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Biography of a Bioswale: New Green Infrastructure at Purchase

by Sonia Barkat

Professor Ryan Taylor and senior Paola Valencia set up the weather station monitor at the bioswale. (photo by Sonia Barkat)

Along the edge of West 1, beside the road, there is a ditch in the land; manmade and filled with plants—and sometimes, water. A white and green sign stands in front of it, the header reading “A Living Laboratory” in large letters. Completed near the beginning of this semester, it is Purchase’s newly built bioswale.

“I describe it as a rain garden,” said Angie Kim, the school’s sustainability coordinator, “which is supposed to help capture runoff and take up a lot of the sediments and pollution using native vegetation. A bioswale is that times one hundred. It has the capacity to capture close to 27,000 cubic feet of runoff.”

The Water the bioswale captures comes not only from the W1 parking lot, but the main campus as well, Kim explained.

“When you walk down to the W lots, you are at a slight incline,” said Kim. “Our campus is a lot of concrete and brick, so you don’t have the rain permeating directly into the ground, just running along the surface. The bioswale is taking in a lot of that water from the academic mall.”

Without the bioswale, the water would run, unfiltered, to a wetland on campus and from there into Blind Brooke, which goes through Rye and Harrison only to end up in Long Island Sound, according to environmental studies professor Ryan Taylor.

“There used to be storm drains in the parking lot, and all the water runoff would go through those and into the detention basin [wetland],” said Taylor. “Now all those storm drains have been capped, so the water is going to run on the surface of the parking lot and come into the bioswale first.

The bioswale has drains of its own that only let water pass through once it has reached a certain depth.

“Any big storms it just goes right out like the bioswale wasn’t here,” said Taylor. “Its job is to absorb the small rain events and feed the plants with it, because the first part of a storm is when all the dirt gets washed up—that’s the nastiest water.”

Before the bioswale could be built, community approval was needed from the town of Harrison.

“Within Westchester County, it was shown that the water quality in this area was below a lot of other nearby places, so I think Harrison, the town itself, saw a need for the project,” said Kim.

On Purchase’s side, Kim says the school is very receptive to new green infrastructure.

“The only fallback is a lot of the funding; budgetary issues and trying to allocate money for these things when you have money that needs to be elsewhere, too,” said Kim. “It is kind of complicated because being a state institution there is some red tape, but ultimately I feel the college is so supportive that they want to see it happen and will do what they can to let it flow.”

he bioswale in full bloom. (photo by Paige DeMaio, Communications & Creative Services)

The bioswale project was initially proposed by the school’s Senior Energy Manager, Tom Kelly.

“He took it upon himself to do way more than what was in his job description, and to start looking at other ways the college could be more sustainable, and he found this grant opportunity through The Environmental Facilities Corporation (EFC),” said Taylor

Tom Kelly said that is because he’s always been interested in sustainability.

“Before Angie Kim came on, I was essentially doing the work of both energy manager and sustainability manager,” said Kelly, who explained that he started grant writing for the project back in 2014.

The project total had been estimated at $850,000, and after the grant was approved, the EFC provided $765,000.

“When the project was completed, we were only about $3,000-$4,000 over, so basically we paid about $90,000 and the state picked up the $765 thousand,” said Kelly.

The company hired to build the bioswale was R. Pugni and Sons, based in Katonah, NY.

“I really believe in local first,” said Kelly. “There was a little bit of a challenge in the beginning, I guess, because they hadn’t really done state work before, and weren’t sure what the process was and how to go through the motions, but they’ve done previous non-state-related work that they did a phenomenal job with, so they were chosen for their experience in that regard.”

During the design process, R. Pugni and Sons provided lists of native plants that would likely survive in the region, which Angie Kim helped choose species from. In addition to this, according to Kelly, there were several occasions where the company could have charged extra for various delays but did not.

“They were a real pleasure to work with, and if I could work with them again in the future, I certainly would,” said Kelly.

Kelly also said that the multiple delays caused the project to take five years before its recent completion.

“Those delays were in terms of procurement, contracts, design and construction, etc.,” said Kelly. “Ideally, I would have loved to have this done three years ago, but there are factors that sometimes come into play that slow down the works.”

On the science side, Professor Taylor said the delays were a benefit in the long run.

“The waiting had a positive effect; people never talk about that,” Taylor said. “New technologies came available from when this was all proposed five years ago, and the cost of those technologies decreased.”

Taylor, who assisted with the monitoring portion of the grant, is now overseeing the monitoring process. He, along with environmental studies major Paola Valencia (who is taking on the research as her senior project) set up five monitoring systems across campus—a task that took over seven hours—to gather data about water runoff.

Most of the setups consist of a small box and solar panel, Valencia explained, but at the bioswale the duo assembled a larger monitor called a weather station. The equipment they were able to get allows for remote monitoring, which Taylor explained will send the water level data to the Cloud and post it on a website that can be accessed by anyone.

“Being able to do remote monitoring, so that I don’t have to send Paola out here every day that it rains to measure the water with a stick—that’s nice,” Taylor said.

Taylor and Valencia are studying both water quality and quantity and have set up a monitoring system near West 2 as well as West 1, for comparison.

“We’ll be able to see how much water leaves this site and compare it to how much water leaves W2,” said Taylor. “The two parking lots are identical, in size, in every way, except this one has a bioswale and that one doesn’t.”

With the bioswale in place, the expectation is that less water will be leaving West 1.

If the data shows a positive result, Tom Kelly hopes to create a second bioswale at the West 2 lot.

“We had initially anticipated doing both W1 and W2 at the same time, but the cost to do so was just too much,” Kelly said. “We already have a design for a W2 bioswale, so I think in a three-year time period I would submit another grant to the EFC to cover the cost of that.”

“We want to be the best we can to show other institutions that they can do it as well,” said Kim. “I was just at a conference in New York City that gathered sustainability people across all state agencies; state government, local governments, even national parks, where we all shared our accomplishments and things we’ve implemented over the last year. They were like, ‘wow, it’s amazing what Purchase was able to incorporate, can you tell us about your processes?’”

Kim says the most exciting part of the project to her is that the bioswale can be used in future curriculum and research.

“I can’t get over the fact that you can literally just walk a couple hundred yards and you are in the midst of this massive green infrastructure project that took a lot of research and a lot of manpower to make,” Kim said. “To have something like that on campus and be able to refer to it is inspiring.”



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