Road Sand: Out of Sight but in the River, Keep it in Mind!

Written by Liana M. Boop for the Naubesatuck Watershed Council

While snow peacefully falls on northeastern Connecticut, our roads are brown with sand. We are all familiar with it—that gritty, mucky mess that lingers far after the snow has melted. This past winter, the State of Connecticut used primarily salt on its highways and roads, using sand only when necessary and on hills. Although our roads need to be clear during the winter months, both salt and sand have high environmental costs. Salt is highly corrosive to bridges, cars and roadways, enters drinking water to make it too salty to drink (especially for people with health problems) and easily destroys valuable habitat for native species.

Sand is no better. Once the snow or ice that sand was spread on melts, it becomes a huge problem. Aside from being an eyesore, when picked up by the wind it is abrasive on buildings, cars, and people walking.

People say, “I hope it rains soon and washes this sand off the road.” So where does it go? First, it is washed into storm drains or roadside ditches. This huge amount of sand can clog storm drains, which leads to flooding of roads and lawns during spring rains.

Sand cannot be swept up after every application because of the resources needed to do so. Most towns budget for sand to be swept up once, which means waiting until there is no possibility for more winter precipitation. This involves waiting until late March or April—by this time a good amount of rain has fallen, and most of the sand applied throughout the winter was transported elsewhere. Aside from clogging drains, this causes many environmental problems; the Environmental Protection Agency’s website, www.epa.gov, astonishingly states that because road sand, aside from containing heavy metals that leach nutrients from the soil, has the ability to soak up oil, grease, and other leaking automotive fluids, if the sand is collected it may have to be disposed of as hazardous waste.

When sand enters a storm drain, it discharges into a stream. This eventually makes it to a larger stream, pond, or river. According to www.rivers.gov.au, by weight, sediment is considered the largest single pollutant of rivers in the United States; this sediment can harm aquatic ecosystems in many ways.

It is possible to fill up a body of water with sediment. Birds stand twenty feet from the shore of UConn’s Mirror Lake because of the sediment that has been deposited there over the years. In this case, the Lake was created as a detention basin, to keep sediment out of the Fenton River.

When this happens naturally from road runoff, deeper water habitat is lost to sediment because the body of water is literally filling up with sediment. If this continues, it will fill up entirely and turn into a marsh. On a smaller scale, sediment fills in between rocks, also a loss of habitat for fish and other aquatic organisms. Excessive sediment usually becomes depleted in oxygen, which, aside from being unpleasant smelling, limits fish and other animal use of the river. When sediment fills the gaps between rocks, water cannot flow between the rocks; trout eggs need this oxygen-rich water in order to hatch. Some eggs become completely covered with sediment, but even partial covering limits oxygen to the point where the eggs cannot hatch.

When deposited sediment fills gaps between stones before eggs are laid, spawning ground is lost. If oxygen is not necessary, the eggs that have been laid become covered and do not hatch, or the fry cannot emerge. West coast Salmon are currently fighting this trouble—and losing.

Sand is usually carried by rainwater to a stream. Faster moving water carries more sediment, called suspended sediment. Clays and silts stay suspended in slow moving water, whereas sands and pebbles do not. After a rain, you may find a puddle containing clear water, but if you step in it, you will disturb the sediment at the bottom, and it will turn cloudy, or muddy. A rainfall will have this effect on rivers and ponds; new sediment is added to the water by runoff and existing sediment is disturbed from the fast moving water, a process called scouring. In extreme circumstances, this can damage and even dislodge aquatic plants and organisms.

Without human influence, our rivers constantly erode, and natural processes bring new sediment. Rivers maintain equilibrium; erosion equals sedimentation. If, by human influence, a river receives more sediment, the river erodes more from its banks to maintain equilibrium. According to Trout Unlimited (www.tu.org), this widens stream channels, making the overall channel shallower, which reduces habitat. In Connecticut, we are fortunate to still have a native Trout population. These fish, however, require cool water temperatures, and shallower streams means higher water temperature.

Another problem facing aquatic organisms, warns Trout Unlimited, is suspended sediment clogging the respiratory membranes in gills, which damages them or inhibits their ability for gas exchange (breathing). This is similar to the dust created from crushing road sand between tires and the road, causing respiratory problems such as asthma, according to the Environmental Protection Agency. Suspended sediment also hinders underwater photosynthetic plants that depend on sunlight for energy. When water is cloudy, predatory fish have trouble finding food, and predatory birds have the same problem from above.

Any seasoned fisherman or recreational boater can report that our water bodies are getting shallower. We need to use environmentally safe and economically justifiable alternatives to road sand and salt if we want high quality water for drinking and recreation. Degrading aquatic habitats degrades our drinking water. We need to reduce our use of salt and sand during winter months, as well as find ways to retain what enters aquatic ecosystems. Some storm drains have sumps, or sediment traps, that can be pumped during the spring; these retain sand from entering streams while preventing clogging. These drains are not widespread, and the Department of Transportation (DOT) currently has only one truck in northeastern Connecticut that is equipped for pumping these drains. More detention basins should be constructed (like UConn’s Mirror Lake), which capture sediment before it enters a viable river. These basins can also create healthy environments if managed correctly. Please remember that just because the rain washes sand away does not mean that it is gone for good—in fact it damages us and our water while it is out of sight and out of mind.

The Naubesatuck Watershed Council, a nonprofit organization, was established in 2000 to promote stewardship and sustainable development of the Naubesatuck Watershed, which includes the Fenton, Mount Hope, and Natchaug Rivers, which converge in Naubesatuck Lake (Mansfield Hollow) and provide the raw drinking water for the city of Willimantic. Visit us on the web at: http://nwc.ctgaia.net