Green Infrastructure Planning
In Green Infrastructure, rain and irrigation water is held on site as long as possible to be absorbed into the ground rather than allowed to runoff into streets and onto storm drains and creeks picking up pollutants along the way.
Green Infrastructure (GI) is an infrastructure design approach that uses vegetation, soils, and natural processes to manage stormwater and create healthier urban environments. At the county or city level, it refers to the patchwork of natural areas that provide habitat, flood protection, cleaner air, and cleaner water. At a neighborhood level, or project site, applying GI means managing stormwater systems and features so as to mimic wetland processes by absorbing, filtering, and storing water on site.
Green Infrastructure incorporates the use of resilient, sustainable landscape features and methods. Bioswales are used to slow, filter, harvest, infiltrate and/or evaporate rainwater runoff utilizing engineered soil and plants, ranging from grasses to trees. Paving systems, such as interlocking concrete pavers, porous asphalt, and pervious concrete allow water to seep into the ground. Rainwater harvesting systems like cisterns and rain barrels, and other methods to capture and treat stormwater may also be used. These types of practices are also known as Low Impact Development (LID) site design and treatment measures.
Green Infrastructure is a “multi-benefit” stormwater treatment solution. That is, it provides benefits beyond water quality improvement and groundwater replenishment, including: creation of attractive streetscapes, reduction of the heat island effect, bicycle and pedestrian accessibility, clean air, climate change resilience and mitigation, community.
Municipal Regional Stormwater Permit Provision C.3.j. requires most Bay Area municipalities to complete and implement a Green Infrastructure Plan for the inclusion of Low Impact Development drainage design into storm drain infrastructure.
Each Green Infrastructure Plan will describe how, over the long term, the municipality will shift their streets, roads, storm drains, parking lots, and building roofs from conventional “gray” storm drain infrastructure—where runoff flows directly into storm drains and then to creeks and the Bay/Delta—to a more resilient, sustainable system that slows runoff by dispersing it to vegetated areas, promotes infiltration, and uses bioretention to clean runoff. The Plan will also describe how implementing Green Infrastructure will help meet load reduction targets for mercury and PCBs entering the Bay/Delta.
The municipalities’ Green Infrastructure Plans must be submitted to the San Francisco Bay Regional Water Quality Control Board by September 30, 2019. Each municipality has adopted a framework for completing their Plan by that date, including tasks and timeframes.
Required Green Infrastructure Plan elements include:
- Targets for the amount of impervious surface to be retrofitted by 2020, 2030, and 2040
- Prioritized projects and areas for potential projects for implementation
- Process for tracking and mapping completed projects
- Updates to planning documents (General Plans, Storm Drain Master Plans, Complete Streets Plans, etc.)
- Design guidelines
- Standard specifications and details
- Evaluation of funding options
- Policies and ordinances needed to implement
- Outreach and education
Municipalities must also review their current infrastructure projects, identify and prioritize where Green Infrastructure can be included as part of these projects (“no missed opportunities”), and include a workplan for completing prioritized projects.