Slippery Rock Watershed Coalition takes on mine pollution in creek tributaries for more than 30 years
WASHINGTON TWP — In the tributaries of Slippery Rock Creek, pollution from mine drainage had been a brewing problem for more than 100 years.
Abandoned and unreclaimed mines began to experience chemical reactions, leading to water drainage that started polluting the creek. By the 1990s, the waters had, at certain places, become unsustainable for life.
However, through the combined efforts of nonprofits, government agencies, academic institutions and private companies, the Slippery Rock Watershed Coalition formed in 1994 to begin assessing and treating the polluted waterway.
“In some ways, when you look back at the cost of coal that was mined out of here, that wasn’t the true cost of it. We’re still paying for it,” Stephen Smith, a coalition member, said.
The coalition has carried its mission forward for the past 32 years working to restore a 27-square-mile section of creek headwaters called the “Slippery Rock Creek Study Area,” which stretches across Venango, Washington, Marion and Cherry townships.
The creek is polluted with acid mine drainage as a result of 260 underground mines and 15,000 acres of unreclaimed surface mines.
“Pennsylvania just had such a historic coal mining legacy that was done before laws were in place to control how it was done,” said Cliff Denholm with the nonprofit Stream Restoration Incorporated. “We had this massive problem in Pennsylvania. So this was just the center of people doing research and trying to improve that.”
Acid mine drainage is a byproduct of mining operations, exacerbated by Pennsylvania’s deep history of coal mining, which dates back to the 1760s.
According to the watershed coalition’s book, “Accepting the Challenge,” there are about 7,800 old, abandoned or inactive underground mines and roughly 250,000 acres of abandoned surface mine land in Pennsylvania.
These abandoned mines, which were usually dug around river valleys to easily connect with train lines, allow materials normally found underground to chemically react to oxygen and water getting in.
According to the coalition’s book, roughly 4,600 miles of freshwater streams are impacted by drainage in the state, causing a loss of $67 million in recreational fishing opportunities each year.
Reclaiming polluted streams and land in the state would cost an estimated $15 billion, but that number is likely higher now due to inflation.
Chief among the materials polluting waterways is pyrite, also known as “fool’s gold,” an iron sulfide. Its reaction with water can create sulfuric acid and pollute it with iron. Other metal pollutants common in acid mine drainage include aluminum and manganese.
Acid mine drainage can usually be recognized by reddish-orange staining on rocks, discolored water and the absence of vegetation, but can also appear completely clean.
Even identifying streams with acid mine drainage pollution can be a challenge. Experts evaluate pH levels, alkalinity, turbidity, sulfate levels and iron levels to determine if water is impacted. While some signs point clearly to pollution, each stream and drainage source is unique.
Since the Surface Mining Control and Reclamation Act of 1977, mine operators have been legally required to restore land to its original state and treat acid mine drainage to avoid pollution.
Operators primarily use “active treatment,” such as using machinery to add chemicals such as limestone and ammonia. However, these systems require constant maintenance and can cost over $10,000 per year to keep running.
The problem is further exacerbated by much of the acid mine drainage coming from abandoned mines.
Research on wetlands revealed that plants and other organic materials could retain drainage and improve water quality. After further testing with different organic materials, such as moss and cattails, researchers were able to devise a “passive treatment” system by constructing human-made wetlands.
The constructed wetlands allow the drainage to flow slowly, causing the suspended solids to settle in a “settling pond.” But, due to the need for extended retention, the water moves to “treatment cells,” shallow ponds filled with cattails where metals can oxidize.
Other systems include open limestone channels, anoxic limestone drains, vertical flow systems and diversion wells. Determining which system works for a specific drainage source requires studying water quality, flow and the composition of the drainage’s chemicals.
Since starting its mission, the watershed coalition has installed more than 20 passive treatment systems which treat more than 1.5 billion gallons of acid mine drainage each year.
One such passive treatment system, SR 114, uses an anoxic limestone drain, settling ponds and wetland cells to treat about 135.5 million gallons of drainage each year.
