Effect of management on water quality and perception of ecosystem services provided by an urban lake

Abstract

Costadone L, Sytsma MD, Pan Y, Rosenkranz M. 2021. Effect of management on water quality and perception of ecosystem services provided by an urban lake. Lake Reserv Manage. 37:418–430.

Integrating the perception of water quality in management efforts can be an effective way of developing and evaluating management plans targeted at preserving lake ecosystem benefits. We present a case study of Oswego Lake (OR), an urban lake that has been intensively managed for the past 20 yr to preserve valuable esthetic and recreational benefits. We combined the analysis of a long-term water quality dataset with survey data to assess whether management efforts over time successfully met the expectations of people using the lake. The synergistic impact of both in-lake and watershed management activities significantly reduced whole-lake nutrient concentrations; however, high external phosphorus loading from native soil sources and the surrounding urbanized watershed likely continued to contribute to episodes of cyanobacteria blooms during the summer and partially limited in-lake management efforts. Although there was no statistically significant change in mean summer water transparency over the 20 yr management period, more than 60% of the people that have access to the lake thought the water quality had improved since they started using the lake. The lake was also perceived as “suitable” for esthetic and recreational enjoyment by users. As with other lakes in highly developed urban watersheds, Oswego Lake requires ongoing interventions to maintain adequate water quality. Management challenges include coordination of multiple stakeholders and jurisdictions with sometimes conflicting goals and constituencies, maintaining a long-term monitoring program that can produce consistent high-quality data, and keeping in touch with user groups to ensure that lake water quality meets expectations.

Keywords:

• Ecosystem services
• in-lake management
• long-term water quality dataset
• survey data
• urban lake

Acknowledgments

This study would not have been possible without the contribution of all the water quality interns at the Lake Oswego Corporation responsible for field sampling and data management. Their work through the years guaranteed the collection of the long-term water quality dataset used in this study. LC also thanks the Lake Oswego Corporation, the Oregon Lake Association, and the Edward D. and Olive C. Bushby family for their financial support.