Section 319
NONPOINT SOORGE PROGRAM SUCCESS STORY
Stormwater Wetland Basins Trap and Treat Nonpoint Source Pollutants
WatPrhndv Imnrnvpd Governor Bond Lake suffered from excessive algal growth and
turbidity, causing Illinois to list the lake on its 1998 303(d) list
of impaired waters. The impairments were caused by suspended solids, nutrients and other
nonpoint source pollutants both from within the lake (from legacy bottom sediments) and from
the lake's watershed. Project partners implemented best management practices (BMPs) such
as stormwater wetland basins (SWBs) and shoreline protection and stabilization practices. As
a result, levels of nutrients and suspended solids decreased, allowing Illinois to remove the
lake from its 2006 303(d) list of impaired waters for those pollutants. However, the waterbody
remains impaired by a high concentration of manganese from an unknown source.
Problem
Algal blooms and suspended sediment had
reduced clarity and dissolved oxygen in
Governor Bond Lake, which caused it to not
support its designated uses of recreation,
swimming, overall use and public water sup-
ply. Illinois Environmental Protection Agency
(EPA) identified the potential causes of the
impairment as manganese, phosphorus, total
suspended solids, excessive algal growth/chlo-
rophyll a and atrazine. The source of manganese
in Governor Bond Lake is unknown, but monitor-
ing results found concentrations exceeding the
state standard of 0.15 milligrams per liter.
Turbidity is a measurement of the cloudiness
of water due to solids suspended in the water
column. This can be detrimental to fish and
macroinvertebrates because it clogs their gills,
limits their visibility for feeding and reduces
growth.
High concentrations of phosphorus released
from bottom sediments result in eutrophica-
tion and low dissolved oxygen levels due to the
decay of algal blooms. This lack of dissolved
oxygen degraded water quality and reduced fish
populations.
In 2002 Illinois EPA completed nutrients and
sediment total maximum daily loads (TMDLs)
for Governor Bond Lake. Illinois EPA selected
water quality endpoints for the TMDLs that
were considered acceptable for the most
sensitive designated uses (e.g., to meet all
designated uses, the waterbody must meet the
guidelines identified for the most sensitive use).
Consequently, the most stringent values serve
as the endpoints for the TMDL analysis. In this
case, the endpoints for the TMDLs included the
Trophic State Index and Secchi depth values
required to meet the swimming use guidelines;
the non-volatile suspended solids value required
to meet the recreation use guidelines; and chlo-
rophyll a, total phosphorus, and siltation rate
values required to meet additional applicable
guidelines.
Project Highlights
To fulfill the goals set forth in the TMDLs, the
project partners implemented a series of BMPs
in the Governor Bond Lake watershed between
2002 and 2006. They constructed four SWBs
on the two main tributaries of Governor Bond
Lake—two on the Kingsbury Branch and two
on Dry Branch (see Figure 1). The basins were
designed to enhance aesthetics, provide excel-
lent wildlife habitat and remove nutrients and
suspended sediments from the stormwater that
flows off a portion of the watershed. The wet-
land plants absorb and filter nutrients and other
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Figure 1. Stormwater wetland basin: pre-construction.
soluble nonpoint source pollutants. Sediment
settles out and is stored at the bottom of the
SWBs (Figure 2).
Using section 319 funding and local match-
ing funds, project partners also implemented
shoreline protection and stabilization practices
(concrete seawalls, steel seawalls, riprap and
riparian plantings) along 4,608 linear feet of
Governor Bond Lake's shoreline. These practic-
es reduced shoreline erosion, which eliminated
a source of sediment entering the lake.
Results
The Illinois EPA in partnership with the city
of Greenville and cooperating landowners
have made great progress in meeting the
endpoint for the Governor Bond Lake TMDLs.
Implementing BMPs (SWBs, shoreline protec-
tion and stabilization) resulted in an estimated
75 percent reduction in total suspended solids,
45 percent reduction in phosphorus and 28
percent reduction in total nitrogen contributed
Figure 2. Stormwater wetland basin: post-construction.
to the lake. In 2006 Illinois removed four of the
five sources of pollution from the 303(d) list of
impaired waters, and the lake reached attain-
ment for three of the four designated uses. The
project partners' combined efforts are achieving
water quality improvements in Governor Bond
Lake. According to Illinois EPA's 2006 303(d) list,
only one impaired designated use (public water
supply) and one pollutant (manganese) remain.
Partners and Funding
The Illinois EPA administered $523,542 in sec-
tion 319 funding. Conservation 2000 and Illinois
Clean Lakes Program provided $383,339 in
matching funds as well as technical and admin-
istrative assistance. The Illinois EPA Nonpoint
Source Unit, Clean Lakes Unit and the city of
Greenville helped review, develop and install
the completed BMPs. The city of Greenville
contracted with several environmental engineer-
ing firms for creating design specifications and
overseeing construction.
\
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-08-001B
February 2008
For additional information contact:
David Willey, Manager, City of Greenville
618-664-1644
inquiry@greenvilleillinois.com
Scott Tomkins, Illinois EPA, Bureau of Water
217-782-3362
scott.tomkins@lllinois.gov
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