- Claire Oliver
- Lake Oswego Review - News
Rain gardens grow greenery, green thinking
Offering aesthetic value and ethical onsite stormwater management solutions, rain gardens like those created by Monogram Custom Homes are a growing trend in modern landscaping.
Rain gardens are sunken, generally flat-bedded gardens that collect and treat stormwater runoff by mimicking natural conditions, diverting runoff from impervious surfaces.
These onsite filtration systems help prevent the pollutants contained in stormwater runoff from reaching the streams, lakes and rivers in an area's watershed.
These systems are especially important in older neighborhoods like Lake Oswego's First Addition, which was platted in 1920 before stormwater runoff was a consideration.
At first, neighborhood residents let their downspouts drain directly into the ground beneath them.
Since then, however, impervious surfaces such as driveways and curbed streets have been added, creating a pathway that lets runoff drain into sewers and nearby bodies of water such as Oswego Lake.
Because of this, homeowners must take extra measures to ensure stormwater runoff is diverted to the underground drainage systems the city has since installed.
While onsite underground filtration systems are available, rain gardens provide a practical, more affordable option.
'It's managing the water before the city has to,' said Brian Noffz of Monogram Custom Homes.
Noffz said he's been installing these 'gardens with a purpose' for three years now, working with Dan Edmunds of Landscape Oregon on their designs.
Each garden's dimensions are calculated to specifically suit the roof of each house, as the surface area of the roof correlates to the amount of stormwater runoff the garden will have to accommodate.
Each sunken garden contains a drainage pipe, which directs runoff from a house's roof to the rain garden. The water collected then hydrates the garden's plants, and the rest seeps through rocks into the soil below.
Rain gardens also contain an overflow pipe, positioned about two feet higher than their drainage pipes to catch excess water collected in case of a large rain event, Noffz said.
Noffz said he stocks the center of his rain gardens with plants like grasses, reeds and rushes that easily soak up water. He then lines its edges with native plants such as snowberry and Oregon grape. Shade trees planted near the perimeter of the rain garden ensure these native plants survive during the summer months.
Aside from their environmental benefits, rain gardens are aesthetically pleasing and user-friendly, Noffz said.
'If you do it with design in mind, you can make it look great,' he said.
And, because rain gardens treat stormwater runoff at ground level, homeowners can see when problems in filtration occur and address them faster than with an underground filtration system.
Plus, the cost of a city permit for a rain garden is less than its underground alternative.
Noffz said he suggests homeowners considering installing a rain garden consult with the city of Lake Oswego for permitting and construction information.
The Oregon Sea Grant, a program of the Oregon State University Extension Service, also published 'The Oregon Rain Garden Guide,' a step-by-step handbook for installing and maintaining a rain garden.
Tips from the guide include how to:
* select a site where water flowing into the garden will be higher than where water will naturally exit the garden;
* look for a location in your yard where overflow from a rain garden can be absorbed or safely directed into an approved stormwater collection point, such as a streeside gutter or storm drain;
* avoid locations where soil stays wet throughout the season, as this suggests poor draining soil;
* avoid sites that could damage nearby tree roots; and
* select plants that are appropriate to the conditions of your yard.