Rain is a wonderful thing for the parks: it is essential for the plants to grow, the air to clear of dust, and the wildlife in the streams to stay healthy. But because the urban landscape is so covered with buildings, pavement, pipes, and compacted lawns, rain can also cause a host of problems because the ground is no longer able to absorb water the way forests and fields do naturally. Streams that might naturally have been equipped to handle a major storm event now receive too much water at a time, which flows into Pittsburgh’s combined sewer system and picks up sewage on its way into the rivers. To help mitigate this complicated problem, the Parks Conservancy has installed a new rain garden and rain barrels at the Schenley Park Café, which helps to manage the flow of storm water into the Panther Hollow Watershed.
Part of one of the largest sewer sheds in Pittsburgh, the Panther Hollow Watershed is 780 acres, encompassing parts of Schenley Park, Oakland, and Squirrel Hill. Increases in impervious surfaces both in the park and in surrounding neighborhoods have resulted in an increase in the intensity and frequency of storm water runoff, resulting in quicker and more powerful flows that cause stream channels to move and water quality to degrade.
The rain garden, which was installed in late April, captures rainfall from more than a third of the Schenley Park Café roof and infiltrates more than 600 gallons for every inch that it rains, up to 1,500 gallons for a “2 year frequency” storm event. Water is collected from the downspouts on the northeastern side of the building, piped under the sidewalk, and directed into the rain garden. The rain is then soaked up by the soil and water-loving plants like royal fern, cardinal flower, and blue flag iris.
Under the direction of an ecological engineer with the nonprofit SEEDS, the Parks Conservancy, Department of Public Works, and volunteers from BNY Mellon and Carnegie Mellon University’s Engineers Without Borders worked together to create the garden. The crews excavated part of the Café lawn so that pipes from the building could flow beneath the grass into the concave garden bed, which consists of native soils amended with compost and sand. Then, the plants were installed as part of the Panther Hollow Extravaganza volunteer day.
In addition, five rain barrels from the Nine Mile Run Watershed Association were installed at the back of the café. Each of these barrels captures 133 gallons and holds the water from the downspouts at the back of the building. The water will be used to irrigate the landscape plants at the Café, and during summer can be used to water trees throughout the park system. On the weekend after the new features were installed, hundreds of gallons of water were collected in the rain barrels, with even more infiltrating into the rain garden, giving the project an immediate impact.