Green stormwater infrastructure is crucial for protecting our local ecosystems. The City of Goleta Environmental Services division would like to share some information with the community on green streets, low impact development, and bioswales. Read on to learn where you can find green infrastructure in our community.
Green Streets
According to the United States Environmental Protection Agency, a green street is one that “incorporates vegetation (perennials, shrubs, trees), soil, and engineered systems (e.g., permeable pavements) to slow, filter, and cleanse stormwater runoff from impervious surfaces (e.g., streets, sidewalks)” (US EPA 2024). By using natural solutions to catch, redirect, and filter stormwater runoff, municipalities can reduce expenditures by avoiding costly underground collection systems. Green streets also provide flood mitigation benefits, and support community health by providing safe, aesthetic pathways for people to walk, run, bike, use a wheelchair/mobility device, or utilize other forms of transportation.
Low Impact Development
Low impact development, or LID, is a critical component to maintaining green street infrastructure. Asphalt, concrete, and other impervious surfaces cause a large volume of stormwater runoff to wash over land at high speeds. This maximizes the amount of trash and contaminants that collect in runoff, and discharge into creeks, watersheds, and the ocean. This creates an unhealthy environment for plants, animals, and humans.
In contrast, low impact development uses pervious surfaces, such as large stones and gravel and concrete pervious pavers, to maximize the infiltration of stormwater and filter pollutants. Not only does this reduce pollutant loads, but also recharges the underground aquifer, which is critical in drought-prone areas like California.
What is a bioswale?
Have you wondered why there is vegetation and pipes in some of the ditches in Goleta? These ditches are called bioswales, and this type of green stormwater infrastructure plays a critical role in removing pollutants from our local environment. Bioswales are channels that collect, transport, and filter stormwater runoff, preventing runoff from flowing down storm drains and polluting local waterways. A perforated, underdrain pipe collects runoff from streets and parking lots, filters contaminants, and conveys outflow. Bioswales can filter a variety of contaminants including organic contaminants (nutrients, oil, bacteria) and heavy metals.
Typically, bioswales consist of several layers, including mulch, soil, and gravel. Bioswales also use native plantings to absorb water and limit erosion. An infographic of a bioswale is displayed on the right.
Where has the City installed bioswales?
The City has built a bioswale near San Jose Creek and is planning to build a bioswale near Armitos Park. These bioswales help to protect the natural habitat in the creek area from runoff. Heavily trafficked roadways, such as Hollister Avenue and US Highway 101/State Route 217, can produce oil, gas, grease, and other pollutants. By installing bioswales in these areas, the City protects local species from the harm these organic contaminants can cause.
The City of Goleta has numerous projects and initiatives that aim at keeping contaminants from harming local waterways, habitats, and the ocean. You can learn more about the projects the City is completing, as part of the Creek and Water Management Plan implementation process, at www.CityofGoleta.org/CWMP.
Works Cited
US EPA. 2024. Lean about Green Streets. Accessed at https://www.epa.gov/G3/learn-about-green-streets
