How Two Utilities Coped With The "Flood Of The Century"

By Michael MacMillan

In April, residents living along the Red River, from North Dakota to Manitoba, experienced one of the worst episodes of flooding this century. Grand Forks was gutted. And a large area of southern Manitoba was transformed into an inland sea. Electricity Today spoke with representatives from Manitoba Hydro and Northern States Power to learn how they served their customers during what has since become known as the "Flood of the Century."

Experts had been predicting heavy flooding for the entire Red River valley. An unusually cold winter -- combined with a massive blizzard and ice storm in north central U.S. in early April -- meant that spring runoff down river would be heavy. And sudden.

Residents of Grand Forks, North Dakota were already in a disaster frame of mind during the weeks leading up to April 18th. A severe winter storm battered the Northern U.S. only a week earlier. Most residents had known for weeks that this year's spring runoff was going to be heavier than normal. But officials were confident that the situation was well in hand. Grand Forks was surrounded by dikes, and there was no shortage of volunteer sandbaggers. All residents could do was wait.

Nonetheless, few were prepared when, on April 18, the dike gave way. Volunteers were still piling sandbags when the rapidly rising water simply became too much for them. With water pouring into the city, residents and businesses had only minutes to gather their valuables.

Russ Bartunek, electric operations manager with Northern Sates Power, one of the largest energy suppliers in North Dakota, said he and his colleagues were also caught off guard. NSP's priority from that point on was to minimize damage as much as possible.

"As the flood waters rose, we intentionally isolated about ninety per cent of the electric system in Grand Forks," Bartunek explained.

NSP followed a rough guideline in the de-energization process. First, they isolated the entire system. At that point they started isolating individual meters and transformers. This way, homeowners who wanted power for their pumps were assured a supply of electricity.

Feeders in NSP's substations were isolated using remote telecommunication units (RTUs). When the area's telephone circuitry eventually succumbed to the water, rendering the RTUs useless, NSP dispatched employees to the substations. Their job: keep the sandbags piled high and the water pumps pumping.

By the time the flood waters finally stabilized, NSP has literally shut down the city of Grand Forks. Of the 20,900 meters NSP operates in the area, all but around 900 were de-energized.

Those who were not evacuated -- electric contractors, gas workers and other essential employees -- found shelter at NSP's regional business headquarters in downtown Grand Forks, one of the few buildings left standing after the flood and subsequent fire. Employees who lived within 30 to 40 miles of the facility -- almost the entire staff -- had no homes left to return to. All of the town's food stores were closed, and the water treatment plant no longer operated. The company hired a caterer to keep everyone fed.

Bartunek said North Dakota experiences many weather-related problems over the course of a year. Ice storms, high winds and lightning routinely wreak havoc on their system. But what makes floods particularly difficult is the long recovery process. Not only do staff have to visit all their customers, they also have to be prepared to face all sorts of different problems.

"You recover by hooking customers up one at a time," he explained. "We're used to going out and repairing a pole. . . .or fixing a cable and restoring service to a hundred or two hundred customers at a time."

Considering the level of devastation Grand Forks sustained, NSP's transmission system and the substations fared well. However, their distribution equipment inclu-ding underground cable runs, meters, pad-mounted transformers and switch centers with exposed light parts sustained moderate to heavy damage. Most of the recovery effort is being concentrated on these areas.

Before individual homes could be energized, NSP first restored power to the 17 primary feeders that provide electricity to Grand Forks. Next, lines into neighborhoods were re-energized. For those lucky enough to escape without major flood damage, power was quickly restored. But others were not so fortunate; the re-energizing process is still on-going. Some residents, whether by choice or by circumstance, still have not moved back to Grand Forks, and Bartunek believes that life in the community will not return to normal until August.

If there is a bright spot on what must amount to the worst April in the history of Grand Forks, it is that everyone got through it safely.

