With all of the rain lately, it seems like a great time to blog about a simple, innovative solution to water problems. A rain garden is a form of ‘bio retention’ in which a low area with specific varieties of plantings hold runoff water like a giant sponge, cleanse it, and slowly release it back into the groundwater table.

Why bother? In addition to solving many drainage problems caused by incorrect grades, it is important to filter runoff water before it finds it’s way back to our local pond, lakes, and streams. In a large rain event, water from our properties will runoff of our sites, collecting fertilizers from our lawns, oil and road salt from our streets and discharging them directly into our water bodies. This spoils drinking water and can make areas inhabitable for fish and other water critters.
This project, completed in the spring of last year, addressed a major drainage problem right by the front door. Formerly the garage to the home, the grade rolls right into a low spot by the back door. With nowhere for the water to go and downspouts adjacent to the area, large storm events would result in water creeping under the french doors.
During the conceptual design process, it was decided that we would retain the grade with a 2′ high retaining wall, and then collect runoff from the downspouts and lower terrace with a rain garden. The rain garden would be nestled into a small sitting area to the far right, attracting birds and butterflies to this quiet nook. These changes would be done in conjuction with Greenbridge Architect’s plan for a revised entry and new kitchen renovation. Inside touches by lmk interiors, ltd., of course.


The garden is sized according to the amount of roof and surface runoff it will be taking. There are also recommendations for location, based on utilities, septic systems, and foundations. The light requirements of the plantings need to also be taken into consideration. The plantings are unique in that they will be dry most of the time, yet saturated for several hours during larger storm events. The soil mixture is crucial for proper drainage of the garden and is determined via a soil test. It is the roots of plants like Eupatorium purpureum (Joe Pye Weed), Lobelia cardinalis (Cardinal Flower), and New England Aster (Aster novae-angliae) which will ultimately help to cleanse the water of harmful pollutants before gradually seeps back into the ground water table.

In this project, the downspouts were tied in and piped under the patio to the rain garden. The 4″ PVC perforated pipe is cleverly disguised under a bed of Maine beach rock between the retaining wall and patio, illustrated above. We were fortunate to work with Will Leroyer, a skilled mason who has a creative eye required for this type of stone work. Large Pennyslvannia fieldstone slabs were hand selected and placed by Will, artfully tying the wall into the rain garden. We’ve been constructing some nice projects with Will lately. A little more than one year later, the client is the beneficiary of a well drained and beautiful project!

More photos of this one on the project page of www.matthewulrichdesign.com