Name: Community Supper Series: The Whip Tavern To-Go
Start: 2021-01-22
End: 2021-01-22
Location: Rushton Conservation Center

Road Salt and Its Impact on Fresh Water

January 12, 2021 By Evan Hunt

As winter quickly approaches so does the threat of salt pollution. Since the 1940s, salt has been the number one choice for fighting road ice in the United States. Over the last five years, PennDOT used an average of 844,000 tons of salt per year to keep Pennsylvania’s roads free of ice during the winter months. As effective as salt is at melting ice, it can cause major environmental problems after it washes off roads and into nearby waterways. Scientists have known for a long time that salt can be a serious pollutant in freshwater ecosystems, affecting multiple species of fish, insects, amphibians, and plants. More recent studies have shown that road salt is the main culprit of salt pollution in the northern United States.

According to a USGS survey, 84% of streams in urbanized areas of the northern United States have seen increases in chloride levels attributed to road salt. While 40% of streams have experienced levels that are considered dangerous to aquatic species. Furthermore, 29% of those streams have seen spikes in chloride levels during the winter that would make the water unsafe for drinking.

Armed with this knowledge, PennDOT and local municipalities have made efforts to limit the amount of salt laid on roadways. PennDOT limits salt treatments to high-traffic areas and dangerous intersections or curves. At the same time, municipalities have started mixing sand in with salt to improve traction and reduce the overall amount of salt used. Unfortunately, these changes might not be enough as private businesses and homeowners still contribute significantly to the amount of salt introduced into the environment. Over-salting of sidewalks and parking lots is far too common since private snow shovelers are understandably more concerned with the safety of pedestrians than the environmental costs associated with using salt.

However, there are ways to achieve a balance that prioritizes safety while also taking into account the risk of salt pollution. The most straightforward solution could be sweeping up salt from sidewalks after the ice has melted but before a snowmelt or rain event can wash the salt away. Not only does this prevent salt from reaching our freshwater ecosystems but the salt can be reused during the next snowstorm to save some money. Adding salt before snowfall rather than after is another technique that could reduce the amount of salt needed to keep sidewalks free from ice. Another option is to reduce the amount of salt used by cutting it with sand or even beet juice like some Canadian cities have successfully experimented with. All of these methods can be implemented by anyone who finds themselves shoveling snow during the winter.

Even those of us who do not have any snow shoveling responsibilities can play a big part in addressing this issue. The Izaak Walton League is a national organization that trains citizen scientists to measure the amount of salt in their local streams, especially after snowstorms. This kind of data can help determine the local impact or source of salt pollution. Maybe more valuable, measurements collected by citizen scientists will increase the national dataset used to help scientists and policymakers make decisions about mitigating the effects of our increased reliance on road salt.

For more information about becoming a volunteer citizen scientist, you can visit iwla.org.

From Tops of Trees to the Base of the Food Chain

October 13, 2020 By Lauren McGrath

There is a chill in the air and the leaves are starting to turn, signaling that fall is here! Have you ever wondered what happens to the leaves that fall every autumn? When the trees shed their leaves, the leaves continue to play an important role in the environment. They fall onto the land and return the nutrients back into the soil or blow into streams, where they are vital in sustaining our freshwater ecosystems through winter months. As the leaves gather in our waterways, they get caught on rocks and on sticks and form masses called leaf packs.

Leaf packs are so much more than just bundles of leaves and sticks. They are nutrient rich pockets in the stream that provide cover and food for a wide diversity of stream insects. Raw leaves that enter the stream are hard to for insect larvae to eat, and need to be broken down before they can be consumed. When leaves enter the waterway, they quickly become coated in a slimy biofilm, a name for a collection of algae, fungi and bacteria, which work quickly to condition leaves and turn them into a more palatable meal for macroinvertebrates. Some insects, like stoneflies, prefer to scrape the biofilm off of the leaves while others, like mayflies enjoy eating the leaf itself! As the leaf is broken down by the biofilm or shredded by insects, nutrients get carried downstream by flowing water and provide sustenance for other parts of the stream. Insects like caddisflies, live just downstream of the leaf packs and collect the floating leaf particles to eat.

Aquatic insects are a discerning group of organisms, and have preferences in what leaves they consume. Just as you and I may not order type of food at a restaurant, not all insects will prefer the same leaves! It has been documented that stream insects prefer native plants to non-native plants, and most insects studied have preferred types of native plants. It is important to have a diverse community of trees and shrubs along our waterways to provide a variety of leaves every fall to feed the aquatic community.

Leaf packs sustain a variety of insects throughout the winter months, and the annual addition of leaves into our headwater streams is critical for the health and survival of the aquatic ecosystem. These leaves feed the insects at the base of the food chain, which in turn feeds the many fishes, birds and mammals that rely on streams to survive. We can be good stream stewards by planting a diverse community of native trees and shrubs along waterways and leave leaves where they fall to allow the nutrients to be reincorporated into the ecosystem to sustain another generation of life!

You can learn more about leaf packs from our friends at Stroud Water Research Center here!