Blueprints for a Bioswale
Using Low Impact Development to Manage Stormwater
By Linda Hunter
Nature is the ultimate landscape architect. From just a few molecules of stardust, natural systems have created a complex and beautiful world. Yet humans have altered or even destroyed these systems in many ways. We've dammed rivers and streams, channelized creeks, and paved over much of the green in our environment to accommodate more buildings, sidewalks and cars. One need only look at maps of the Bay Area 100 years ago to realize how many creeks, lakes and rivers we've lost. Thankfully, there is still hope. We can restore natural systems, and ensure the integrity of the built environment, by copying nature's ingenious blueprints - especially when dealing with rainwater.
Low Impact Development (LID) employs a basic principle from nature to control stormwater. That is, to manage rainfall at its source using uniformly distributed and decentralized micro-scale controls. LID's goal is to mimic a site's predevelopment hydrology by using design techniques that detain runoff and allow for increased infiltratration and storage of water close to its source. The mantra of this approach is that rainwater is an invaluable asset - not something to get rid of. Instead of transporting stormwater through pipes to large and costly treatment facilities located at the bottom of a watershed, LID manages stormwater through small, cost-effective landscape features - just as nature would do.
With respect to nature's handy blueprints, The Watershed Project is excited to announce The Richmond Greenway Bioswale and Native Habitat Garden Project to address issues of stormwater pollution, runoff, and access to open space at the Richmond Greenway. Using extensive community input and volunteer labor, we will create a native habitat garden and bioswale. Bioswales are landscape elements designed to remove silt and pollution from surface runoff water. They consist of a shallow, gently sloped drainage course filled with vegetation, compost and/or riprap. This design maximizes the amount of time that rainwater spends in the swale, which helps trap pollutants and silt before they can reach the Bay. Swale biology then helps break down harmful substances like mercury, arsenic, and PCBs.
Replacing a drainage ditch, the Watershed Project's creek-like bioswale will become a model green alternative for preventing flooding and reducing pollution. Additionally, we'll be using native plants to create the bioswale and an adjacent garden. This part of the project will help restore local wildlife habitat, provide a peaceful place for Greenway users, and educate students about native flora and fauna. We hope to show how native habitat can eliminate the need for pesticides in adjacent vegetable and fruit gardens.
The Richmond Greenway Bioswale and Native Habitat Garden Project is part of the Richmond Greenway, located within the city of Richmond, California. When completed, the Greenway will transform three miles of abandoned railroad track into a lovely set of trails and green spaces. The Watershed Project has adopted two blocks of the Greenway and has committed to raise funds for its enhancement. We look forward to working with the local community on this project throughout the coming years.
