Bioswale
A shallow, landscaped drainage channel, typically planted with vegetation, designed to slow down, filter, and partially absorb stormwater runoff as it moves across a site, rather than routing that runoff directly into a storm drain untreated.
Why it matters
Stormwater that runs straight off a site carries pollutants, oil, sediment, debris, directly into waterways. A bioswale is a natural filtering step that slows the water down and lets vegetation and soil absorb some of it and filter out pollutants before the water continues on, often as part of a broader sustainable site design strategy.
On a real project
A parking lot's stormwater is routed through a landscaped bioswale running along its edge before it reaches the site's storm drain system, slowing the water down and filtering it through planted vegetation along the way.
Who this matters most to
A Civil Engineer designs a bioswale's size, slope, and plantings to handle a site's expected stormwater volume, coordinating with landscape design.
Where this goes wrong
A bioswale is installed as part of a project's stormwater design but isn't maintained afterward, letting sediment build up and vegetation die off. The swale stops functioning as an effective filter, and the site's stormwater runoff ends up reaching the storm drain largely untreated anyway.