Increasing salt in our streams has been a concern at the Cary Institute for many years. Even in the relatively undeveloped watershed of the East Branch of Wappinger Creek, the salt levels have increased since 1985 when sampling began.
Using this long-term stream chemistry dataset together with the characteristics of the watershed feeding our stream we have shown that road salt represents over 90% of the salt in our stream. In addition, we've discovered that salt accumulates in the subsurface (soil and groundwater) or in wetlands, ponds or lakes and slowly leaks into the stream over time.
This information helps direct policy decisions about road salt use. From this work, we've been able to recommend ways to reduce the amount of salt necessary to keep our roads ice free during the winter.