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Sixmile Run Beginning to Run .. lean Due to Treatment Practices
Waterbody Improvsd Petals anc' acidity in discharges from abandoned coal mines
impaired Pennsylvania's Sixmile Run, prompting the Pennsylvania
Department of Environmental Protection (PADEP) to add 7.4 miles of the stream's mainstem and
an unnamed tributary to the state's Clean Water Act (CWA) section 303(d) list of impaired waters
in 1996. Project partners installed 15 passive treatment systems at a cost of over $2.5 million to
address the impacts of the mine drainage discharges entering the stream. Water quality and aquatic
habitat have been improving; with the construction of one more system scheduled for 2018, PADEP
hopes the stream will soon be fully restored.
Problem
The Sixmile Run watershed drains approximately 14.6
square miles in south-central Pennsylvania's Bedford
County (Figure 1). This watershed is predominantly
forested but has experienced significant impairments
from abandoned mine drainage (AMD) dating back to
the 1800s. These AMD discharges deliver high metals
and acidity loads to Sixmile Run.
A stream survey conducted by PADEP in 1980
indicated that Sixmile Run was a degraded aquatic
ecosystem with depressed aquatic life due to AMD
impacts. As a result, PADEP included 6.17 stream miles
of the main stem and 1.23 stream miles of a tributary
of Sixmile Run on the state's 1996 CWA section 303(d)
list of impaired waters for not meeting the aquatic life
designated use due to elevated levels of metals and
acidity delivered through AMD. Broad Top Township
assessed the AMD discharges in Sixmile Run in 2000 to
diagnose the chemical and physical characteristics of
the problem and prioritize treatment.
Using the assessment data, project partners devel-
oped an AMD remediation plan in 2001. This plan was
updated in 2005 as a watershed implementation plan
to include treatment implemented since 2001, as well
as to reprioritize needs. PADEP developed a total maxi-
mum daily load (TMDL) in 2003 to serve as a pollution
diet for the Sixmile Run watershed. The TMDL set
limits for metals (aluminum, iron and manganese) and
acidity loads systematically along stations on Sixmile
Run. These limits, which differ per station based on the
site-specific existing pollutant loads, served as goals
for remediation.
Figure 1. Sixmile Run is in south-central Pennsylvania.
Story Highlights
Project partners analyzed the AMD discharges in the
Sixmile Run watershed and developed a remedia-
tion plan and TMDL. To help achieve TMDL targets,
partners designed and constructed passive treatment
systems to reduce metals and neutralize acidity in the
AMD discharges while improving the water quality
and aquatic habitat of Sixmile Run. When the water
comes into contact with limestone the pH levels are
raised, which in turn helps neutralize the acidity and
allows dissolved metals to precipitate out of solution
in a controlled environment (outside of the stream
ecosystem). Practices installed included a sediment
basin, a lined waterway/outlet, a vertical flow treat-
ment system, eight limestone leach bed/ponds, and
three constructed wetlands (Figures 2 and 3).
Sixmile Run
• Sixmile Run Sample Points
Streams
/V Not Attaining
/\y Unassessed
Attained
I I Psubbasins
Sixmile Run
Bedford County
Brewsters Hollow
townBram

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Figure 2. An aerator helps to neutralize acidity and
raise pH in the Sixmile Run drainage.
Figure 3. A limestone settling pond treats an AMD
discharge.
Results
Project partners attribute the improvement of this
stream segment to the passive treatment systems
installed to address the AMD discharges in this
watershed. As project partners continued to construct
passive treatment systems in the watershed, water
quality has been steadily improving. Monitoring has
been occurring at various sites along the stream since
2012. The results have been very promising, indicating
that quality may be good enough in the near future
to reassess the stream. The township has slowly built
systems starting in the headwaters and working their
way downstream. To show improvement, a few TMDL
points were chosen as sample points (Table 1). The
Table 1. Data collected at TMDL points 53 and 50 on
Sixmile Run show the TMDL limits and sample
results for the pollutants of concern before and after
treatment.
Sixmile Run
Monitoring
Iron
(mg/L)
Aluminum
(mg/L)
Manganese
(mg/L)
Acidity
(mg/L)
TMDL monitoring point 53
Before treatment
2.74
2.08
0.62
16.0
TMDL limits
0.70
0.20
0.36
0.00
After treatment
0.37
0.35
0.17
0.00
TMDL monitoring point 50
Before treatment
1.89
3.29
0.91
26.0
TMDL limits
0.70
0.20
0.36
0.00
After treatment
2.15
2.28
0.69
0.00
first point is located 0.5 miles from mouth but down-
stream of constructed systems (TMDL monitoring
point 53), while the second point (TMDL monitoring
point 50) is at the mouth of the stream.
Although not all metals have been removed, the
stream is now alkaline, showing that acidity has
been neutralized. This is a significant step towards
re-estabiishing aquatic life. A few fish have been
noticed swimming in the area. An area of discharges
affected by AMD remains active between the two
mentioned TMDL monitoring points. Hopefully the
construction of the next planned passive treatment
system will reduce metals significantly enough to sup-
port aquatic life.
Partners and Funding
Broad Top Township, Bedford County Conservation
District, the engineering firm of Skelly and Loy,
Western Pennsylvania Coalition of Abandoned Mine
Reclamation, U.S. Office of Surface Mining and PADEP
partnered to address the water quality problems in
the Sixmile Run watershed. Broad Top was awarded
$30,000 in an AMD Watershed Assessment Grant
from PADEP to collect data on the AMD discharges
in the watershed. Through 2014, the township has
been awarded $378,810 from Growing Greener;
$191,000 through Surface Mining Conservation and
Reclamation Act (SMCRA) grants (bond forfeiture); and
nearly $1.9 million from CWA section 319 to treat the
discharges.
U.S. Environmental Protection Agency
Office of Water
Washington, DC
W .1
^ EPA 841-F-18-001U
pRot^° October 2018
For additional information contact:
Donna Wagner
Pennsylvania Department of Environmental Protection
717-772-5173 • donnawagne@pa.gov

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