Mouse River Enhanced Flood Protection Project – Phase MI-1

After the historic 2011 flood in Minot, ND, the Souris River Joint Board wanted a solution to protect their residents for years to come.

Hard Days Along the River

For residents of North Dakota near the Canadian border, the Mouse (Souris) River brings life to agricultural lands and is a notable backdrop to many cities like Minot, ND. However, along with the life-giving international waters comes the threat of extreme flooding.

The Flood

In 2011, a major and historic flood event—greater than the 100-year event—caused significant damage and incalculable difficulties for the Mouse River Valley, including the city of Minot. As cleanup and assessments began, harsh realities set in. Many homeowners did not carry flood insurance, and the costs of the aftermath quickly added up for the community. While initial estimates put the damage at around $600 million, it is now thought to be closer to $1 billion.

The Souris River Joint Board (SRJB) initiated a plan to create permanent flood protection that would shield Minot, its infrastructure, and more than 40,000 residents from recurring flood events.

Designing a Solution

As a firm with a long history in North Dakota’s flood regions, HEI was honored to play a key role in designing and overseeing construction of many of the project’s large infrastructure improvements as part of the MI-1 phase. With a local office in Minot, many of our employees felt the Mouse River flood firsthand and also contributed to emergency flood fight activities. The SRJB retained HEI to complete Phase MI-1 of this project. This phase incorporates designs of major new flood protection infrastructure near 4th Avenue Northeast.

The project began with an alternatives evaluation to develop the most cost-effective solution for this reach. HEI designed new concrete floodwalls, earthen levees, tie-back levees, and closure structures.

The floodwall opens at Broadway Plaza, creating a focal point for the city with access to the scenic riverfront views. If needed, the plaza gate can be closed to protect major intersections and area businesses from rising waters.

This project also includes the new Broadway Pump Station, which will service a 640-acre area north of the river. At full capacity, the pump station can discharge 180,000 gallons per minute. On an ordinary day, the pump station provides stormwater drainage for a 40-acre area north of the Mouse River.

HEI completed project administration, preliminary engineering services (including surveying), final designs, public outreach, bidding services, and construction administration. HEI also assisted with the Conditional Letter of Map Revision (CLOMR) and US Army Corps of Engineers (USACE) permitting to ensure that the project meets all necessary guidelines.

Construction began in the spring of 2018 and was substantially completed in the fall of 2021. Estimated construction costs are $43 million.

Construction included earthwork for the Broadway Pump Station (which was brought up in elevation) and levees; riprap placement along the north bank of the Mouse River and along levee sides; nearly 7,000 cy of concrete for the floodwall and 5,600 cy for other structural components; concrete paving of a new roadway intersection; asphalt paving of a new roadway; mechanical, electrical, and building work for the Broadway Pump Station; and several hydraulic gate installations, including flap gates, sluice gates, and combination gates. Concrete floodwalls included self-consolidating concrete.

What’s Next?

On May 6, 2022, the SRJB hosted a ribbon-cutting ceremony to pause and celebrate the milestone accomplishments to date. Yet, the group is keenly aware that there is still work to be done.

While the SRJB is well on its way to reaching 60% flood protection for Minot and area residents, they will embark on upcoming projects currently under development with HEI, including phases MI-4, MI-5, and MI-6.

Learn more about this project in our StoryMap.