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BIG SPRING: FARMING FROM THE GROUND "WATER" UP: EVOLUTION OF A WATER QUALITY PROJECT
Gerald A. Miller1 and Susan S. Brown2
1
Associate Dean for Extension & Industry Programs, College of Agriculture, Iowa State University, Ames, IA 50011Table of Contents: |Introduction| |Monitoring Results| |Forming a Team| |Developing a Plan of Action| |Funding| |The Plan of Action: A Review||Implementation| |Achieving Success| |Conclusion| |References|
The Big Spring Basin Demonstration Project was Iowa’s initial multi-agency, multi-funded water quality demonstration project. The project was established to demonstrate the protection of groundwater in an area of intensive agriculture where groundwater is readily susceptible to contamination.
Initial monitoring conducted by the Iowa Geological Survey of the quality of the groundwater at Big Spring began in the fall of 1981. These results, as well as the water quality test results of individual on-farm wells, caused local citizens to express concern about the quality of their drinking water. They recognized that elevated nitrate levels in their wells and continuous detection at the Big Spring of commonly used herbicides were due in part to agricultural practices occurring on the land within the basin.
The 229 households located within the Big Spring groundwater basin and the families experiencing this situation requested assistance from the Clayton County Soil and Water Conservation District. District leaders responded by turning to their state and federal partners. They asked these partners to help address water quality, crop and land management issues.
The initial monitoring in the Big Spring basin began in the fall of 1981. Funded by the U.S. Soil Conservation Service, the U.S. Environmental Protection Agency (EPA) and conducted by the Iowa Geological Survey. This study concentrated on understanding the mechanisms of nitrate and pesticide contamination, their distribution both in time and space, and concentration of contaminants, and the relationships of water quality to agricultural practices. Hallberg and others (1983) mapped appropriate geologic and hydrologic systems in detail, as well as land use, and monitored groundwater flow and chemical concentrations from wells and springs.
In the Big Spring basin they found systematic nitrate contamination in unprotected portions of the aquifer and intermittent or continuous herbicide contamination at very low concentrations in the same unprotected aquifer areas. The highest concentrations of herbicides were found associated with spring and early summer rains. The average loss of nitrate-nitrogen during 1982 and 1983 into groundwater was 602 tons (equivalent to about 30% of average total fertilizer applied N); average loss of atrazine (the most common herbicide found) in groundwater was 23 pounds (less than 0.1% of the applied atrazine). During 1982 and 1983 the average loss of nitrate-nitrogen in both groundwater and surface waters was 1,169 tons, equal to over 35 pounds of nitrogen for every acre in the basin, and is equivalent to about 50% of the total fertilizer nitrogen applied during those years.
Hydrologic analysis revealed that about 90% of the total flow at Big Spring resulted from infiltration and that about 95% of the nitrate and between 53 and 84% of the atrazine was delivered through this infiltration process. The highest concentrations of pesticides occur with surface runoff to sinkholes. As measured at Big Spring, flow-weighted mean concentrations of atrazine were two to five times higher during periods when runoff was occurring than during periods dominated by infiltration water. Mean annual nitrate concentrations at Big Spring were found to be 40 mg/L in 1982 and 45 mg/L in 1983. Such mean concentrations are at or close to the drinking water health standard of 45 mg/L set by EPA.
Beginning in June 1983 representatives of local, state and federal programs began meeting to develop a plan of action. The purpose of these planning sessions was to forge a program of research, information and education and management practice implementation which integrated soil and water management programs, groundwater protection and profitability for producers.
