Onorato Announces Construction of Rain Garden in North Park

Facility will improve water quality in North Park Lake and Pine Creek

Allegheny County Executive Dan Onorato today announced the construction of a 1200-square-foot rain garden at the intersection of Lake Shore Drive and Walter Road in North Park. The garden is a joint effort between Allegheny County and the
Pennsylvania Department of Environmental Protection.

“The Lake Shore Drive Rain Garden will help to improve water quality in North Park Lake and Pine Creek by filtering out pollutants before they reach the watershed,” said Onorato. “The garden will also retain stormwater and help to reduce flash flooding.”

The garden area is currently being excavated to create a depression where native vegetation will be planted. Runoff from nearby parking lots, adjacent roadways and other impervious surfaces will flow into the depression and be filtered through layers of sand, stone and soil, thereby removing silt, chemicals and pollutants that would otherwise reach the lake and creek. The garden will also help to control erosion of stream banks and the lake shore.

In addition, the garden will serve as an educational tool for people of all ages. An informational sign placed at the garden will teach visitors about the benefits of rain gardens, and presentations at the site will encourage residents to mitigate their impacts on the environment.

Residential and commercial rain gardens can be planted in yards and other green spaces to help offset stormwater rushing into combined sewer systems and streams. Developing a rain garden is as easy as digging a depression and planting it with native plants, such as shrubs or perennials, that tolerate water that may pool, as well as plants that tolerate droughts. The cost to develop a rain garden is normally $6-$8 per square foot and provides increased value to homes and

“We must come together as a community to address the issue of stormwater management, and green infrastructure is a key component,” added Onorato. “Allegheny County government is proud to provide leadership in this area by developing rain gardens, green roofs and other water retention and filtering projects.”

Allegheny County is currently in the process of converting the planters in the Courthouse Courtyard into rain gardens and developing a green roof on the County Office Building – the first green roof on a public building in the County.

In the Courthouse Courtyard, four downspouts that currently drain into the city’s sewer system are being diverted into four existing planters, which are being planted with native vegetation. In the long term, additional planters will be developed and placed around the Courthouse’s perimeter, a previous architectural detail of the building. Half of the County Office Building’s roof, an area of 8400 square feet, will be converted to a green roof. This entails covering the roof with waterproof fabric, adding soil, and planting the area with native plants. The roof will increase the building’s insulation, thus saving on heating
and cooling costs. It will also absorb rainwater that would normally drain into storm sewers, thus reducing runoff and pollution. The green roof will reduce air and noise pollution, decrease the “urban heat island” effect, lessen flooding events and sewer overflows, provide urban habitat for birds and butterflies, and increase roof life at least two to three times.

In Southwestern Pennsylvania, an average rain storm can produce two inches of rain in a 24-hour period. Even two inches of rain falling on a roof can result in more than 600 gallons of water rushing through downspouts and into sewer systems. As little as 1/10 inch of rain can cause combined sewers to overflow. As rain travels over hard surfaces, it picks up and carries pollutants, such as oils, silt, chemicals and debris. The large amount of impervious surfaces in urban areas does not allow rainwater to permeate into the soil. Instead, rainwater flows into storm and sanitary sewers, as well as local streams, which are often unable to handle the higher water volumes, causing back up and eventual flooding.

For information about rain gardens, visit 3 Rivers Wet Weather and the Three Rivers Rain Garden Alliance.