Grantee Research Project Results
Final Report: An Integrated Ecological and Socio-Economic Approach to Evaluating and Reducing Agricultural Impacts on Upper Mississippi River Watersheds
EPA Grant Number: R825761Title: An Integrated Ecological and Socio-Economic Approach to Evaluating and Reducing Agricultural Impacts on Upper Mississippi River Watersheds
Investigators: Gowda, Prasanna H. , Burgess, Andrew F. , Haro, Roger J. , Napier, Ted L. , Mendez, Aida , Ward, Andy , Dalzell, Brent , Mulla, David , Kollman, Fred , Tucker, Mark , Stombaugh, Susie
Institution: University of Wisconsin - La Crosse , The Ohio State University
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 1997 through August 30, 2000 (Extended to March 31, 2003)
Project Amount: $650,921
RFA: Water and Watersheds Research (1997) RFA Text | Recipients Lists
Research Category: Watersheds , Water
Objective:
The main objectives of this research project were to: (1) use a process model to predict agricultural discharges from two watersheds in the Upper Mississippi River basin; (2) use observed and predicted runoff, sediment, and nutrient loadings to estimate the contribution of urban areas, wastewater treatment plants, and point sources to the total loading; (3) use the model to evaluate potential water quality benefits associated with the adoption of alternative management strategies on these watersheds; (4) develop regional-scale predictive models of ecosystem "health," biodiversity, and sustainability by relating information on biota and ecosystem functional processes to current and potential landscape composition and structure; and (5) identify factors that affect the adoption of conservation production systems among land owner/operators in the two watersheds. The Lower Minnesota River watershed in eastern Minnesota and the Maquoketa River watershed in northeastern Iowa were studied. The socioeconomic component was extended to include Big Darby Creek watershed in central Ohio.
Summary/Accomplishments (Outputs/Outcomes):
Physical Component
The watershed methodology applied using the ADAPT model is able to adequately simulate quantity and quality of flow from Lower Minnesota and Maquoketa River watersheds. Calibration results indicated that the model performed well where land use is dominated by row-crop agriculture and urban development is minimal. Model agreement between predicted and observed data tends to worsen on subwatersheds in close proximity to the Twin Cities metropolitan area in the Lower Minnesota River watershed.
In the Lower Minnesota River watershed, reductions in nitrate loads from agricultural
subwatersheds can be achieved by reducing the N-fertilizer application rates
and by changing from fall to springtime application. Model results indicate
that reducing the N-fertilizer application rate by 20 percent and changing to
springtime N-fertilizer application can reduce annual watershed contributions
by up to 33 percent. Nitrate losses are more sensitive to changes in N-fertilizer
management for watersheds with denser subsurface tile drainage systems. Similar
results were found in the Maquoketa River watershed.
The adoption of conservation tillage reduces sediment and increases flow and
nitrate losses from agricultural watersheds. Increased crop residue via conservation
tillage on agricultural fields improves infiltration, resulting in decreased
overland flow and subsequent decreased sediment loading. Crop residue also improves
soil water storage capacity and can prolong leaching events, resulting in increased
flow and nitrate losses.
Increasing subsurface tile drainage density decreases sediment and increases flow and nitrate losses from crop lands. Tile drains improve infiltration and create drier antecedent moisture conditions, promoting less surface runoff and more drainage flow. This reduces sediment contributions from fields, while simultaneously increasing flow and nitrate losses through tile drains.
Water quality benefits realized by the adoption of N-fertilizer best management practices (reduced application rate and springtime application) may be offset by the increased adoption of conservation tillage and increasing area under subsurface tile drains. Although conservation tillage and subsurface tile drainage systems help to reduce sediment loads from agricultural systems, they promote nitrate leaching. This dichotomy among agricultural management practices should be evaluated to determine the most severe problem and most appropriate solution when considering efforts to improve water quality.