A number of Iowa’s agricultural and natural resources agencies joined together to form the Ad Hoc Karst Committee. The active participants in the Ad Hoc Karst Committee included (agency and organizational names listed as of 1983; several groups now have a different name and organizational structure):
Northeast Iowa Conservancy District (Co-Chair, now county Soil and Water Conservation Districts)
Iowa State University Cooperative Extension (Co-Chair, now Iowa State University Extension)
Iowa Geological Survey (now Iowa Department of Natural Resources Geological Survey Bureau)
Iowa Department of Soil Conservation (now Iowa Department of Agriculture and Land Stewardship, Division of Soil Conservation)
Iowa Department of Water, Air, and Waste Management (now Iowa Department of Natural Resources)
USDA-Agricultural Stabilization and Conservation Service (now Farm Services Agency)
USDA-Soil Conservation Service (now Natural Resources Conservation Service)
U.S. Environmental Protection Agency (U.S. EPA)
Iowa State University Agricultural Experiment Station
University of Iowa Institute of Agricultural Medicine
University Hygienic Laboratory
Iowa Fertilizer and Chemical Association (now Agribusiness Association of Iowa)
Other agencies became involved in the Ad Hoc Karst Committee as the program evolved. A detailed description of the activities of the Ad Hoc Karst Committee is given by Mueller (1994).
The Ad Hoc Karst Committee was renamed in 1986 as the Iowa Consortium on Agriculture and Groundwater Quality. This new organization name was chosen as a result of the response received from potential funding agencies and organizations. External groups stated that ad hoc organizations would not be considered for funding.
In considering the groundwater contamination problems of northeast Iowa, members of the Ad Hoc Karst Committee recognized that some tools were available to reduce the effects of agriculture on our water resources. As a result, the group met and formed a special task force to: 1) define specific problems; 2) identify potential solutions; 3) compile pertinent agency activities; 4) determine agency needs; 5) identify research needs; and 6) present recommendations for action to the Ad Hoc Karst Committee.
Among other things the task force recommended that a pilot project be
conducted in the Big Spring groundwater basin. This project was to be cooperative and
include:
on-farm demonstration and applied research to document effective local best management
practices for protecting water quality; provision of cost share incentives and technical
assistance to promote widespread implementation of approved alternative management
practices; and intensive groundwater monitoring.
In accordance with the recommendations of the Ad Hoc Karst Committee, the Committee’s Implementation Task Force developed a Big Spring Basin Demonstration Project proposal. As proposed, the project consisted of a coordinated group of agencies and researchers, with individual responsibilities cooperating to find suitable ways to protect groundwater. The project’s plan was coordinated, but funding for work items was identified separately. Therefore, contractual and professional responsibilities remained separate between participating agencies.
Iowa State University Extension staff followed up the project proposal with a marketing publication (Glanville and Wishart, 1985).Designed in booklet form, the 8-page illustrated publication described the Big Spring Basin Groundwater Demonstration Project. The booklet contained an easily read statement of the problem and identification of solutions and funding requirements for each of the three components; research, education and implementation. Individual members of the team used the illustrated booklet as a vehicle to introduce the detailed project proposal to potential funding organizations.
The comprehensive proposal to secure funding for the Big Spring groundwater basin was completed in February 1985. Within the basin, and within the county, interest in seeking solutions to degrading water quality was moving the project forward. Starting in crop year 1985, limited funds were secured from the USDA Agricultural Conservation Program and Iowa Department of Agriculture and Land Stewardship, Division of Soil Conservation to implement conservation structures, refined crop nutrient and pest management, and livestock management practices within the 1,100 acre Bugenhagen subbasin, an intensively cropped subwatershed of the Big Spring groundwater basin.
At the same time, funds provided by the U.S. Environmental Protection Agency and the USDA Soil Conservation Service allowed for the installation of an automated monitoring station within the subbasin. The Big Spring research and implementation project began to evolve.
The rest of the story involves a number of related state initiatives that culminated in the Groundwater Protection Act of 1987 and supported Big Spring efforts for another 5 years. The first element was an energy management initiative. Thanks to a ruling by the U.S. Supreme Court concerning excessive charges during the 1970s for retail petroleum projects by major oil and gasoline suppliers, a windfall of energy funds was rebated to each state. These funds, based on per capita energy use, became known as the "oil overcharge funds." They were administered nationally by the U.S. Department of Energy.
