Proper management of recreational lakes and rivers is an issue of increasing importance. The popularity of water-based recreation has continued a steady growth for three decades, but the supply of recreational lakes and rivers has remained relatively constant. In light of this increasing pressure on available water-based recreational resources, maintenance of a quality level suitable for a range of activities is crucial. But while point-source pollution such as municipal sewage and industrial effluent entering into Illinois' water bodies has been substantially controlled, non-point source pollution from agricultural and urban run-off continues to degrade many of our lakes and rivers.

From a manager's point of view, it is not enough to only provide recreational sites when recreators demand a safe and high quality environment in which to enjoy a wide range of activities from swimming to game fishing to water skiing. For the manager, the problem of defining quality in a recreational lake or river becomes central to effective management of the resource.

While water quality has obvious impacts upon public health, recreational researches have begun to recognize that the enjoyment of water-based recreation is not solely or even largely tied to objective water quality standards. Instead, an individual's evaluation of a lake or river as a potential site for recreation depends not so much on objective or empirical water quality criteria as upon their images or impressions of individual lake and river sites and upon their experience. These subjective characteristics are those which recreators can perceive through their sensory system —most often sight, but also touch and smell. Research conducted by E. L. Davidin 1971 and S. H. Dinius in 1981 shows significant disparities between the public's perception of water quality and empirical measurements. In a 1978 Environmental Protection Agency study, researchers C. W. Binkley and W. M. Hanneman point out that a recreator's perception of water quality can not always be linked to actual water quality because the human sensory system cannot detect objective water quality indicators such as fecal coliform count and dissolved oxygen concentration.

Managers, when defining what characteristics of a lake or river make it a high quality recreational resource, must consider there creator's subjective criteria. A manager's perception of a resource and its quality may differ drastically from a recreator's. In particular, managers have more knowledge and information about the physical, chemical, and biological measurements in the lakes and rivers they administer. However, when a manager makes judgments and decisions based solely on these parameters, he or she is ignoring the recreational population who will be affected by these decisions. Managers and recreators will generally have areas of agreement and disagreement. It is crucial, however, that the resource manager be aware of how his or her perceptions and attitudes differ from recreationists.

This study compares managers' and recreators' importance ratings of 13 characteristics which might be used as indicators of quality in a waterbody. One hundred recreational users of Southern Illinois lakes were asked to complete interviews concerning their knowledge and attitudes about lake quality. The interviews were conducted around five lakes (Crab Orchard, Devil's Kitchen, Little Grassy, Lake Kinkaid and Lake Murphysboro) in the area of Giant City State Park and within the community of Carbondale. Sixty managers of Illinois state recreational lakes were also mailed questionnaires to obtain information about their knowledge and attitudes towards a water body's quality; 30 questionnaires were returned. Thirteen separate lake quality parameters were rated on a scale from one (least important) to 10 (most important). Respondents were asked to indicate if they did not have knowledge of a characteristic, and those responses were considered separately.

The three most important characteristics to recreators were the absence of unpleasant odors, litter and floating debris (See Figure 1). These characteristics also received the greatest degree of agreement among the recreators sampled as they had the three lowest standard deviations (the standard deviations is a measure of variability around the mean). For managers, the three top rated characteristics were the absence of litter, odor and dissolved oxygen (DO). Like the recreators, managers' responses displayed the least variability for their top three rated characteristics. Surprisingly, managers' ratings overall had higher standard deviations, indicating that disagreement among managers regarding the importance of the 13 characteristics was greater than among recreators.

There was a significant difference between recreators' and

managers' importance ratings for 10 of the 13 characteristics (See Figure 1). Floating debris, average temperature, lake clarity, litter, odor, landscape, pH, and lake bottom material were all rated significantly higher by recreators. Managers rated the importance of water level, and dissolved oxygen (DO) significantly higher than did recreators. No significant differences occurred between managers' and recreators' evaluations of the importance of vegetation, coliform bacteria and biochemical oxygen demand (BOD).

The percentages of recreators and managers who indicated that they had no knowledge about one or more of the 13 characteristics were also compared. A large percentage of recreators indicated that they did not have knowledge of coliform bacteria count (62%), biochemical oxygen demand (58%), dissolved oxygen level (46%), and the pH of the water (37%). It is interesting to note that those recreators who had knowledge of coliform bacteria and biochemical oxygen demand did not significantly differ with managers in their attitudes of the importance of the characteristic.

The implications for recreational resource management are that managers and recreators often use different indicators when evaluating the quality of a resource. Managers must acknowledge the importance that recreators place upon perceptual quality indicators such as odor, litter and floating debris. The recreational literature also suggests that perceptual evaluation of water quality and actual water quality are not necessarily linked because the human sensory perception of water quality is inaccurate.

Public attitudes and perceptions are therefore crucial in managing a recreational lake or river. Managers however, must also be careful to inform recreators when a lake or river has potentially dangerous concentrations of unobservable pollutants. By acknowledging the importance of recreators' perceptual indicators as well as their limitations in detecting harmful pollutants, managers will be in a better position to provide recreationists with high quality recreational experiences.

About the Authors
Jo Both Mullens is a Ph.D. candidate in the Department of Geosciences at Oregon State University. Christopher Lant is an assistant professor in the Department of Geography at Southern Illinois University, Carbondale.