What's a stream without water? Landowner perceptions of intermittent streams as disproportionate sources of water quality pollution

Over the past decade, interdisciplinary approaches to environmental problems have grown increasingly popular. The concept of disproportionality provides useful framework for analyses of nonpoint water pollution in human-natural systems. Under this approach, past research identified harmful property management behaviors, such as excessive manure application, when coupled with hydrologically active areas, contributed a disproportionate amount of nutrients to surface water bodies compared to other types of arrangements on the social-biophysical landscape (Nowak et al. 2006). We employ the concept of disproportionality to analyze landowner perceptions of intermittent streams and how these perceptions influence riparian management behaviors in a small, urbanizing watershed of Central Pennsylvania. Intermittent and first order streams are critical drivers of surface water quality, as they generate large proportions of surface water flows (Walter et al. 2009). Our three-part analysis uses landowner mail survey data, aerial photography, and spatial statistics to draw connections among landowner attitudes, perceptions, management behaviors, and their position on the landscape in relation to stream order. Landowners are less aware of intermittent and ephemeral streams than perennial streams, and intermittent streams are perceived as less important than those with regular flow. Landowners who do not recognize they have a stream on their property (and are therefore unlikely to take on riparian conservation practices) are located in headwater regions, where intermittent streams are likely to occur. Therefore, the interaction between landowner disinterest and the potential pollution contributions from intermittent reaches creates a scenario in which these social and biophysical conditions determine water quality at the watershed scale. Our analysis may help explain why watersheds in which there are high rates of conservation practice adoption still see excessive nutrient contamination. Based upon this research, watershed policymakers and managers can better target intermittent streams for water quality conservation.