Early in 1985 a group of Iowa legislators petitioned the U.S. Department of Energy to authorize use of the oil overcharge rebate to address agriculture energy use and the environment. The U.S. Department of Energy granted an exception to their guidelines, allowing Iowa to prototype an energy and the environment program. The Iowa Legislature responded by approving in 1986 Senate File 2305, a bill that established the Agricultural Energy Management Advisory Council, chaired by the Iowa Secretary of Agriculture. The Council included membership from each of the three regent universities as well as the Iowa Department of Agriculture and Land Stewardship and the Iowa Department of Natural Resources.
At the initial meeting of the Council in July 1986, the membership requested that at least one proposal be written to embrace the concepts of the Big Spring Basin Demonstration Project proposal. However, the Council directed that the proposal they would consider must be designed for statewide application on a county-by-county basis rather than targeted to one location. In August 1986 a group of research scientists and education specialists met and developed a project plan that became known as the Integrated Farm Management Demonstration Project.
The Integrated Farm Management Demonstration Project proposal was presented to the Advisory Council during its quarterly meeting in the fall of 1986. The Council approved the concept and directed the Iowa Department of Agriculture and Land Stewardship to request proposals for implementing the various provisions of the plan. The scope and results of the Integrated Farm Management Demonstration Project have been described and reported in other publications (Lindquist et. al., 1995). Support for elements of the Big Spring plan were included in the Integrated Farm Management Demonstration.
Also during 1986, a group of specialists within the newly formed Iowa Department of Natural Resources prepared a detailed strategy for protection of Iowa’s groundwater (Hoyer et. al., 1987). This document became the foundation for the landmark Iowa Groundwater Protection Act which was enacted by the Iowa General Assembly during the spring of 1987.
A major provision of the Iowa Groundwater Protection Act was to reaffirm the Agricultural Energy Management Act approved during the previous legislative session and inclusion of a separate provision for funding the Big Spring Basin Demonstration Project. Funding for the Big Spring initiative was identified at $3.1 million over a period of 5 years. Since project staff for the Big Spring Project had been selected and employed as part of Integrated Farm Management Demonstration, the Big Spring information, education and implementation activities were implemented immediately as well as an expansion of the research and monitoring efforts.
1970s
Upper Explorerland RC&D (including Clayton County) in 1970 identified chemical pollution of streams and farm wells as a serious problem needing study. In 1973 a RC&D project proposal asks for funding for a research study and educational program to reduce groundwater pollution. The need for "sinkhole protection conservation practices" first appeared in the Elkader, Iowa Soil Conservation Service Field Office Annual Work Load Analysis in 1967.
Clayton County soil and Water Conservation District’s Long-Range Program and Work Plan, 1973-1980 (revised) requested practical systems to control feedlot runoff; cooperation with Iowa State University Extension Service to monitor wells for nitrogen and bacteria levels in drinking water; cooperation with Upper Explorerland RC&D to apply conservation practices to abate contaminant run-in to sinkholes; and the establishment of monitoring systems to determine the extent of possible excessive use of fertilizers and agriculture chemicals, and effect of animal waste runoff.
1978-1979
The Iowa Geological Survey conducted a regional study of nitrates in wells and the correlation of nitrates to well depth. More than 20,000 water analyses across 22 northeast Iowa counties were included in this study.
1981
September — USDA-Soil Conservation Service Northeast Iowa River Basin Planning Committee held public hearings. Groundwater quality was identified as a high priority issue.
October – The Iowa Geological Survey begins the Big Spring Basin Monitoring Study by collection water samples on a systematic schedule at the Big Spring.
1982-1983
Big Spring Basin Monitoring Project findings are documented by the Iowa Geological Survey and discussed among cooperating groups.
Iowa State University Cooperative Extension Service publishes a Best Management Practices report for the state 208 Nonpoint Source planning process.
