Signs of spring are everywhere: Warmer temperatures, more daylight and street sweepers picking up tiny pebbles deposited by snowplows after three months of winter.
But what happens to those little rocks after they’re gobbled up? Are they reused during next winter’s snowplow activities?
Not quite.
All the dust, dirt and refuse collected by street sweepers is emptied at Durango’s Centennial yard before being taken to the Bondad landfill, where it is used as earthen cover to bury trash, said Levi Lloyd, director of city operations.
“We’re picking up dirt from one place and taking it to another,” he said with a laugh.
Medians and gutters are cobbled with dirt and rocks this time of year. That’s because city street sweepers don’t run during the winter. To stay in compliance with air-quality standards, street sweepers must spray water to keep dust at a minimum, Lloyd said.
“We typically can’t do that in the wintertime because the temperatures are too low,” he said. “So what you’re seeing on the streets right now is sort of an accumulation from most of the winter.”
Chip rock deposited by snowplows has to be a specific size, three-eighths of an inch to be exact. Meanwhile, street sweepers pick up pretty much everything in their paths, including coins, cellphones, sunglasses and metal shards, Lloyd said.
“When we sweep, we pick up all that stuff plus a lot of really fine sand, and if we try to reuse that as sanding material, it clogs up our sanders,” he said. “It’s just sort of the wrong size sand.”
The material also is sprayed with water, which turns it into a sort of powdery muck. And the city doesn’t have a screening facility to sift out the right size rocks for snowplows.
Street sweepers occasionally snag something of value, like a dollar bill, but anything in their path is almost certainly destroyed.
“It’s a pretty violent process, so anything that goes through there is pretty beat up,” Lloyd said. “The vacuum that we use is a high-pressure vacuum, and it goes up through a chute and it bangs through there. That stuff is always in flux back there, so it’s just getting bounced around. By the time we dump it, if there is a cellphone or something in there, it’s shot – there’s no bringing it back.”
The city has two street sweepers that move a whopping 3 to 5 mph along shoulder ways. Both are in operation this month. Come April, one will be used almost exclusively in the Central Business District, and the other will work neighborhoods – typically following the trash pickup route, Lloyd said.
“It’s a big area, so we don’t always get it finished, but we try to hit each of the neighborhoods a minimum of twice a month,” he said.
shane@durangoherald.com
