Montour Run Watershed Assessment & Implementation Plan

Table 3.1.1-Abandoned mine discharges in the Montour Run Watershed as identified in the AMD Cleanup Plan.
Future Goals &
Recommendations
i. Quantifiable Goals &
Objectives
Water Treatment and Best Management Practices
(BMPs) Already Implemented or Planned
Existing Stormwater BMPs and Enhancements to
Existing BMPs: We identified over 40 sites where Best
Management Practices, (BMPs) were employed to
manage stormwater (Figure 3.1.1). Two rain gardens,
documented as part of the 3 Rivers Wet Weather Green
Infrastructure Atlas (http://www.3riverswetweather.org/
green-infrastructure), are located in the business district
of the E. Upper McClaren subwatershed. One raingarden
is located on property next to the Moon Township Municipal
Building and the second is located on the grounds
of the Kenny Ross Toyota dealership. There may be other
BMPs located in the Montour Run Watershed. In particular,
smaller-scale green infrastructure installations such as
residential-scale rain gardens cannot be located via GIS/
spatial analysis.
Through visual assessment of spatial data and specific
spatial analysis, over 30 detention basins were identified,
designed to capture stormwater from impervious surfaces
and release it to receiving waters. We also identified
10 retention basins, designed to capture and hold water.
There are also likely other smaller detention basins
that could not be identified via spatial analysis. These
detention and retention basins were commonly located
down-gradient from large parking lots in shopping centers
and suburban housing developments.
Usually, existing detention basins were not designed to
capture and detain frequent small storms, instead channeling
water to nearby streams quickly. Storm basins can
be retrofitted to hold, absorb, and filter stormwater runoff.
For example, adding a sediment forebay (via the addition
of a berm to the bottom of the basin) slows water
and allows sediment to drop out, increasing the removal
effectiveness. Decreasing the orifice size in the outflow
control structure increases retention time in the basin.
This allows the water to infiltrate into the soil, undergo
biofiltration and evapotranspiration processes, and capture
a greater range of storms. Converting the detention
basin to a bio-retention basin through the use of filtering
media, engineered soils, plants, etc. adds wildlife habitat,
increases biofiltration evapotranspiration processes, and
increases nutrient and sediment retention.
AMD Treatment Sites, Existing and Planned: To date,
there are five AMD treatment sites in the watershed that
significantly reduce metal loading into Montour Run (Table
3.1.1). As a result of these treatment sites, BioMost
projected that metal loading could be reduced by between
23-25 tons annually and ~45 tons of acidity may be
removed from the stream water (Stream Restoration, Inc.).
AMD increases sediment and metals (part of sediment)
and can change pH of water. Bedrock in Western Pennsylvania
has a high carbonate content that buffers acid
effects from the AMD, which makes pH less of an issue
in this area. The BioMost report on AMD evaluated each
site, measured water quality parameters in water draining
from each site, and then quantified the pollutants from
each site. The study also provided specific conceptual
plans for remediation and quantified reductions based on
these conceptual plans. For Subwatershed Areas 2 and 3
Site Treatment? Estimated Sediment (as metals)
- from BioMOST study
MP5 (McCaslin Road)
NFMU9/(MP1) (North Fork)
MP2
NFMU5/(MP8)
NFMU6
MP6
SFMU2/Pre1 (Boggs Road)
SFMS6
SFMS7
SFMD7
SFMD3
MKR3* (Milk Run)
Pre2 (Clinton Road)
in particular, focus should be placed on implementing the
remediation plans outlined in the BioMost report, including:
• address the sites examined, but not yet remediated.
• evaluate the efficacy of each existing AMD treatment
site.
• continue to make sure existing and future sites are
climate-change ready.
Increases in groundwater volume will potentially result
in drainage from mines to streams, which will lead to an
increase in sedimentation and erosion. The increasing
drainage is accompanied by increases in water-borne
sediment and erosion. Therefore, it is important to ensure
that the AMD remediation sites are adequately sized for
increased water inputs due to changing rain regimes.
No
Yes
No
No
No
No
Yes
Yes
No
No
No
Yes
Yes
General Policy and Focus Recommendations for
the Montour Run Watershed
Focus on up-gradient efforts that filter/detain runoff
and prevent it from directly entering the stream:
The Montour Run Watershed has two major categories
of water quality problems that can be sourced to either
Abandoned Mine Drainage or non-point source (NPS)
stormwater inputs. AMD sources can generally be traced
1.1 tons/year
2.8 tons/year
1.4 tons/year
1.9 tons/year
1.3 tons/year
1.6 tons/year
1.7 tons/year
2.3 tons/year*
1.3 tons/year
0.4 tons/year
0.1 tons/year
3.9 tons/year*
21.4 tons/year
Approx. Costs
$160,000
$330,000
$450,000
$550,000
$600,000
$230,000
$120,000
$520,000
$330,000
$300,000
$250,000
$1,200,000
$282,000
*This discharge is largely Aluminum, which can be fatal to aquatic life in high concentrations.
to a point source and are relatively well-quantified. On
the other hand, stormwater carries pollution from across
the landscape to the stream, and concentrated flow
paths cause erosion. Existing TMDLs for the Montour Run
Watershed address abandoned mine drainage. The NPS
erosion, pollution inputs, and sediment caused by stormwater
runoff is not covered by a specific water quality
standard or TMDL agreement. Water quality improvement
efforts should focus on this gap and work to reduce
NPS pollution, including sediment and nutrients, entering
streams. Increasing infiltration of surface runoff to
groundwater will increase the physical filtration of sediments,
add to groundwater resources, and aid in the mitigation
of downstream flooding. In addition, infiltration
increases contact time with soil bacteria and plants that
can process chemicals and/or incorporate nutrients into
biomass, thereby preventing transportation downstream.
Each of these problems is best addressed in the upland or
source zones, before overland flow enters the stream.
Pursue a Better Basemap to increase modeling efficiency
and accuracy: Stormwater and associated problems
are the other category of water quality problems in
Montour Run. Stormwater rushes across the land surface
carrying pollutants from atmospheric deposition, leaking
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