Blog

Season Finale: Results from Winter Salt Watch

04/29/2019
With the arrival of spring, the Izaak Walton League is wrapping up its first full season of Winter Salt Watch. This program, part of the League's flagship Save Our Streams initiative, engages volunteers across the country to monitor chloride levels in their local streams. It is known that salt used on roads to improve traction and safety in the winter often leaches into streams, where the chloride from the salt is harmful to aquatic life adapted to freshwater environments. What is not known is how severe and how widespread the problem is.

Citizen scientists are now helping to answer that question. This winter, the League distributed almost 500 test kits to volunteers nationwide. 340 completed tests were returned, documenting salt levels in streams from 17 states and 39 watersheds.

Of those watersheds, 31 always tested at normal, safe chloride levels. High levels of chloride were found in the other 8 watersheds, which drain metropolitan areas.

Repeated testing of the same streams – before winter storms, after road salt application, when snow begins to melt, and after a spring rain – helped to establish a pattern. Rather than showing occasional spikes in chloride levels, these watersheds had consistently high levels of salt: 25% of test results from these watersheds were above the maximum level of salt considered tolerable for freshwater organisms, and an additional 31% were noticeably higher than normal levels of salt found in freshwater. Of the watersheds that tested high in chloride, the Lower Delaware and the Schuylkill in the Philadelphia metro area, the Middle Potomac-Anacostia in the Washington D.C. metro area, and the Clinton in the Detroit area showed abnormally high salt levels on more than half of their results.

The citizen scientists who collected this important data are already working to raise awareness in their communities about the impacts of road salts on stream health, and to advocate for smarter application of road salt by sharing their findings with local and state agencies.

Road salt is an emerging water quality issue that researchers and government agencies around the country are trying to understand and solve. The members and volunteers of the Izaak Walton League are collecting the data that will be used to implement new and better practices.


Road salt in the summer? Yes! Summer rainstorms can wash last season's salt out of the ground and into streams, and new research shows that salt is even more harmful to stream life when the water is warm. Learn more about how you can protect your stream year-round.