The Contra Costa County (County) Green Infrastructure (GI) Plan is a blueprint for how the County will add to and replace its “gray” infrastructure system of pipes and storm drains with “green” infrastructure or low impact development practices throughout unincorporated areas over the next two decades. The GI Plan is a requirement of the National Pollutant Discharge Elimination System (NPDES) Municipal Regional Stormwater Permit (MRP), issued by the San Francisco Bay Regional Water Quality Control Board (RWQCB) on November 19, 2015.¹ The County is among 76 other municipal “permittees” in the SF Bay Area who have developed long-term GI plans to show how they will move away from traditional stormwater infrastructure and toward green stormwater infrastructure. By doing this, the Permittees will mitigate some of the impacts of urbanization on water quality to the creeks and waterways in the San Francisco Bay Area, and ultimately to the San Francisco Bay Estuary itself. In addition to improving water quality, GI will serve to offer a myriad of environmental, place-making, and community benefits, such as: increased green space, potential for carbon sequestration opportunities, mitigation of urban heat island effect, reduction of localized flooding, and enhancement of bicycle and pedestrian facilities.
1 Order No. R2-2015-0049.
“Tactical” Green infrastructure installation by Urban Tilth volunteers along the Richmond Greenway in Unity Park on Martin Luther King Day, 2018 (photo by Nathan Bickart)
What is Green Infrastructure?
Green Infrastructure (GI) refers to constructing and retrofitting storm drainage systems to mimic natural processes by enabling stormwater to infiltrate the soil rather than to runoff into storm drains and pipes. This relatively new approach is being used to reduce runoff volumes, disperse runoff to vegetated areas, harvest and use runoff where feasible, promote infiltration and evapotranspiration, and use bioretention and other natural systems to detain and treat runoff before it reaches tributary creeks and, ultimately, San Francisco Bay. GI facilities include, but are not limited to: pervious pavement, infiltration basins, bioretention facilities, green roofs, and rainwater harvesting systems. GI can be incorporated into construction of new and redeveloped parcels, roads, and other infrastructure within the public right-of-way (ROW).
El Cerrito Plaza BART Station rain garden
Green infrastructure benefits communities in a number of important ways. As well as being a cost-effective and resilient approach to water infrastructure, implementation of green infrastructure in neighborhoods and common areas of the community provides residents with emotional and physical health benefits, opportunities to enjoy outdoor living spaces, and an improved quality of life.
|Breathing ground level ozone and particulate pollution can cause respiratory ailments including chest pain, coughing, aggravation of asthma, or worse. More green space and parks encourage outdoor physical activity, assisting in weight management and the prevention of chronic diseases.|
|Green infrastructure’s focus on vegetation and trees improves publicly available recreation areas, allowing urban communities to enjoy greenery without leaving the city. Such measures can also reduce noise pollution by damping noise from traffic, trains, and planes.|
Strong Property Values
|The inclusion of green infrastructure strategies in home construction, as well as increased vegetation and tree cover, can increase property values through enhanced aesthetics and improved land use.|
|Sense of Place|
|The presence of a GI features, such as rain gardens, tree planter boxes, and the like, enhance the aesthetics of a road or parking lot and provides a window into nature with its calming and grounding influences.|
|Reduction of Localized Flooding|
|Larger scale and regional GI projects can serve to reduce the effects of flooding in a locality where the detention qualities of GI can serve to function as retention basins to mute the effects of flood incidents.|
Enhanced Bicycle and Pedestrian Facilities
|GI along roads can provide a buffer between car lanes and bicycle lanes, thereby protecting both cyclists and pedestrians. This protection encourages pedestrian and cyclist road use, creating "green streets" instead of only “complete streets".|
Green infrastructure is a critical component of sustainable urban communities. Its benefits include air quality regulation, erosion management and protection, support of manageable water runoff and aquifer recharge, preservation of pollinator habitats, maintenance of soil structure and quality, purification of water, and contributes to healthy climate regulation at the global level.
Green infrastructure can reduce urban heat island effects through its positive impact on infiltration and rainfall runoff, improved air quality through shade, and the filtering of pollutants provided by increased vegetation.
Pollinator Habitat Preservation
Green Infrastructure projects to preserve and restore open space within urban areas can provide habitat for pollinators and wildlife, increasing biodiversity, particularly when the areas are managed to support a variety of native plant species.
Improved Water Quality
Stormwater from urban areas delivers many pollutants to streams, lakes, and beaches – including pathogens, nutrients, sediment, and heavy metals. In cities with combined sewer systems, high stormwater flows can send untreated sewage into public waters.
Green Infrastructure Examples
Green infrastructure provides the “ingredients” for solving urban and climatic challenges by building with nature. These practices include rain gardens, vegetated swales, green roofs, and porous pavements. Green infrastructure also includes preserving or restoring natural areas, such as forests, stream buffers and wetlands, and reducing the size of paved surfaces.
Green roofs (roofs with a vegetated surface and substrate) provide ecosystem services in urban areas, including improved stormwater management, better regulation of building temperatures, reduced urban heat-island effects, and increased urban wildlife habitat.
Photo source: City of Emeryville
Permeable pavement is a material designed to allow for percolation or infiltration of stormwater through the surface into the soil below where the storm water is naturally filtered and pollutants are removed. Permeable concrete, permeable asphalt, and other engineered systems are used depending on the amount and type of foot or vehicle traffic.
Similar to a rain garden, downspout planters place plants along or at the end of a downspout to capture the water before it enters a sewer. They range from very simple planters on the ground to one or more planters along a downspout. Rainfall is captured by the planter allowing for infiltration and capture of pollutants.
Bioswales are a linear, sloped retention area designed to capture and convey water, allowing water to slowly infiltrate the ground over a 24 to 48 hour period. The slopes are usually planted with native species similar to a rain garden. A bioswale built into a sloped area can also help prevent erosion.
All Green Infrastructure techniques capture rain water in some way. Rain water harvesting means collecting and storing rain water in large, durable containers, typically collecting from rooftop gutters. Rain water harvesting systems come in a variety of shapes and sizes. Simple systems can be installed by a homeowner while larger and more complicated systems may require a skilled contractor.
A rain garden includes native shrubs, perennials, and grasses that can withstand both drought and occasional flooding. Typically planted in a small depression on the low point of a natural slope, rain gardens are designed to hold and soak in rain water runoff from roofs, driveways, patios, or lawns.
Enhanced Tree Pits
Enhanced tree pits collect rain water by diverting street runoff into a cut into the curb. Enhanced tree pits are specially engineered with soils and native plant species to absorb water and filter associated pollutants. In some enhanced tree pits, storage chambers hold additional runoff, available for plant uptake or ground water recharge.
Photo source: NYC Environmental Protection
Building Resilience with Green Infrastructure
Resources & How to Get Involved
Volunteer Opportunities and Options to Support County Projects
The natural beauty of our County’s flora, fauna, and natural areas make living in Contra Costa County special. Help protect and improve our watersheds by participating in a creek clean-up with your community creek group or by incorporating green infrastructure into your home.
To get started, check out our Resources & How to Get Involved page. Here you can find information on volunteer opportunities, projects, and organizations regarding GI in Contra Costa County.
For more information on the Green Infrastructure Plan, email John Steere, Watershed Planner in the Watershed Program of Contra Costa County Public Works.
Special thanks to Kathi Tevlin of In the Woods and Sharon Korotkin of Korotkin Associates for contributing the prototype of this green infrastructure webpage design.