1983
During June a tour was conducted in the Big Spring Basin area. The tour was coordinated by Iowa Geological Survey and involved various state and federal agency representatives. As a result of the field tour the idea to form an interagency group to develop a strategy for addressing issues in the Karst region was seeded.
Ad Hoc Karst Committee formed and the initial meeting was conducted in October. The committee charge was to develop solutions to the groundwater contamination problems evident in northeast Iowa. Co-Chairs: Dr. Vivan Jennings – Iowa State University Cooperative Extension Service; Mr. William Gasper, Northeast Iowa Conservancy District.
1984
July– First issue of the newsletter "Water Watch" was published and distributed by the Clayton County Extension staff.
A door-to-door inventory of farm operations and survey of attitudes was conducted by Dr. Steven Padgitt, Iowa State University Cooperative Extension Service Rural Sociologist. The study showed that farmers were just as concerned about their drinking water as about profitability and they were willing to reduce fertilizer and chemical use because of concerns with water quality and family health and safety.
Two different five-part TV news series about the northeast Iowa groundwater study and related issues were broadcast.
October – First major public "seminar" about groundwater was held. This seminar titled "Groundwater Quality in Northeastern Iowa" was held at Luther College in Decorah, Iowa, with sponsorship by the Soil Conservation Society of America, Iowa Chapter.
Ad Hoc Karst Committee Task Force groups were formed with an objective of formulating recommendations for a Big Spring basin demonstration project which pulled together all resources and expertise to focus on workable solutions.
1985
February – Ad Hoc Karst Committee published Big Spring Basin Demonstration Project proposal.
First meeting held with landowners in the "Bugenhagen Subbasin Demonstration Project" area.
Ad Hoc Karst Committee members seek funding and resources to implement a project in the Big Spring Basin.
Little success was achieved in securing funding from foundations and limited success was achieved with federal agencies because of limited funds available.
The Big Spring Project was mentioned in floor language/intent in the federal FY ’86 Agriculture Appropriations bill in the U.S. Senate and related discussions of the Clean Water Act, 99th Congress.
USDA-Soil Conservation Service receives special funds, albeit limited, to support the project; Agricultural Stabilization and Conservation Service gets approval for special project cost-share funds; Iowa Division of Soil Conservation approves special cost-share funds for the subbasin demonstration area.
Farmers in the Bugenhagen subbasin of the Big Spring Basin "can’t be reined in any longer." The first special project funded terraces were built in the subbasin in summer and fall 1985. Farmer interest for the Project was very high.
1986
Groundwater Quality becomes a visible public issue in both statewide and regional media.
Ad Hoc Committee changes its name to "Iowa Consortium on Agriculture and Groundwater Quality" and broadens membership.
Utilizing special cost-share funds the Consortium declares the implementation of the initial phase of the Big Spring Basin Demonstration Project.
Special grants from USDA Soil Conservation Service and U.S. EPA-Region VII, and state agency resources allow other phases of project to be implemented.
State agencies are reorganized. Iowa Department of Natural Resources and Iowa Department of Agriculture and Land Stewardship merge former agencies. Search for significant funding continues but slowed by adjustment to the new state agency organization.
Iowa Groundwater Protection Strategy written by Geological Survey Bureau, Iowa Department of Natural Resources staff. The Strategy identifies agricultural impacts as a major contributor to nonpoint source pollution.
Iowa Senate File 2305 was enacted by the 71st General Assembly. This legislation established the Agricultural Energy Management Advisory Council, which in turn formed the Integrated Farm Management Demonstration Project. A $1.0 million special appropriation was made to implement information, demonstration and educational programs on a statewide basis. The Big Spring Basin Demonstration project is identified as one of the first year demonstration areas.
Eighty-nine percent of the land area in the Bugenhagen subbasin is covered by Long-Term Contracts with plans to apply needed soil conservation and nutrient and pest management practices.
1987
Governor Brandstad’s State of the State message calls for support of efforts such as the Big Spring Basin Demonstration Project.
The Consortium holds a public meeting in Des Moines to emphasize coordinated effort, describe challenges and develop support for efforts.
