MINIMIZING SALT CONSUMPTION ON GROUND WATER AREAS IN THE UUSIMAA REGION OF FINLAND

The southern portion of Finland is located at latitude 60 degrees North. Located on the south coast, the Uusimaa Road District has started reducing the amount of salt applied on the roads in areas with ridges because these roads contain sand and gravel and are highly permeable to water. Reducing the amount of salt used is especially appropriate when freezing weather is becoming warmer and the road surfaces become frosted, causing a slight increase in slipperiness. Less salt is also being used for eliminating slipperiness following a snowstorm. The purpose of this paper is to determine what opportunities are available for the reducing the use of salt for controlling slippery conditions while simultaneously reducing the road surface friction requirement form 0.30 to 0.25. The aim is to prevent a rise in the chlorine concentration of groundwater. On the roads used for the experiment, the effect of reduced salting on the groundwater has been studied by determining the chlorine concentration of groundwater over a five-year period. In the roads studied, it was possible to reduce the amount of salt by 40% compared to the average for previous winters. The costs of winter road maintenance have not fallen on the roads used because it has been necessary to increase other means of controlling slippery conditions at the same time as the amount of salt applied has been reduced. The experiment has also taught salt applying personnel to be more careful when spreading salt in other regions.