Winter Road Salt - the Next Acid Rain? - May Threaten Adirondack "Queen of American Lakes"
National Geographic
November 1, 2014
Is road salt the next acid rain? Lake George in New York’s Adirondack Mountains may hold the answer.
Tendrils of fog curl above the waters of the Queen of American Lakes, as Lake George in New York’s Adirondack Mountains is known. Biting winds gusted out of the northwest yesterday, and an early snow is forecast for tomorrow. But for this one afternoon in late fall, cold winds fetching across slate-gray waves have gone elsewhere. The queen is holding her breath, granting one last look at autumn on a day that seems suspended in time.
Lake George is waiting, her future in question. For the first time in the history of the 32-mile-long lake – a gift from long-ago glaciers that once covered the land, then melted – our actions may have imperiled her health.
Thomas Jefferson referred to Lake George, the Queen of American Lakes, as the most beautiful water he ever saw. Will the lake stay that way?
Two centuries and more ago, it was a different picture. “Lake George is without comparison, the most beautiful water I ever saw,” wrote Thomas Jefferson in 1791. “Formed by a contour of mountains into a basin…finely interspersed with islands, its water limpid as crystal, and the mountain sides covered with rich groves…down to the water-edge.”
Lake Developing Aquatic High Blood Pressure?
I’m at that water’s edge in Bolton Landing, N.Y., midway along the lake’s western shore, with Rick Relyea, an aquatic ecologist and director of the Jefferson Project. The high-tech, data-intensive project is a partnership of Rensselaer Polytechnic Institute’s Darrin Fresh Water Institute (DFWI) in Bolton Landing, with which Relyea is affiliated; IBM; and The FUND for Lake George, an organization dedicated to the protection of the lake.
But for a sensor platform moored alongside the DFWI dock, the view harkens back to Thomas Jefferson’s time.
Beneath the lake’s surface, however, the queen’s status may be slipping from good to fair. Efforts like the Jefferson Project, which began last year, are underway to prevent her from going critical. In one of the first cases of telemedicine for a lake, Lake George is being monitored by sensors loaded with IBM “smart technology.” The instruments, some floating, some submerged, track vital signs such as water temperature and dissolved oxygen and send the measurements back to shore. The gauges also keep tabs on salt content.
“Salt is becoming a major concern for the lake,” says scientist Jeff Short, a consultant to The FUND for Lake George. “It’s being called the acid rain of our time.”
The Lake George region receives more than 70 inches of snow each winter. During those months, some 9,000 tons of road salt, or sodium chloride – an estimated 13 tons per lane mile – are applied to snow- and ice-covered streets and highways in the Lake George watershed. Where is all that salt going? “Much of it eventually drains into the lake,” says Short. “It may be starting to affect how Lake George functions.”
Salt levels in the lake have tripled since 1980, scientists reveal in the 2014 report The State of the Lake: Thirty Years of Water Quality Monitoring on Lake George. Short is a co-author of the document, jointly released by the DFWI and The FUND for Lake George. “Allowing salt to continue rising,” he believes, “risks irreversible changes in the lake’s ecosystem.”
Finding out how extensive the effects may be, says Relyea, “requires doing the research to learn how the lake works and how humans are affecting it. Through the Jefferson Project, we have an opportunity to understand Lake George with a level of detail that was previously unimaginable.”
For example, “runoff and circulation models in development will show us how road salt is transported and how it moves through the lake,” says Harry Kolar, distinguished engineer at IBM and the company’s lead on the Jefferson Project.
Each winter, some 9,000 tons of road salt, or 13 tons per lane mile, are applied to Lake George watershed roads.
Low-Salt Diet Needed
Water bodies with limited outflows like Lake George are especially affected by salt-laden inflows, according to Walt Lender, executive director of the Lake George Association (LGA), a group that works to safeguard the lake. Lake George has one narrow outflow at its northern end, down the steep La Chute River and into Vermont’s Lake Champlain. Increasing levels of sodium chloride, Lender says, degrade water quality in the lake’s tributary streams and brooks and create an environment conducive to invasive species. Lake George is already battling Asian clams, Eurasian watermilfoil and zebra mussels.
