In 1996, West Virginia's BRWA and WVWRI developed a plan to treat Swamp Run’s acid mine drainage. 28 years later, 2 projects had dramatically improved the stream’s pH with lasting gains

Acid mine drainage (AMD) can create long-term water quality problems in areas affected by abandoned coal mining. At Swamp Run in Upshur County, West Virginia, polluted water from buried coal refuse had caused violations of water quality standards for decades. Efforts led by the Buckhannon River Watershed Association (BRWA) and the West Virginia Water Research Institute (WVWRI) have since produced substantial improvements in the stream’s water quality.

A Longstanding Acid Mine Drainage Problem

Surface coal mines abandoned before 1977 left coal refuse buried in the headwaters of Swamp Run. As rainwater and melting snow moved through the soil of a meadow, they experienced the buried spoil and refuse. The material contained pyrite, which reacts with air and water to generate dissolved iron and sulfuric acid. These reactions also release dissolved aluminum and manganese from soil and rock.

Swamp Run drains a 780-acre watershed in Upshur County, West Virginia. The Upper, Middle, and Lower Kittanning Coal Seams were strip mined in the Buckhannon River watershed and neighboring watersheds.


Water emerging from springs in the meadow could have pH values as low as 2.5, while the state standard requires a minimum pH of 6.0. Aluminum concentrations reached as high as 49 milligrams per liter (mg/L), and iron concentrations reached as high as 225 mg/L. The state standard for metals is no more than 1.5 mg/L.

Regulatory Changes and Watershed Planning

In 1977, the United States enacted the Surface Mining Control and Reclamation Act, bringing water discharges from mining operations under the control of the Clean Water Act (CWA). During this transition, several mining operations, that includes those within the Swamp Run watershed, were abandoned.

Mining operations in nearby watersheds received permits but eventually stopped mining in the 1980s because of challenges controlling AMD. The state of West Virginia assumed responsibility for pollution control and continued monitoring water quality in Swamp Run while treating AMD in neighboring watersheds. In 1996, the West Virginia Department of Environmental Protection (WVDEP) placed Swamp Run on the CWA Section 303(d) list because the stream violated standards for pH and metal concentrations.

In 2001, WVDEP published a total maximum daily load (TMDL) for metals and pH in the Tygart River eight-digit hydrologic unit code (HUC) watershed. The Buckhannon River Watershed is a 10-digit HUC subwatershed within it. The 2001 TMDL called for no reductions in metal loads in the Swamp Run watershed. A second TMDL for the Tygart River watershed was published by WVDEP in 2016. Unlike the earlier plan, it called for reductions in AMD pollutants.

The Highlands Institute for Environmental Research and Education published a watershed-based plan for the Upper Buckhannon River in 2006. The plan identified projects in the Swamp Run watershed aimed at reducing the 84,000 pounds (lbs)/year of acidity generated by abandoned mine lands.

First AMD Treatment Project

WVWRI, working with BRWA, proposed a project to treat AMD entering an unnamed tributary to Swamp Run at river mile 0.69. The project was completed in 2016.

The treatment system includes a small dam that forms a forebay capable of holding around 1.3 acre-feet of polluted water. From there, the water moves through a primary limestone leachbed having 4,600 tons of limestone. When the larger leachbed is being maintained, the water can instead pass through a smaller secondary leachbed containing 2,900 tons of limestone.

Water leaving either pathway then flows through a serpentine channel. Along this channel, neutralized acid compounds settle out of the water column.

Preconstruction monitoring at the first project site measured yearly loads of 37.7 tons of acidity, quantified as calcium carbonate (CaCO3), along with 4,300 lbs of dissolved aluminum and 1,400 lbs of iron.

The 4,600-ton leachbed minimized those annual loads by 34 tons of acidity, 3,200 lbs of dissolved aluminum, and 1,180 lbs of dissolved iron.

Second Treatment Project

A second treatment project was constructed in 2020 by WVWRI and BRWA. It treats AMD entering the unnamed tributary to Swamp Run at river mile 1.0.

Although the pollutant load at this location was smaller, the treatment components were similar to those used in the first project. One important difference is that the more problematic of the two sources is first directed through an “iron oxidation terrace” before reaching the limestone leachbed.

The terrace removes a significant amount of iron from the polluted water. Without this step, iron could precipitate inside the leachbed and minimize its treatment capacity.

Before treatment, the second project site had annual acidity, aluminum, and iron loads of 8.5 tons, 80 lbs, and 6,300 lbs, respectively. The project removed an additional 7.3 tons of acidity, 37 lbs of aluminum, and 5,600 lbs of iron each year.

Treatment Results

Together, the two projects have removed substantial quantities of pollutants from Swamp Run. Their combined annual reductions total 41.7 tons of acidity, 3,200 lbs of aluminum, and 7,300 lbs of iron.

These reductions feature a substantial portion of the pollutant reductions identified in the 2016 TMDL for the Tygart River watershed. That TMDL called for reductions of 102 tons/year of acidity, 300 lbs/year of aluminum, and 20,500 lbs/year of iron.

As a result of the treatment projects, water quality measurements at the mouth of Swamp Run are currently meeting water quality standards.

BRWA will continue monitoring Swamp Run, its tributaries, and the remediation projects for at least two more years. The monitoring is intended to ensure that the treatment systems continue to perform well and that water quality standards remain satisfied.

The Swamp Run work represents a long-term effort to address AMD from abandoned mine lands. Beginning with watershed planning and continuing through two treatment projects, BRWA and WVWRI have reduced acidity and metal loads and achieved water quality measurements at the mouth of Swamp Run that currently meet state standards.

Source: U.S. Environmental Protection Agency

FAQs:

Q1. What is acid mine drainage?

Acid mine drainage is polluted water associated with abandoned mining areas. It can contain acidity and dissolved metals.

Q2. Why was Swamp Run affected by pollution?

Buried coal refuse in the watershed contributed to the formation of acid mine drainage. Polluted water entered Swamp Run and its tributaries.