The ubiquitous bags are essential in fighting floods, but they're not easy to dispose of once the water recedes.
Sandbags might be challenging daffodils as the symbol of spring in Minnesota.
This year, communities from the Red River of the North to the Mississippi River in the southeast have filled or bought roughly 5 million of them to hold off high water. That's about one for every Minnesota resident.
Sandbags can achieve near-celebrity status during a flood. In Fargo in 2009, flatbed trucks carrying sandbags through town got police escorts. But after their weeks of sturdy service, sandbags tend to become so many little headaches. Or, at 40 pounds apiece, a 100-ton problem this year across the region.
So what happens to them all?
Generally, used bags are considered contaminated, since floodwater usually carries raw sewage, animal waste, chemicals and other pollutants. So the sand gets dumped out and the bags get disposed of, usually shredded and landfilled.
The sand, which also may be contaminated, is generally used as construction fill or spread on pavement during winter storms -- not in playground sandboxes, at any rate.
The city of Fargo, N.D., now sitting on a stockpile of 2.5 million bags assembled by volunteers since Feb. 14, may use much of that sand as a protective liner in a landfill expansion, said Bruce Grubb, who supervises three of the city's public works departments.
Cities don't usually keep unused sandbags from year to year. Storing them requires space and money, and the conventional wisdom is that the bags will deteriorate if exposed for long periods to sunlight.
But Fargo, with its outsized appetite for sandbags (volunteers made 6 million to fight the record river level in 2009), is rethinking that. After last year's flood, the city saved 350,000 unused sandbags on pallets -- half of them inside, shrinkwrapped, and half outside, covered by black plastic. Grubb said the bags kept outside survived and even warmed up, which dried the sand inside, while those in the warehouse required a dehumidifier.
Fargo and Moorhead have found that sandbagging has cost between $1 and $3 per sandbag for each flood, accounting for materials, labor, delivery and disposal.
Moorhead's 1.8 million bags this year is far fewer than the 2.5 million it needed in 2009, because buildings have been cleared out of the flood plain and permanent levees have been built in many places where sandbags used to go.
"There's nothing that will compare with a good old clay levee," said city engineer Bob Zimmerman. "When you think about hundreds of thousands or millions of bags, it's very costly, and very labor-intensive. It's not the kind of thing you want to be doing year after year."
Grubb said he'd like to have Fargo keep 500,000 sandbags in case they're needed next year.
"I just don't see this flooding thing going away for a while," he said.
Bill McAuliffe • 612-673-7646