Surprisingly, there wasn’t much to see at the actual accident scene – but take a look at our exclusive photos of the damage four blocks away, caused by a hit-and-run big-rig driver who knocked over a fire hydrant …
The serious water main problem started here, at here, at SE Division Street at SE 112th Avenue when a truck knocked over a fire hydrant. Officers said a passerby rolled it out of the street and set it upright on the sidewalk next to the utility pole.
Story and photos by David F. Ashton
The result of the accident about 9:45 p.m. on February 3 in the Mill Park neighborhood on SE Division Street at SE 112th Avenue wasn’t much to look at, only an hour after it took place.
A plumbing collar stuck up from the slightly damp looking sidewalk on the southwest corner of the intersection; a yellow fire hydrant sat, upright, a couple of feet away from where it used to be mounted.
“A metallic purple semi, pulling a long trailer, cut the corner too close and took out a fire hydrant,” commented Portland Police Bureau spokesperson Detective Mary Wheat. “It was a hit-and-run; the description of the driver is unknown. The driver may not even have known the accident occurred.”
At SE 106th Avenue, the cascading water quickly starts pooling into a deep pond.
Further east along SE Division St., water rushes westward.
Division Street quickly floods
There wasn’t any water geyser shooting into the air, as one sees in the movies when a fire plug is knocked over. Fire hydrants are made to break off cleanly when struck, preventing damage to the pipes to which it is attached. That kind of break causes an internal valve, down in the supply pipe, to snap shut – stopping potential flooding.
But, four blocks west on S.E. Division, in front of the Bike Gallery store near SE 108th Avenue, it was an entirely different story.
The pavement in Division Street’s eastbound lane started to buckle, as a torrent of water forced its way up through the pavement and flowed westward, down the slope. Businesses and residences on S.E. 108th looked as if they’d be inundated with the ever-increasing flow of water.
Not knowing if the water would cause a sink hole, Portland Police Bureau officers closed S.E. Division Street in both directions, from S.E. 105th to 112th Avenue.
The torrent of water below buckles and lifts sections of pavement on eastbound SE Division St. near SE 109th Avenue.
A Portland Water Bureau worker attempts to “throttle down” the water flow as it gushes up from the pavement beneath him.
‘Water hammer’ wreaks havoc
The first Portland Water Bureau (PWB) worker on-site shook his head as he surveyed the situation. He was probing the murky water, trying to locate a shut-off valve to “throttle down” the water flow. “Probably caused by ‘water hammer’,” he said.
“Water hammer” occurs when fluid motion is suddenly forced to stop or change direction – such as when a when a valve is closed abruptly. This causes a pressure wave to propagate within the pipe, which can result in a pipe collapsing – or, as in this case on a downhill slope, an implosion.
Firefighters use ladders – and plastic sheeting – from Portland Fire & Rescue Engine 25 to construct a sluiceway, diverting water from businesses and homes.
Firefighters to the rescue
As time went by, with the torrent of water racing westward along the thoroughfare, businesses looked as if they’d be flooded. And, a large puddle of water on SE 108th Avenue soon became a brackish pond.
A Portland Fire & Rescue truck crew at the scene decided to do more than just keep bystanders from being hurt in the flood. Using their extension ladders, and a roll of plastic sheeting, the firefighters constructed and installed a makeshift dam that successfully diverted much of the water stream into a nearby storm sewer.
In the morning’s light, a PWB worker closes off the water main so repair work can begin.
Water workers tackle major repair
Overnight, PWB crewmembers worked to shut off the water main and drain the water from the system. Then, they located all underground utilities – so they wouldn’t back-hoe through gas mains or communication systems as they up the street to make the repair.
One lane westbound and one eastbound on Division Street was opened to traffic in time for the morning rush hour on February 4, as Water Bureau workers dug into the muck, looking for the broken pipe.
By midmorning, workers had excavated the site of the break. PWB supervisor Doug Quan reported that an eight-inch water main had ruptured at the point where it connected to a 12 inch main.
This photo, supplied by Portland Water Bureau, shows the extent of the split pipe.
“When crews unearthed the portion of the affected main, it revealed an impressive split, estimated to be between six and eight feet in length,” confirmed PWB spokesperson Jennie Day-Burget.
By late that afternoon, the water workers replaced the broken portion of the pipe, and were preparing to fill in chasm – but afternoon rush hour traffic slowed to a crawl while being diverted around the construction site.
Eastbound traffic on SE Division St. was rerouted while PWB workers fixed the broken water main.
“Customers in the general affected area might experience dirty water at their taps,” Jennie Day-Burget admitted. “They were advised to let their water run until it clears out. At that point it’s safe to drink.”
© 2010 David F. Ashton ~ East Portland News