\ UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
o REGION
1650 Arch Street
Philadelphia, Pennsylvania 19103-2029
Decision Rationale
Total Maximum Daily Loads
Acid Mine Drainage Affected Segments
Wallace Run Watershed
Fayette County, Pennsylvania
Signed
Jon M. Capacasa, Director
Water Protection Division
Date: 7/10/2008
Printed on 100% recycled/recyclable paper with 100% post-consumer fiber and process chlorine free.
Customer Service Hotline: 1-800-438-2474
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Decision Rationale
Total Maximum Daily Loads
Acid Mine Drainage Affected Segments
Wallace Run Watershed, Fayette County, Pennsylvania
I. Introduction
The Clean Water Act (CWA) requires that Total Maximum Daily Loads (TMDLs) be
developed for those waterbodies identified as impaired by the state where technology based and
other controls will not provide for attainment of water quality standards. A TMDL is a
determination of the amount of a pollutant from point, nonpoint, and natural background sources,
including a Margin of Safety (MOS) that may be discharged to a waterbody without exceeding
water quality standards.
The Pennsylvania Department of Environmental Protection (PADEP) Bureau of
Watershed Management electronically submitted the Wallace Run Watershed TMDL, Fayette
County, for Acid Mine Drainage Affected Segments (TMDL Report), dated April 16, 2008, to the
U.S. Environmental Protection Agency (EPA) for final Agency review on April 16, 2008. This
report includes the TMDLs for the three primary metals associated with acid mine drainage
(AMD), i.e., iron, manganese, and aluminum, and addresses one segment on Pennsylvania's
1996 Section 303(d) List of impaired waters.
EPA's rationale is based on the TMDL Report and information contained in the
attachments to the report. EPA's review determined that the TMDL meets the following
seven regulatory requirements pursuant to 40 CFR Part 130:
1. The TMDL is designed to implement applicable water quality standards.
2. The TMDL includes a total allowable load as well as individual wasteload allocations
(WLAs) and load allocations (LAs).
3. The TMDL considers the impacts of background pollutant contributions.
4. The TMDL considers critical environmental conditions.
5. The TMDL considers seasonal environmental variations.
6. The TMDL includes a MOS.
7. The TMDL has been subject to public participation.
In addition, these TMDLs considered reasonable assurance that the TMDL allocations
assigned to the nonpoint sources can be reasonably met.
II. Summary
Table 1 presents the 1996, 1998 and 2002, Section 303(d) Listing, and the 2004 and 2006
Integrated Report listing of information for the impaired segment first listed in 1996
(Pennsylvania's 1996, 1998, and 2002 Section 303(d) Lists; and 2004 and 2006 Integrated
Reports were approved by the EPA. The 1996 Section 303(d) List provides the basis for
measuring progress under the 1997 lawsuit settlement of American Littoral Society and Public
Interest Research Group of Pennsylvania v. EPA).
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Table 1. 303(d) Listed Segments - State Water Plan Subbasin: 19C
HUC: 05020005 Lower Monongahela River
Year
1996
1996
1998
2002
2004
2006
2006
2006
2006
2006
Miles
0.8
0.5
1.29
1.3
1.3
1.33
0.27
0.71
0.38
0.67
Use
Designation
*
*
*
*
*
Aquatic Life
Aquatic Life
Aquatic Life
Aquatic Life
Aquatic Life
Assess-
ment ID
*
*
*
*
*
7617
13195
13195
13195
13195
Segment
ID
4913
4913
4913
4913
4913
*
*
*
*
*
DEP
Stream
Code
41088
41088
41088
41088
41088
41088
41088
41089
41090
41093
Stream
Name
Wallace
Run
Wallace
Run
Wallace
Run
Wallace
Run
Wallace
Run
Wallace
Run
Wallace
Run
Wallace
Run, Unt
Wallace
Run, Unt
Wallace
Run, Unt
Desig-
nated
Use
WWF
WWF
WWF
WWF
WWF
WWF
WWF
WWF
WWF
WWF
Data
Source
305(b)
Report
305(b)
Report
SWMP
SWMP
SWMP
SWMP
SWMP
SWMP
SWMP
SWMP
Source
RE
RE
AMD
AMD
AMD
AMD
AMD
AMD
AMD
AMD
EPA
305(b)
Cause
Code
Metals
Other
Inorganics*
Metals
Other
Inorganics*
Metals
Other
Inorganics*
Metals
Other
Inorganics*
Metals
Metals
Metals
Metals
Metals
Resource Extraction=RE
Warm Water Fish = WWF
Surface Water Monitoring Program = SWMP
Abandoned Mine Drainage = AMD
See Attachment D, Excerpts Justifying Changes Between the 1996, 1998, and 2002 Section 303(d) Lists and the 2004 and 2006 Integrated Water
Quality Report. The use designations for the stream segments in this TMDL can be found in PA Title 25 Chapter 93.
