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The Headache of Water Main Breaks

June 3, 2014

Like actors who never utter the word “Macbeth” in a theater for fear it will bring them bad luck, or characters in Harry Potter who don’t dare speak the name of the evil Lord Voldemort, members of Golden Valley’s utilities crew refuse to say the words “water main break.” 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 


(Photo credit: Hennepin County.)
 
“Those words will never come up,” says Bert Tracy, public works maintenance manager. “It’s ‘that which shall not be named.’ ” 
 
Whenever Tracy hears about a water main break in another city, he cringes. “You feel for those crews,” he says. “Because you know what they’re going through.” 
 
Water main breaks are critical incidents for a city public works crew because residents and businesses in the area are without water until the break is repaired.
 
When a water main breaks in the winter, it means a minimum of six—and as much as 20—hours of digging up frozen ground just to get to the pipe, where crews sometimes have to wade through pools of water in below-zero temps. 
 
Add the responsibility of keeping a crew safe during a dig and the concern for people who don’t havewater until the break is fixed, and it’s enough to keep maintenance managers awake at night. 
 
“You don’t sleep through storms, because you know something is going to go wrong,” says Kelley Janes, utilities maintenance supervisor. “In today’s age, uninterrupted service to the community is everything. If something goes wrong, we have to fix it right away, day or night.”
 
And (this past) winter, hardly a week passed where something (didn't go) wrong. Between December and the end of February 2014, Golden Valley had 12 water main breaks, more than the average.
 
The cold weather has a two-fold negative effect. First, the colder it gets, the more likely it is that water mains will break. Second, the colder it gets, the harder, longer, and more  difficult it is to fix the break. 
 
Janes recalls working on a water main break this January for so long, under such wet and cold conditions, that one of his extreme-weather, industrial-grade boots literally froze and broke apart.
 
“It can be a long day,” Janes says.
 

Why Water Mains Break 
There are two primary reasons a water main will break. In winter and spring, the reason is usually ground frost. 

Pipes are buried eight feet underground, because ground frost generally won’t go that deep. This winter, however, the frost went much lower than its usual three to four feet, and when that happens, the area above a pipe loses its give and the ground no longer acts like a cushion. For example, when a truck drives over that frozen area, it’s as if the truck is driving on the pipe directly. The pipes, especially older ones, can’t take the strain.

The other primary reason a water main breaks is due to something called a “water hammer.” If water is flowing through a pipe and then for some reason the pipe gets shut off abruptly, the halted momentum of all those thousands of gallons of water creates a sudden spike in pressure. To relieve that pressure, the water will bust out of wherever the pipe is weakest. 

Fixing A Water Main Break
The first step to fixing a water main break is finding out, exactly, where the break is located. Crews do this by putting their ear to the ground, using sonar technology to listen for the leak. Before they had this technology, Tracy says, crews had to use trial and error, digging up parts of the street in several locations to find the source of the problem. 
 
Once the break is located, the crew will start digging. Sometimes they can’t find a way to turn off the water flow, meaning they’ll have to go into a watery hole wearing waders as a sump pump sucks out the water. 
 
But before they even get to the pipe, they have to navigate all the other utilities on top of the pipe, such as gas and fiber-optic lines.
 
“We have to go through them or around them, some way,” Janes says. 
 
Crews will often need to dig around a concrete conduit that’s holding other utilities. They then need to place one or two wooden beams the size of telephone poles under the conduit to support it. In the hole, workers are protected from cave-ins by temporary metal walls not unlike a shark cage.
 
When the hole is dug, parts of the earth get exposed to sunlight, which thaws the sides of the wall. Combine this with the fact the ground is already so much softer below the frozen surface, and you have a recipe for collapse. 
 
That’s why it’s essential to follow proper safety procedures, says Tracy.
 
Even though you’re protected by the metal box, when a cave-in happens it’s terrifying, like a car just slammed into the side of the box, he adds. 
 
Even with the cold and the wet and the pressure to get the job done quickly, Janes and Tracy agree there are some lighter moments. Janes recalls a time the hole was full of water when the sides caved in. The resulting geyser showered every crew member in sight. When crews get done digging the hole, navigating the other utilities, and wading through the water, they can finally fix the pipe.
 
To fix a water main break, crews replace the broken section of pipe with a metal band or with new piping made of metal that’s more flexible than the material used in the past. Most piping under Golden Valley is more than 50 years old, before the enhanced metal was available, and it will be several more decades before all that old piping gets replaced.
 
After the repair is made and the hole is refilled, crews use a special cold-weather material to patch the street. This patch is only effective in winter, meaning that come spring, crews must replace it with a more permanent patch. 
 
Water main breaks are a fact of life in Minnesota, especially in areas like Golden Valley, where soil conditions are less than kind to the lifespan of the pipe materials. Wholesale replacement of aging water mains will cost millions, so for years the City has been handling it on a priority basis. Each year, the City evaluates its water and sewer system, identifies the deficiencies, and replaces and rehabilitates those facilities as needed as part of its Pavement Management Program.
 
Reprinted with permission from Golden Valley CityNews (pdf), March/April 2014, City of Golden Valley, MN.

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