加州奥兰治县低影响开发：实施和评估中的挑战与对策

Implementation of Low Impact Development in Orange County, California: Challenges and Solutions in Implementation and Assessment of Progress

本文首先介绍美国加利福尼亚州奥兰治县从严重破坏自然溪流形态、栖息地和水质的粗放发展方式,转向平衡城市开发前后水文特征和自然环境的低影响开发历程;然后总结奥兰治县在实施和评估低影响开发绩效方面的逻辑框架和创新方法。奥兰治县通过参与区域低影响开发项目评估研究、制定低影响发展指导文件、创造评估低影响开发性能的系统框架,将低影响开发的实施和评估标准化,而在低影响开发受限区域则利用水质信贷交易建立替代性项目。本文通过对两个实际案例(格拉塞尔园区评估项目和莱格西园区水质交易项目)的分析,认为低影响开发设计前的场地调查、模拟和监测工作,实施后的标准化监测和数据共享,以及灵活的水质交易机制是低影响开发项目成功的关键。奥兰治县经验可为中国城市进行低影响开发实施和评估提供方法借鉴。

This paper discusses Orange County＇s transition from a conventional urban development approach that resulted in significant damages to natural stream morphology, habitat, and water quality to a more balanced approach that attempts to balance predevelopment and post-development hydrology to protect these resources. It then summarizes the framework and innovative approaches being undertaken to implement and assess the Low Impact Development（LID） in Orange County. Participating in the regional study to understand the effectiveness of LID, Orange County has developed guidance documents and created a systematic framework to assess the LID performance. These are aimed to standardize the LID approaches and develop alternative compliance program through water quality credit trading in the LID-restricted areas. Through two case studies, Glassell Campus Stormwater LID Retrofit Project and Legacy Campus Water Quality Credit Trading Program, we find out key factors to the success of LID implementation include： the site survey, modeling, and monitoring prior to the project design; the post-project standard monitoring and data sharing; and the flexible water quality credit trading system. China can potentially learn from Orange County＇s experiences for its implementation and assessment of LID.