Grantee Research Project Results
1999 Progress Report: Integrating Modeling and Management of Agriculturally-Impacted Watersheds, Issues of Spatial and Temporal Scale
EPA Grant Number: R825290Title: Integrating Modeling and Management of Agriculturally-Impacted Watersheds, Issues of Spatial and Temporal Scale
Investigators: Brezonik, Patrick L. , Perry, James A. , Easter, K. William , Mulla, David
Current Investigators: Brezonik, Patrick L. , Perry, James A. , Smith, Richard C. , Fang, Andrew F. , Gowda, Prasanna H. , Birr, Adam S. , Easter, K. William , Gleason (Dovciak), Anne , O'Connor, Ben , Dalzell, Brent , Wheeler, Daniel , Mulla, David , Davis, David , Tidwell, Jason , Bell, Jay , ZumBerge, Jeremy , Westra, John , Marr, Kara , Brooks, Kenneth , Olson, Kent , McCann, Laura , Mathews, Leah , Hatch, Lorin , Gerlach, Luther , Talmadge, Philip , Johansson, Robert
Institution: University of Minnesota
EPA Project Officer: Packard, Benjamin H
Project Period: October 1, 1996 through September 30, 1999 (Extended to March 31, 2001)
Project Period Covered by this Report: October 1, 1998 through September 30, 1999
Project Amount: $813,085
RFA: Water and Watersheds Research (1996) RFA Text | Recipients Lists
Research Category: Watersheds , Water
Objective:
The overall objective of the study is to improve understanding of how biophysical and social-economic variables interact in agricultural watersheds of varying scales, landscape conditions, and land-use management practices to affect export of nutrients and their effects on in-stream biological communities, and in turn, to assess the role of knowledge about those effects in decisionmaking processes affecting local-level land use.Progress Summary:
The major accomplishments include: (1) significant new data collection in all research areas, (2) refinement of short-term and medium-term goals, (3) two synthesis papers are in review and two papers are in preparation, (4) new funding, and (5) interactions have occurred with stakeholders in the Minnesota River Basin.Landscape Processes. Our efforts have focused on collecting datalayers and developing erosion modeling techniques at various scales. At the basin scale, we obtained 1:250,000 scale STATSGO soil and landuse/landcover datalayers for the entire Minnesota River Basin (MRB). At the minor watershed scale, we obtained 1:24,000 scale digitized soil and detailed landuse/landcover datalayers for selected locations. The small scale (large region) datalayers were used along with the Universal Soil Loss Equation to estimate potential erosion rates for the entire MRB. At the field scale, several hundred erosion estimates for steep slopes were made near creeks and streams for the entire basin using data obtained from the National Resource Inventory. At the major watershed scale, estimates of sediment loads were made in each of the 12 major tributaries draining into the Minnesota River. Comparisons across these two scales showed that the trends in sediment load among major watersheds were strongly controlled by climatic gradients and terrain characteristics. Erosion estimates from the National Resource Inventory were closely correlated with sediment loadings in each of the tributaries, except in cases where a major dam was located at the mouth of the tributary. Erosion estimates from the STATSGO database for each of the tributaries were poorly correlated with sediment loadings in the major tributaries. Agreement between the STATSGO scale erosion estimates and the sediment loadings obtained by water quality monitoring was improved by considering only STATSGO scale erosion estimates from the steepest lands. These results show that comparisons between erosion and sediment loads are better for erosion estimates made at the fine scale small regions than for estimates over a large region. This conclusion is likely the result of errors in estimating slope steepness and length produced by spatial averaging at the 1:250,000 scale.
The spatial variability of soil properties are being examined at several spatial scales from the pedon to the MRB scale. Analyses include organic carbon, pH, depth to CaCO3, depth of A horizon, and the Profile Darkness Index. Preliminary results indicate that a significant amount of spatial variation in soil properties occurs at the pedon scale. An additional project, which received funding from the Minnesota Pollution Control Agency, is examining how soil phosphorus bioavailability (to algae) varies across the MRB according to properties such as soil organic carbon content and soil pH.
