For the Conservation Curious

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Winter Floods are no Joke February 21, 2014

Filed under: Science — newdomino @ 12:45 PM
Tags: , , , , , , , , , , , , , , ,

Will the snow ever go away? That’s what a lot of people are thinking these days. In the ten years I have lived in the Harrisburg area I have never seen so much snow accumulate over one winter. Sure, we had a February blizzard or two in years past, but nothing like the piles of snow and ice that dominate the urban landscape right now.

I think people’s biggest concerns right now are: Where all this snow and ice is going to go once it melts. Will it cause significant flooding downstream? And what will happen to the rock salt, cinders and gravel that is now trapped in the ice, leftover from over-zealous public works staff?
Those are reasonable concerns that I will try to explain here.

According to a recent article in Smithsonian Magazine by Joseph Stromberg, on average the U.S. uses 137 pounds of salt per person each year to keep roads and sidewalks free of ice – that’s 22 million tons! His article goes on to say the following:

“A group of scientists that tracked salt levels from 1952 to 1998 in the Mohawk River in Upstate New York, for instance, found that concentrations of sodium and chloride increased by 130 and 243 percent, respectively, with road salting the primary reason as the surround area became more developed. More recently, a study of a stream in southeastern New York State that was monitored from 1986 to 2005 found a similar pattern, with significant annual increases and road salting to blame for an estimated 91 percent of sodium chloride in the watershed.”

That can’t be good for the environment, and it’s not. Scientific studies have shown that the chloride in rock salt negatively impacts amphibians, fish, plants and other aquatic organisms. The salt can dehydrate trees, particularly those in urban areas along sidewalks and parking lots. Plus the dried salt may attract deer to roadsides (they lick it for its nutrients), creating more traffic hazards. Occasionally the salt may enter drinking water wells too, although that is very rare.

What can be done to improve this situation? Municipalities are beginning to try out new combinations of salt and gravel, salt and water, salt and sugar beet juice, and even salt with cheese brine. Whatever works, especially if it’s safer for everyone. They are also varying the timing of salting. If you put down salt prior to a storm, rather than during or after, it is much more effective and less likely to wash away with the melting snow and ice.

But this doesn’t get to the heart of the matter – the sheer magnitude of the snow and where it will end up when it melts. That’s a trickier issue. If our days warm gradually, the snow and ice should be able to melt slow enough to be absorbed into the ground and carried off by streams and rivers without causing major flood events. However, if we have numerous warm, sunny days in a row, possibly followed up with rain, that could spell trouble. If you live in an area that experiences periodic flooding, make sure you have an emergency plan, just in case.

Building our homes and businesses in floodplains is never a good idea, but people like to live with a view of water, so there’s no way around it. All we can do is be prepared, design those structures with flooding in mind, and stay as safe as possible. Be careful out there, everyone!


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