Division of Water Resources Update
The Forecast: A Cold and Snowy Winter
Well it's that time of year again. The long days of summer are over and instead of drinking lemonade on the porch, we're thinking about recent snow flurries and dropping temperatures. As we prepare for winter, we are making sure we have snow shovels and deicing salt in the garage and possibly hiring someone to plow. We may have even heard that this year the National Oceanic and Atmospheric Administration (NOAA) predicts a wetter and cooler than average winter for the Midwest and Great Lakes, which could mean above average snow fall with totals similar to last winter.
Whether you are maintaining a driveway or a parking lot, snow and ice control is a big deal. Removal of snow and ice from pavement is essential for both public safety and the local economy, in which pavement deicing chemicals keep pavements safe and passable, not to mention allowing you out of your driveway. Pavement deicing is typically accomplished through the use of road salts. Sodium chloride, or common salt, is by far the most popular roadway deicing chemical because of its reliability, economy, and usability. But have you ever stopped to wonder where all those salts go after they have been applied?
Once placed on pavement there is no way to stop salt from getting into the environment. Road salts can enter air, soil, groundwater, and surface water from direct or snowmelt runoff, release from surface soils, and/or wind-borne spray. Once in solution, these salts remain in solution in surface water and groundwater and are not subject to any significant natural removal mechanisms.
So what's the big deal?
Once applied to pavements, approximately 55% of road-salt chlorides are transported in surface runoff with the remaining 45% infiltrating through soils and into groundwater aquifers (Church and Friesz, 1993). In McHenry County, groundwater is the sole source of drinking water and chloride (salt) levels are increasing. Salt used for pavement de-icing has been found to be one of the primary sources for chloride levels increasing in the water.
FACT:
Illinois Environmental Protection Agency standard for Class I Potable Groundwater Resource: 200 mg/L. Elevated levels of Chlorides make water non-potable at Secondary Drinking Water Standard: 250 mg/L. 1 teaspoon of salt in 5 gallons of water = 230 mg/L.
The use of salt has environmental and economic drawbacks. Road salts have been found to be corrosive to vehicles, roadway surfaces and bridges. They also have adverse effects on groundwater and environmentally sensitive areas (Panno, 2002). Salt can affect the taste of water and corrode plumbing infrastructure. It can also increase the cost of drinking water treatment. For public water suppliers, it is very expensive to add and operate the necessary technology to remove salt from the drinking water supply. In private homes utilizing wells, the same is true. Salt also reduces the suitability of water for irrigation and other industrial operations as well as contributes to the loss of productive farmland. Finally, salt can be toxic to aquatic life, plants and wildlife thus contributing to a loss of species diversity.
Fortunately there are several easy steps we can take to reduce our footprint. First, shovel as much snow as you can off your sidewalks and driveways and let the sun work for you. Fact: It takes four times more salt to remove snow and ice than prevent it. Second, when using a deicing chemical know the effective melting temperature of that chemical and use only enough to break the ice-pavement bond. Once the bond has been broken, remove slush by shoveling. For information on effective melting temperatures of different products, read the label on the bag or visit www.mchenryh2o.com and view the McHenry County Snow and Ice Control Handbook or the Winter Parking Lot and Sidewalk Maintenance Manual. Both handbooks offer tips for effective snow and ice control. Third, remember that all de-icing chemicals have an environmental impact, but some are considered more environmentally friendly, such as calcium magnesium acetate, potassium acetate, calcium chloride or magnesium chloride. Remember, a little bit of these products goes a long way. Also, avoid using any de-icing products near wetlands, streams or other waterways. Fourth, consider hiring a "certified" operator, who have successfully completed a full day training and certification workshop and passed the exam. The list can be found under Winter Snow and Ice Operators at www.mchenryh2o.com. Finally, shovel first, shovel often.
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