Section 319
NONPOINT SDURCF PROGRAM SUGCESf STORY
Land Treatment Practices Lower Atrazine Levels
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R°ut'ne monitoring conducted by the Nebraska Department of
Environmenta| Qua|ity (DEO) in 1997 identified high concentrations of
atrazine in southeast Nebraska's Swan 5A Reservoir, prompting DEQ to
add it to the state's 1998 Clean Water Act section 303(d) list of impaired waters for atrazine. In response,
stakeholders developed and implemented a watershed management plan. The reservoir's atrazine levels
dropped, and DEQ removed Swan 5A Reservoir's atrazine impairment from Nebraska's 2006 303(d) list.
Problem
The 95-acre Swan 5A Reservoir was designed
and developed as a multipurpose, flood-con-
trol/public use area in Saline County, Nebraska,
and falls within the Big Blue River Basin.
Approximately 52 percent of the reservoir's
4,590-acre watershed is used for crop produc-
tion (2,399 acres). Monitoring data collected in
1997 showed that the reservoir had elevated
levels of the herbicide atrazine. This herbicide
is typically applied to crops such as corn and
sorghum—both of which are grown in the
watershed.
The Nebraska water quality standard for
chronic exposure to atrazine is 12 micrograms
per liter (ji/g/L), which is equivalent to 12 parts
per billion (ppb). Eight of the 24 samples col-
lected from the reservoir in 1997 exceeded the
chronic water quality standards with a median
concentration of 5.6 ppb and a maximum
concentration of 42.56 ppb. For the reservoir to
meet standards, regulations would allow only
4 exceedances of the standard in a sample size
of 24. Consequently, DEQ added the reservoir
to the state's 1998 303(d) list of impaired
waters due to an impairment of the aquatic life
use from high atrazine concentrations.
Project Highlights
The majority of watershed landowners (35 of
43) participated in the project. Participants
implemented numerous pollution control mea-
sures, including placing an additional 65 percent
of the cropped ground (1,550 acres) under
no-till and nutrient and pesticide manage-
ment practices, installing 29,345 linear feet of
terraces on highly erosive crop ground, con-
structing or restoring 16 water quality basins
to original holding capacity, converting 237
acres of crop ground to grass, installing 2 new
waterways, planting 7 acres of trees, decom-
missioning 5 abandoned wells and bringing 6
septic systems into compliance with current
standards (Figures 1 and 2).
Figure 1.
Watershed
landowners and
operators attend-
ed water quality
workshops to learn
about the benefits
of no-till farming
and nutrient and
pesticide manage-
ment.
Figure 2.
Constructing a weir
has established a
wetland area directly
above the reservoir.
The wetland will
complement other
nonpoint source
controls in the
watershed aimed at
reducing sediment,
nutrient and pesti-
cide loads.
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In 2003 the Lower Big Blue Natural
Resources District partnered with sev-
eral local, state and federal agencies to
initiate a Community Based Planning
process. Through this locally led process,
the partners developed a Watershed
Management Plan that incorporated a
unique mix of cost share and incentives
to encourage farmers to implement a
host of agricultural management practic-
es. The plan also requires that landown-
ers upgrade septic systems and close
abandoned wells.
Results
Atrazine Concentrations in Swan 5A Reservoir
40-
30-
.Q
Q.
Q.
•i 20-
ro
10-
0-
NE Standard - 12.0
Water quality data collected between
2004 and 2006 showed that all 13 atra-
zine samples were below the standard
with a post-project median concentration
of 2.85 ppb, which led DEQ to remove
Swan 5A Reservoir from the state's
303(d) list in 2006 (Figure 3). Two samples
collected in 2007 exceeded the chronic stan-
dard; however, Swan 5A remained off the 2008
303(d) list because of a large sample size.
Loadings of other targeted pollutants such as
sediment and nutrients have also decreased.
To date, land treatment measures in the water-
shed have helped reduce sediment loading by
almost 69 percent and phosphorus loading by
58 percent—exceeding the 50 percent reduc-
tion goals established for both.
Pre-Project Atrazine
Post-Project Atrazine
Partners and Funding
The project was made possible through a
strong partnership of the Lower Big Blue
Natural Resources District, U.S. Department
of Agriculture (USDA) Natural Resources
Conservation Service, Nebraska Environmental
Trust, Nebraska DEQ, U.S. Environmental
Figure 3. Boxplots indicate the interquartile range (25th-75th percen-
tile), median (represented by dots) and outliers (represented by aster-
isks) of the date in each of two periods: Pre-project data (years 1997
and 2003) and post-project data (2004-2007).
Protection Agency, Saline County Cooperative
Extension, Nebraska Game and Parks
Commission, Swan Reservoir Watershed
Council and watershed landowners and opera-
tors. Section 319 funding supported efforts to
conduct resource inventories ($7,500), engi-
neering design ($100,000) and management
practice cost-share and incentives ($300,000).
Additional sources of cost share and incentive
funds include the USDA Environmental Quality
Incentive Program ($215,000), Nebraska
Environmental Trust ($275,000), Lower Big Blue
Natural Resources District ($124,000) and land-
owners ($175,000). This project to implement
land treatment measures began in 2004 and
will continue through fall 2008. Maintaining a
high-quality reservoir will continue to be a pri-
ority for the resource management agencies,
so they will maintain and implement traditional
and nontraditional practices as needed in the
future.
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-08-001S
September 2008
For additional information contact:
Paul Brakhage
Nebraska Department of Environmental Quality
402-471-4224 • paul.brakhage@ndeq.state.ne.us
Scott Sobotka
Lower Big Blue Natural Resources District
402-228-3402 • sobotka@lbbnrd.org
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