THE PROBLEM
All unpaved roads during the summer season will give off dust under traffic. The main reason for this problem has been a prolonged period of dry weather without any rain. Other reasons include the high volume of vehicular traffic on this little island and the speed at which people drive. We kindly ask you please slow down.
Common Questions
Q: Why doesn’t Public Works apply dust suppressant to the roads?
A: Optimum conditions to apply magnesium chloride (our dust suppressant agent) to the roads is typically after the roads have been graded. This allows the magnesium chloride to absorb properly into the roadway. If the magnesium chloride were applied now, it would not absorb into the road as intended. Early failure is often a result.
Q: Can’t the roads just be graded now?
A: No. The roads in their current state are too hard and require rain to soften the surface. Grading them now would also make the dust problem worse. Using a water truck to try to soften the roads would also most likely not work, as the time needed to allow the water to penetrate the road would not be enough with the water quickly drying up. Grading the roads while they are hard would likely damage the equipment on the grader.
THE SOLUTION
When dealing with unpaved roads, weather is the ultimate deciding factor. After we receive some rain, the roads can then be graded and reshaped by a grader. As each road is completed, magnesium chloride will be applied with a water truck and as a result the on-going dust problem will be corrected.
Road preparation
A critical step in dust control for gravel roads is road preparation. After arainfall, it is recommended to grade the roads while they still hold some moisture. Grading the road too early can make them worse and grading them too late can result in equipment damage. Once it is determined that the roads are ready to be graded, they will be reshaped to ensure the road has an adequate crown and shoulders to ensure proper drainage.
Optimum Moisture
Once the roads are graded, these conditions will allow for the magnesium chloride to penetrate evenly and quickly into the road surface.
Applying Magnesium Chloride
Magnesium chloride generally comes in liquid form and can be very effective if used properly. The product we use also will not harm plants, animals, or fish. Typically, it is mixed with water in a water truck and applied onto the road using a spray bar attachment. Once magnesium chloride is applied to the roads it will have cumulative effects. Each new application will build on previous residuals and will reduce the reapplication rates. This will help save on resources and on our road maintenance budget.
IN CLOSING
This work needs to be carefully coordinated and is primarily dependent on weather. Moving forward without the required optimal conditions will result in unnecessarily using up resources we will need later on. We thank you for your understanding and continued patience during this time.
Public Works Department