Minot, North Dakota

Destructive flood prompts Minot to invest in floodwall to protect its water supply

In 2011 spring snowmelt poured down the Souris River into Minot, flooding thousands of homes and businesses and sending sewage into the city’s reservoir. For eight weeks, more than 100,000 people from the city and surrounding communities had to boil water to avoid contamination.

In the wake of the disaster, the city secured a $22.5 million FEMA grant to build a floodwall around the water treatment plant and to acquire water sterilization equipment. It was the region’s most expensive flood recovery project at the time, but it reduced the flood risk to the city’s critical infrastructure.

Photo by City of Minot Public Works, Houston Engineering and Ackerman-Estvold Engineers

Community facts

Population
47,338
Homes
22,790
Businesses
4,620
Source: US Census Bureau.

Mitigation actions

In 2011, Minot was inundated by a 0.1-percent annual chance flood. Water rushed into the city at an estimated 27,400 cubic feet per second—five times the rate of a 1-percent annual chance flood, according to Dan Jonnason, director of the Public Works Department. Comparatively, the Souris River average flow rate in 2017 was 265 cubic feet per second.

The event flooded the city’s water treatment plant, leading to a boil order that stayed in force for eight weeks and affected over 100,000 people in the facility's service area. It was a huge financial burden on the community, as homes and businesses had to either purchase bottled water or spend hours boiling contaminated water to make it safe for consumption.

To mitigate the risks of another flood event like the one in 2011, the city built a 0.7-mile-long floodwall and levees around the water treatment plant. The city’s overall mitigation plan also involved acquiring UV sterilization equipment to supply potable water to the service area on demand. With a price tag of $30 million, it was the most expensive flood mitigation project in the region at the time, according to Justin Messner, state hazard mitigation officer at the North Dakota Department of Emergency Services.

Benefits of mitigation

Economic benefits
$33.2 million
Total monetized benefits
Return on investment
11.0%
Estimated return on investment
Benefit-cost ratio
1.11
Benefit-cost ratio of the floodwall around the Minot water treatment plant
Source: Interview with Justin Messner (December 20th 2017). State of North Dakota (2014). Multi-Hazard Mitigation Plan.

Project challenges

The project took several years to fund and complete

Getting approval for the $22.5 million FEMA grant took more than a year, and design and construction took four additional years. That was longer than the city had hoped, but according to Messner construction went smoothly after it began in March 2015. He attributes the efficient implementation of the project to the fact that the city had a full engineering plan in place prior to seeking final grant approval from FEMA. Messner feels that this preparation streamlined the process and helped to save on time spent managing change requests.

“Everybody supported this project, from the locals all the way up to the congressional team. [North Dakota] Senator [John] Hoeven, Senator [Heidi] Heitkamp, and Congressman [Kevin] Cramer have all been big supporters of all the floodplain projects that we've done”
Justin Messner, state hazard mitigation officer, North Dakota Department of Emergency Services

Future considerations

Construction of the floodwall around the Minot water treatment plant.
Photo by City of Minot Public Works, Houston Engineering and Ackerman-Estvold Engineers
Floodwall reduces the risk to Minot’s most critical piece of infrastructure from future flood events

The project was completed in early 2018, and residents are now confident that the floodwall has significantly lowered the risk that they will lose access to clean water in the future. “I know the entire service area of the Minot Water Treatment Plant, with a population over 100,000 people, was significantly impacted by the loss of clean water and would have really loved if there had been something in place ahead of time,” Messner says.

In early 2016, Minot was awarded $74.3 million from the US Department of Housing and Urban Development (HUD) in its National Disaster Resilience Competition. Minot was one of just 13 communities in the US to receive the award. The community will utilize the award funds in three key areas: reducing flood risk and increasing resilience; building affordable, resilient neighborhoods; and fostering economic resilience and diversification. The city and HUD will determine how the funds will be used.

Flood mitigation resources

Below is a non-exhaustive list of other flood mitigation information resources.