Iowa League of Water Resources Districts passes resolution supporting the Big Spring Project.
Iowa Groundwater Protection Act of 1987 passed by the Iowa General Assembly. The Act provides $3.1 million funding for Big Spring Basin Demonstration Project over 5 years and continues funding for Iowa Farm Management Demonstration Project for 5 years. The Act developed related environmental protection activities to include the establishment of the Leopold Center for sustainable Agriculture located at Iowa State University.
The first Big Spring Basin Demonstration Project field day is held in 1987, attracting 135 visitors.
While at the state level members of the Ad Hoc Karst Committee were developing strategies and proposals during the period of 1983 to 1985, local staff of Iowa State University Extension and the Clayton County Soil and Water Conservation District initiated targeted information, educational programs and technical assistance to Big Spring groundwater basin farmers. Farmers were concerned about the quality of their drinking water, and eager to implement refined crop and livestock management practices that would reduce the potential contamination of their drinking water resources. In Extension Service lexicon, this was "the teachable moment"!
On- farm management demonstrations began prior to state funding of the long-term Big Spring Basin Demonstration project. However, their intensity was increased after 1986 to provide farmers with the local information they would need to adopt refined management practices. Twenty four ag-nutrient management farm demonstrations on cropland, some multi-year, were conducted between 1987-1992. Seventeen dealt with nutrient, and particularly nitrogen, management. The balance dealt with establishing and maintaining N-fixing legumes, tillage and equipment as they relate to nutrient management. Calculation of optimum economic yields from five years of demonstrations showed that, when all best management practices for N were used, rates could be reduced even below current university recommendations while maintaining yields. The demonstrations also documented manure management for crop nutrients and confirmed that first-year corn following alfalfa, a common rotation in the area, does not need N from other sources (Hallberg, 1991).
Fifteen weed control demonstrations were conducted, five of which were part of the 70 Integrated Farm Management Demonstration Project-sponsored state-wide series of research/demonstration sites. Control methods included mechanical practices only, mechanical plus herbicides, and both banding and broadcast herbicide methods. The demonstrations documented that banding herbicides can reduce use rates without sacrificing yields. Some non-chemical control methods, however, had management requirements that were in conflict with time management needs of farms that had both crops and significant livestock operations. Farmers in the area were introduced to the practice of intensive crop scouting and the economic value of timely Integrated Pest Management recommendations.
Conservation tillage alternatives to protect soil resources were also demonstrated. Returns to land, labor and management inputs were calculated for all tillage systems demonstrated between 1988 and 1992. The profitability of no-till was shown to represent not only energy savings in reduced fuel and N fertilizer use, but also improved labor time management by season. Measured residue, 1988-1992, on the soil surface after planting for soil erosion protection averaged over 2 times greater for no-till than fall chisel.
Additional demonstrations conducted by the project included two low-energy-use swine building heat exchangers, plugging abandoned wells, and two tree plantings and two permanent grass plantings to protect sinkholes.
Nine farmers in Bugenhagen subbasin received one-on-one assistance with nutrient and pest management beginning in 1987. Assistance was provided with soil test sampling and interpretation, establishment of realistic yield goals, pest scouting and IPM recommendations, calibration of sprayers and manure spreaders, determination of nutrient credits for manure and legumes, and other tillage and forage management. Management practices and crop inputs of this group were monitored, along with groundwater in the subbasin, from 1987-1994. From 1986-1988 farms in the Bugenhagen subbasin also received over $178,000 in cost-share incentives through a special allocation from Iowa Department of Agriculture and Land Stewardship, Agricultural Conservation Program special project funds, and a special project agreement with the Clayton Soil and Water Conservation District to cover 75% of the cost of installing permanent soil conservation practices such as terraces, grassed waterways and contour strips.
