Snowy, icy days can make us thankful for the salt applied to make our roads safer yet road salt has a less safe side for our waterways. When ice and snow melt, the salt goes with it, washing into our streams and groundwater. As with people, streams are healthier on a low-salt diet as high salt concentrations can harm plants, fish and other wildlife. And considering how easily salt can corrode our cars it’s not surprising that high salt levels can impact infrastructure including roads and pipes and municipal and industrial processes that use water from streams.
Road salt applied to parking lot.
To understand the potential issues with road salt, volunteers and staff from the White Clay Wild and Scenic Program, Delaware Nature Society, and the Nature Conservancy have been monitoring our local streams.
On Mill Creek - a tributary of White Clay Creek - in Hockessin, average conductivity (a measure related to the level of dissolved salts) have shown large spikes over the winter season as melting snow and rain have flushed salt into streams and groundwater.
These high peaks – which correspond to winter rain & snow events – are not seen during other times of the year.
Larger spikes were also documented on Hurricane Run, a small stream near Talleyville DE, which flows into the Brandywine Creek. The high spikes are probably correlated to snow melt and rain washing salt off the many roads and parking areas around Concord Pike that drain into Hurricane Run. Chloride concentrations over 250 ppm can make water taste salty and levels over 800 ppm are harmful to aquatic life.
While there are no easy solutions to the road salt quandary, municipalities and homeowners can consider smart salting practices including:
- Consider using sand and alternate products for sidewalks and driveways
- Reposition downspouts and snow piles so that water and melting snow isn’t refreezing on paved surfaces
- Keep salt piles covered
- Proper calibration of salting equipment and training programs for salt applicators
To learn more and get involved with other monitoring projects contact:
www.nature.org/ourinitiatives/regions/northamerica/unitedstates/delaware/index.htm