Water Quality and Land Use Relationships in the St. Louis Bay Area of Concern: A Study of Three Urban Watersheds in Duluth, Minnesota.

Abstract

European settlement and industrialization has profoundly changed the water quality and aquatic ecosystems of the Great Lakes and its tributaries. Virtually untreated municipal and industrial wastes were dumped into the Lakes from the late 1800s to 1960. Fisheries were exploited and forests were felled to provide growing Great Lakes communities with agricultural land and wood products. In the 1970s, an era of environmental consciousness was ushered in with the passage of the Clean Water Act and the signing of the Great Lakes Water Quality Agreement. Significant water quality improvements were achieved under these authorities through regulatory and voluntary point source pollution control programs. In spite of these successes, however, water quality remains impaired in many parts of the Great Lakes and its tributaries. These impairments are due in part to the plethora of diffuse or non-point sources of pollution. This report explores linkages between water quality, land use, environmental law, and the geological characteristics of three small urban watersheds in Duluth, Minnesota. The three urban watersheds, Miller Creek, Knowleton Creek, and Kingsbury Creek, reported in this study were selected because they contain different land use patterns. Water quality data suggest that pollutants found in national storm water studies were also in evidence in the most developed watershed, Miller Creek, while trace metal concentrations were generally lower in all three watersheds. Suspended solids concentrations in the Miller Creek Watershed of 117 to 254 mg/I indicate a rapidly developing drainage basin. Significant gaps were also detected between the purpose and applicability of key environmental and water resource protection laws. Competing interests reflected in society are present in the intent and organization of these laws. Historical records suggest that Duluth streams are generally prone to flooding problems; flooding and the conveyance of storm water pollutants continue to be exacerbated by the area's rapid growth, steep slopes, bedrock channels, small drainage basins, and thin soil.