“There’s actually three treatment systems right here along this stretch of Slippery Rock Creek,” Denholm said. “Those have helped really improve this stretch. And then these mines’ discharges actually tend to improve over time as those reactions that are taking place inside the mine kind of run their course.”
He said that the coalition’s systems have managed to significantly improve water quality and cause an uptick in the amount of freshwater macroinvertebrates and fish living in the creek.
Denholm also explained that because of the amount of mining done in Pennsylvania, the watershed coalition was one of the first testing grounds for passive treatment systems.
Passive systems are in heavy use in Pennsylvania, but are also present in heavy historical coal mining areas like West Virginia and even Spain.
However, with some of the coalition’s systems reaching 30 years of operation, the coalition has focused much of its energy on maintaining, restoring and rebuilding its preexisting systems. SR 114, for example, was rebuilt in 2023.
“Over the last few years, we’ve rebuilt several of these. We’re in the design phase for redesigning two other projects,” Denholm said. “We’re picking the ones that we think are either the most important or need the most care and prioritizing them.”
He said the coalition is facing rising costs for building, maintaining and restoring these systems.
“Most of the systems we’re building now are ranging around $500,000 to even over $1 million per system,” Denholm said. “I’m actually going through some old SRI records and I came across a receipt for limestone. It was like $9 a ton for limestone, and now we’re paying like $40 or $50 a ton.”
Janice Belgredan with Stream Restoration Incorporated said the issue is compounded by the way the coalition is funded — primarily through grants given specifically to establish new systems. Funding for these projects remains a constant question and pursuit.
“I think that ongoing maintenance, though it doesn’t take a whole lot of energy or effort, it’s figuring out having funding and support to do that,” she said. “There’s been so many systems that we’ve put in time, energy and money. How do we make sure they continue to do their job over time?”
Belgredan said one thing she considers unique about the Slippery Rock Watershed Coalition is how it is built on community partnerships.
According to the coalition’s website, the group includes Marion, Venango and Washington townships; the Pennsylvania Game Commission, Fish and Boat Commission and Department of Environmental Protection; Slippery Rock University; Grove City College; about a dozen mining and excavating businesses and more.
“There was just this attitude of ‘Let’s just get things done, who can we bring in to increase our capacity and who makes sense?’ So everything that was done, quite literally if you look at all the different projects, they all represented various partnerships,” Belgredan said.
She also said there are two major benefits to building these partnerships: work can get done more efficiently and it helps establish connections with the community. The coalition has always worked to build a connection with private landowners where it seeks to do a project.
“One thing that (coalition founder) Margaret Dunn said to me once if they were working on somebody’s private property doing this, to make it work for a private landowner, they need to feel comfortable,” Belgredan said. “So, first of all, there was an awareness and a respect for that as they did their projects. But I know (Dunn) told me they’d ask ‘What’s something we can do for you if we’re putting this on your property?’”
Dean DeNicola, professor emertius at SRU, used to bring university students to the creek’s tributaries to study its water.
“We’d pull up with a university van and say ‘Do you mind if we walk across your property?’ Almost all of them said sure. Then they wanted to know what you’re doing. I think most of everybody around here knows by now what’s going on,” he said.
Belgredan said she believes the acid mine drainage and watershed coalition’s work to control pollution is almost a microcosm of a larger, societal viewpoint that places convenience and efficiency over everything else.
“In this whole area, mining has been so important. So this is just a piece of a much bigger story about what was important but also how we have a tendency to do great when we’re starting a project and not paying attention to what the ramifications will be afterward,” she said.
Belgredan and coalition member Stephen Smith agreed that there is a risk of repeating the same mistakes in different circumstances.
He said community members can help the watershed by attending meetings or volunteering with the coalition.
More information on the Slippery Rock Watershed Coalition, its projects, how to participate and free digital copies of “Accepting the Challenge” are available on its website, www.srwc.org.