"I have not heard of any injuries sustained by employees of our company, or by the general public," he said. "As far as I am aware, we didn't have so much as anyone break a fingernail."

Manitoba Hydro

Gerry Aubry will never forget the spring of 1997.

As Manitoba Hydro's customer service co-ordinator for an area called EastMan South (bordered by Winnipeg to the north and the U.S. border to the south), Aubry is used to dealing with unexpected problems. Nothing, however, could have prepared him for the events of this past April.

Earlier that month Aubry attended a flood preparation meeting. Like their counterparts south of the border, authorities were cautiously optimistic. Attitudes quickly changed when Aubry and his colleagues saw the devastation in Grand Forks, North Dakota on television.

"They were predicting levels that were quite optimistic at that point," he recalled. "Then on the following weekend Grand Forks was completely submerged and we knew then. . . . that our targets were a little low."

Everyone scrambled. Teams traveled around "getting a handle" on the number of pad-mounted transformers that might be affected, and taking note of what equipment was protected by dikes. The pad-mounts were de-energized. Meters and other equipment were raised up on poles. And alternate feeds were planned out, so that if a line was lost, an option would remain. It was Manitoba Hydro's intention to maintain service to as many customers as possible -- for as long as possible -- whether or not their homes were submerged.

This stretched resources to the limit. Manitoba Hydro rented and borrowed everything from flex-track equipment (for muddy terrain) to utility construction trucks and boats. They even made helicopter service available when necessary.

The flood water brought with it several unexpected problems. Unlike North Dakota, temperatures in Manitoba were still low. Large chunks of ice, resembling mini-icebergs, came hurtling down the river with such force that it snapped utility poles in half "like matchsticks." About 30 poles were lost this way. To restore distribution, workers removed stumps from damaged poles and cut wire out of the span, tightening it like a clothes-line. "We made some very long spans," Aubry recalled.

Low-hanging wires were another problem. Dump trucks carrying sand to dike-building teams were backing into them. And boaters, not accustomed to such hazards, were putting themselves at risk. Although the media and Manitoba Hydro launched a wire safety blitz, tragedy could not be avoided. Two Canadian Forces soldiers patrolling in the Emerson area happened upon a low-hanging wire. When they attempted to mark it, one of them was seriously electrocuted.

Then there was the risk posed to low-lying stations. "In particular, there is one major terminal station of ours, near Letellier, that we were very concerned about," Aubry explained. "ItÔs not very far from the river, and that is one of our major export stations."

The 230 kV Letellier station, 50 km from the U.S. border, is crucial to the transmission and distribution of power to southern Manitoba and the northern U.S.. Even as water rose around the station, Manitoba Hydro was still supplying power to utilities in North Dakota still recovering from damage suffered in the earlier ice storm.

Aubry initially had the station diked to the three foot level. But by week's end, the sandbags were piled nearly seven feet high. A four man crew kept the barrier in place. Several large pumps also worked around the clock to keep out the water. On April 25th one of the station's workers, Armand Juenke, reported that, "the water level in the yard ranged as deep as two or three feet in some areas." Inside the water was nearly a foot and a half deep. The effort at Letellier, however, was not in vain.

"We saved the station," Aubry said. "Another eight inches of water and we would have incurred a lot of damage, but it worked out."

Meanwhile, the flood was taking its toll on Manitoba Hydro staff. Many workers had homes in areas that were directly threatened by the Red River. The sight of so much devastation left them unnerved.

"Their families were evacuated, and their houses were at risk. And yet they were continuing to work with this in the back of their minds. It put everyone in a pretty stressful situation."

In all, nearly 500 homes were de-energized, far less than Manitoba Hydro initially thought necessary. Because workers patrolled neighborhoods, shutting off power only to homes that had been abandoned, none of the affected service areas experienced any large-scale decrease in supply. Restoration efforts are proceeding rapidly, and everyone should be back to normal by mid-summer.

"Overall, there were no major surprises, but it was devastating, no question about it." ET