Work focused on three areas in 1999. The first was statistical evaluation of drainage status and erodibility index for agroecoregions, watersheds, and agroecoregion-watershed intersections in the MRB. We found that agroecoregion boundaries were better indicators of differences in drainage and erodibility than watershed boundaries, indicating that agroecoregion boundaries will be useful for delineating regions with high susceptibility for nitrate losses through tile drains versus regions with high susceptibility for erosion losses from upland areas. The second area of focus was physical and economic modeling of sediment, phosphorus, and nitrate losses and control strategies from key soil types within the Sand Creek and Le Sueur watersheds of the eastern MRB. Each soil type was investigated for: impacts of conventional versus conservation tillage; broadcast versus incorporated application; and low, medium, or high rates of fertilizer application for their impact on pollution losses to surface waters. An economic analysis of the results showed that costs of abating pollution were significantly different between soil types. The third area of focus was the evaluation of the phosphorus site index method for delineating regions with a high susceptibility for phosphorus losses to rivers and lakes. This index is based on potential for runoff and erosion, proximity of land to watercourses, rates of phosphorus applied in fertilizer and manure, soil test phosphorus levels, and method of application of phosphorus in fertilizer and manure. From 65 to 70 percent of the variability in total phosphorus losses in Minnesota rivers and lakes could be explained using the phosphorus site index. Regions with a phosphorus site index value greater than 32 were strongly associated with severely impaired water quality. Complementary to this study are results in the laboratory where bioavailability of phosphorus from a wide range of soil types was studied. Results showed that bioavailability of phosphorus was strongly controlled by soil pH, and that degree of phosphorus sorption was strongly related to Bray P-1 soil levels.
Aquatic Processes. We have focused on identifying the spatial scale in the Minnesota River Basin at which the variance in in-stream biological properties is best explained. We selected 28 sites within three major watersheds, which also are within three agroecoregions. Benthic organisms and stream habitat were sampled at each of those 28 sites using a variety of techniques, primarily a low-gradient stream system developed by the U.S. Environmental Protection Agency (EPA). In-stream habitat was quantified by broad habitat assessment (e.g., Qualitative Habitat Indices) and by specific tools such as pebble counts. Analysis focused on identifying the suite of independent, landscape-scale variables that best explained the variance in both biological and habitat variables. Preliminary results indicate that habitat quality differs significantly between agroecoregions within a given major watershed. In 1998, additional invertebrate samples were collected at the 28 sites and assessments were made of riparian habitat and aquatic chemistry. Complementary invertebrate collections also took place in the Redwood River major watershed in the western part of the MRB as part of the Undergraduate Research Opportunities Program (UROP). ANOVA results indicate that the agroecoregion significantly affects suspended chlorophyll and sediment, while the affects of major watershed on dissolved phosphorus is not independent of agroecoregion effect. Forty sites were added for stream habitat assessments to provide additional statistical power.
We electroshocked for fish at 55 stream sites in the lower MRB. Fish community data were gathered, from which an index of biotic integrity (IBI) will be determined. Geographic information systems (GIS) analysis tools are being used to allow more spatial patterns and scales to be explored. Using IBI scores as an independent variable, we will compare them to geological formations, soil types, and land use. A determination will be made as to whether major watershed, agroecoregion, or their intersection explains IBI scores the best. The relationship among stream morphology, riparian habitat conditions, and the Hilsenhoff Biotic Index (HBI) at 24 sites in the lower MRB also has been investigated. The Pfankuch streambank stability evaluation and quantitative habitat evaluation index (QHEI) were evaluated separately with the Rosgen stream classification to determine if the prediction of HBI scores was enhanced. Additionally, the watershed and agroecosystem units were evaluated for their influence on predicted HBI scores. Results of this study suggest that stream morphologic grouping and local riparian habitat conditions together can help to explain the variability in water quality conditions in the MRB.
Aquatic chemistry efforts have focused on in-stream sediment and phosphorus dynamics in three different ways. First, particle grain-size distributions were developed for inorganic suspended materials in the Minnesota River, and results indicate that almost all particles are silt- and clay-sized (< 63 microns). The majority of particle sizes were found to be in the 2-20 micron range. Assessment has begun on sediment phosphorus sorption/desorption characteristics in the Minnesota River. Modeling these characteristics using the Langmuir isotherm gave excellent results (r2 > 0.9), which will be used as we continue to characterize phosphorus sorption throughout the MRB. Phosphorus mass balance work also has begun for stream reaches in the MRB, with preliminary results indicating that the majority of phosphorus is being transported during/after rainfall events. Second, quarterly water quality samples were taken at 64 sites to assess sediment, phosphorus, and chlorophyll variability across the MRB. Results indicate that the concentrations of these variables are greater in the eastern half of the MRB than in the western half, which parallels previous work that estimated constituent loads across the MRB. Third, long-term water quality data (1980-1992, U.S. Geological Survey and the Metropolitan Council of Environmental Services) from a Minnesota River mainstem sampling station at Jordan, MN, were examined. Preliminary results indicate that chlorophyll concentration is controlled by water discharge, although dissolved oxygen concentration is primarily a function of water temperature.