The project included a dedicated information specialist who publicized demonstration results and groundwater protection issues through regular news releases and a bimonthly newsletter, Water Watch. The specialist also prepared informational materials for project field days and meetings. The Clayton Soil and Water Conservation District and Extension offices received many requests for information and assistance with management practices to protect groundwater as a result of this intensive information marketing campaign.
Total
Big Spring Basin Demonstration Project field activities, 1987-92, included 68 field days that drew 2,791 people, self-guided information tours at 71 sites that attracted 2,316 persons, and 60 basin tours that brought an additional 1,320 visitors. A total of over 6,500 people visited and/or worked at the BSBDP research-demonstration sites, including farmers and agricultural scientists from 51 nations and many state and national organizations.
One measure of success for the plan of action developed by the Ad Hoc Karst Committee was receiving funds to implement all or part of the plan. However, all success was not to be measured in terms of funds garnered. The ultimate measure of success was identifying and documenting implementation of best available technology and changes in crop and livestock management practices by farmers within the basin.
In 1984, local Extension staff in cooperation with the Iowa Geological Survey, with support by the USDA Soil Conservation Service, conducted a door-to-door survey of the 229 residents of the Big Spring Groundwater Basin. A total of 208 farm operators responded to the six-page survey which documented farming operations and management practices. This initial survey revealed that only 18% of the farmers gave full credit for nitrogen availability to first year corn following a "decent" stand of alfalfa (Padgitt, 1985). On-farm replicated demonstrations subsequently documented that no additional nitrogen is required for first year corn following a "decent" stand of alfalfa (Hallberg et al., 1991). In addition, less than 60% of the farmers took credit for nitrogen in animal manure.
A follow-up survey two years later, in 1986, suggested that farmers were already making changes. In 1986 farmers in the Basin had reduced their nitrogen rates for corn by 16 units per acre (Padgitt, 1987), primarily by taking credit from alfalfa and animal manure sources. By 1992, surveys and farm census inventories showed basin average fertilizer N rates had decreased from 158 lb /A. in crop year 1986 to 117 lb/A. in crop year 1991. Rates on continuous corn had decreased from 169 lb/A. to 131 lb/A. and rates on first-year corn after alfalfa had decreased from 115 lb/A. to 59 lb/A. in the same period.
The Big Spring Basin Demonstration was also successful in causing long-term change - by enhancing the interest of northeast Iowa farmers generally in best management practices for water quality protection. In 1990 the Soil and Water Conservation Districts of three additional counties, Winneshiek, Allamakee and Fayette, joined with Clayton County and with the state-level partners to propose a large-scale Northeast Iowa River Basins Water Quality Demonstration Project to the USDA Water Quality Initiative. This project, which was funded beginning in 1991, has been able to continue the successful programs of the Big Spring Demonstration to assist many more northeast Iowa farmers. The emphasis on providing local demonstration of and assistance with profitable, refined manure and nitrogen management remain. The intensive information marketing, and publication of the Water Watch newsletter have been continued and distributed over a larger area. In addition grazing management, forestry and riparian protection best management practices have been promoted by the new project.
Like the Big Spring Basin Demonstration, the Northeast Iowa Demonstration has continued to benefit from broad interagency cooperation. Under the leadership of Iowa State University Extension, the Northeast Iowa Demonstration Project has also received support from the Natural Resources Conservation Service, Farm Services Agency, the Iowa Department of Agriculture and Land Stewardship Division of Soil Conservation, the Iowa Department of Natural Resources, U.S. EPA, the Iowa Leopold Center for Sustainable Agriculture and other sources. Also as in the Big Spring basin, the Northeast Iowa Demonstration Project has enjoyed strong local support from farmers and agribusinesses. The Big Spring Basin Demonstration Project provided received one-on-one assistance with refined nutrient and pest management practices to nine farmers in the Bugenhagen subbasin. Now nearly 200 farmers have received similar assistance through the Northeast Iowa Demonstration. And, while many new on-farm demonstration cooperators have been recruited in the four-county area, some in the Big Spring basin continue to contribute significant time and effort to long-term management demonstrations. These farmers have become respected local advocates of water protection best management practices.
