"*A\ Section 319
M/ NONPOINT SOURCE PROGRAM
STORY
Improved Herbicide Management Restores Safety of Drinking Water Source
WatPrhndv Imnrnvpd Aquilla Reservoir is an important source of drinking water
and recreation but was found to have excessive levels of the
herbicide atrazine beginning in 1997. Project partners initiated efforts to reduce agricultural
atrazine sources—and to a lesser extent, urban sources—in the watershed. As a result
of technical assistance to corn and sorghum producers, using agricultural best manage-
ment practices (BMPs), and educating urban residents, atrazine concentrations in Aquilla
Reservoir declined by 60 percent. The waterbody now meets atrazine concentration stan-
dards, and in 2004 the Texas Commission on Environmental Quality (TCEQ) recommended
that Aquilla Reservoir be removed from the state's 303(d) list of impaired waters for 2004.
Problem
Aquilla Reservoir was built in 1983 for water
supply, flood control, and recreation purposes.
Approximately 10 miles southwest of the city
of Hillsboro in east-central Texas, it controls
drainage from a 255-square mile watershed.
Corn and sorghum production comprise 40
percent of land use in the watershed. The res-
ervoir is the sole source of water for the Aquilla
Water Supply District's treatment plant.
Atrazine is an herbicide used by many corn
and sorghum producers. It is also an ingredi-
ent in many residential lawn products. During
the late 1990s, monitoring of finished drinking
water showed that atrazine concentrations
consistently exceeded state and federal drink-
ing water standards mandating a maximum
contaminant level (MCL) of 3 micrograms per
liter (3jL/g/L). Three consecutive MCL violations
led the state to place the reservoir on its 303(d)
list of impaired waters in 1998.
The Aquilla Water Supply District took immedi-
ate steps to ensure public safety by reducing
atrazine in drinking water through its treatment
process. Meanwhile, TCEQ began an examina-
tion of atrazine loading to the reservoir.
The study found that all loading originated
from nonpoint sources. This led TCEQ and
the Texas State Soil and Water Conservation
Board (TSSWCB) to establish a total maximum
daily load (TMDL) for atrazine. EPA approved
5.0
„ 4-°
c
| 3'°
I 2.0
1.0
-Atrazine in Aquilla
Feb-97 Feb-98 Feb-99 Feb-00 Feb-01 Feb-02 Feb-03 Feb-04 Feb-05
Atrazine concentrations in Aquilla Reservoir. Data represent
running annual averages. Concentrations have steadily remained
below the maximum contaminant level (MCL) since 1998. With the
reservoir meeting the MCL requirement for more than 2 consecu-
tive years, Texas has recommended that it be removed from the
state's 303(d) list.
the TMDL in 2002. It required the reservoir
to maintain a running annual average atrazine
concentration not to exceed the 3^/g/L MCL for
2 consecutive years. This would amount to a 25
percent atrazine load reduction.
Project Highlights
The atrazine threat to drinking water triggered
several coordinated projects to address urban
and agricultural atrazine sources and restore
water quality in Aquilla Reservoir. State, fed-
eral, regional, and local agencies collaborated
to formulate and implement plans designed
to reduce reservoir pollution, protect against
new pollution sources, and monitor progress
through water quality testing.
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Sample best management
practices used to reduce
atrazine loads. Afield of corn
(1) is cultivated. Atrazine is
tilled into the soil, rather
than simply applied on top
of the ground. Farmers
may install filter strips (2)
between the field and an
adjacent creek (4). A grassed
waterway (3) may also be
used to direct runoff to the
creek while filtering out pol-
lutants at the same time.
Agricultural producers, affected water
supply companies, government agencies,
and other stakeholders formed the Texas
Watershed Protection
Committee, which identified
BMPs for use in the water-
shed and documented BMP
adoption. Recommended
BMPs included incorporat-
ing atrazine into the soil,
filter strips, grade stabiliza-
tion, grassed waterways,
terraces, integrated pest
management (e.g., targeted
herbicide application), and
education. The committee
also worked to increase pes-
ticide dealers' awareness of
the problem and gain their
assistance and support in
solving it. Finally, corn and
sorghum producers received
technical and financial
assistance to implement the
BMPs.
Results
Project leaders also tar-
geted urban areas for
atrazine reductions. They
prepared fact sheets about
atrazine and alternative
lawn management. Through
the Texas Master Gardener
program, they delivered
television public service announcements
about proper application and storage of
herbicides and pesticides. Finally, they
distributed fact sheets and general articles
to local newspapers, to feature columnists,
and at local meetings.
To measure the effectiveness of reduction
efforts, TCEQ conducted monthly water
quality monitoring. In addition, a private
corporation that markets atrazine continued
its voluntary pesticide monitoring program
with the area's public water suppliers.
These efforts led to a 60 percent atrazine load
reduction, far exceeding the TMDL. As pre-
sented in the graph on the previous page, over 2
consecutive years of monthly reservoir sampling
showed atrazine concentrations well below the
3jL/g/L requirement. The waterbody now meets
atrazine concentration standards, and TCEQ has
recommended that it be removed from the state
303(d) list.
TCEQ will continue collecting quarterly samples
to monitor reservoir water quality. In addition,
finished drinking water will continue to be
monitored for compliance with the Safe Drinking
Water Act.
Partners and Funding
TCEQ and TSSWCB led the atrazine reduction
project and developed the TMDL. Various Texas
Watershed Protection Committee activities
were also vital to the effort. Led by the Texas
Department of Agriculture, the committee
consists of representatives from TCEQ,
TSSWCB, Texas Agricultural Experiment Station-
Blacklands Research Center, Texas Cooperative
Extension, USDA-Natural Resources
Conservation Service, Brazos River Authority,
and Texas Farm Bureau.
Other partners included the Aquilla Water
Supply District, Woodrow-Osceola Water
Supply Corporation, Hill County Appraisal
District, Hill County Blackland Soil and Water
Conservation District, Sabine River Authority,
U.S. Environmental Protection Agency, U.S.
Army Corps of Engineers, and Syngenta (for-
merly Novartis).
Since 1999, approximately $2.8 million in EPA
section 319 and nonfederal matching funds have
helped to support this restoration effort. In addi-
tion, the USDA-Natural Resources Conservation
Service provided more than $1.9 million in cost-
share funds between 1998 and 2003 to assist
producers implementing BMPs in the watershed.
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-06-003F
June 2006
For additional information contact:
Arthur Talley
Texas Commission on Environmental Quality,
TMDL Program
512-239-4546 • atalley@tceq.state.tx.us
Aaron Wendt
Texas State Soil and Water Conservation Board
254-773-2250 • awendt@tsswcb.state.tx.us
Frank Burleson
Texas Commission on Environmental Quality,
Region 9 Office-Waco
254-751-0335
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