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Installing Restoration Projects Improves Poplar River Water Quality
Waterbody Improved For morethan a decade'the Poplar River	Board
(PRMB), community groups, and local and state partners tackled
stormwater runoff, streambank erosion, and slumping bluffs—and won. Work on restoring the river
began nearly 10 years ago, with the formation of a dedicated community group in 2006, intensive
and focused diagnostic studies conducted from 2007 to 2012, and large-scale targeted restoration
projects that began in 2008 and continue today. The Poplar River now meets water quality
standards for total suspended sediment and is proposed for removal from the state's impaired
waters list in 2018. In addition, the river boasts healthy habitat conditions that support and sustain a
diverse population of key fish and macroinvertebrates.
Problem
Poplar River is in northeastern Minnesota, it flows
approximately 25.5 miles through a picturesque
landscape of boreal forest and steep hills, eventually
draining to Lake Superior (Figure 1). The headwaters of
the 14-square-mile Poplar River watershed originate
within the Boundary Waters Canoe Area Wilderness.
The watershed includes a premier Midwest resort
area with ski runs, hiking trails, and boating and fishing
access sites for recreation. Downstream portions of
the Poplar River and watershed are characterized as
having significant drops in elevation (i.e., an average
gradient of nearly 4 percent). The area contains both
forested and non-forested steep slopes that are
dominated by soils derived from glacial lake deposits
of fine, easily erodibie material. Citizen interest in the
health of the river is high, whether they are anglers
concerned about the native trout fishery or area
residents concerned about water quality.
The Minnesota Pollution Control Agency (MPCA) listed a
portion of the river as impaired in 2004, which required
that a total maximum daily load (TMDL) study be
completed. The lower 3 miles was listed as impaired due
to exceedances of the turbidity standard (10 nephelo-
metric turbidity units), which was replaced in 2015, with
total suspended sediment (TSS) as the applicable water
quality standard. Sampling data demonstrated that
exceedances occurred frequently at flows greater than
68 cubic feet per second. The TMDL used a variety of
technical approaches and analyses to evaluate turbidity
and total suspended solids sources in the watershed
and near channel areas. Water quality modeling, a
Figure 1. I he Poplar River empties into Lake Superior in
northeastern Minnesota.
physical channel assessment, field investigations and
various statistical techniques were used to define the
source, nature, frequency and magnitude of sediment
loading in the river. Sediment sources identified by
the TMDL investigation included natural and human-
influenced land use issues associated with ski runs,
Christine I
County
Lake Superior
I Meters
Legend
I | Poplar River Watershed
I [ County Boundaries
Lakes (dnrpy2 and openwpy3)
¦I Wetlands (wetl_dnrpy2)
		 Streams (Baseln3)

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roads, trails, impervious surfaces related
to development, and ravines, gullies, and
slumping bluffs within the stream corridor.
Story Highlights
Poplar River TSS: Percent Exceedance of the Water Quality Standard
Samples collected: April - September
Percent of samples > 10 mg/L
Organized in 2005, the PRIVIES partnership
was primarily comprised of area landown-
ers, but also included elected officials,
resource agency members, including the
Cook County Soil and Water Conservation
District (SWCD) and the MPCA. Multiple
sediment management projects were
implemented to curb the amount of sedi-
ment entering the river. Projects targeted
highly erodible soils and land uses in the
lower watershed. Some projects were new
for the immediate area and innovative for
northern rivers, such as the area's first
very large-scale channel restoration. Also,
the "tightline" stormwater management
conveyances are more typical In the
western mountains than in northeastern
Minnesota. Partners installed targeted best manage-
ment practices (BMPs) near channel sources of erosion
and in upland areas to better manage stormwater
during high-flow events and to eliminate flow path-
ways that concentrated runoff. Streambank restoration
projects targeted slumping hillsides and repaired
significant ravines and gullies using new stormwater
management products. Several flow-path mitigation
projects closed roads and trails and re-configured
those needed for operations with updated BMPs to
slow, filter, divert and trap stormwater. Ski runs were
evaluated for adequate vegetated cover and proper
location of water bar BMPs. New development follows
low impact design criteria to minimize impacts.
The project work is currently transitioning from a
restoration-focused effort to a protection-focused
effort. Other partners in the watershed include lake
associations that have worked continuously to ensure
the upper watershed remains in good condition.
» Pre-BMP 6-year Average
~ Post-BMP 8-year Average
» TSS Standard

IU ¦ ¦ I ¦
I
2002 2003 2004 2005 2006 2007 2008* 2009 2010 2011 2012 2013 2014 2015 2016
Year
*2008 is probably too small/low given that several events were misssed.
Figure 2. Poplar River estimated daily TSS concentrations (April 2002-
September 2016).
story of the river's transition Including the Lake Superior
Streams web page, the Cook County News Herald, and
WTIP, the local radio station. The newspaper and radio
station have updated their audiences regularly regard-
ing the status of the river. The resorts and business in
this area, especially those part of the PRMB, changed
their business practices to improve the river.
The Cook County SWCD has developed more capacity
and skill in managing watershed science and monitor-
ing needs for impaired streams. Educational training
events for erosion and sediment control are held at
the resorts. In addition, resort staff are certified in
erosion and sediment management practices.
Results
The average annual sediment load in the river declined
by 300 tons from 2000 to 2010. At present, concentra-
tions of TSS are within the state standard 92 percent of
the time (Figure 2). Several organizations followed the
Partners and Funding
Funds spent on the project have included private
money, state grants from the Clean Water Land and
Legacy Funds, and federal funding sources, including
the Great Lakes Restoration Initiative and the National
Oceanic and Atmospheric Administration's Coastal
Program. Approximately $2.8 million have been
invested in the river to date: $874,008 from private
funds and the remainder from public funds. Ongoing
monitoring by the MPCA will provide the record of
this river's change. As runoff reduction efforts mature,
water quality will improve and be sustained.
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PRO^°
s
©
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA 841-F-19-001QQ
November 2019
For additional information contact:
Karen Evens
Minnesota Pollution Control Agency
218-302-6644 • karen.evens@state.mn,us

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