Madison Road Salt
The Doctor Prescribes Less Salt!!
We’ve all heard that less dietary salt is good for a healthy heart…..well Madison knows that less salt is also good for lake and aquifer health! In 2021 the Co-Chairman of the Madison Conservation Commission asked the Town about potential use of brine for road treatment. As a result, the Madison Department of Public Works Director examined Town use of salt on road surfaces. He found that by using liquefied brine spray, instead of solid salt, Madison could reduce the amount of salt purchased and use by 66%…or $30,000!!
Rock salt, or solid salt, is simply crystals of sodium chloride. Until it has gone into solution – that is, until it has formed brine – it will do nothing to stop snow from freezing to the pavement surface. The use of rock salt in winter road maintenance activities is to create brine on the road surface. Therefore, brine is an integral and critical part of snow clearing. Because the salt brine is in a solution of water, that solution has a lower freezing point than pure water. At a 23.3% concentration, it will freeze, without any additional dilution, at about -6 degree F. And no – the brine will not freeze on the road when it is applied. Studies have shown that using brine is a 20-25% reduction of hard salt. Data was provided by the American Public Works Association.
Madison purchased a liquid brine spray tank with computerized controls which minimize the amount sprayed and keeps a record of amounts and locations sprayed. The system has simplified controls and allows immediate changes when directed by the operator driving the tank-equipped truck. The Town can make its own brine or purchase it from a local contractor.
The positive effect on the reduction of run-off into Madison streams and Silver Lake could also be enormous. The detrimental effects of road salt runoff into water bodies are well documented. In the US, salt damage to infrastructure is estimated to total between $19-45 billion annually. That includes damage to roadways, bridges, vehicles, tourism, and property values. If trends continue, the many lakes will be too salty to support life within 50 years! Excess salt can damage entire aquatic food chains, including zooplankton, salamanders and frogs, fish, shellfish, and aquatic plants. At high concentrations, salt can stunt the growth of some fish; it can tilt the male-to-female ratios of amphibian populations out of balance. And it can kill off algae-eating zooplankton allowing algae to grow unchecked into smelly, goopy, hazardous blooms.
This new system for Madison is not only for winter use. While this started with salt reduction for winter road treatment…it can also be used for summer road treatment. What? Treatment of the roads with calcium chloride in the summer reduces air particulate (dust). Madison has 57 miles of roads, much of which is unpaved. The new system will use less salt for this purpose as well!