Visitor perception of lake water quality in two highly managed urban lakes in Saint Paul, Minnesota

Urban lakes provide important recreational and aesthetic benefits but often require intensive management to restore and maintain water quality. However, if there are mismatches between measured and perceived water quality, improvements may go unnoticed. While conventional water quality indicators such as chlorophyll a and Secchi depth are routinely monitored, it remains unclear how well these biophysical metrics align with public perceptions. We conducted a survey to measure visitors’ perceptions of water quality at two highly visited urban lakes in Saint Paul, Minnesota—Como Lake, a shallow eutrophic lake undergoing intensive in-lake management, and Lake Phalen, a deeper mesotrophic lake with fewer recent interventions. Across three years (2022–2024), we recruited over 800 survey respondents via signage that encouraged volunteers to participate by exchanging text-messages with a custom chatbot. Comparing long-term open water measurements with visitors’ water quality scores showed mixed relationships with chlorophyll a levels. Visitor perception scores were lower for eutrophic Como Lake, but this difference was small relative to the four-fold difference in chlorophyll a concentrations between the lakes. Open-ended responses suggest that visitors base their evaluations on a combination of visual cues such as water clarity, trash, and aquatic vegetation. These findings underscore the complexity of human–lake interactions and suggest that perception of ecological conditions may be informed by additional factors including expectations, communication, and lake-specific context. Incorporating visitor perception into lake monitoring and management may help align restoration goals with visitor experiences in urban settings.