Sodium chloride concentrations as low as 250 milligrams per liter, the equivalent of one teaspoonful of salt in five gallons of water, are harmful to aquatic life and permeate drinking water enough to affect its taste. If the trend in Lake George continues, in years hence its waters might no longer be classified by New York State as AA-Special – drinking water.
Look at any vehicle in the northern tier of the U.S. in winter, and you’ll see why roads need to go on a low-sodium diet. From November through March, cars, trains and buses in cold climes are covered in a spray of white: road salt.
Although road salt, or sodium chloride, is the most widely used substance to treat snowy, icy roads, alternatives are on the horizon.
The first major attempts at snow removal came in the early 1860s with snowplows attached to horse-drawn carts. After the great blizzard of 1888, which paralyzed the U.S. Northeast, transportation officials realized they had to do more than just plow streets. As roads were cleared of snow and ice, the exposed pavement retained melted snow that refroze into ice.
Enter salt.
But salt’s time has passed, say Short and other scientists. On November 12, 1987, the New York Times published an editorial that argued for a salt substitute, concluding that “salt, an increasingly anachronistic element of 20th century travel, deserves a 21st century replacement.”
Salt Substitutes for a Queen
Thanks to its low cost in dollars, sodium chloride is still the most widely used substance to treat snowy and icy roads, according to the recent Adirondack Council report Low Sodium Diet: Curbing New York’s Appetite for Damaging Road Salt. But alternatives are on the horizon.
Sodium chloride substitutes are being tested by Lake George-area highway departments.
Calibrated snowplow spreaders and road temperature sensors can reduce the amount of salt applied to roads, states the 2014 LGA report Lake George Winter Road Maintenance: Best Practices Initiative for Water Quality Protection.
A new deicer named Clear Lane, made with liquid magnesium chloride, is being tested on Lake George watershed highways.
Traditional salt loses its effectiveness below 15 degrees Fahrenheit. Clear Lane continues melting when the thermometer goes below zero. Salt from snowplow spreaders often bounces to pavement edges; Clear Lane sticks to the center, reducing spray into roadside streams.
Some Lake George-area highway departments have switched to Magic Salt, salt that’s treated with liquid magnesium chloride and an agricultural by-product. Magic Salt works at temperatures as low as minus 35 degrees Fahrenheit.
Calcium chloride has been suggested as a replacement for traditional sodium chloride salt, but it won’t work for Lake George, says Lender. The lake has low levels of calcium, good news for stopping invasive zebra mussels, which need calcium to build their shells. “Adding calcium would be an open door for the mussels,” Lender says. Sand, another choice, is also a no-go. “Where streams flow into the lake, runoff carrying sand forms deltas,” says Relyea. The deltas fan out across the lake bed, depositing sand grains and other materials on everything in their paths.
Once a standard asphalt street, Beach Road at Lake George’s southern end has been repaved using porous materials to reduce runoff into the lake.
Changing the materials in roads may hold promise, if a project on Beach Road is an indicator. Beach Road runs cheek-by-jowl with the south end of the lake, connecting a sand beach open to the public with the bustling Village of Lake George. Once a traditional asphalt street, Beach Road has been repaved using “pervious,” rather than impervious, materials. The porous pavement is reducing the amount of salt and other chemicals leaching into the lake by 50 percent, says Tom Baird, chief engineer at Barton & Loguidice, the design and engineering firm that managed the project.
It’s day’s end, and the first rays of sunset are crossing Beach Road. A mile offshore, in half-sun and half-shade, a Jefferson Project sensor platform watches over a darkening bay. Will it – along with Magic Salt, pervious pavement and whatever the queen’s subjects might proffer – be enough to keep her right as rain?
