Upper
Mississippi
River
, MN
WHY IS THIS WATERSHED SPECIAL?
The Des Moines Lobe, the central focus of this project, is
drained mostly by the Des Moines, Raccoon, Iowa, and
Skunk rivers in the "prairie-pothole" region in
north-central Iowa. Thanks to artificial drainage, this
land boasts some of the most valuable and productive
farmland in the country. In 2002, the average land value
for the 22-county area making up most of the Lobe was
approximately $2,500 an acre, and more than
80 percent of that area was used for row crops,
42.9 percent for corn and 37.6 percent for soybeans.
ENVIRONMENTAL CHALLENGES
Nitrate leaching from extensive areas of drained
cropland in Iowa and other areas along the Corn Belt is
transported down the Mississippi River and is believed to
be a contributor to hypoxic (low in dissolved oxygen)
conditions in the Gulf of Mexico and to local drinking
water quality concerns. Although mismanagement and
overuse of fertilizer and manure contributes to water
quality problems, hydrological and land-use changes
(that is, the conversion of prairies and marshes to
row crops) are the leading causes of degradation.
• Extensive subsurface drainage of the Corn Belt (25
percent of Iowa is drained) accelerates the transport
of nitrate entering the Mississippi River.
• Subsurface drainage creates very productive
croplands and reduces other water quality concerns.
Scientists examine a soil sample. (Charlie Rahm)
RESTORATION ACTIVITIES
A permanent solution to this watershed's challenges
involves "structural modifications" of the drainage
systems that could have both water quality and crop
production benefits. EPA Targeted Watersheds Grants
funds will be used to test new technologies involving
modified drainage systems, combined with
nitrate-removing wetlands. Project partners will:
• Use actual soils, topography, and weather data with
improved crop growth, hydrologic, and wetland
models to design integrated wetlands and controlled
or shallow drainage systems to reduce nitrate
loading while maintaining or improving crop
performance
• Develop an optimum drainage-wetland system
design for specific study areas with landowner
cooperation, install it, and monitor its water quality
performance
• Conduct outreach to publicize the results to other
landowners, the farm media, downstream water
users, and policy makers at all levels and explore
technology transfer opportunities to other areas in
Iowa and beyond
EPA's TARGET ED WATERSHEDS GRANTS
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A STRONG PARTNERSHIP
FOR CHANGE
The Iowa Department of Agriculture and Land
Stewardship and Iowa State University, which together
developed the nitrate removal wetland technologies that
led to Iowa's Conservation Research Enhancement
Program, lead the project team. Further support
through expertise, staff, and financial resources
comes from:
• Iowa Drainage District Association
• Agri Drain Corporation
• Natural Resources Conservation Service
• Iowa Farm Bureau Federation
• Iowa Environmental Council
• City of Cedar Rapids
• Des Moines Water Works
I A restored wetland. (Lynn Betts)
"Our P
ig new appr
.naging water on cropped
ams, and ultimately, to the Gulf
of Mexico hypoxic zone. Farmers will be able to see these technologies through
demonstrations under actual field conditions, both to demonstrate the environmental
gains as well as impacts upon crop production and farming practices."
- Dean W Lemke, RE., Iowa Department of Agriculture and Land Stewardship
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