Engineering division’s Matt Bray and Tim Grundhoffer fought two swiftly rising rivers, blizzard conditions and extreme temperatures only to be overcome by conditions beyond their control and to lose portions of a town not just once, but twice, in the same flood.
Bray, a geotech engineer, and Grundhoffer, a structural engineer, were assigned as flood subarea engineers in Wahpeton, N.D., and Breckenridge, Minn., during the 1997 floods that wreaked havoc across the Red River Valley. Although they worked together closely, Bray worked primarily in Wahpeton and Grundhoffer in Breckenridge. Pete Corkin, from Rock Island District, assisted them.
The two cities are situated across from each other at the confluence of the Ottertail and Bois de Sioux rivers. The two rivers converge in the cities’ downtown areas and form the Red River of the North.
Flood fight efforts are generally simpler for Wahpeton than Breckenridge, as Wahpeton only requires protective measures to be taken along the east side of town due to flooding on the Bois de Sioux/Red River. Breckenridge requires protection along its west side due to flooding on the Boise de Sioux/Red River but also requires protective measures be taken through the central portion of town due to flooding on the Ottertail River.
Bray and Grundhoffer arrived in Wahpeton mid-March, about three weeks before the first predicted crest, and began working on advance measures. Initially the City of Wahpeton wanted to provide protection for its park, and Breckenridge wanted to have snow cleared out from one of its major drainage ditches. However, as river stages began to rise and predicted river crests were increased, it became apparent to both communities that more significant measures would be required. Ultimately, both communities built extensive emergency levee systems. Breckenridge also put in place several hundred feet of sandbag levees for areas where earth fill levees could not be built.
The levees were fairly well finished to the predicated crest the night before the Ottertail crested – the night Blizzard Hannah moved into the area – but then it began to rain.
“We were ahead of the crest and prepared for that, but we had two to three inches of rain and that was the last straw,” said Grundhoffer. “I knew when the [weather] forecast came out, and it started raining. I didn’t think we were going to make it.”
It rained all night and all day. “We were trying to get levees built in the north part of Breckenridge along the Ottertail River, but we couldn’t keep up with the rising river,” said Grundhoffer. Water was also flowing into the area behind the levees through the city’s storm system, which had not been entirely blocked off from the river. Ultimately the north end of town was inundated with flood water.
That night, the temperatures dropped around forty degrees to below zero, and it began to snow. “Both cities were essentially shut down due to the white out conditions from the blowing snow. The blizzard did help us in that it slowed down the rate of raise on the river,” said Bray.
“We had to do some repair work the next day to a portion of the Wahpeton levee that had been cut to allow drainage from behind the levee back to the river. Several truckloads of clay fill had to be brought to the site, a distance of two to three miles,” he continued. “We put together a caravan of about 10 dump trucks loaded with fill. We were traveling bumper-to-bumper very slowly, but still managed to lose half the group due to the whiteout conditions.”
As the water levels dropped on the Ottertail, it continued to climb on the main stem.
In the 10 days it took for the second crest, the cities began to let their guard down. Grundhoffer said they began to cut holes in some of the levees. “We had to have a meeting with the city to say, ‘Hey, this isn’t over. There will be a second crest,’” he said. “Finally, water was rising again in some of the levee openings, and they took it seriously at that point.”
The National Weather Service published higher crest forecasts within days after Hannah had dumped more precipitation on the already soaked valley, and Bray and Grundhoffer continued to add height to the levees.
At the same time, the Corps continued to release water out of White Rock Dam downstream. White Rock Dam was in danger of overtopping.
“They [the water control section] would call us every day and tell us, ‘Sorry, but we have to let more water out of Lake Traverse for safety reasons,’” said Bray. “So even though we couldn’t handle any more water, there was no choice. It just kept coming up, and we just kept building the levees higher.
“Most days, we worked 18-hours or more,” he continued. “There were a couple of times where we worked a day-and-a-half straight without any sleep.”
He said the city had given him a cell phone, because they could not reach him on the Corps’ issued phone. Often, they were both ringing at the same time.
Within days of the crest, they experienced a breach in the levee on the Wahpeton side. Grundhoffer said he received a call from Bray and went over to help him. “Water was blowing through the levee probably about the size of a manhole,” he said. “It was just shooting out of the levee.”
The breach took place where the levee had been tied into an abandoned railroad embankment. “It hadn’t occurred to me at the time we constructed that reach of levee that I shouldn’t be relying on that to hold back the water,” said Bray. “You don’t know what materials were used to construct it.”
The location of the breach was especially difficult to work in as water had ponded behind the levee to a depth of about three feet and there was a propane tank, still connected to a mobile home, floating in the water.
“We had a lot of town people on the levee, putting sandbags in the area of the breach trying to get the flow to stop,” Bray continued. “Eventually, we got it to slow down by putting sandbags on the riverward levee slope. At that point, a large backhoe from the railroad was brought on site. It was used to place fill in the breach. The backhoe was able to stop the flow entirely. The next day we fortified the area with more clay fill using our crews.
“When I went back [there] in 2001,” he added, “the first thing I did was have our crew remove that portion of the railroad embankment entirely and build a new levee section.”
The next day, April 15, Wahpeton and Breckenridge experienced their second crest and the Bois de Sioux began to cause overland flooding on the southern end of Breckenridge.
Grundhoffer said they recommended a plan that included building a levee that left a few businesses and around a dozen homes out of the protected area, but the city did not want to leave anyone out.
Later that night, as the south end of town began having more and more water, they came back and requested to follow the originally-suggested plan. “We went ahead and did that but knowing that it would be almost impossible, at that time, to try and build that other line up in that short time,” he said. “It must have been four or five o’clock in the morning when the mayor finally came out and told us to call it quits.
“We actually were trying to fight the flood during the flooding and essentially ran out of time,” he explained. “The levees that were completed were overtopped in some locations.”
The water stayed high for several days, and Bray and Grundhoffer stayed in town to monitor the conditions of the levees. They had some that were getting soft, as well as some seepage problems. They ended up staying until the city felt comfortable again.
Although he knew it wasn’t his fault, Grundhoffer said he felt like he had let the people down. “It was something that took a long time to process,” he said.
“It being my first emergency duty, it was an extremely challenging situation,” he said. “You are there helping the city as a team to provide guidance to them. You are not there by yourself. There are other experienced flood engineers, the district office, the city to help you out. All of that support was very welcome.”
Although the topic of a permanent flood control project did not come up during the fight, within a year both cities contracted with a private engineering firm to begin building flood protection for both cities.
Bray said they built permanent levees on both sides of the river, as well as two flood walls in Breckenridge. The engineering firm approached the district to review its plans, he added, and the district recommended modifications. Shortly after that, the district initiated a feasibility study.