As Winter Comes Should VDOT Use Salt?

In the last week of October NOAA’s Climate Prediction Center released the long range weather forecast through February for the country. Northern Virginia is predicted to have warmer-than-average temperatures combined with a wetter-than-average winter. Nonetheless, VDOT’s Northern Virginia District covering Fairfax, Loudoun, Prince William Counties and Arlington is preparing for winter.

The Northern Virginia District serves a region with almost 2.4 million people and 13,585 lane miles of roadways that are maintained by VDOT. In the winter VDOT needs to clear the roads of snow in a timely fashion to keep the government open and community services operational, while still protecting the source water for the region. VDOT will have a snow budget this winter of almost $54 million to cover the costs of contracting road treatment and snow removal and maintaining a limited amount of staff and equipment.

The Northern Virginia District of VDOT also has 120,000 tons of salt, 25,000 tons of sand and 250,000 gallons of brine or magnesium chloride. While salt (sodium chloride and magnesium chloride) products are cheap and effective at helping to keep us safe during winter storms, they have a number of harmful impacts to the environment, water quality, infrastructure and public health. VDOT has to balance public safety during winter storms and environmental impacts.

VDOT uses sprayed on salt solution that is only about 23% salt to pretreat the interstates (66, 95, 395 and 495) and the major roads (for example Routes 1, 7, 28, 50, 15 etc.) In total VDOT only applies brine to pretreat 2,150 lane miles of interstates, major roads and bridges- just the interstates and major roads, none of the suburban communities. You’ve seen the brine as light white lines sprayed in roadway lanes before storms. The anti-icing treatment is most effective during the first hour when it prevents the snow from bonding to the roadway. This makes it easier and more effective to plow a road.

Pretreating the roadway is most effective when temperature are above 20 degrees Fahrenheit and there is no rain forecast. Pretreating is not effective if a storm starts with rain. The brine is simply washed off the road and into our water ways. VDOT has its own MS4 permit to prevent pollution to the storm sewer system or our streams, waterways and groundwater. VDOT has a pollution prevention and mitigation program to minimize the infiltration and runoff of brine solution from storing, mixing, loading and washing equipment.

The source water protection program and addressing deicing salts in particular are currently a top priority for Fairfax Water and the Virginia Department of Environmental Quality (DEQ). None of the local water utilities have the equipment to remove salt from their source water. The only available technology to remove salt from the source water is reverse osmosis which is cost prohibitive and requires a significant amount of energy to run. The brine solution currently in use by VDOT have reduced the salt use by 30%-65% depending on storm duration, temperature and storm intensity. To further protect the waterways VDOT will not be pretreating any of the suburban communities/ development roads.

DEQ and the Northern Virginia Regional Commission have gathered together stake holder to tackle the challenge of striking a balance between benefits and impacts in a Salt Management Strategy (SaMS). This strategy will be under development throughout 2020, but VDEQ is holding a meeting to hear the concerns of the communities. There will be a meeting at Kings Park Library on December 3, 2019 at 6:30 pm where DEQ is going to listen to the community. You can sign up at the link. If you want to read about what has been going on at the meetings you can at this link.