Section 319
NONPOINT SOORCE PROGRAM SUCCESS STORY
Erosion Control Projects Reduce Manganese Levels in Reservoir
\A/atP hnrl I n n prl Erosion from agriculture and other land-based activities resulted
in elevated levels of manganese, sediment and phosphorus
in the Charleston Side Channel Reservoir (CSCR). The pollutants contributed to excess algal
growth. Illinois Environmental Protection Agency (Illinois EPA) added the CSCR to the state's
Clean Water Act (CWA) section 303(d) list of impaired waters beginning in 1998 for a variety of
pollutants, including phosphorus, sediment and manganese (added in 2004). To reduce erosion
and manage nutrients, project partners installed shoreline stabilization structures and other
best management practices (BMPs). Manganese levels dropped, prompting Illinois EPA to
remove the reservoir from the 2008 CWA section 303(d) list for manganese.
Problem
The CSCR is a 346-acre public water supply in
Coles County, Illinois, which serves Eastern Illinois
University and the city of Charleston (population
21,149). The reservoir also serves as a public recre-
ational area (Figure 1).
In 1895 Charleston constructed a channel dam in
the Embarras River to create its first water supply
reservoir. In 1947 the city constructed a second
dam to create a larger reservoir (Lake Charleston)
to serve a growing population. In the early 1950s
Charleston began addressing the problem of
sedimentation in the reservoir. In 1982 Charleston
created a side-channel reservoir (the CSCR) to use
as its public water supply by building a dike in Lake
Charleston to create two separate waterbodies.
Adding the CSCR greatly reduced the city's prob-
lems with siltation, but it did not alleviate all the
water quality problems. In 1992 the city completed
a U.S. Environmental Protection Agency (EPA) Clean
Lakes Program (CWA section 314) Diagnostic/
Feasibility report on the CSCR—just 10 years after
it was built. The report identifies land use activities
in the 1,133-acre CSCR watershed as a significant
source of sediment, nitrate and phosphorus. It also
pinpoints shoreline erosion as a significant source
of the phosphorus and sediment.
When phosphorus, nitrate and manganese reach
the reservoir in the form of eroded soil and excess
fertilizers, they support excess algae growth.
Decomposing aquatic plants consume dissolved
oxygen and release manganese into the lake.
Figure 1. A boat is docked in the CSCR near a
shoreline stabilization site.
Excess manganese in water can cause objection-
able discoloration effects and odors of the drinking
water supply. When reduced oxygen and warmer
temperatures combine, fish and macroinverte-
brates that are less pollutant tolerant die, only to be
replaced by those that are less desirable.
The applicable Illinois water quality standard for total
phosphorus (TP) in lakes is 0.05 milligrams per liter
(mg/L). In 1998 the reservoir's average TP concentra-
tion was 0.10 mg/L, prompting Illinois EPA to add
the CSCR to the impaired waters list. In 2003 Illinois
EPA developed a total maximum daily load for the
CSCR that addressed dissolved oxygen, excess algal
growth, TP, sedimentation/siltation and total sus-
pended solids. In its 2004 Integrated Report, Illinois
EPA noted that the reservoir was also impaired by
manganese and excess algal growth.
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Project Highlights
Since 1993 CWA section 319 funds supported three
restoration projects in the CSCR and Embarras River
watersheds. Numerous traditional erosion control
projects were sponsored by the U.S. Department
of Agriculture Natural Resources Conservation
Service, Illinois Department of Agriculture, and the
Coles County Soil and Water Conservation District.
Projects included stabilizing 5,731 lineal feet of
shoreline (Figure 2) and 1,650 lineal feet of stream-
bank, planting 4.5 acres of grassed waterways,
installing 3 grade stabilization structures, and build-
ing an in-lake sediment detention basin (Figure 3).
Also, partners worked with landowners to imple-
ment 184 acres of conservation tillage and nutrient
management planning to further control erosion.
Figure 2. The
city used a
barge designed
specifically
for shoreline
stabilization,
complete with
riprap conveyor
belt, to install both
the in-lake basin
and the shoreline
stabilization
practices.
Figure 3. The city
installed an in-lake
sediment detention
basin; note the
difference in water
clarity between the
upstream side (left)
and lake side (right).
Partners installed BMPs on city property and on
privately owned land in the two watersheds. All
the practices were designed to control erosion
and reduce sediment delivery to the lake and river
and, in turn, reduce the amount of nutrients being
transported by the sediment to the lake.
Project partners relied on many of the practices to
serve as demonstration sites where neighboring
landowners could watch and learn. The city experi-
mented with different types of shoreline erosion
control practices and compared not only the ease
of application, but also the erosion control benefits,
wildlife habitat benefits and safety issues.
Results
The BMPs installed in the CSCR watershed reduced
the pollutant load by an estimated 1,627 tons of
sediment per year, 1,371 pounds of phosphorus
per year and 2,738 pounds of nitrogen per year.
Reservoir monitoring showed a decrease in man-
ganese concentrations to levels below the state
water quality standard,
which requires concen-
trations to be less than
150 micrograms per liter
(jUg/L) for a public water
supply (Table 1).
Table 1. CSCR manganese
(Mn) concentrations met water
quality standards in 2007
Sample Date
4/19/2007
7/10/2007
9/4/2007
10/23/2007
Mn (|Ag/L)
50
130
120
92
On the basis of those
data, Illinois EPA
removed the CSCR
from the state's 2008
CWA section 303(d) list
of impaired waters for
manganese. The reduced levels of manganese
in the lake will lead to a smaller algal population
and will help decrease objectionable discoloration
effects and odors in the drinking water. In addition,
the projects implemented in the watershed will
continue to benefit the community by further reduc-
ing soil, nitrogen and phosphorus entering the lake,
thus improving wildlife habitat.
Partners and Funding
EPA provided $194,449 in CWA section 319 fund-
ing to Illinois EPA to support implementation of
BMPs that reduced sediment and nutrient loads,
including streambank and lake shore stabilization
and installation of an in-lake sediment detention
basin. The city of Charleston, Coles County Soil and
Water Conservation District, Illinois Department of
Agriculture, and Eastern Illinois University also used
section 319 funding to install BMPs.
I
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-10-001M
August 2010
For additional information contact:
Amy Walkenbach
Nonpoint Source Unit Manager
Illinois EPA
217-782-3362 • amy.walkenbach@illinois.gov
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