Parking Lot Island Out, Rain Garden In

By Tom Salzer on May 10, 2012 in Water quality & quantity

The Clackamas County Soil and Water Conservation District recently assisted a local church in replacing a parking lot island with a new rain garden.

Rain gardens work like a native forest by capturing and infiltrating stormwater from rooftops, driveways, and other hard surfaces. These small, attractive landscape features provide many benefits:

Reduce flooding by absorbing water from impervious surfaces
Filter oil, grease and toxic materials before they can pollute streams, lakes and bays
Help to recharge the aquifer by increasing the quantity of water that soaks into the ground
Provide beneficial wildlife habitat, including flowering plants for pollinators

The new church rain garden is performing all of these functions, and the sign designed by Erik Carr helps educate people about these benefits.

Our role in this project was largely helping with design, helping to marshal some resources, and designing the interpretive sign. But we learned some things during the project!

Most startling was the impact of a nearby creek that overflowed during monsoon-like rains this past winter. The rain garden was not designed to handle that volume of water…and it didn’t. The overland flow carried leaves into the rain garden, and those leaves plugged the overflow drain. Some topsoil was washed out of the garden and had to be replaced this spring.

However, the new garden is now growing. It looks nice and is a welcome addition to the neighborhood. Just as important, it protects water quality and benefits wildlife.

Read about rain gardens and rainwater harvesting in our library to learn how a rain garden might fit in your landscape!