Section 319
NONPOINT
RDGR2M SUCCESS STORY
Watershed Project Reduces Sediment and Nutrient Loading
Waterbodv Improved Excess sediment and nutrient loads from crop produc-
1 "' * ^ tion practices impaired the aquatic life designated use of
Nebraska's Wildwood Reservoir, prompting the Nebraska Department of Environmental
Quality (NDEQ) to add the waterbody to the state's 1994 Clean Water Act (CWA) section
303(d) list of impaired waters. Landowners implemented best management practices
(BMPs) that reduced nutrient and sediment loading in the reservoir. Water quality improved,
and the reservoir now supports its aquatic life designated use. As a result of the improve-
ments, NDEQ removed Wildwood Reservoir from the Nebraska CWA section 303(d) list of
impaired waters for nutrients and sediment in 2004.
Problem
Wildwood Reservoir is a 103-acre multipurpose
impoundment (Figure 1) in southeast Nebraska.
The Lower Platte South Natural Resources
District (LPSNRD) built the dam in 1978 in coop-
eration with the U.S. Department of Agriculture
Natural Resources Conservation Service (NRCS).
The watershed drains an area of approximately
4,835 acres, most of which is used for crop produc-
tion. Watershed slopes are typically 6 to 12 percent,
and soils are considered to be highly erosive. NDEQ
and LPSNRD conducted a Clean Lakes Phase I
Diagnostic and Feasibility Study of Wildwood
Reservoir in 1988. The study indicated that exces-
sive sediment and nutrient loads from crop pro-
duction practices along with highly erosive soils
adversely affected water quality in the reservoir.
As a result of the study's findings, NDEQ added
Wildwood Reservoir to the Nebraska 1994 CWA
section 303(d) list for impairments to its aquatic
life designated use because of excessive sediment
loading. In 1998 NDEQ added nutrients and atrazine
to the list of pollutants impairing the aquatic life
designated use. NDEQ removed the atrazine impair-
ment in 2002 after Nebraska's atrazine water quality
standard/aquatic life criterion was increased.
I Base map (2003) provided by the Nebraska
Game and Parks Commission. Fisheries Division
Project Highlights
In 1992 LPSNRD, NDEQ, and University of Nebraska
Cooperative Extension Service initiated a watershed
treatment project to reduce sediment loadings. Of
the 40 watershed landowners, 16 participated in the
project, treating approximately 38 percent of the
cropped ground and 60 percent of the critical areas
targeted for treatment. Landowners implemented
Figure 1. The 103-acre Wildwood Reservoir is in extreme
southeast Nebraska. Green areas represent islands.
numerous BMPs, including storage terraces, grade-
stabilization structures and sediment control basins.
An additional sediment basin was constructed
in the upper end of the reservoir on the primary
inflow, thereby allowing sediment to settle out
before the water reaches the reservoir (Figure 2).
In 2001 LPSNRD and Nebraska Game and Parks
Commission (NGPC) drained the reservoir to remove
organic, rich-bottom sediments; repair eroding
shorelines; and develop habitat. Additional restora-
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Figure 2. Projects partners constructed a sediment
basin above Wildwood Reservoir to complement land
treatment measures implemented in the watershed.
tion efforts included stabilizing shoreline, removing
sediment, developing habitat and renovating the
fishery within the reservoir.
Results
The watershed project effort was a success—
it achieved the sediment loading reduction target
by 1998 (Figure 3). The U.S. Environmental
Protection Agency's (EPA's) Spreadsheet Tool for
Estimating Pollutant Load was used to determine
nutrient loading reductions associated with the
implemented BMPs. Model results show that
BMPs reduced sediment loads by 4,893 tons per
year (39 percent), equating to an annual volume
loss reduction of 0.58 percent. While partners'
efforts helped to achieve targeted reductions by
1998, a watershed loadings assessment was not
conducted until the lake restoration project was
completed. The assessment concluded that the
reservoir's average annual volume loss (reduced to
0.58 percent) met the state criterion of 0.75 percent
per year.
In addition, by draining the reservoir and removing
organic, rich-bottom sediment, LPSNRD and NGPC
helped reduce annual loadings of total phosphorus
and total nitrogen (49 and 63 percent, respectively).
On the basis of those findings, NDEQ believes that
Wildwood Reservoir is supporting its aquatic life
designated use and removed it from the state's
2004 CWA section 303(d) list of impaired waters for
nutrients and sediment.
NDEQ added Escherichia Co/i bacteria to the
monitored parameter list in 2009 to assess the
recreational/full body contact designated use.
Results indicate that bacteria is not a pollutant
of concern and does not impair recreational use.
However, NDEQ will not officially document that
result or designate the reservoir as fully supporting
its recreational use until the next Integrated Water
Quality Report is completed in 2010.
Partners and Funding
Numerous partners supported the watershed proj-
ect, including LPSNRD, NDEQ, NRCS, watershed
landowners and EPA. Partners relied on CWA sec-
tion 319 funding to support land treatment projects
($114,629), in-lake wetlands and sediment basin
construction ($54,563), monitoring and modeling
($51,500), technical assistance, education and
project coordination ($65,000), and project admin-
istration ($9,375). LPSNRD also contributed funding
for land treatment projects ($146,585), in-lake wet-
lands and sediment basin construction ($32,652),
and monitoring ($12,402). Watershed landowners
contributed $81,198 toward land treatment mea-
sures. The NRCS provided technical assistance to
landowners in designing management practices.
The reservoir restoration project, conducted from
February 2001 through June 2003, was funded by
LPSNRD ($201,877) and NGPC ($551,100).
Sediment Loading and Loading Reductions to Wildwood Reservoir
14,000
2,000
Assessment Criteria and Target Load • 9,450 tons/year
Pre-project Reduction from Reduction from Reduction from Post-project
Sediment Load Watershed Basins Terraces In-lain Basin Sediment Load
Figure 3. Bar graph showing sediment loading reductions from
various protection measures in addition to pre- and post-project
loads. Pre-project loads were determined by analyzing water-
shed data collected from 1988 through 1991, while post project
loads were determined from watershed data collected in 1999.
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-09-001BB
September 2009
For additional information contact:
Paul Brakhage
Nebraska Department of Environmental Quality
402-471-4224 • paul.brakhage@nebraska.gov
Paul Zillig
Lower Platte South Natural Resources District
402-476-2729 • pzillig@lpsnrd.org
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