Ecological Component
Habitat conditions and Qualitative Habitat Evaluation Index (QHEI) scores in the Lower Minnesota River watershed were much lower among channelized than nonchannelized macroinvertebrate sampling sites. This may be due to the fact that most channelized sites were found adjacent to areas with extensive tile drainage systems. Leveled stream bottoms in combination with a lowered water table resulting from tile drainage limited the longitudinal water storage capabilities of the channelized streams. The channelized sites were characterized by lack of stable substrate and a depauperate macroinvertebrate community, which was tolerant of sedimentation and nutrient enrichment. Nonchannelized sampling sites contained a variety of habitats potentially beneficial to the macroinvertebrate community, including woody debris piles and large inorganic substrates.
In the Lower Minnesota River Basin, the relationship between the Macroinvertebrate Index of Biological Integrity (M-IBI) and reach-scale conditions (QHEI) effectively discriminated between channelized and nonchannelized sampling sites. However, there was no relationship between M-IBI and QHEI scores among exclusively channelized or nonchannelized sites. Thus, QHEI alone was not useful to measure habitat critical to macroinvertebrate community.
In the Maquoketa River watershed, the streams were differentially affected by geological conditions and groundwater inputs. However, macroinvertebrate community composition was strongly correlated with stream habitat and landscape features. Critical habitats were evenly distributed throughout the watershed. General availability of inorganic substrates made the presence of woody debris less of a defining factor in macroinvertebrate composition.
Habitat quality and quantity in the Maquoketa River watershed was much greater than that in the Minnesota River Basin. Also, inorganic substrates samples from the Maquoketa River watershed supported a more diverse macroinvertebrate community containing several functional groups not represented in the Lower Minnesota River Basin.
In both watersheds, the existing rate of adoption of conservation tillage was strongly related to M-IBI scores.
Socio-Economic Component. Farmers in all of the study watersheds had adopted a number of soil and water conservation practices; however, they continued to use production practices that could negate the positive environmental benefits of the conservation practices employed.
Respondents indicated that they were aware of environmental consequences associated with production agriculture. However, they perceived that the greatest damage to the environment was being done by other farmers in their watershed rather than pollution coming from their farm operation.
The examination of correlates of efficient use of agricultural nutrients (ratio of pounds of nutrient per bushel of grain produced) revealed that few variables were predictive of rates of nutrient use. Production agriculturalists operating large farms did not use fertilizers less efficiently than small-scale producers.
The comparison of adoption rates among the three watersheds revealed that extensive investments in conservation programs within the Darby Creek watershed have resulted in little benefits in terms of conservation behaviors compared with farmers in the other watersheds.
Research revealed that respondents were using extensive sources and multiple channels to obtain information about soil and water conservation within the study watersheds. Farmers sought information about soil and water conservation issues from conservation agencies. Respondents seldom used the extension for conservation information.
Many farmers reported that they did not expect to transfer their farm operations to their children, and respondents perceived little risk associated with farm-use chemicals.
Research findings focused on the use of conservation systems strongly suggest that existing intervention approaches employed to motivate land owners/operators to adopt and to use conservation production systems will be marginal at best and there probably will be failures in the long term.
Future conservation programming within the study watersheds should place primary emphasis on advancing production systems that will produce profits in the near term. Many farmers reported that they did not expect to derive profits in the near term, and did not expect that their children will be operating the farms in the future. This suggests that long-term protection of land resources will not be highly valued.
Benefits. A comprehensive geographic information system (GIS) database that includes detailed land cover and tillage practice maps has been developed and utilized for predicting water quality in the Lower Minnesota River watershed. This database also was used in the biological component of this study to identify potential sites for macroinvertebrate surveys and to evaluate the impact of existing agricultural management practices on stream biology. Apart from this study, this database was used by researchers at the Department of Applied Economics to develop point-nonpoint emission trading permits for the Minnesota River Basin. Both land cover and tillage maps are unique in their classification systems as they identify crop types and tillage types and these are the most recent maps available for the Lower Minnesota River watershed. Also, this database is being used by the Minnesota Pollution Control Agency for total maximum daily load (TMDL) development and in the High Island Creek watershed project.
