Movement of road salt to a small New Hampshire lake

Water, Air, & Soil Pollution
By: , and 



Runoff of road salt from an interstate highway in New Hampshire has led to contamination of a lake and a stream that flows into the lake, in spite of the construction of a diversion berm to divert road salt runoff out of the lake drainage basin. Chloride concentration in the stream has increased by over an order of magnitude during the 23 yr since the highway was opened, and chloride concentration in the lake has tripled. Road salt moves to the lake primarily via the contaminated stream, which provides 53% of all the chloride to the lake and only 3% of the total streamflow to the lake. The stream receives discharge of salty water froth leakage through the diversion berm. Uncontaminated ground water dilutes the stream downstream of the berm. However, reversals of gradient during summer months, likely caused by transpiration from deciduous trees, result in flow of contaminated stream water into the adjacent ground water along the lowest 40-m reach of the stream. This contaminated ground water then discharges into the lake along a 70-m-wide segment of lake shore. Road salt is pervasive in the bedrock between the highway and the lake, but was not detected at all of the wells in the glacial overburden. Of the 500 m of shoreline that could receive discharge of saly ground water directly from the highway, only a 50-m-long segment appears to be contaminated.
Publication type Article
Publication Subtype Journal Article
Title Movement of road salt to a small New Hampshire lake
Series title Water, Air, & Soil Pollution
DOI 10.1023/A:1005041632056
Volume 109
Issue 1-4
Year Published 1999
Language English
Publisher Kluwer Academic Publishers
Contributing office(s) Toxic Substances Hydrology Program
Description 28 p.
First page 179
Last page 206
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