Turning Germantown parking lots into rain gardens to prevent water pollution

Turning Germantown parking lots into rain gardens to prevent water pollution

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It was just after 8 a.m. on a sunny day last June and a volunteer work crew, clad in work gloves and old t-shirts, had already begun turning a former parking lot at the Germantown Historical Society into a lush, green oasis.

The workers — college students, neighborhood volunteers, landscape architects and green advocates — marked spots for plants, dug holes, hauled trees, transported water, sprinkled fertilizer and removed countless bits of brick from soil.

In the afternoon, they moved on to plant trees and tall grasses at a nearby courtyard so it, too, could absorb water when it rains.

“Any effort on our part to lessen the storm water flow into streams or city resources is not only better for us, but it also would contribute to the larger effort to be more environmentally responsible,” explained Trapeta Mayson, executive director of Historic Germantown, which initiated the project.

Trapeta Mayson, executive director of Historic Germantown, digs in. (Photo by Dan Sardaro)

The plantings around the historical society building at 5501 Germantown Ave. in the city’s Germantown section are part of a bold initiative by the Philadelphia Water Department to combat the problem of storm-water runoff by planting what are known as “rain gardens.”

There are now more than 120 such greening projects installed or in the making around the city, including a growing number in Germantown. Green Street Friends School has recently planted a rain garden, as has La Salle University.

The effort, which has gone on for the past several years without much public notice, has put Philadelphia in the vanguard of cities that are trying to address one cause of a major national problem – water pollution

The problem

According to the U. S. Forest Service, storm-water runoff in urban areas like Philadelphia is the leading cause of polluted streams and rivers – those that don’t meet the water quality standards in the 1970 Clean Water Act.

“Storm-water runoff is something environmental regulators are becoming aware of and they’re trying to figure out what to do about it,” said Philadelphia Water Department Project Manager Erin Williams, who oversees the storm-water billing and incentives program.

The problem is a relatively simple one.

Over centuries, forests have been cut down for human needs such as residential homes, malls, parking lots, highways – you name it. Places that were once dominated by a forest ecosystem have now been transformed into cities.

Where there was once porous soil that supported a forest now there is a city that sits on hard, impervious cement and asphalt. This doesn’t pose a problem when it’s sunny, but it does when it rains.

Claudia Levy (middle) a landscape architect, instructed a group of volunteers in how to build a rain garden that can soak up excess storm-water runoff, reducing water pollution in the Schulykill River where Philadelphia gets part of its drinking water. (Photo by Dan Sardaro)

Picture for a moment a single raindrop forming in the atmosphere above Philadelphia right before a heavy rainstorm.

When the raindrop leaves the atmosphere and plummets toward Earth, it is essentially clean, reborn water thanks to the water cycle and some other man-made treatment processes.

But the moment that raindrop meets land, things can start to get messy.

“What happens is that rain hits the ground and eventually it creates so much runoff that it ends up flowing into the nearest storm drain inlet,” explained Williams. Instead of seeping into the permeable soil that would allow it to be absorbed by roots or find its way to an underground aquifer, the rain lands on impenetrable ground and creates storm-water runoff.

“That water runoff then goes to a pipe. That pipe under the street, along with most in the city and those in the Germantown area, is known as a combined sewer pipe,” said Williams.

When that single raindrop lands in the street, it joins a surge of water pouring into the combined sewer pipes. Those combined sewer pipes are a way to manage both storm-water runoff and sewage from buildings.

But what the old city infrastructure may have gained in efficiency, it has lost in accountability and cleanliness.

“On a good day when there’s no rain, that pipe is just getting sewage,” said Williams. “There’s enough capacity in the pipes, and the treatment plants can accept and treat all that flow.”

But an excess of flow in the combined sewer pipes, like an additional influx of water when it rains, has unintended consequences.

“When it rains, the pipes and the treatment plants both may be at capacity and may not be able to accept all that flow,” said Williams.

When the pipes hit capacity, the backed-up sewer system can flood residential areas since there is nowhere for that toxic sewage-water to go. Of course, flooding has its obvious health and safety risks to the public, so the sewer system discharges that watered-down, untreated sewage into the rivers in certain spots. These discharge spots, called combined sewer outfalls, span the banks of the Delaware and Schuylkill rivers, and the Cobbs, Tookany/Tacony-Frankford, and lower Pennypack creeks.

