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CARD: Center for Agricultural and Rural Development

Summer 2004, Vol. 10 No. 3

pdf for printing Valuing Water Quality in Midwestern Lake Ecosystems

Kevin Egan

Joseph Herriges

Catherine Kling

John Downing

Editor's note: This content is reprinted from an award- winning poster presented at the U.S. Environmental Agency's 2004 Science Forum.

As increased attention is focused on the issue of water quality in the state of Iowa, policymakers must grapple with the pressures of balancing federal water quality requirements, tight conservation budgets, and citizen concern for environmental preservation and restoration of Iowa's water resources. Efforts to improve water quality typically entail significant costs, either in the form of state resources to fund cleanup efforts or private costs associated with altering land uses, farming practices, municipal treatment facility expansions, or other investments.
To make good policy decisions regarding water quality, it is important to understand not only the physical processes that affect water quality but also the degree to which citizens value improvements in water quality and are willing to make trade-offs to enjoy improved quality in Iowa's lakes. Since water quality improvements may be costly, it is necessary to know how much benefit people obtain from these improvements if society is to answer the question of whether it is "worth it" to undertake these projects. In many cases the question will be one of degree: that is how much improvement in water quality should we strive for? What amount of improvement in water quality is simply too expensive and would thereby require forgoing other public investments that are more valuable to the citizenry?
To provide this information, researchers from Iowa State University have initiated an ambitious, multi-year study effort termed "The Iowa Lakes Valuation Project."
The Iowa Lakes Valuation Project is an economic study of the use and value Iowans place on water quality in Iowa lakes. Data for this study will be collected for a four-year period through the use of annual mail surveys to a random sample of Iowa residents. The data gathered will include
  • actual trips to Iowa's 130 principal recreational lakes for the years 2001-2006;

  • water quality evaluations used to measure willingness to pay for quality improvements;

  • knowledge and perceptions regarding lake quality; and

  • socio-demographic data.
The value of water quality improvements in Iowa lakes is measured using the economic value concept of maximum willingness to pay. The maximum amount that an individual is willing to pay for an environmental good measures the value they place on that good in that it represents the value of other goods and services they are willing to forgo to acquire or preserve the environmental resource.
The Iowa Lakes Valuation Project is a collaborative study involving economists and ecologists from the Iowa State University Department of Economics, Center for Agricultural and Rural Development, and Department of Evolutionary Ecology and Organismal Biology. Dr. John Downing and other members of the ISU Limnology Laboratory have a complementary five-year project to provide the Iowa Department of Natural Resources with a lake database that will include water chemistry, biological analysis, and watershed GIS data for 130 of Iowa's principal recreational lakes.
EPA's STAR grant augments work begun with Iowa DNR funding and ISU-CARD
The funding for the first year of the survey was provided by the Iowa Department of Natural Resources. A STAR grant from the U.S. Environmental Protection Agency provided the necessary funding to continue the survey for the full four years, thereby allowing the collection of this unique multi-year data set and interdisciplinary study.

Figure 1

Results Table 1
First Year Study
Iowans report a high usage of lakes in the state of Iowa. Approximately 62 percent of Iowa households visited one of the 130 lakes listed in the survey and the average number of trips per year was just over eight in 2002.
Water quality is more important than either proximity or local park facilities in determining where households recreate. Figure 1 shows the results of a question that asked respondents to allocate 100 importance points to a number of factors they might consider when choosing a lake for recreation. The average point allocation is shown. Respondents indicated that water quality was the most important factor they consider when choosing a lake for recreation, with proximity of the lake and park facilities also being relatively important. In contrast, activities near the lake or town are not particularly important in their choice of a lake site.

Figure 2

Results Table 2
Among water quality attributes, households view safety from bacterial contamination and water clarity as the most important, above the diversity or quantity of fish caught or the diversity of wildlife. Figure 2 shows the results of a question that asked respondents to allocate 100 importance points to a number of lake characteristics that might be important to them. Again, the average point allocation is shown. Respondents indicated that safety from bacteria contamination was the most important lake characteristic, with water clarity also receiving a fairly large point allocation. The lack of odor and the presence of a hard, clean, sandy bottom in swimming areas are also important to some respondents.
For more information about this project, visit