Balancing Permit Requirements, TMDLs, and the Nexus between Green Infrastructure Plans and Stormwater Resource Plans for the San Francisco Bay Area: City of Dublin Case Study
Cities have challenges and opportunities related to implementation of green infrastructure and multiple benefit projects. In the San Francisco Bay Area, this includes implementation of green infrastructure that can achieve permit goals related to load reduction of pollutants addressed by Total Maximum Daily Loads (TMDLs) and identifying potential opportunities for implementation of multiple benefit projects that can be incorporated into a Stormwater Resource Plan. City of Dublin has begun to examine the integration between these implementation objectives.
The San Francisco Bay Area Municipal Regional Permit (MRP) provision C.3.j. requires permittees to develop a Green Infrastructure Plan, to be submitted with the 2019 Annual Report. The MRP requires a number of components to be included in the Green Infrastructure Plan, including but not limited to: a mechanism to prioritize and map areas for potential and planned projects for 2020, 2030, and 2040 (consistent with assessing load reductions specified in Provisions C.11 and C.12); outputs from the selected mechanism; and targets for the amount of impervious surface (public and private) to be retrofitted within the identified time frames (i.e., by 2020, by 2030, and by 2040). A framework or workplan which outlines the purposes, tasks, and timeframes to complete the elements described in the Green Infrastructure Plan must be approved by the permittee’s governing body by June 30, 2017.
Preliminary targets for public impervious surfaces to be retrofitted by the identified timeframes to meet the requirements were calculated for input into the Green Infrastructure Framework for the City of Dublin. The City of Dublin spatially identified all public and private green infrastructure projects that had been installed since 2002 or were planned to be installed before 2040. City of Dublin Specific Plans and the General Plan were identified geospatially and assumed to represent future green infrastructure installations for the purposes of calculation. All existing, planned, and future projects were mapped using GIS and categorized by completion dates. The San Francisco Bay Area Interim Accounting Methodology was utilized to calculate the load reduction attributable to each project. Based on the total load reduction calculated for each timeframe, the remaining impervious area retrofits required to achieve compliance with MRP and/or TMDL goals was calculated.
Following this calculation, a GIS-based green infrastructure opportunity analysis was conducted to identify potential locations for public green infrastructure retrofit locations. Rights of way, parcel, and regional based projects were identified. Utilizing prioritization parameters provided by City of Dublin, identified projects were prioritized based on calculated potential load reduction and other City goals. Planning level cost estimates are also prepared to identify the potential financial implications of implementation of green infrastructure to meet the load reduction requirements for the City.
In addition to the Green Infrastructure Plan analyses, City of Dublin is examining the potential to integrate their Green Infrastructure Plan with a Stormwater Resource Plan for the City. A comparison of the Green Infrastructure Plan requirements and the Stormwater Resource Plan requirements is being conducted to examine the additional components needed to prepare a Stormwater Resource Plan.
This presentation will discuss City of Dublin’s approach to preparing and planning for their Green Infrastructure Plan and longer term Green Infrastructure Implementation goals and will describe the methods conducted to assist the City and the results of those analyses. Additionally, the presentation will describe the findings of the comparison between the Green Infrastructure Plan and Stormwater Resource Plan requirements, and the City of Dublin’s decision relative to developing a subsequent Stormwater Resource Plan.
Shannan Young is a stormwater, pollution prevention, and sustainability professional with 20 years’ experience in the public sector. Shannan started her career with the City of Hayward in Water Pollution Source Control and worked for the Union Sanitary District and the City of Fremont, managing NPDES stormwater requirements. Shannan is the Environmental Coordinator for City of Dublin, serving as the Stormwater Program Manager and leading the City’s energy efficiency, air quality, and Climate Action Planning efforts. Shannan has a BA in Biology from the University of California, Riverside and a Masters in Environmental Management from the University of San Francisco.
Kelly Havens, P.E., has eight years of experience in management and technical support of projects focusing on urban, industrial, and construction-phase stormwater management, including stormwater BMP sizing, design, and evaluation, NPDES permit compliance, and development of BMP technical guidance manuals. She received her B.S. in Engineering Geology and her M.S. in Civil Engineering from UCLA.
Austin Orr, EIT, has four years of experience providing technical support on stormwater management projects, including stormwater control measure design and monitoring, biological nutrient processing, and hydrologic modeling to regional stormwater mitigation projects and development of water quality control guidance. Austin received his B.S. and M.S. in Civil and Environmental Engineering from the University of Utah.