In Washington State (and Oregon) there are benefits to using them rather than the big stormwater ponds surrounded by chain link fencing. We are seeing more of them because the Dept. of Ecology is encouraging their use and developers gain more square footage on their site plans.
Typically laid out by civil engineers, my office is usually asked to design the planting and provide a legend of suitable plants. Most jurisdictions that we work with have specific guidelines for those plantings.
In my own neighborhood, here in Vancouver, WA, Luke Jensen Sports Park was built utilizing Rain Gardens for parking areas. The park opened last spring and a couple of Rain Gardens are located in the parking area.
|Rain Garden at Luke Jensen Sports Park, Vancouver, WA|
(click on image to enlarge)
This pond includes Ajuga for perimeter ground cover and a variety of sedges and grasses that slope down into the swale. By using a swale this parking area has a much larger amount of landscape area than it would have had without it.
I previously wrote about the Rain Gardens in Port Townsend. The city used a variety of native plantings, heavy on flowering perennials, making the swales that run along downtown streets very attractive gardens. Those Rain Gardens were really well done and I look to them as a template.
Check out more photos and info on my Pinterest board, Rain Garden.
For more information on the work we do in my office, see the button on the sidebar to the right for Planning Solutions, Inc.