ROSEAU, Minn. - A $46 million diversion completed in 2015 to protect this northern Minnesota city from floodwaters of the Roseau River has water flowing in it for the first time and is working as advertised, officials say.
“It was great to see the project working,” Todd Peterson, community development coordinator for the city of Roseau, said Monday morning, April 8. “No worry about where the sandbags go first.
“This the first time we’ve ever seen water flow over the weir.”
The 4½-mile, east-side diversion on the southeast side of the city includes an inlet with a restriction structure near Roseau City Park that doubles as a pedestrian bridge and basically acts as a dam. The restriction structure directs water from the river into the inlet, Peterson said, and the weir, which is about 300 feet from the river channel, keeps additional water from flowing into the diversion until the river gets reaches a certain level.
That level appears to be about 16 feet, which is flood stage in Roseau and the approximate level at which water began flowing over the weir Monday morning, Peterson said. The diversion channel then carries floodwaters around the city before emptying into the river north of Roseau at the mouth of Hay Creek.
“If the weir wasn’t there, the water would have been flowing a lot sooner into the diversion, which again for maintaining the regular flow of the river and not trapping fish and other things in the diversion channel,” Peterson said. “They only really want the high, high water to go in there.”
City crews did a manual check, and the Roseau River in Roseau was at about 16 feet Monday morning, Peterson said, about 7 inches lower than the National Weather Service indicated on its website. The NWS projects the Roseau River in Roseau will crest at 17.5 feet early Tuesday.
Because this is the first time water has flowed into the diversion, city crews will monitor the restriction structure and river levels, Peterson said, but the flood protection system appears to have alleviated concerns about flooding in city limits.
Peterson said he hasn’t gotten any calls from residents wondering about sandbagging or equipment.
The east-side diversion was part of a flood protection project completed after the Roseau River flooded the city of Roseau and other parts of the county in June 2002. The Roseau River crested at 23.4 feet during that flood, the worst in the city’s history.
Temporary levees from previous flood fights protect Roseau to a river level of about 22 feet, Peterson said.
“We don’t even know what kind of flow you’d have to have in the river to get to 22 feet anymore because the diversion will take off so much of that water,” he said.
A Red River tributary, the Roseau River originates in Beltrami Island State Forest and flows about 215 miles before emptying into the Red River near Letellier, Manitoba.