It’s that time of year when studded tires are cautiously swapped for smoother treads; when the plow drivers’ working days are waning; when the shoe rack holds snowboots and sandals alike. Just when you breathe a sigh of relief at no longer driving on snowy roads, the asphalt shifts and settles itself after a long, frozen winter, revealing a pocked and rutted surface that’s hardly suited to driving. These are the scars of a ceaseless battle between human infrastructure and water.
Many factors contribute to the formation of potholes, but in general it goes something like this. Water has a way of breaching our defenses. When warm spring temperatures melt the snow, the liquid water sneaks into tiny cracks in the asphalt or seeps into the compacted surface below. This in itself is not necessarily a problem. But of course, as we all know based on our crisp mornings, temperatures still drop below freezing well into spring. As water freezes and expands into a solid state, it pushes the road surface upwards, cracking it further and leaving a raised chunk perfect for the next tire to scrape off the road.
Interlocking pavers allow more water to infiltrate soil than impervious surfaces like asphalt and concrete.
Damage begets damage, and every tire that passes over the spot weakens it further and opens the way for more water. Around town, these are mostly an annoyance; you slow down or move over a little to avoid a bent rim. Where they get scary is on the freeway, particularly in the ruts formed by heavy semi-truck traffic.
In a futile counterattack, legions of workers repave and reseal, desperately barricading the road surface to make it impervious to water.
Unfortunately, even when the battle against water seepage is (temporarily) won, we still lose in other ways. Impervious surfaces are a problem. Every asphalt road and parking lot used to be a surface that could absorb some water. Now, instead of infiltrating the soil, water runs right off of these surfaces. Garbage, engine oil, washer fluid, silt, abundant microplastics from tires, and anything else on the roads are dispassionately deposited in the rivers and streams next to roadways. Floods are worse and groundwater is steadily depleted.
Water seeping into road surfaces is a driver of pothole formation.
Doesn’t it seem a little silly that every summer I-70 and other roadways are repaved, and every following spring they are so damaged that the rutted roadway is almost as treacherous as during the worst winter blizzard? You could be thrown into another lane of traffic going 75 miles per hour but one groove, only to run right into a pothole that puts your tires to the test.
Perhaps we need to end the war, to recognize water as the friend that it is. I-70 certainly presents a challenge with its literal heavy traffic, but new asphalt mixes and alternatives show promise. Interlocking pavers make beautiful surfaces for roads with lighter traffic. Parking lots are a great place to use permeable asphalt, which lacks fine particles and therefore allows water to move through it into the soil below.
Spring’s freeze-thaw cycles present challenges for any surface we wish to keep level and smooth. Perhaps one day we will befriend water, and the annual repaving of I-70 will become obsolete. In the meantime, remember to slow down; stay in your lane; and keep a ready eye on the horizon for the next pothole.
Lydia Delehanty loves the feeling of driving on a dirt road, even in her Camry. She’s also the After-School Programs Manager at Walking Mountains.
