Basin-Scale Methodology for Evaluating Relative Impacts of Pollution Source Abatement

The Blackstone River Watershed covers approximately 475 mi² in central Massachusetts and northern Rhode Island. Its headwaters are composed largely of the urban and industrialized areas of Worcester, Massachusetts, the third largest city in New England. The river played a key role in the industrialization of the northeast, at one point having one dam for every one mile of river. The impact of these impoundments on contaminant fate and transport, in particular their affect on propagation of improvements in upstream water quality to downstream reaches, is not well understood. The Blackstone thus represents a key case study for understanding watersheds with a history of industrialization and heavy suburban development. While already a stressed environment, the Blackstone faces additional degradation due to development pressures. The following paper presents a basin-wide analysis of pollutant sources and sinks within the Blackstone River watershed. Data collected during the Blackstone River Initiative (BRI) was used to analyze spatial trends in water quality along the river during wet and dry weather monitoring. Loads were compared to consecutive stations along the river to determine any potential sources or sinks between the stations as well as differences in water quality behavior between wet and dry weather conditions. Additional analysis was conducted to determine the relative loads of point and nonpoint source pollution to the Blackstone River under current and future conditions.