Officials: Muck on roadways not from change in de-icing

By Kathryn Reed

Every spring the sides of the roads in the basin and on the highways leading to Lake Tahoe are black and not the pristine white of fresh snow. The difference this year is locals have noticed the black has been more prominent throughout the winter.

However, snow removal officials on both sides of the state line say nothing new is going on.

A South Lake Tahoe street sweeper creates dust. Photos/Kathryn Reed

Caltrans is responsible for the highways throughout Lake Tahoe in California, while the Nevada Department of Transportation handles them in the Silver State. On city streets and in the county it is those jurisdictions that take care of the side streets.

The Tahoe Regional Planning Agency does not oversee what is put on the roads each season, but it does take a look at the reports the various jurisdictions compile. On the California side, the Lahontan Regional Water Control Board looks at what was put on the roads and what the sweepers took off.

“We don’t regulate public safety,” TRPA spokesman Jeff Cowen said.

Public safety is the main focus of snow removal policy.

“You have to find that fine line to provide for public safety and be environmentally conscious,” said Tom Celio with the El Dorado County Department of Transportation. “Our primary skid resistance material we use for ice control are cinders, volcanic cinders. We’ve been using them for 20 years. There’s been no change.”

Those cinders are also what are used in South Lake Tahoe. In the city it’s a mix of two-thirds cinders and one-third salt.

John Greenhut, public works director for South Lake Tahoe, said his department believes cinders create less fine sediment. It’s the fine sediment that people charged with protecting the clarity of Lake Tahoe want to keep from reaching the water.

Caltrans uses a mix of sand and salt. Years ago the agency was blamed for the dying trees along state highways because of the amount of salt being used. Part of the problem was blowers spraying the salt into the foliage and then the conifers turning a rust color.

“If the sand is wet, it may appear black in color. It’s gray or brown in color when it’s dry,” Deanna Shoopman, Caltrans spokeswoman said. “We use the purest sand we can get for Tahoe.”

The state and an independent environmental agency tests each delivery of sand and salt to make sure it meets appropriate standards, Shoopman said. The same components used in the basin are used on the highways on the outskirts of Tahoe.

NDOT uses three parts sand to one part salt on the 150 lane miles it services in Lake Tahoe.

“This ratio, with a relatively smaller amount of sand than used in some other situations, helps reduce sand particulates form being blown into the air,” said Meg Ragonese, NDOT spokeswoman. “When spread on the roads, salt and sand is wetted with brine (a water-salt solution) to create heavier sand that keep roads ice-free at lower temperatures and will not as easily bounce off roadway surfaces. Brine is also sprayed on wet road surfaces prior to snowfall to delay ice pack build up.”

NDOT has reduced the amount of sand it uses from about 4,300 cubic yards in 1990 to a little more than 800 cubic yards in recent years.

Celio said one of the benefits of the cinder is they are easier to pick up with a sweeper because they are coarser than sand.

“We sweep it up as soon as it is practical, as soon as we get dust,” Celio said.

Lahontan requires the county and city to keep a log of the material put on the road, what is swept off and what is collected in sediment traps the in various detention basins.

Russ Wigart, an engineer with the county DOT, along with others in the basin keep researching the best methods to melt snow and ice. Crushed walnuts have been used other places, but it’s cost prohibitive at $300/ton. Cinders cost about $20/ton.

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