The Big Spring Groundwater Basin Demonstration Project is unique in the annals of Iowa’s efforts to protect the environment. It represents the first multi-agency project that brought together grassroots consensus supported by multiple local, state and federal agencies and organizations in a combined information/demonstration/education, technical implementation and monitoring and research effort supported by external funds. Mueller’s (1994) thorough review and analysis emphasizes how the efforts of all involved coalesced to bring about a project in which no one single entity could have achieved success without the other partners.
The processes involved in making the Big Spring project a success have served as the foundation for succeeding efforts to include, but not limited to: the Integrated Farm Management Demonstration Project; the Model Farms Demonstration Project; the Agricultural Drainage Research and Demonstration Project; Iowa Water Protection Fund projects administered by the Division of Soil Conservation, IDALS; the Section 319(h) nonpoint pollution projects; and Iowa’s successful USDA Water Quality Demonstration and Hydrologic Unit Area projects.
Big Spring provided the institutional "lessons learned," which in turn were readily transferred to succeeding projects. Big Spring provided models for interagency coordination, for maintaining local involvement, for addressing local farmers’ concerns in practical on-farm demonstrations, intensive information marketing, and for individualized management assistance. Staff of follow-up projects could "hit the ground on a run" and greatly reduce the typical 12 to 24 months needed for learning how to organize and implement water quality project activities.
The statewide legacy of the Big Spring Basin Demonstration has been a high level of communication and cooperation between agencies, education and research institutions and other organizations dealing with agriculture and the environment. The Big Spring model has shown that such multi-faceted, cooperative projects can be successful in causing farmers to voluntarily adopt improved management practices for water quality protection.
Glanville, T. and Wishart, D., 1985, Preserving good water in northeast Iowa: Iowa State University Cooperative Extension Service, Ames. 8 p.
Hallberg, G.R., Libra, R.D., and Bettis, E.A., III, and Hoyer, B.E., 1983,. Hydrogeology, water quality, and land management in the Big Spring Basin, Clayton County, Iowa: Iowa Geological Survey, Open File Report 83-3, 191 p.
Hallberg, G. R., Contant, C.K., Chase, C. A., Miller, G.A., Duffy, M. D., Killorn, R.J., Voss, R. D., Blackmer, A.M., Padgitt, S. C., DeWitt, J.R., Gulliford, J. B., Lindquist, D.A., Asell, L. W., Keeney, D.R., Libra, R.D., and Rex, K.D., 1991, A progress review of Iowa’s agricultural-energy-environmental initiatives: Nitrogen management in Iowa: Technical Information Series 22, Iowa Department of Natural Resources, 29 p.
Heitmann, N., 1980, Water Source of Big Spring Trout Hatchery, Clayton County, Iowa: Proceedings of the Iowa Academy of Science, v. 87, p.143-147.
Hoyer, B.E., Combs, J.E., Kelley, R.D., Cousins-Leatherman, C., and Seyb, J.H., 1987, Iowa Groundwater Protection Strategy, 1987: Iowa Department of Natural Resources, Des Moines, 106 p.
Lindquist, D.A., Miller, G.A., and Hallberg, G.R., 1995, Introduction – the Integrated Farm Management Demonstration Project, pp. i-iv, in Integrated Farm Management Demonstration Program Comprehensive Report, Iowa State University Extension, Ames, IFM 16, 169 p.
Mueller, W., 1994, Big Spring: Anatomy of Environmental Cooperation: REAP International, Solon, 100 p.
Padgitt, S., 1985, Farming Operations and Practices in Big Spring Basin: Iowa State University Extension, Ames, CRD 229, 48 p.
Padgitt, S., 1987, Agriculture and Groundwater Issues in Big Spring Basin and Winnesheik County, Iowa: Iowa State University Extension, Ames, 80 p.
Prior, J.C., 1991, Landforms of Iowa: University of Iowa Press, Iowa City, 153 p.