Project Summary:

In cooperation with the Vermont Agency of Transportation (VTrans), the USGS is conducting a study on the effects of roadway deicing practices on stream-water quality in Vermont. The Phase I study assessed the current knowledge of road deicing impacts in the New England region, evaluated changes in deicing practices in Vermont over the last 20 years, and provided a general description of chloride levels and other salt components in Vermont's surface waters. Based on findings from Phase I, a research study has been designed and will be conducted during Phase II to better understand how state roads contribute to the chloride, sodium, and calcium levels in Vermont streams.

As part of the Phase II effort, a monitoring program will be undertaken from October 2005 to September 2006 at three streams in the Burlington area: Allen Brook at Rte. 2A in Williston, Alder Brook at I-289 in Essex and Mill Brook at Rte. 117 in Jericho. Each of these streams represents a different road type. Allen Brook represents a 2-lane mid-density state highway, Alder Brook a 2-lane interstate highway, and Mill Brook a rural 2-lane state road. Each stream site will be monitored upstream and downstream of the roadway so that the contribution of the roadway to salt concentrations and loads in the stream can be quantified. Continuous specific-conductance measurements will be made in the field and samples will be collected for analyses of chloride, sodium, and calcium in the laboratory. A statistical relation between chloride, sodium, and calcium concentrations and specific conductance will be developed so that concentrations of these constituents can be estimated from continuous data on conductance. Using this approach, the frequency and duration that chloride levels exceed the chronic and acute criteria for protection of aquatic life in streams will be assessed. Additional streams across the State may be monitored in 2007 and later as part of the Phase II study. A USGS Scientific Investigations Report (SIR) is a planned product of this project.