Snowstorm Solution: Salt or Sand?
Snow and sleet blanketed the Northeast on Mar. 16, with as much as 18 inches of snow expected to fall in parts of New York and Massachusetts. JetBlue Airways (JBLU), Delta Air Lines (DALRQ), and other carriers canceled hundreds of flights, turning airports throughout the region into hotels.
Meanwhile, cities and counties scrambled to clear roads of the icy mess. The question they're all wrestling with: What is the best snowstorm solution, sand or salt?
Salt Gains Favor
The answer is clear in Norwalk, Conn. As the storm moved in, the town's Public Works Director Harold Alvord said that he plans to use 100% salt to combat the snow and ice. At $53 per ton, salt is twice as expensive as sand. But Alvord says sand is pretty ineffective and needs to be plowed up immediately after a storm. He also worries that the sediment gets into the city's streams and even plugs up the storm drains. "It's going to be cheaper in the long run," says Alvord.
The American public doesn't spend much time worrying about what gets sprinkled on the ground during a snowstorm. But for public officials, from mayors to the engineers who run snow-removal operations, the debate over salt or sand can inspire near-religious fervor.
The reason is that neither one is a perfect solution. Sand requires repeated application and extensive cleanup. Salt can hurt the environment by ending up in streams and rivers, killing fish and plants. In recent years, the balance has shifted to the salt supporters, with more and more municipalities moving away from sand.
Damage to Groundwater
Environmental groups say that the U.S. uses about 18 million metric tons of rock salt a year in the Northeast and Midwest each winter. With the increased use of salt over the past two decades, groundwater supplies are starting to become more salty. A study conducted by New York State found that the problem is quite serious, and officials are in the process of surveying several towns. "There has been salt contamination in private wells," says Leila Goldmark, an attorney at Riverkeeper, an independent environmental organization in Tarrytown, N.Y.
Goldmark made a presentation last year at a forum titled "Breaking the Ice—Impacts of Road Salt." She pointed out that the waters in New York's Hudson River Valley are beginning to show much higher-than-normal levels of chloride. (Salt is made of equal parts sodium and chloride.) She estimated that the region's waters have as much as 25% more chloride concentration than seawater and 100 times that of forest streams that are not close to areas where streets are salted.
It wasn't always this way. In the early 1970s, New York State did a cost comparison of sand and salt. It showed that it was much more expensive to use sand that gave only moderate traction. It didn't melt the snow and it didn't make the roads safer. In the mid-1980s, much of the state began applying salt directly to the road before the snow could bond. "We ended up using much less sand and had much less cleanup," says James J. Dean, superintendent of highways for Orangetown, N.Y. "Sand also creates particulates and dust, and you end up with air-quality problems."
Canada's Salt Reduction
In Canada, however, where snowstorms are a way of life for several months each winter, there's much more caution. A few years ago, there was a huge public outcry over how salt was affecting the environment, particularly the water supply. The government's environment agency even considered listing road salt as a toxic substance. Starting in 2001, several cities and towns worked hard to reduce the use of salt for snow removal. Toronto, for instance, found that every winter it used an average of 130,000 tons of salt to maintain the 3,300 miles of roads in the city. But the city devised a way to reduce the use of salt by pre-wetting it before applying it to roads, a process that melts ice and snow much faster. "We also focused on greater training among the operators and staff that handle road salts so they wouldn't overapply the salt," says Peter Noehammer, director of transportation services in Toronto.
The results have been dramatic. The city decreased its annual salt usage by almost 37,000 tons. Noehammer says that Toronto uses only salt on its roads and mixes a little sand for sidewalks to allow pedestrians more stable footing. However, he says that at colder temperatures in towns and cities farther north in Canada, salt becomes less effective and they have to use more of it to combat the snow.
Back in Norwalk, Alvord is headed for a busy weekend of trying to keep the roads clear. The town's truck drivers will be pre-treating their 25 plow routes with salt to help the snow and ice melt as soon as they touch the ground. But it still promises to be a difficult storm for travelers—no matter what gets sprinkled on the roads.