I just received this email from the state:
Dear Mr. XXXXX,
Thank you for your recent e-mail to the Washington State Transportation
Commission regarding an upcoming pilot test of salt on state highways. My
name is Brian Ziegler and I am responsible for maintenance and operations at
the department of Transportation. In light of the relatively high number of
notes/calls from citizens regarding this matter, we have developed a more
detailed response to provide additional information about this project (see
enclosure).
The concerns that you have expressed have been amongst our concerns as we
have developed this winter's test of salt. As such, we have developed a very
cautious approach to this pilot project that minimizes potential adverse
impacts, yet still provides us with meaningful scientific and management
data with which we can make well-informed policy choices. The data from this
project will significantly add to the current body of knowledge on this
topic so we can make the best decisions considering all facts and costs. As
your e-mail suggested, we will certainly include corrosion costs and impacts
in our analysis.
If you have any further questions, comments, or would like additional
information regarding this matter, please contact me via e-mail or by
telephone at (360) 705-7801.
<<WSDOTSaltReply.doc>>
Brian J. Ziegler, PE
Director, Maintenance and Operations
Washington State Dept. of Transportation
P.O. Box 47350
310 Maple Park SE
Olympia, WA 98504-7350
Office: (360) 705-7801
Cellular: (360) 280-4282
Several people have recently contacted us to ask why the Washington State Department of Transportation (WSDOT) is conducting a pilot project to re-look at using salt to help keep snow and ice off roads. Many recall that in the 1980’s, rock salt was phased out for several reasons, including salts corrosive effects on cars, trucks, bridges and potential environmental impacts. So why a new pilot project in 2002?
There are several good reasons. Dozens of states, Canadian provinces, and countries around the world still relying on salt have dramatically modernized its use. Older methods relied on waiting until the snow fell, plowing as much of it off as possible, then applying dry rock salt on top to evaporate the remaining snow or ice. The new approach is to apply a liquid salt brine to the road before the snow or frost to keep it from sticking. This approach uses much less salt and yields better results.
Automakers have also changed the way they make cars and trucks. Six to ten year corrosion warranties are now standard as composition materials and painting/finishing procedures have reduced susceptibility to rust. The National Association of Corrosion Engineers has conducted evaluations to identify the presence of rust perforation. In 1970 models, 90% of six-year-old automobiles were found to have rust. In 1984 cars, 61% were rusting. In 1989 models, the number was down to 3% of cars with some rust. Regarding rust on highway bridges, corrosion-resistant coatings and sealants are now applied to all rebar and concrete used in bridge construction.
From an environmental standpoint, WSDOT has monitored creeks, streams and rivers for several years to determine the amount of salt that is entering the water from our snow and ice control activities. Two examples are the Wenatchee River and Peshastin Creek, streams directly adjacent to highways with active anti-icing programs. We found that minimal salt levels were present – less than 10 parts per million (ppm), far less than the Environmental Protection Agency water quality guideline of 230 ppm.
Other research has demonstrated that 2,000 to 8,000 ppm causes toxic effects on small aquatic organisms that comprise the diet of larger fish. When exposed to sodium chloride for several days, toxic effects show up in fish at levels between 10,000 and 12,000 ppm. With the levels we’ve found – 10 ppm - it indicates that modern road salting methods minimize environmental impacts. In fact, the water quality impacts are so low that state environmental regulatory agencies didn’t require any environmental permits to conduct the pilot project. The majority of problems with salt have resulted from poor handling such as stormwater runoff from uncovered stockpiles of salt. WSDOT has eliminated this concern by locating all stockpiles of rock salt inside enclosed storage units.
Reduced cost is an important factor as well. The current cost for rock salt is half the price of the equivalent anti-icing chemicals. Part of our pilot project evaluates different ways to manufacture salt brine. We think we can save five to ten times the current cost of other de-icing chemicals.
It is critical to remember, this is a test. We will use the findings to answer questions like “Will the new ways of using salt work better than the old? Will the project show better or worse corrosion performance? Will intensive testing of roadsides and streams as part of the pilot show that new ways of using salt can fit into acceptable environmental limits?” We think the idea is worth a look. By next year we’ll have results from which to draw conclusions for the longer term. Meanwhile, we appreciate hearing the concerns of people who care about how we operate highways during the winter season. We care too, and we are carefully noting their views.