Economic and Social Processes. Efforts have been focused on determining the characteristics, capabilities, and limitations of the main institutional arrangements used in the MRB to reconcile tensions between what we term the "ecosystemic imperative" (managing at relatively large spatiotemporal scales with complex sociocultural systems) and the "ethnological imperative" (managing locally to meet the claims of individuals, interest groups, and local communities, taking into consideration their local cultures and interests). Institutional arrangements that are used to resolve these tensions include the open market, command/control, multisectoral stakeholder partnerships, environmental education programs, and social movements (environmentalism and property rights groups). Combinations of these arrangements also are present. We have focused on the emerging institutions of stakeholder collaboration, environmental education, and social movements (very important, but poorly understood). We hypothesize that there is a general movement for ecological change in the Minnesota River Basin, which is in conflict with the "Wise Use/Property Rights" movement. Much has been learned about these emerging institutional arrangements by reading documents and searching Internet sources; attending conferences, meetings, and major events; observing farm sites and riparian areas where environmental problems are being addressed; and interviewing participants involved in activities relevant to the project.
Five segments of questions were used for extensive telephone interviewing, including adaptive strategy, watershed understanding, group dynamics, meaning and identity, and management approaches. From these data, three categories of stakeholders emerged: nongovernment utilitarian (e.g., corn, soybean, and beet growers; pork, poultry, and beef producers), government new-style (e.g., U.S. EPA, Minnesota Pollution Control Agency, Department of Natural Resources, Bureau of Water and Soil Resources, Minnesota River Joint Powers Board, Redwood-Cottonwood Rivers Control Area, Blue Earth River Basin Initiative), and nongovernment ecological (e.g., CURE, CCMR, Friends of the Minnesota River Valley, Friends of Big Stone Lake, Audubon Society). Government "old-style," defined by a generally bureaucratic method of organization, did not seem to be prominent among the stakeholders who were interviewed (government "new-style" is based upon collaborative partnerships between agencies). Evaluation of the interviews allowed for postulating relationships and characteristics for each stakeholder group. For example, it was postulated that decisionmaking is done by individuals for nongovernment utilitarian organizations, by committees for government new-style organizations, and by moral authority for nongovernment ecological organizations. Sixteen other such relationships have been derived, and others are presently being generated through further data analysis and interviews. We now understand that the Minnesota River and its water quality issues are culturally constructed in significantly different ways according to the different stakeholder groups.
Our economic efforts have involved measuring the magnitude of transaction costs associated with policies to reduce agricultural nonpoint source pollution and determining whether transaction costs help explain the prevalence of the policies actually observed. Analysis of Natural Resources Conservation Service (NRCS) data indicated that transaction costs associated with a cost sharing/technical assistance program represented 38 percent of the total costs (abatement costs plus transaction costs) per acre for those data points with public sector involvement. Two mail surveys and a series of interviews were conducted to explore the magnitude and determinants of transaction costs in the context of policies to reduce Minnesota River agricultural phosphorus pollution.
Farmers were surveyed regarding their production practices and their opinions about alternative policies to reduce phosphorus loading. The two most acceptable policies were a requirement for conservation tillage on highly erodible land and educational programs on best management practices. The two least acceptable policies were a tax on phosphate fertilizers and a tax on manure. A survey of persons from government agencies and farm and environmental organizations indicated that expected farmer resistance was a more important determinant of agency preference for policies than either farmer costs or administrative costs. A requirement for conservation tillage on highly erodible land also was the preferred policy among this group, and a tax on manure was the least preferred policy.
Interviews with agency staff were conducted to estimate transaction costs associated with four policies to reduce agricultural phosphorus pollution in the Minnesota River. The tax on phosphate fertilizers had the lowest transaction costs ($0.935 million), followed by educational programs on best management practices ($3.109 million), the requirement for conservation tillage on all cropped land ($7.851 million), and expansion of the permanent conservation easement program ($9.371 million).
Contingency valuation was conducted for a 40 percent reduction in agricultural phosphorus pollution in the Minnesota River. Respondents were willing to pay $10.44 per year in state income taxes per household, or $10.83 per year in water bill surcharges per household. A panel model yielded an individual value of the same water quality improvement of $38.88. The recreational value of the Minnesota Valley National Wildlife Refuge was $28.81 per individual per trip.
