Rain Gardens and Shoreline Stabilization
by Carol Mack
Rain gardens have much in common with bio-engineered shoreline stabilization projects. Both depend on plants that tolerate water-saturated soils part of the year—but can survive dry times when waters recede, or when rain doesn’t fall. Both add aesthetic and wildlife value to the property. One important difference is that rain gardens usually collect extra precipitation which is diverted from another source. But where shorelines are unstable, extra water might actually increase the chances of bank collapse. Plantings along fragile banks should NOT incorporate the usual rain garden profile (a slight depression or saucer shape) since that might concentrate runoff and cause sloughing at that point.
Although the design and location of rain gardens near shorelines should be approached carefully, rain gardens can play an important part in stabilization projects. In some cases, bank erosion is partially due to surface runoff flowing over the land or down a ravine during storms. Rain gardens can play an important part in diverting and absorbing that runoff before it gets near the shoreline. Rain gardens also provide a beautiful and functional buffer zone at the edge of lawns, and can keep runoff from roads or roofs away from the bank.
To find out more about participating in the Pend Oreille Rain Garden Challenge (and how to receive free plants for your rain garden) attend one of the rain garden classes, the shoreline stabilization workshop, or contact Pend Oreille Conservation District at 509 447-5370.