解析绿地调控雨水径流的作用机理及其场空间特征；在明确北京城区雨涝驱动机制与绿地调蓄径流功能基础上，通过优化调整绿地资源的空间布局、群落结构和景观设计，提升绿色空间调蓄雨水功能的场效应，促进城市雨水径流的生态调控。该研究有助于拓展城市水环境安全与生态服务功能研究视角，改进经典生态功能评估技术，同时为城市内涝缓解和雨水资源利用探索一条生态学途径。

近年来逢雨必涝成为我国许多城市的通病，而不断提高排水系统标准似乎成为应对城市内涝问题的唯一手段。该项目基于北京市遥感影像数据和典型样地水文观测实验，综合利用GIS技术与景观生态学方法，分析了2000-2010年北京城区绿色空间格局变化，定量解析了绿地调蓄雨水径流功能特征，并探讨了提升绿地滞蓄雨水径流功能的景观格局优化途径。2000-2010年北京城区绿色空间面积缩减207 km2，主要是大量农田和水域被改变为城市建设用地，尤其是5-6环之间最为严重，4环内绿色空间较为稳定；绿色空间斑块数量和形状指数均持续增大，空间邻近度、聚集度和结合度指数均显著减小，城区绿色空间破碎化趋势明显。北京城区绿地年均调蓄雨水径流1.54亿m3，接近北京市每年生态景观用水总量，不过2000-2010年期间，城区绿地调蓄雨水功能明显下降，雨水径流滞蓄率下降6%；北京城区绿地控制雨水径流能力由内环向外环降低，5-6环内绿色空间滞蓄雨水径流功能最高，滞蓄雨水径流率高达22%-32%，2-3环内滞蓄雨水能力最低，需要重点加强暴雨内涝防治。绿地调控雨水径流能力不仅与绿地组成类型有关，也与绿色空间斑块的聚集度指数和最大斑块指数有较强正相关关系。只有当城市内绿色空间有较好的连通性和较大面积时，才能保证绿色空间缓解内涝功能的充分发挥。因此，北京城市绿色空间建设不应仅停留在简单的“点线面”几何学或美学的考量，而是需要在增加立体绿量的基础上，强调绿色空间网络的自然本底，优化绿色空间格局，持续稳定的发挥生态服务功能。该研究探讨了绿地景观格局对雨水径流调控功能的影响，为缓解城市内涝和利用雨水资源探索出一条生态学途径。