Impact of Riparian Landscape Patterns on Water Quality in an Urbanizing River Basin: A Case of Cedar River - Lake Washington Watershed

Abstract

The increasing concern about the deteriorating water quality in rivers and streams in urban areas has led to a focus on protecting natural riparian land covers along these water bodies. The conversion of these land covers, such as forests and wetlands, to urban and agricultural land puts pressure on riparian ecosystems and their ability to perform important ecological functions, including maintain water quality. This thesis explores the Cedar river-Lake Washington watershed, with the intent of identifying the spatial and temporal relationships between riparian landscape patterns and selected physical and chemical parameters, thereby allowing the prediction of water quality trends. The analysis shows that there is a link between the spatial and temporal patterns of the riparian landscape within 100m and 300m buffer width and a few physical and chemical parameters of water quality. Specifically, there is a significant relationship between the composition and configuration of the riparian landscape and Total Nitrogen and Nitrate-nitrite concentrations. No significant relationship was found for other tested parameters. The findings indicate the need to consider the riparian landscape patterns at multiple scales in defining strategies to protect water quality.