Rebuilding Sewer And Water Infrastructure Takes Massive Effort

High River Water & Utility Services helps lead the town to recovery after a devastating flood in June 2013.
Rebuilding Sewer And Water Infrastructure Takes Massive Effort
The June 2013 Highwood River flood in High River, Alberta, caused severe infrastructure damage and left most of the town under water.

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Heavy rains struck southern Alberta on June 19, 2013, compounded with a sudden release of heavy snowmelt from the Rocky Mountains. The provincial government labeled the resulting flood the worst in Alberta history. While Calgary was paralyzed, the Town of High River, about 20 miles to the south, was completely evacuated as the Highwood River flooded its banks.

“I was awoken at 4:35 a.m. on the morning of June 20, by a phone call from the director of emergency management,” says Jason Craigie, manager of operational services with the Town of High River. “At 5:05 the entire operations staff was at the shop. We’re all versed in high-water event protocol and we went about our business, placing sandbags in strategic locations, deploying pumps and calling in vacuum trucks in addition to the town’s Vactor 2100 to help dewater the collection system. Personnel were also monitoring key lift stations and other critical infrastructure. By 5:30 a.m. it was evident that this was not going to be a normal flood. Our previous record-breaker occurred in 2005 and the peak flow was estimated at 850 cubic feet per second. This time we were seeing 1,800 cfs. It was a tsunami of mud and silt.”

By 7:30 a.m., the town entered full-out disaster mode. Waterworks staff had sandbagged the town’s water treatment plant along the river with a 6-foot berm, just in time to avert the flood. It was too late, however, to protect the main lift station – the largest of 13 – which was inundated by raging water. Operators were soon ordered to abandon their respective lift stations as it became obvious that pumping the wet wells was a losing battle. The vacuum trucks brought in to maintain lift stations were diverted to search and rescue of residents.

Evacuation ordered

“All of the city’s 13,000 residents were ordered to evacuate and I instructed the remaining staff to evacuate as well,” says Craigie. “The water came so quickly over land that there was nothing we could do. The only thing we might have done differently is to evacuate sooner.”

Treatment facility supervisor Chad Moore evacuated the main lift station and found a heavy hauler to drive him back to the water plant, which was powered by a backup CAT generator. He and fellow operator Colin Andrews refused to evacuate throughout the flood, even after automated systems failed and the plant had to be run manually.

“I called Chad and told him that a helicopter would evacuate him if necessary,” says Craigie. “All of the town’s 12 shallow ground supply wells were already underwater and out of operation. We couldn’t bring them online because the turbidity of the water would have taken out the plant. We couldn’t risk depressurizing the system, so the plan was to maintain pressure in the distribution system, shut down outside users and protect the 3.5-million-gallon water supply in the reservoir. Fire flows needed to be maintained, but we turned down water pressure to help decrease usage. Residential curb stops were shut off, but many were buried under a foot of silt. In many cases, the culprit in the homes was dislocated washing machines, floating in the basement.”

Craigie also had to make the tough decision to shut off water to the town’s largest employer, a meatpacking plant belonging to Cargill Canada.

As the water plant’s diesel supplies dwindled, the utility attempted to deliver fuel by both tanker and boat. One of the town’s largest wheel loaders was eventually pressed into service and managed to get close enough to the berm to deliver cans of fuel.

The emergency operations center itself was soon abandoned and relocated as waist-deep water poured into downtown.

Silt accumulates

Due to high turbidity readings, a boil-water advisory was put into effect. Silt had accumulated in the water treatment plant’s backwash pipe. Canadian Armed Forces personnel helped to flush the backwash pipe and assisted utility staff in assessing the condition of generators in the lift stations.

On June 21, town staff members were able to fully assess the damage, using a hotel parking lot as emergency headquarters.

