TAMPA — With nearly 2,200 miles of water mains, the city of Tampa averages about eight breaks a day, but doesn't see many like the two that bedeviled traffic and businesses Tuesday.
They were big.
A 20-inch transmission main broke Monday evening under S Dale Mabry Highway just south of Gandy Boulevard. Tuesday morning, a 12-inch transmission main split open downtown at Ashley Drive and Tyler Street.
They were inconvenient.
Northbound lanes of Dale Mabry, which carries about 34,000 vehicles a day between Ballast Point and Gandy boulevards, were closed in that area, though Florida Department of Transportation officials hoped to have repaving done and the road reopened by late tonight. The downtown break closed two lanes of Ashley Drive, part of Tyler Street and the 10-story Times building at 1000 N Ashley Drive.
And they were unusual.
These weren't common-place breaks — those that occur near a customer's water meter, or those caused by construction mishaps or aging pipes alone.
Instead, both appeared to be the result of a phenomenon known as "water hammer." That takes place when turning pumps on and off or opening and closing valves causes moving water to change direction, sending a shock wave through the distribution lines. Over time, those shocks can cause pipes to fail at their weakest points.
"This happens in water systems throughout America, throughout the world," Tampa Water Department director Brad Baird said.
A sign of a water hammer break is a pipe that splits open along its length, as both of Tampa's mains did. Aging is a contributing factor, but not the primary one, Baird said. The Dale Mabry main was 60 years old, the downtown main 50.
Baird did not think the two breaks were related. They took place more than 5 miles and more than 13 hours apart. Still, city engineers plan to look at the data over the next two weeks for clues about the causes.
First come the repairs.
"We'll continue to work on both of these," Baird said. "We worked through the night last night on the Dale Mabry one."
'Just like a river'
The first signs of the Dale Mabry break were small.
"I walked out, and there was just water gushing out of the ground," said Jimmy Croft, a driver at Papa John's Pizza on S Dale Mabry. "Within 30 minutes, the entire road was like a river."
The force of the water raised the asphalt on the westernmost lane of Dale Mabry from a couple of hundred feet north of Ballast Point Boulevard to where the turn lane begins for Gandy.
"That explosion caused the failure of the asphalt all the way to that point," Baird said. This is not unheard of, especially with big pipes where the water is moving with a lot of force. Years ago, when a 54-inch main broke under Bruce B. Downs Boulevard, chunks of sidewalk were propelled 50 feet into the air, he said.
Monday night's break created a small lake and knocked out water service overnight to businesses that include the Home Depot, Sam's Club, a Region's Bank, Pinarama Bowling and a strip shopping center that houses Papa John's. Water service was restored early Tuesday, but those businesses will have to boil drinking water for 48 hours, Baird said.
Nearby apartments and surrounding neighborhoods were not affected, but the break "definitely slowed us down today," Croft said. Instead of the usual 20 orders, the store got three.
"Everybody assumes that we're not accessible," he said.
Offices, library close
Tenants at the Times building on N Ashley Drive, a key entrance to downtown off Interstate 275, learned around noon that the office building was being closed. No water meant no rest rooms, no air conditioning and no sprinkler system.
"Seems to be a bad week for water lines," Mayor Bob Buckhorn tweeted to a downtown office worker who asked about the Ashley break on Twitter.
The John F. Germany Public Library closed at 6 p.m. Tuesday, with no immediate indication whether it would be ready to reopen Wednesday.
Earlier in the day, the library shut the rest rooms and air conditioning system in its main eastern building because there was no water to supply them, Hillsborough County library services director Joe Stines said. The air conditioner's chiller needs water to function. But the library stayed open through the afternoon because the western annex is served by a different water main.
Baird said he doubted that the Ashley Drive break had anything to do with a nearby $4 million project that started in July to install a mile-long, 36-inch water transmission in downtown Tampa. That project is being done to meet additional demands for water.
The project's first phase entails creating a 500-foot-long tunnel under the Hillsborough River. First, however, workers have to dig vertical shafts on both sides of the river, one at Fortune Drive and Doyle Carlton Drive and one at Cypress Street and Julian B. Lane Riverfront Park.
Contact Richard Danielson at email@example.com or (813) 226-3403. Follow @Danielson_Times