There are 164 of these combined sewer outfalls across Philadelphia, and hundreds more across the country, all of which are spewing contaminated water and sewage into our waterways.

Runoff’s consequences

The implications of sewage leeching into Philadelphia’s waterways can be disastrous. Dr. Stefan Samulewicz, a professor of biology at La Salle University, warns of possible pollutants that combined sewage may pick up as it makes its way to a river or creek.

“From a chemical standpoint, the world is much different now. There are way more drugs, cleaning products, lotions, soaps, and household things that we own and get rid of. Where do they go? They go down the drain most times,” Samulewicz explained. “A little of one might not be bad, but when you mix them all together, it’s bad.”

A myriad of pollutants can end up in larger waterways over time – everything from the dirty oil that spilled on the street after an oil change, to the chemical fertilizer that is used to fill in a front lawn, to the cleaning product used to whiten a shirt can filter into a river or creek. As water travels over the impervious streets and sidewalks, it picks up those pollutants, mixing them with whatever is already flushed down the pipes into a toxic slurry.

“The environment is where this problem shows up. Hermaphroditic amphibians, fish kills, liver disease and types of cancers in wildlife are some of the effects,” said Samulewicz.

Other effects are also hard to ignore. Those fertilizers that made their way from front lawns into waterways often lead to explosive algal bloom growth. While large amounts of algae gorge on precious oxygen in the water, fish and aquatic life can practically suffocate.

In addition to wildlife harm, excess storm-water runoff can literally alter the landscape itself. Large torrents of water plowing through rivers or creeks after a rain storm can carve out wide swaths of riverbank, leaving in its wake a poor environment for native plant roots to take hold.

“Clearly we do not want raw sewage, even if it’s diluted with rain water, getting into the rivers. So can we stop this from happening?” said Williams.

The question looms: Can storm-water runoff, a destructive process born out of nature and human development, be controlled? The answer is yes.

The solution

The idea is relatively straightforward.

If you can initially prevent enough storm-water runoff from getting into the combined sewer pipes, ejecting untreated sewage water into our waterways can be avoided. The easiest way to do stop storm-water runoff in its tracks? Simply convert the city’s impervious ground back into porous land.

Volunteers Jonah Nicols (right) and Bud Bretschneider dig in to plant a new rain garden in Germantown. (Photo by Dan Sardaro)

“The green infrastructure approach is basically saying if we put in a rain garden, porous pavement, or some sort of green infiltration project, when it rains, you direct the water to the rain garden for example,” said Williams. “The garden allows for that water to percolate back into the ground, preventing it from getting into the combined pipe in the first place.”

The Philadelphia Water Department has been leading the charge in green infrastructure across  the nation. It acted after the federal Environmental Protection Agency said it was out of compliance with the Clean Water Act.

Under a 2011 consent decree with the Commonwealth of Pennsylvania, Philadelphia has agreed to plant rain gardens to prevent pollution of its waterways from its combined sewer outfalls. So far, the city has awarded about 120 green infrastructure projects — and the number is growing.

These projects vary in how they work. One approach, called a green roof, involves growing vegetation on rooftops to absorb and slow runoff. Another is installing porous pavement, a material that withholds the same structural support as asphalt, but allows runoff to seep into an underground stone reservoir.

The simplest approach is a rain garden, which uses plants and soil to absorb and store runoff until it evaporates or percolates back into the soil.

With help from the Philadelphia Water Department, the Germantown Historical Society is planting its own rain gardens for both its courtyard and its parking lot, which include ripping up the existing asphalt to plant sod, bushes, and trees.

“From what I’ve learned, the asphalt and concrete that surrounds us can be very demanding on the current systems the city has in place,” said Mayson, referring to the combined sewers. “Any way that we can mitigate that and manage storm water runoff so that we’re not adding further burden on the city system makes an overall difference for all of us.”

Mayson oversees the 16 historical sites that span across Germantown, one of the most historic and culturally rich neighborhoods of Philadelphia. With its cobblestone streets and colonial homes, it was once a crucible of the American Revolution. These days, Historic Germantown is at the forefront of a new movement, one to protect the city’s waterways.

