Section 319
NONPOINT SOORGE PROGRAM SOGGESS STORY
Implementing Best Management Practices Reduces Herbicide
Concentrations in Monroe City Route J Lake
A/ t h H I H Herbicides applied to row crops, combined with subsequent
VVaterDOay improved stormwater runoff/ |ed to periodic high concentrations of atrazine
and cyanazine in the Monroe City Route J Lake, a drinking water source in northeastern Missouri.
As a result, the Missouri Department of Natural Resources (MDNR) placed the lake on the state's
Clean Water Act (CWA) section 303(d) list of impaired waters for atrazine (1996) and cyanazine (1998).
Through an outreach program, farmers were encouraged to apply herbicides more carefully and
implement best management practices (BMPs). Herbicide concentrations in the lake declined and
began to meet Missouri's water quality standards, prompting MDNR to remove the lake from the CWA
section 303(d) list of impaired waters in 2006.
Problem
The 94-acre Monroe City Route J Lake is the larger
of two lakes that provide the drinking water sup-
ply for Monroe City and three rural water districts
in northeast Missouri (Figure 1). Located within
the Salt River Basin, the reservoir's subwatershed
includes 5,000 acres of primarily agricultural land.
State records indicate that, beginning in 1990, the
lake water contained elevated levels of atrazine and
cyanazine, two agricultural herbicides that were
commonly applied in Missouri on corn and grain
sorghum for broadleaf weed control. As the result
of a U.S. Environmental Protection Agency (EPA)
Special Review, cyanazine was gradually withdrawn
from use by 2002 after being linked to a range of
adverse health effects. Since then, cyanazine in
Missouri waters has virtually disappeared.
Since 1993, atrazine use has been restricted, but it
continues to be widely used in Missouri. Atrazine
is considered a human carcinogen, so the state
standard is set at a low level, 3.0 micrograms
per liter (/jg/L). Unlike many herbicides, atrazine
is weakly adsorbed (attached) to soil particles;
therefore, the herbicide is readily transported off
a field by runoff, regardless of the erosion control
measures in place. In the 1990s, MDNR measured
high levels (as high as 20/jg/L) of both cyanazine
and atrazine in the lake. As a result, MDNR added
the Monroe City Route J Lake to the state's CWA
section 303(d) list of impaired waters for atrazine
(1996) and cyanazine (1998). The lake was restored
before a TMDL was developed.
Monroe City
RouteJLake
Figure 1. The Monroe City Route J Lake is in an
agricultural area in northeast Missouri.
Project Highlights
In 1998, a group of watershed partners (including
city residents, elected officials, farm owners and
producers, representatives of agricultural business
and manufacturing, and government) completed the
Monroe City Water Resources Management Plan,
which identified action items needed to protect
drinking water reservoirs and address atrazine
and other contaminants. The following year, the
Missouri Food and Agriculture Policy Research
Institute (FAPRI) developed a Monroe City Route J
Watershed Farm Level Environmental Assessment
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using $151,000 in CWA section 319 funding. The
study provided baseline information for several
water quality concerns in the watershed and found
that single-pass herbicide applications (one applica-
tion after the crop emerges from the ground) were
typical for farms in the study area.
Also, in 1999, the Rails County Soil and Water
Conservation District (SWCD) received $5,000 in
CWA section 319 funds to implement demonstration
projects and educational efforts targeting atrazine
runoff. A strong partnership of stakeholders helped
to ensure the project's success. The Clarence
Cannon Wholesale Water Commission received
additional CWA section 319 funds ($136,000) in
2000 to develop a watershed-based Watershed
Restoration Action Strategy (WRAS) for the North
Fork Salt River, which included conducting out-
reach to identify and promote alternative herbicide
management practices. Although focused on the
North Fork Salt River watershed, outreach efforts
regarding herbicides extended to other basins in the
geographic area, including the Salt River.
The education and outreach projects convinced
farmers to implement changes in their herbicide
application procedures. Before the outreach efforts,
agricultural producers treated about 95 percent
of corn acres in the subbasin with a 3:1 pre-mix
of cyanazine and atrazine applied in the spring of
each year. The average amount of active ingredi-
ent applied per acre was 1.5 pounds atrazine and
2.25 pounds cyanazine. After the outreach effort,
farmers applied only 1.0 pound of atrazine per acre
and applied it post-emergence—after the spring
rains and as part of a two-pass program, which
involved treating fields both before and after new
crops emerge from the ground. Reduced applica-
tion rates and partial treatment of fields provided
excellent weed control and reduced costs to grow-
ers. Landowners also implemented other BMPs,
including installing filter strips, planting buffer
zones, moving tile outlets and improving terrace/
outlet construction practices.
Results
Atrazine concentrations in Monroe City Route J
Lake declined as a result of outreach and consen-
sus-building programs that promoted improved
herbicide management practices and BMP imple-
mentation throughout the watershed.
Data show that atrazine levels in raw or untreated
water at the Route J reservoir during the criti-
cal period of April through July were reduced
Annual Average and Three Year Running Average
Atrazine Levels in Monroe City Rte J Lake
Annual Average —•—Three Year Running Average
^^— Water QualityStandard
1990
2010
Figure 2. The lake has met standards for atrazine since 2002.
by 72 percent in 2000 as compared to average
concentrations during the same time period from
1995-1998 (Figure 2). Once EPA had phased out
cyanazine in 2002, levels dropped in lakes across
Missouri, including Route J Lake. Because the lake
now meets water quality standards for atrazine and
cyanazine, MDNR removed it from the state's CWA
section 303(d) list of impaired waters in 2006.
Partners and Funding
Over a six- to eight-year period, collaborative efforts
involving many partners changed approaches to
agricultural atrazine use and improved water quality
in portions of northeast Missouri.
Strong partnerships in the efforts described in the
preceding sections helped to reduce herbicide levels
in the Monroe City Route J Lake. Watershed part-
ners included the U.S. Department of Agriculture,
Natural Resources Conservation Service (NRCS);
Lincoln University Extension; University of Missouri-
Columbia; University Outreach and Extension-
Columbia; Mark Twain Water Quality Initiative; Quinn
Farm Supply; Monroe City COOP; EPA and MDNR.
Funding for the 1998 Monroe City Water Resources
Management Plan was provided by the NRCS,
University of Missouri Outreach and Extension, and
Missouri Department of Conservation. A number of
CWA section 319 grants supported the project imple-
mentation, including (1) $151,000 to the University
of Missouri FAPRI for the Monroe City Route J
Watershed Farm Level Environmental Assessment,
(2) a $5,000 mini-grant to the Rails County SWCD
for outreach and demonstration projects, and a
(3) $136,000 sub-grant to the Clarence Cannon
Wholesale Water Commission for outreach and
WRAS development. Farmers received cost-share
funding from the SWCD to help implement BMPs.
5
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-12-001UU
November 2012
For additional information contact:
Greg Anderson
Missouri Department of Natural Resources
Water Protection Program
573-751-7144 • greg.anderson@dnr.mo.gov
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