Section 319
NONPOINT SOURCE PRMRAM SUCCESS STORY
Agricultural BMPs Reduce Herbicide Concentrations in Five Drinking Water Lakes
Cameron Lakes, Mark Twain Lake, and Smithville Lake, Missouri
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runoff impaired the water quality of five lakes in northern Missouri
that were used as sources of drinking water. In 1998 the three Cameron Lakes, Mark Twain Lake,
and Smithville Lake were placed on the 303(d) list of impaired waters for periodic high-atrazine
concentrations. The project partners used a science-based approach to identify priority watersheds
with the highest pollutant loading contributions. Through an outreach program, farmers were
encouraged to measure and time atrazine applications more carefully, which allowed all five lakes to
successfully meet water quality standards and to be removed from the 303(d) list in 2003.
Problem
In 1998 the Missouri Department of Natural
Resources placed five lakes in northern
Missouri (three Cameron Lakes, Mark Twain
Lake and Smithville Lake) on the 303(d) list
because they exceeded state water qual-
ity standards for atrazine. All had periodic
atrazine concentrations above the Maximum
Contaminant Level (MCL) of 3 parts per billion
(ppb) established for public drinking water
supplies.
Atrazine is a low-cost herbicide used for
combating grass and broadleaf weeds in corn
and is widely used. Farmers were concerned
that they would have to greatly restrict use of
the herbicide in their corn and soybean opera-
tions. The Environmental Resources Coalition
(ERC), a nonprofit organization, used 319 fund-
ing and, with partners, formed the Watershed
Research, Assessment and Stewardship
Project (WRASP) to put together a strategy
to improve water quality without negatively
affecting farmers' business profits.
Project Highlights
Monitoring was conducted from 1999 through
2004 to evaluate the origin and quality of
the water running into the affected lakes.
Lake monitoring was conducted before and
throughout the growing season.
Approximately 50 automatic monitoring
samplers were placed at field edges and in
large and small streams that flowed into the
lakes. Strategically sited monitoring stations
measured the relative contribution of smaller
subwatersheds into the lakes. Stream flow was
taken into account at each sampling location.
Each station had instrumentation that allowed
simultaneous sampling and flow measure-
ments during peak rainstorm flow events. The
lakes themselves were sampled in late March
(before seasonal atrazine applications) and
continued every 3 weeks until September. The
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Results
Edge-of-field runoff monitoring equipment
resulting data identified subbasins that contrib-
uted disproportionately to pollutant loads into
the lakes.
Farmers were encouraged to voluntarily install
best management practices (BMPs) to cost-
effectively reduce pollutant runoff. Two tillage
practices—no-till and minimum-till—were
combined with selected atrazine application
methods. Atrazine was applied at one of two
rates—0.75 Ib/acre or 1.5-2 Ib/acre—using
one of three methods: incorporation into
the soil before planting, surface application
before planting, or surface application after
crop emergence. Grass buffer strips were
also planted to retard and capture field runoff
before it entered waterways. To promote these
voluntary farmer practices, WRASP conducted
field demonstrations, informational meetings,
and one-on-one consultations with farmers
from 2002 to 2004.
Levels of atrazine (and other contaminants
in the lakes) began to decrease after the first
year of the project. The lakes' average levels of
atrazine dropped below the MCL of 3 ppb for
drinking water, and the Missouri Department
of Natural Resources removed the lakes from
the303(d)listin late 2003.
Concentrations of Atrazine
in Smithville Lake
WRASP Began 1998
3 parts per billion
^^^^^^^^^^H
ACCEPTABLE STANDARD
1996
1998
2000
2002
2004
Collaboration under the WRASP project led to reduced
concentrations of herbicide in Smithville Lake.
Partners and Funding
The Missouri House Interim Committee on Water
Quality visit a WRASP site.
ERC managed the WRASP project and
administered the 319 funding. They formed a
partnership with the Missouri Corn Growers
Association who put together an alliance of
business and governmental organizations
including the Missouri Department of Natural
Resources, U.S. Department of Agriculture—
Agricultural Research Service, Environmental
Protection Agency, Syngenta Crop Protection,
Inc., and Bayer Crop Sciences. Funding for
the 319 portion of the project was $1,000,000,
while the total project cost was $5,000,000
over 5 years. To ensure future longevity of
protective water quality practices, an ongoing
Stewardship Implementation Project has been
put in place. It continues the water-monitor-
ing component of WRASP and extensively
expands the one-on-one work with farmers to
implement BMPs on larger, field-scale sites in
the watersheds.
U.S. Environmental Protection Agency
Off ice of Water
Washington, DC
EPA841-F-07-001J
June 2007
For additional information contact:
Linda Paule
Environmental Resources Coalition
3118 Emerald Lane, Suite 110
Jefferson City, MO 65109
573-634-7078
www.erc-env.org
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