A “win-win”

As much as these projects help water quality, they don’t pay for themselves. Some of them can cost several thousand dollars, and non-profits like Historic Germantown don’t have the money.  Given the money and time required to create a rain garden, why are people building them?

The answer lies in Philadelphia’s water bills. The majority of the Philadelphia Water Department’s approximately 500,000 customers pay a small storm-water charge. But some 90,000 commercial and industrial properties pay a relatively large charge – as much as hundreds of dollars a month.

Piper Burnett helps prevent water pollution by making way for tree-planting at a Germantown courtyard. (Photo by Dan Sardaro)

This high fee wasn’t always the case. Up until 2010, the water department charged customers strictly on the size of their service connection. Now, it charges them on the amount of impervious property. That shift was significant for many, said James Pollum, a water department  engineer.

“A lot of people were hit pretty hard by that,” said Pollum. “Their bills went up from maybe $50 per month to maybe a $1,000 per month.”

Even though the fee is necessary to defray the cost of vital water services, the water department realized they had to lend a helping hand to some of their customers. So in 2012, they devised a grant program that would benefit both them and their customers.

That program is called SMIP – the  Stormwater Management Incentive Program. It’s a means for non-residential customers to reduce their storm-water bill through actively minimizing runoff on their properties. The reasoning behind it is this: if organizations are doing their part to stop runoff and help the water department maintain water quality regulations, why shouldn’t they be rewarded?

Without such a program, Trapeta Mayson’s plans to revitalize her courtyard and parking lot may never have gotten off the ground. The grant will end up paying for most of the expenses.

“We explored the SMIP grant as a way to not only beautify the space back here,” explained Mayson, “but we also recognized that we can better manage storm water runoff by participating in that incentive program.”

Historic Germantown as a whole has always promoted both the environment and the vibrancy of the public, Mayson explained. The SMIP grant allows organizations like Historic Germantown to continue being environmental stewards, while also allowing them to keep more money in their pockets. Williams describes it as a “win-win.”

La Salle University sought out the same option to reduce its storm-water charge. Construction began in 2015 for its own rain garden, a massive rectangular channel fitted with drainage systems on the south end of the campus adjacent to its Communication Center.

La Salle University installed this rain garden on its south campus. It not only helped the environment, but cut down on its water bill. (Photo by Dan Sardaro)

The large strip of excavated ground retains water from flowing down towards Lindley Avenue, where it would meander into the combined sewer pipes through a storm drain.

Trees and bushes line the inside and banks of the garden, feeding off the water that fills up inside it after a rainstorm. When including other smaller gardens around La Salle’s south campus, the entire project manages approximately 18 acres of impervious land.

The future

The program is growing in leaps and bounds. According to Williams, the project’s budget has tripled from $5 million in 2012 to $15 million in 2017.

“And we’re adding funding each year,” she added.

Pollum also laid out a goal the water department aims to keep. “We’re under consent order from our federal and state regulators to get 9,000 green acres in the city by 2036. SMIP is helping with that,” he explained. With an augmented budget and heightened awareness in the community, the goal is feasible.

Volunteers take a break on a courtyard green space, which was once covered with asphalt. From left, Claudia Levy, Denis Lucy, Bud Bretschneider and Piper Burnett. (Photo by Dan Sardaro)

The SMIP grant is becoming increasingly popular with properties around Germantown. The Greene Street Friends School recently installed a porous paver system on their property. The Awbury Arboretum, found on Chew Avenue, is a green haven in the middle of city blocks. Other sites also continue to build green infrastructure – St. Vincent’s Seminary, Gypsy Lane Condominiums, Settlement Music School and others.

Besides keeping runoff out of rivers and saving property owners money, green infrastructure also lends itself to other opportunities, such as helping elementary school students understand environmental issues.

“This project would really be able to explain the importance of being more environmentally conscious, and this is something the students can see happening,” said Mayson.

Another benefit of Mayson’s restored courtyard is the intimate space it provides for events. In an active neighborhood like Germantown, a space for meetings is now available. Mayson also stressed the need for a core group of volunteers who would help maintain the garden.

Public awareness and involvement is a significant factor in this green infrastructure movement, something that Williams herself conveyed.

“Other cities are building underground tunnels or tanks, but you’re not really engaging the public. Our program allows the public to interact with and understand what goes on. Plus, I think there’s a trend to generally beautify and kind of enhance our urban environment.”