Rain garden drains excess water

By Gretchen Andersen

Rain in Pittsburgh is inevitable. Rainboots and umbrellas provide coverage for students, but… Rain in Pittsburgh is inevitable. Rainboots and umbrellas provide coverage for students, but campus grounds don’t have those protections — and the potential risks for flooding concerns some environmentalists.

The uneven mounds outside the Baierl Recreation Center are particularly vulnerable because the dips collect rainwater, keeping it stagnant and unable to drain properly. But now a rain garden sits in the valley, an environmentally friendly solution implemented by Engineers for a Sustainable World.

The student group chose to plant the garden on a plot that would soak up excess rainwater and waterproof the surrounding area. A system of greenery and a drainage pripe running under the soil keeps the water from spilling onto the lawn and into the sewer system.

“It is supposed to hold the rain water and naturally infiltrate it into the soil,” junior Dave Palm, ESW president, said.

Pitt geology professor Dan Bain, who assisted with soil measurements for the project, said that keeping water from the sewer system is a key advantage of the new garden.

“For anyone who pays a sewer bill, it saves them money,” he said, explaining that when less water trickles into the sewer system, less water has to be treated — resulting in a lower bill.

The garden sits at the bottom of the hill on the Pete lawn. Its raised edges are made from soil with several plants in the center.  

Palm said ESW wanted to plant greenery native to Western Pennsylvania that could survive the seasons.

Plants such as a serviceberry tree, Joe-Pye weed, switchgrass and swamp milkweed sit in the mulch. Palm said it was difficult for some of the plants to make it through the summer because the organizers planted them later in the season.

ESW proposed the rain garden to Pitt’s Mascaro Center last fall, and it was approved in April.

From April until July, ESW conducted numerous tests including soil and small-scale hydrological tests to determine where the water was coming from down on the Petersen Events concourse area.

“It was definitely an engineering project because of all the different technical variables,” Palm said.

Palm said the Mascaro Center and Facilities Management funded the $4,000 excavation. The Center provided an additional $700 for plants.

The two-day excavation and construction process began in mid-July; however, Palm said things then got a little rocky.  

While trying to dig into the ground, the ESW members learned that the soil contained not only a lot of clay and rock, but also slabs of concrete.

The club had to hire an excavation team to help construct and dig through the slabs. Since ESW had limited funds, Dan Marcinko of Facilities Management helped arrange funding for the excavation.

The team constructed an inlet in the garden that collects rainwater coming from the Petersen Events concourse area and funnels the water into the garden.

A second part of the rain garden includes a dry well, which Palm said is like a miniature drainage system.  

“It is like a tank that is made completely out of soil and gravel that can also hold an extra volume of water to soak into the soil,” he said.

The rain garden was created to hold water for up to 24 hours, allowing it to go through the rain garden.

Palm said the harsh rainstorms two weeks ago hit the new construction hard. It is not expected or built to “hold up to a storm that comes every 100 years.”

But after last Thursday’s mild morning storm, Palm said the garden’s surrounding area wasn’t soaked.

“It seemed we were catching a lot of the water [in the garden]. In very brief exposure, it seems like it is holding up pretty well for the type of storm it was built for,” Palm said.

Marcinko said he agrees with Palm that the garden is already helping with the storms.  

“The rain garden was a solution to a problem,” Marcinko said. “I was up there recently after a fairly heavy rain, and the garden had drained through and the grass around it wasn’t marshy. It was working as intended.”