* Other Inorganics have been removed as a source of impairment.
See Attachment D of the TMDL Report, Excerpts Justifying Changes Between the 1996,
1998 and 2002 Section 303(d) Lists, and the 2004 and 2006 Integrated Report. The use
designations for the stream segments in this TMDL can be found in PA Title 25 Chapter 93.9v,
Section IV. Table 3 shows the TMDLs for the Wallace Run Watershed.
In 1997, PADEP began utilizing the Statewide Surface Waters Assessment Protocol to
assess Pennsylvania's waters. This protocol is a modification of EPA's 1989 Rapid
Bioassessment Protocol II and provides for a more consistent approach to conducting biological
assessments than previously used methods. The biological assessments are used to determine
which waters are impaired and should be included on the State's Section 303(d) List.
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The TMDLs in this report were developed using a statistical procedure to ensure that
water quality criteria are met 99% of the time as required by Pennsylvania's water quality
standards at Pennsylvania Code Title 25, Chapter 96.3c. Table 3 of the TMDL Report lists the
TMDLs for the Wallace Run Watershed, addressing metals in the stream segments listed as
PADEP stream code, 41088.
TMDLs are defined as the summation of the point source WLAs, plus the summation of
the nonpoint source, LAs plus a MOS and are often shown as follows:
TMDL = £WLAs + £LAs + MOS
The TMDL is a written plan and analysis established to ensure that a waterbody will
attain and maintain applicable water quality standards. The TMDL is a scientifically based
strategy which considers current and foreseeable conditions, utilizes the best available data, and
accounts for uncertainty with the inclusion of a MOS value. Since conditions, available data,
and the understanding of natural processes can change more than anticipated by the MOS, there
exists the option of refining the TMDL for resubmittal to EPA.
III. Background
The Wallace Run Watershed is located in southwestern Pennsylvania, occupying the
western central portions of Fayette County. The watershed is located on the Carmichaels 7.5'
quadrangle U.S. Geologic Survey map. The area within the watershed is approximately
4.2 square miles.
Wallace Run is part of the Monongahela River Basin in Fayette County and drains
directly into the Monongahela River. The Watershed area is west of Chestnut Ridge and is
located in the Waynesburg Hill section of the Appalachian Plateaus Physiographic Providence.
This section consists of very hilly terrain with narrow hilltops and steep-sloped, narrow valleys.
Elevations range from 848 to 1,638 feet. Some of the land surface of the section is very
susceptible to landslides.
Wallace Run is affected by pollution from AMD. This pollution has caused high levels
of metals, and in some cases low pH, in the watershed. All of the discharges in the watershed
are from abandoned mines and will be treated as nonpoint.
PADEP treats each segment on the Section 303(d) List as a separate TMDL and
expresses each TMDL as a long-term average loading. See the Wallace Run TMDL Report,
Attachment D, for the TMDL calculations.
The Surface Mining Control and Reclamation Act of 1977 (SMCRA, Public Law 95-87)
and its subsequent revisions were enacted to establish a nationwide program to, among other
things, protect the beneficial uses of land or water resources, protect public health and safety
from the adverse effects of current surface coal mining operations, and promote the reclamation
of mined areas left without adequate reclamation prior to August 3, 1977. SMCRA requires a
surface mining permit for the development of new, previously mined, or abandoned sites for the
purpose of surface mining. Permittees are required to post a performance bond that will be
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sufficient to ensure the completion of reclamation requirements by the regulatory authority in the
event that the applicant forfeits. Mines that ceased operating by the effective date of SMCRA
(often called "pre-law" mines) are not subject to the requirements of SMCRA.
