The complete watershed is being
surveyed by researchers to determine
land use, pesticide use history, and
fertilizer management practices. This
information, as well as all other data, will
become part of the Geographical
Information Systems (GIS) database for
the watershed.
Current research at Walnut Creek is
focused on evaluating the effects of
different farming practices on tile
drainage, groundwater and surface water
quality, and ecological resources. Where
improvement is needed, researchers will
recommend changes to farming practices
and evaluate the results.
Future activities will address agricul-
tural landscape design, economic
analyses of farming system options, and
total agricultural practices and farming sys-
tems design. In addition, the participation
of Walnut Creek Watershed farmers will be
encouraged to achieve the environmental
and economic goals of the project
Monitoring Systems
Monitoring systems located in streams
measure sediment loss and nitrate and
pesticide concentrations. Tile drain
monitors record water flow and
contaminant levels. Surface runoff is
monitored to compare the effects of
conventional tillage, ridge tillage, or no
tillage on erosion; the effects of
composting and manure application on
water quality, and the use of pre-
emergence and broadcast herbicides.
Monitors in below-tile drainage wells
measure the interaction of ground water
and surface water near the stream and
levels of nitrates and herbicides. Rain
gauges record rainfall during storms, and
canopy interception devices quantify the
amount of nitrates and herbicide washed
from plant surfaces during each rainfall.
Multi-Agency Cooperation
Agencies involved in research at the MSEA
sites include the U.S. Department of
Agriculture (USDA), U.S. Environmental
Protection Agency, U.S. Geological Survey
(USGS), State Agricultural Experiment
Stations, the Cooperative Extension Service,
and State Departments of Agriculture and
Pollution Control.
The incorporation of EPA's Midwest
Agrichemical Surface/Subsurface
Transport and Effects Research
(MASTER) and USDA's Integrated Farm
Management System (IFMS) projects add
a unique dimension to the research at
Walnut Creek. These programs shift the
focus from the more traditional research
on erosion control and crop productivity
to a more balanced farm management
approach that encompasses the complete
agroecosystem.
For Further Information
For additional information on research at
the Walnut Creek MSEA site, contact:
Jerry Hatfield, Director
National Soil Tilth Laboratory
U.S. Department of Agriculture
2150 Pammel Drivi
Ames, IA 50011
(515) 294-5723
EPA/600/F-92/030
September 1992
United States
Department of Agriculture
United States
Environmental Protection Agency
United States
Department of the Interior
Management
Systems
Evaluation
Area
Walnut Creek
Watershed
In cooperation with:
State Agricultural Experiment Stations
Cooperative Extension Service
State Departments of Agriculture
State Departments of Pollution Control
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The Problem
Ground water is the primary source of
drinking water for nearly 90% of the rural
U.S. population and more than 40% of the
total population. Groundwater and
surface water contamination from the use
of pesticides and fertilizers has prompted
environmental scientists to examine the
impact of agricultural practices on the
quality of environmental resources.
MSEA Sites
A consortium of Federal and State Agency
researchers is evaluating the impact of cur-
rent and emerging farming systems at ten
midwestem Management Systems Evalua-
tion Area (MSEA) sites. These MSEA sites
are located in Iowa, Minnesota, Missouri,
Nebraska, Ohio, North Dakota, South Da-
kota, and Wisconsin.
Research at Walnut Creek
The Walnut Creek Watershed at the Iowa
MSEA site provides an opportunity for
scientists to study the complex
interaction of soils, weather, water,
agrichemicals, hydrogeology, economics,
and farm management systems.
The Walnut Creek Watershed is an
intensively farmed 18 square mile area
south of Ames, Iowa. The natural
fertility level of the soils is high and crop
productivity is among the highest in the
region. The soils, however, are subject to
poor drainage, and the upper reaches of
the watershed are often covered by
water-filled potholes in spring and early
summer. The upper and middle reaches
of the watershed are tile-drained with a
poorly defined pattern of surface runoff,
while the lower reaches are steep with
predominantly surface runoff. The
watershed is connected to an aquifer that
supplies several communities with their
primary source of water.
Studies in the Walnut Creek Watershed
Field Scale
Current Farming
Practices
Watershed Scale
Current Land Use
Design and
Management Practices
Assessments
Tile Drain
Surface Runoff
Groundwater
Stream Flow
Soil Residual
Watershed and
Regional Scale
| Current:Land Use
Design and
Management Praaicef
Assessments
Wildlife Populations
Fish Populations:
Sedirrient Load
Modifications
Field Scale Farming Practices
Watershed Scale Land Use Design
and Management Practices ; |j;
Regional Scale Land Use Design
and Management Practices
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