“It was surreal,” Craigie says. “The skies were filled with helicopters and we heard the whistling of gas leaks across town. Roads were littered with cars, silt and debris and were impassable using anything less than loaders and graders. Trucks were resting on top of hydrants, while some of the hydrants had been completely sheared off. Lift stations had been destroyed. The entire sanitary system was offline.”

In addition, power and phone service were out and the local railroad tracks were torn up and cast aside. The town’s utility shops had been destroyed along with a dozen fleet vehicles, while the town hall was entirely offline. Even the local hospital was soon evacuated.

Flooding covered almost 60 percent of the community. While some neighborhoods were underwater, an entire lake had formed in the northeast corner of town.

Rescue and evacuation efforts concentrated on people and pets while crews worked to remove more than 40,000 tons of flood debris from 5,000 homes. Every free pump in the province and some from beyond worked to remove more than 2 billion gallons of water from the town.

Maintaining the system

The utility department, meanwhile, concentrated on maintaining the water treatment and distribution system and engineering the renaissance of the wastewater system.

“After ensuring the water treatment plant was secure, we started with the main lift station,” recalls Craigie. “It’s the largest and the last one that conveys sewage to the wastewater treatment plant, so without that station, none of the remaining lift stations that still functioned had a destination to pump to. Just to get to the lift station we had to fight through 4 feet of muddy water and floating debris. The 30-foot-deep dry well, which houses the pumps, was completely filled with floodwater and all of the pumps were submerged.”

Employing diesel pumps, the station was dewatered and inspected. While the pumps themselves were operational, the electric motors had been disabled.

“We found a company in Calgary, Continental Electric, that could bake out the motor and perform a 24-hour rewind of the coil,” says Craigie. “We had the main lift station up and running five days after the flood and we began to pump the water out of the sanitary system and deliver sewage out of town.”

A call to arms

A call for both collection and distribution operators was answered by professionals from across the province.

“Some were sent to the water treatment plant to assist, while others flushed the water distribution system and assisted with flushing the silt out of the sanitary system,” says Craigie.

However, much of the town’s older section was served by a clay tile system. In some cases, flushing the pipes further damaged them.

The distribution system became operational within about 10 days of the flood. A subsequent leak detection survey by Echologics employed the company’s digital correlators to locate flood-related leaks in water pipes.

“Some of the water pipe damage was simply caused by the hydraulic pressure placed on them by the floodwaters above,” notes Craigie.

The utility used its RIDGID SeeSnake to tally the final damage to downtown sewer lines.

“CCTV inspection showed that we now had as much as 5-meter runs with no pipe left,” Craigie says. A 10-year plan to revitalize those sewers and replace clay with PVC had already been ongoing since 2009. The emergency escalated the program to one of rapid replacement.

Five lift stations were completely destroyed after their equipment sat submerged for two weeks. A thorough assessment showed that it would be cheaper to rebuild them, with generators now relocated above potential flood levels. Generators were also relocated on two stations that suffered less overall damage. All lift stations were operational by May 2014.

Flooding also destroyed approximately 80 percent of High River’s water meters. The town is currently tendering a contract to replace them with flood-proof models.

The road to recovery

Today, about three-quarters of the town’s downtown sewage system has been replaced and returning businesses have been reconnected to service. In June, the Alberta government put the finishing touches on the newly constructed West Town Dike, part of almost 4.5 miles of berms constructed around the community.

“Some residents are still returning to town, and some businesses haven’t yet fully re-opened,” says Craigie. “But the town will come back. Looking at all we’ve achieved, it struck me that water and wastewater operators are simply a different breed. The men and women who answered the call during the flood were entering a war zone, yet they didn’t even blink before diving right into the work. The homes of some of our operators had been destroyed and yet they kept working. I have never seen such dedication.”

More Information

Echologics - 866/324-6564 - www.echologics.com

RIDGID - 800/769-7743 - www.ridgid.com

Vactor Manufacturing - 800/627-3171 - www.vactor.com



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