Wallace Run was on the 1996 Section 303(d) List of impaired waters and counts toward
the twelfth year (2009) TMDL milestone commitment under the requirements of the 1997
TMDL lawsuit settlement agreement. The twelfth year milestone is the development of TMDLs,
or delisting, for all remaining waters listed as impaired by AMD impacts on Pennsylvania's 1996
Section 303(d) List of impaired waters.
Computational Procedure
The TMDLs were developed using a statistical procedure to ensure that water quality
criteria are met 99% of the time as required by Pennsylvania's water quality standards. A two-
step approach was used for the TMDL analysis of impaired stream segments.
The first step used a statistical method for determining the allowable instream
concentration at the point of interest necessary to meet water quality standards. An allowable
long-term average instream concentration was determined at each sample point for metals and
acidity. The analysis was performed using Monte Carlo simulation to determine the necessary
long-term average concentration needed to attain water quality criteria 99% of the time, and the
simulation was run assuming the dataset was log normally distributed. Using @RISK2, each
pollutant source was evaluated separately by performing 5,000 iterations of the model where
each iteration was independent of all other iterations. This procedure was used to determine the
required percent reduction that would allow the water quality criteria to be met instream at least
99% of the time. A second simulation that multiplied the percent reduction by the sampled value
was run to ensure that criteria were met 99% of the time. The mean value from this dataset
represents the long-term average concentration that needs to be met to achieve water quality
standards.
The second step was a mass balance of the loads as they passed through the watershed.
Loads at these points were computed based on average flow. Once the allowable concentration
and load for each pollutant was determined, mass-balance accounting was performed starting at
the top of the watershed and working downstream in sequence. This mass balance or load
tracking through the watershed utilized the change in measured loads from sample location to
sample location as a guide for expected changes in the allowable loads.
The existing and allowable long-term average loads were computed using the mean
concentration from @RISK multiplied by the average flow. The loads were computed based on
average flow and should not be taken out of the context for which they are intended. They are
intended to depict how the pollutants affect the watershed and where the sources and sinks are
located spatially in the watershed. A critical flow was not identified, and the reductions
specified in this TMDL apply at all flow conditions.
2
@RISK - Risk Analysis and Simulation Add-in for Microsoft Excel, Palisade Corporation, Newfield,
NY.
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IV. Discussions of Regulatory Requirements
EPA has determined that these TMDLs are consistent with statutory and regulatory
requirements and EPA policy and guidance.
1. The TMDLs are designed to implement the applicable water quality standards.
Water quality standards are state regulations that define the water quality goals of a
waterbody. Standards are comprised of three components: (1) designated uses; (2) criteria
necessary to protect those uses; and (3) antidegradation provisions that prevent the degradation
of water quality. Wallace Run has been designated by Pennsylvania as a warm water fishery
with criteria to protect the aquatic life use, and the designation can be found at Pennsylvania
Title 25 §93.9v. To protect the designated use as well as the existing use, the water quality
criteria shown in Table 2 apply to all evaluated segments. The table includes the instream
numeric criterion for each parameter and any associated specifications.
Table 2. Applicable Water Quality Criteria
Parameter
Aluminum (Al)
Iron (Fe)
Manganese (Mn)
pH
Criterion
Value (mg/1)
0.75
1.50
0.30
1.00
6.0-9.0
Duration
Maximum
30-day Average
Maximum
Maximum
Inclusive
Total Recoverable/
Dissolved
Total Recoverable
Total Recoverable
Dissolved
Total Recoverable
N/A
Pennsylvania Title 25 §96.3c requires that water quality criteria be achieved at least
99% of the time, and TMDLs expressed as long-term average concentrations are expected to
meet these requirements. That is, the statistical Monte Carlo simulation used to develop TMDL
WLAs and LAs for each parameter resulted in a determination that any required percent
pollutant reduction would assure that the water quality criteria would be met instream at least
99% of the time. The Monte Carlo analysis performed 5,000 iterations of the model where each
iteration was independent of all other iterations and the dataset was assumed to be log normally
distributed.
EPA finds that these TMDLs will attain and maintain the applicable narrative and
numeric water quality standards.
