Slow It. Spread It. Sink It. – Helping Nature to Help Ourselves with Bioswales


By Maryann Ridini Spencer

Urbanization of towns and cities has caused many of the natural, grassy, open air landscapes to become gray scapes  — areas with lots of concrete, paved parkways, sidewalks and parking lots and other hard-surface areas.

In urban settings, when it rains, water flows from the sky on to hard, impermeable surfaces.  In this type of an environment, flowing water collects all the sediments, litter and pollutants that, because of the concrete, isn’t able to filter naturally into the ground.   Subsequently, this rain or urban runoff, carries the debris into our oceans, rivers and beaches causing our primary source of water pollution.

In an effort to offset the problems arising from urban runoff, the City of Ventura has constructed a series of man-made bioswales  (naturally engineered and designed systems that mimic nature’s wetlands), throughout key locations in Ventura.

“Bioswales act as natural sponges in the upper watershed,” says Jill Sarick, Environmental Sustainability Specialist for the City of Ventura.  “They’re a wonderful solution to the urban stormwater pollution because they serve as a natural filter.”

Bioswales are usually constructed with gently sloping sides and filled with vegetation, mulch or rip-rap, they aim to maximize the amount of time the water spends in the swale. They work well in a 4-7 inch rainstorm or low fall rain events. Additionally, from time to time, they require maintenance such as removing debris and plant trimming. According to Sarick, sedges, fescues, and other low-growing native plants seem to work the best in the Ventura.

Bioswales that are currently located in Ventura include the Montalvo Hill Park area, Kimball Park, the parking lot recently installed on Santa Clara and Oak Streets, both of the Fresh & Easy grocery store parking lots, the Patagonia parking lot, and the Surfer’s Point Restoration.  There are more planned as a part of the City’s Green Streets Initiative.

Working in partnership with The Surfrider Foundation, The City of Ventura has also helped with installation of bioswales and rain gardens at a few residential sites.

Ventura City resident, Dan Long, recently participated in The Surfrider Foundation’s Ocean Friendly Garden Program where local volunteers helped transform his front lawn into an Ocean Friendly Garden.  He was so pleased with his new garden; he wanted to do something in the parkway in front of his home.  He contacted a local green building contractor, Jeff Zimmerman from Z Dwellings and with the help of consultants from design firm, G3, a design for a curb cut and bioswale in the parkway was proposed.   This outreach led to Surfrider’s West Coast Chapter Conference attendees, thirty in all, to participate in the curb cutting and bioswale construction at his home in Midtown Ventura.

We worked with the City’s Building and Safety Department to test pilot a “no-fee encroachment permit” which enabled Dan to secure the permit to work in the parkway in front of his home.  This may become a model for other communities to replicate.

“Bioswales are a win-win,” continued Sarick.  Not only do they help keep our waterways cleaner, they are beautiful and they are easy to maintain.

“We hope to work with stakeholders to eventually devise a standardized plan and specifications for parkway bioswales and curb cuts.

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