The ADAPT model has been modified to incorporate a frost-depth prediction subroutine to improve model performance during spring and fall months. The original version of the ADAPT model estimated frozen soil based on 3-day antecedent air temperature and did not show good flow agreement in winter months. Using methods described by previous studies, soil-frost depth is now estimated based on air temperature, snow depth, soil porosity, clay content, saturated hydraulic conductivity, and soil moisture content. These changes to the model make it more appropriate for conditions such as those found in the Lower Minnesota River Basin. At present, this model is being used in many doctoral research projects in four departments (Departments of Soil, Water, and Climate; Applied Economics; Forestry; and Biosystems and Agricultural Engineering) of the University of Minnesota, Minnesota Land Steward Project, and Minnesota Department of Agriculture.
Research findings of this study were presented to the Minnesota Pollution Control Agency (which is responsible for developing TMDLs for the Minnesota River Basin), Minnesota Department of Agriculture, Natural Resources Conservation Service, and to many nonprofit environmental organizations in the Lower Minnesota River watershed. The Minnesota Pollution Control Agency is planning to use these findings in developing TMDLs and factor of safety for the Lower Minnesota River watershed.
Journal Articles on this Report : 6 Displayed | Download in RIS Format
Other project views: | All 26 publications | 10 publications in selected types | All 9 journal articles |
---|
Type | Citation | ||
---|---|---|---|
|
Burgess A, Haro RJ, Gowda PH. The relationship among landscape characteristics, stream habitat and composition of benthic macroinvertebrate communities in two Midwestern agricultural watersheds. Journal of Environmental Management. |
R825761 (2001) R825761 (Final) |
not available |
|
Gowda PH, Mulla DJ, Dalzell BJ. Examining the targeting of conservation tillage practices to steep vs. flat landscapes in the Minnesota River Basin. Journal of Soil and Water Conservation 2003;58(1):53-57 |
R825761 (1999) R825761 (2000) R825761 (2001) R825761 (Final) |
not available |
|
Napier TL. Soil and water conservation policy approaches in North America, Europe, and Australia. Water Policy 2000;1(6):551-565. |
R825761 (1999) R825761 (2000) R825761 (2001) R825761 (Final) |
not available |
|
Napier TL, Tucker M. Use of soil and water protection practices among farmers in three midwest watersheds. Environmental Management 2001;27(2):269-279. |
R825761 (1999) R825761 (2000) R825761 (2001) R825761 (Final) |
not available |
|
Robinson JR, Napier TL. Adoption of nutrient management techniques to reduce hypoxia in the Gulf of Mexico. Agricultural Systems 2002;72(3):197-213 |
R825761 (2001) R825761 (Final) |
not available |
|
Tucker M, Napier TL. Determinants of perceived agricultural chemical risk in three watersheds in the Midwestern United States. Journal of Rural Studies 2001, Volume 17, Issue 2, April 2001, Pages 219-233. |
R825761 (1999) R825761 (2000) R825761 (2001) R825761 (Final) |
not available |
Supplemental Keywords:
watersheds, nitrate, sediment, nutrient management, tile drainage, habitat, aquatic, survey, socioeconomic, Midwest, geographic information system, GIS, remote sensing, Minnesota, Iowa, Ohio, MN, IA, OH, EPA Region 5, agriculture, nonpoint, hydrology, streams., RFA, Scientific Discipline, Water, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, Water & Watershed, Nutrients, Hydrology, Ecosystem/Assessment/Indicators, Ecosystem Protection, Environmental Chemistry, State, Ecological Effects - Environmental Exposure & Risk, Wet Weather Flows, Agronomy, Watersheds, anthropogenic stress, agriculturally impacted watershed, aquatic ecosystem, environmental monitoring, fate and transport, hydrological stability, nutrient transport, risk assessment, spatially distributed hydaulic models, wastewater treatment, Minnesota, Iowa, MN, biodiversity, soil and water conservation, agricultural discharges, farming, watershed, agricultural watershed, runoff, downstream effects, anoxia/hypoxia, biological integrity, decision model, hypoxic zones, regional scale predictive model, aquatic ecosystems, nutrient cycling, GIS, non-point sources, water quality, IA, remotely sensed data, land useRelevant Websites:
http://www.soils.umn.edu/~pgowda/epa_project/index.html Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.