The pH values shown in Table 2 were used as the endpoints for these TMDLs. In the
case of freestone streams with little or no buffering capacity, the allowable TMDL endpoint for
pH may be the natural background water quality, and these values can be as low as 5.4
(Pennsylvania Fish and Boat Commission). However, PADEP chose to set the pH standard
between 6.0 to 9.0, inclusive, which is presumed to be met when the net alkalinity is maintained
above zero. This presumption is based on the relationship between net alkalinity and pH, on
which PADEP based its methodology to addressing pH in the watershed (see the Wallace Run
Watershed TMDL Report, Attachment B). EPA finds this approach to addressing pH to be
reasonable.
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2. The TMDLs include a total allowable load as well as individual waste load allocations and
load allocations.
For purposes of these TMDLs only, point sources are identified as permitted discharge
points or discharges having responsible parties, and nonpoint sources are identified as any
pollution sources that are not point sources. Abandoned mine lands were treated in the
allocations as nonpoint sources. As such, the discharges associated with these land uses were
assigned LAs (as opposed to WLAs). The decision to assign LAs to abandoned mine lands does
not reflect any determination by EPA as to whether there are unpermitted point source
discharges within these land uses. In addition, by approving these TMDLs with mine drainage
discharges treated as LAs, EPA is not determining that these discharges are exempt from NPDES
permitting requirements.
Once PADEP determined the allowable concentration and load for each pollutant, a mass
balance accounting was performed starting at the top of the watershed and working downstream
in sequence. Load tracking through the watershed utilizes the change in measured loads from
sample location to sample location as a guide for expected changes in the allowable loads.
PADEP used two basic rules for the load tracking between two ends of a stream segment:
(1) if the measured upstream loads are less than the downstream loads, it is indicative that there
is an increase in load between the points being evaluated, and no instream processes are
assumed; and (2) if the sum of the measured loads from the upstream points is greater than the
measured load at the downstream point, it is indicative that there is a loss of instream load
between the points, and the ratio of the decrease shall be applied to the allowable load being
tracked from the upstream point.
Tracking loads through the watershed provides a picture of how the pollutants are
affecting the watershed based on the available information. The analysis is performed to ensure
that water quality standards will be met at all points in the stream. EPA finds this approach
reasonable.
Table 3. Wallace Run Watershed Summary Table
Parameter
Existing
Load
(Ibs/day)
TMDL
Allowable
Load
(Ibs/day)
WLA
(Ibs/day)
LA
(Ibs/day)
NFS Load
Reduction
(Ibs/day)
NFS %
Reduction
WALL06 - Unnamed Tributary to Wallace Run at mouth
Aluminum (Ibs/day)
Iron (Ibs/day)
Manganese(lbs/day)
Acidity (Ibs/day)
0.25
0.75
0.59
-169.45
0.25
0.58
0.24
NA
.
-
-
-
NA
0.58
0.24
NA
NA
0.17
0.35
NA
NA
22%
59%
NA
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Parameter
Existing
Load
(Ibs/day)
TMDL
Allowable
Load
(Ibs/day)
WLA
(Ibs/day)
LA
(Ibs/day)
NFS Load
Reduction
(Ibs/day)
NFS %
Reduction
WALL05 - Wallace Run upstream of confluence with WALL06 Unnamed Tributary
Aluminum (Ibs/day)
Iron (Ibs/day)
Manganese(lbs/day)
Acidity (Ibs/day)
1.08
0.97
1.67
1.82
0.10
0.14
0.08
0.95
-
-
.
.
0.10
0.14
0.08
0.95
0.98
0.83
1.59
0.87
91%
86%
95%
48%
WALL04 - Unnamed Tributary to Wallace Run at mouth
Aluminum (Ibs/day)
Iron (Ibs/day)
Manganese(lbs/day)
Acidity (Ibs/day)
0.48
0.29
0.1
-322.82
NA
NA
NA
NA
-
.
.
-
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
WALL03 - Unnamed Tributary to Wallace Run at mouth
Aluminum (Ibs/day)
Iron (Ibs/day)
Manganese(lbs/day)
Acidity (Ibs/day)
0.14
1.83
2.58
-167.52
0.14
0.38
0.34
NA
.
.
-
-
NA
0.38
0.34
NA
NA
1.45
2.24
NA
NA
79%
87%
NA
WALL02 - Unnamed tributary to Wallace Run at mouth
Aluminum (Ibs/day)
Iron (Ibs/day)
Manganese(lbs/day)
Acidity (Ibs/day)
0.19
0.20
0.02
-61.86
0.07
0.14
0.02
NA
.
-
-
.