Currently, ADAPT hydrogeologic model simulations are being used to examine variation in phosphorus export according to different tillage practices, fertilizer amounts, application methods, and field proximity to water and/or tile intakes. This information, combined with a comprehensive survey of all farmers within a large area of the Le Seuer major watershed in the MRB, will be used to develop an economic model (General Algebraic Modeling System) to capture the effects of policy on farm income, phosphorus loading in the watershed, and the budget of the agency implementing the policy. Progress in 1999 includes: (1) completing the biophysical simulation (via ADAPT) of cropping systems or practices representative of those commonly occurring in the Le Sueur watershed of the MRB, and (2) developing a mathematical programming model that incorporates the physical outputs (crop yields, phosphorus loss, nitrogen loss, and sediment loss) and costs of production associated with each cropping system represented in the Le Sueur watershed. The mathematical programming model captures the policy constraints and the physical and economic relationships present in the watershed. At this point, we have a simplified version of the economic (math programming) model working. Because of inconsistencies in the results from ADAPT, the simulation of all systems (of which there are approximately 200) will be repeated.
Water quality research from the MRB project has indicated that phosphorus export from the MRB is not uniform across the landscape. To address this discrepancy, the cost effectiveness of uniform policies (same policy for entire MRB) versus targeted policies according to location in the MRB will be examined. Approaches include east-basin versus west-basin policies, or policies for specific major watersheds or specific agroecoregions.
Anthropological work in 1999 focused on those aspects of water quality issues most related to one of our graduate student's dissertation topic, "Resolving the ethnolocal/ecosystemic dilemma through ecological regime formation: a case study of the Minnesota River Basin." Three areas of interest include: (1) pollution trading, as exemplified by the Southern Minnesota Sugar Beet Cooperative/Minnesota Pollution Control Agency Memorandum of Agreement (MOU) process; (2) the ramifications of the recent (April 21, 1999) formation of the Public Input Committee as a replacement for the Citizens Advisory Committee of the Joint Powers Board; and (3) the Minnesota Department of Natural Resources Environmental Indicators Program as it relates to their Environmental Stewardship Initiative.
Future Activities:
The project has received an extension to September 30, 2000. The additional time and resources will be used to "fill in the gaps" and synthesize results. A major focus will be completion of the four multidisciplinary manuscripts (Hatch, et al.; Hatch, et al.; Mulla, et al.; Perry, et al.). The first paper (submitted) presents a framework for management of agricultural watersheds based on experience in the MRB. The second paper (submitted) is an examination of management at the major watershed-agroecoregion intersection. The third paper addresses the meaning of scales in different disciplines and the ability to address scale questions in watershed management. The fourth paper addresses a watershed management dilemma, which consists of scientific understanding of water quality having the best resolution at the regional level, while watershed management decisions are being pushed towards the local level. We will finalize ongoing research that pertains to phosphorus erosion potentials across the Minnesota River Basin, phosphorus erosion rainfall simulations and modeling, the ADAPT-economic model to assess differing farming practices and their affect on phosphorus export, and the cost-effectiveness of spatially-varying management policies across the Minnesota River Basin. Funding has been granted recently for a new Water and Watersheds proposal that focuses efforts from the entire Minnesota River Basin to a few smaller watersheds and management districts in the eastern half of the Basin. We anticipate using the results of the current project to help guide our efforts in the new project.Journal Articles:
No journal articles submitted with this report: View all 17 publications for this projectSupplemental Keywords:
watershed, ecosystem, aquatic, habitat, riparian, wetland, nutrient, hydrology, modeling, Midwest, Minnesota, agriculture., RFA, Scientific Discipline, Toxics, Water, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, Nutrients, Hydrology, Water & Watershed, Ecosystem/Assessment/Indicators, Ecosystem Protection, exploratory research environmental biology, Chemical Mixtures - Environmental Exposure & Risk, State, pesticides, Ecological Effects - Environmental Exposure & Risk, Ecological Effects - Human Health, Ecology and Ecosystems, Watersheds, Ecological Indicators, anthropogenic stress, aquatic ecosystem, basin hydrology, environmental monitoring, fate and transport, nutrient transport, agriculturally impacted watershed, Minnesota, ecological exposure, bacteria, watershed management, agricultural watershed, Midwestern U.S., modeling, spatial and temporal scale, sediment runoff, aquatic ecosystemsProgress 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.