After You Have Built Your LID Project, What Comes Next?
Presentation Overview: This presentation aims at sharing the experiences and lessons learned from a low impact development (LID) demonstration project on contractor management, performance assessment, operation and maintenance, and public education/outreach. The topic addresses the theme of the conference, ‘CASQA in the Capital: Building Bridges for Water’ and is congruent with CASQA’s vision of improving the efficiency and effectiveness of stormwater management. This topic should be of great interest to all LID practitioners.
Project Overview: To showcase leadership and commitment to stormwater quality and to demonstrate the feasibility of completing a complex stormwater retrofit, OC Public Works, County of Orange (County) received a $2.9 million Proposition 84 stormwater grant and recently completed construction of the Glassell Campus Stormwater LID Retrofit Project (Project) at its 9.4-acre office-warehouse complex. The County provided $1.7 million in matching funds and coordinated the design, construction, and project management. The Project was designed to achieve 100% stormwater treatment and 85% retention for the design storm (up to 0.85 inch of rainfall in a 24-hour period) through a wide range of LID best management practices including cisterns, permeable paving (pavers, asphalt, and concrete), bioswales (with native and drought-tolerant plants), flow-through planters, modular wetland, and tree box media filters. Placed strategically within the Project site, these LID best management practices collectively remove 95% of the pollutants, capture more than 80,000 gallons of stormwater for each major storm event for onsite irrigation, and recharge stormwater to the regional groundwater aquifer.
Lessons Learned: Being a unique demonstration project with nearly all types of LID best management practices, this project is the first such project for the County’s project management team, the contract design firm, and the contract construction firm. County’s internal coordination among different departments as well as external coordination with contractors and LID manufacturers have proved challenging. The design, construction, contract management, and post-construction maintenance stages all experienced unique issues. Several illuminating examples will be given and the audience will be engaged to provide additional examples.
Next Steps: The completion of the Project construction marked the start of post-construction maintenance; monitoring and performance assessment; public education and outreach; and stormwater research. The County is committed to continuing these post-construction tasks for up to 20 years and far-reaching partnerships with local municipalities and agencies, environmental groups, and research institutions have been established. A competent contractor with extensive LID experience has been retained to perform LID maintenance. Monitoring will be conducted for all LID features, with differential maintenance frequencies, in collaboration with Southern California Stormwater Monitoring Coalition (SMC) to assess LID performance linked to design parameters. All data will be reported to California Environmental Data Exchange Network. The education and outreach program includes brochures, educational video, web pages, and a dedicated walking tour with educational panels. Over 30 groups and more than 300 individuals have toured the Project, including K-12 and college students, the general public, researchers, and governmental and private sector stormwater practitioners. Controlled stormwater research will be conducted on a series of biofilter test cells and other LID features to test their effectiveness in removing stormwater pollutants, especially fecal indicator bacterial and pathogens. It is currently part of two National Science Foundation projects, a University of California project, and an SMC project, with a total research funding of more than $7M.
Jian Peng, PhD is the Chief of Water Quality Planning Section at OC Environmental Resources, OC Public Works, County of Orange. He manages the county-wide total maximum daily load programs. He received his PhD in marine geochemistry from the University of California.
Chris Crompton is the manager of Water Quality Compliance Division at OC Environmental Resources, OC Public Works, County of Orange. He manages county-wide water quality compliance activities including total maximum daily loads and stormwater programs.