0.07
0.14
NA
NA
0.12
0.06
NA
NA
65%
31%
NA
NA
WALL01 - Wallace Run at mouth
Aluminum (Ibs/day)
Iron (Ibs/day)
Manganese(lbs/day)
Acidity (Ibs/day)
6.70
7.52
4.19
-785.73
0.40
0.75
0.55
NA
-
-
.
-
0.40
0.75
0.55
NA
5.20
4.26
0.11
NA
93%*
86%*
17%*
NA
NA = not applicable ND = not detected
*Takes into account load reductions from upstream sources.
PADEP allocated to nonpoint sources and point sources. There are no active mining
operations in the watershed. Where there are active mining operations, Federal regulations
require that point source permitted effluent limitations be water quality based subsequent to
TMDL development and approval3. In addition, PA Title 25, Chapter 96, Section 96.4d requires
that WLAs serve as the basis for determination of permit limits for point source discharges
regulated under Chapter 92 (relating to NPDES permitting, monitoring, and compliance).
Therefore, no new mining may be permitted within the watershed without reallocation of the
TMDL. Additionally, no required reductions of permit limits are necessary at this time, as all
necessary reductions have been assigned to nonpoint sources.
It should be noted that technology-based permit limits may be converted to water quality-based limits according to
EPA's Technical Support Document For Water Quality-based Toxics Control, March 1991, recommendations.
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3. The TMDLs consider the impacts of background pollutant contributions.
The TMDLs were developed using instream data, which account for existing background
conditions.
4. The TMDLs consider critical environmental conditions.
The reductions specified in these TMDLs apply at all flow conditions. A critical flow
condition was not identified from the available data.
5. The TMDLs consider seasonal environmental variations.
The dataset included data points from all seasons, thereby accounting for seasonal
variation implicitly.
6. The TMDLs include a Margin of Safety.
The CWA and Federal regulations require TMDLs to include a MOS to take into account
any lack of knowledge concerning the relationship between effluent limitations and water
quality. EPA guidance suggests two approaches to satisfy the MOS requirement. First, it can be
met implicitly by using conservative model assumptions to develop the allocations. Alternately,
it can be met explicitly by allocating a portion of the allowable load to the MOS.
PADEP used an implicit MOS in these TMDLs by assuming that the treated instream
concentration variability was the same as the untreated stream's concentration variability. This
is a more conservative assumption than the general assumption that a treated discharge has less
variability than an untreated discharge. By retaining variability in the treated discharge, a lower
average concentration is required to meet water quality criteria 99% of the time than if the
variability of the treated discharge is reduced.
Additionally, calculations were performed using a daily average for iron rather than the
30-day average, thereby, incorporating a MOS.
7. The TMDLs have been subject to public participation.
Public notice of the draft TMDL was published in the Pennsylvania Bulletin and the
Herald Standard on January 22, 2008, to foster public comment on the allowable loads
calculated. The public comment period on this TMDL was open January 19, 2008 to March 19,
2008. A public meeting was held on February 5, 2008, at the Greensburg District Mining Office
to discuss the proposed TMDL. No comments were received.
Although not specifically stated in the TMDL Report, PADEP routinely posts the
approved TMDL Reports on their web site: www.dep.state.pa.us/watermanagement apps/tmdl/.
V. Discussion of Reasonable Assurance
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Aside from PADEP's primary efforts to improve water quality in the Wallace Run
Watershed through reclamation of abandoned mine lands and through the NPDES permit
program, additional opportunities for reasonable assurance exist. PADEP expects that activities
such as research conducted by its Bureau of Abandoned Mine Reclamation, funding from EPA's
§319 Grant program, and Pennsylvania's Growing Greener program will help remedy abandoned
mine drainage impacts. PADEP also has in place an initiative that aims to maximize reclamation
of Pennsylvania's abandoned mineral extraction lands. Through Reclaim PA, Pennsylvania's
goal is to accomplish complete reclamation of abandoned mine lands and plugging of orphaned
wells. Pennsylvania strives to achieve this objective through legislative and policy land
management efforts and activities described in the TMDL Report.
Currently, there is no watershed organization interested in the Wallace Run Watershed.
It is recommended that agencies work with local interests to form a watershed group that will be
dedicated to the remediation and preservation of these watersheds through public education,
monitoring and assessment, and improvement.
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