Maple River Dam | Damage is Being Avoided Every Minute

Spring waters are receding after reminding us of all the potential for catastrophic flooding. Some areas were impacted more than others, but for the most part, projects built years ago are now paying off.

For the first time since completion, several water mitigation projects are now being tested, with great success. “We’re definitely seeing the payoffs on these projects,” said Kurt Lysne, Water Resources expert with Moore Engineering.

Large-scale water projects advance the notion of sustainable development by fully considering the impact on wildlife and undeveloped land, disturbing both only to the degree that project needs are met. Human health, safety and economic growth are protected and enriched with these water projects by reducing flood risk to highly productive farmland, roads, city infrastructure, homes and businesses.

Read below to learn more about a couple of these projects.

Upper Maple River Dam: Steele County, North Dakota

The upper reach of the Maple River watershed, located in portions of the Steele, Barnes and Cass Counties, has been prone to flooding that has caused significant damage to roadways, cropland and structures. The floodplain topography is very flat and the river can widen to two miles in some locations during floods. An existing flood control dam was severely undersized to provide adequate protection and was also in need of costly repairs. The Maple-Steele Joint Water Resource District sought to provide more robust and cost effective flood protection for landowners impacted by the river.

After several studies of the upper portions of the Maple River watershed, the Upper Maple River Dam was identified as the preferred site for construction of a new dam. Moore Engineering led the effort to study the best location for the new dam and then completed the engineering required to design and construct the dam, including the navigation through the regulatory and permitting process, conducting public outreach activities, assisting the district in securing funding and administering the right of way acquisition process. Moore also assisted the district during the construction phase of the project by providing contract administration services, construction staking and materials testing coordination.

The Upper Maple River Dam culminates almost 20 years of planning and preparation. This dam reduces flood damages over more than 20,000 acres in portions of Steele, Barnes and Cass counties where the river has damaged growing crops and public and private infrastructure for many years. The dam has a flood peak reduction of 86 percent in a 100- year, 24-hour rainfall and 58 percent in a 100-year snowmelt. The Upper Maple River Dam is a dry dam, meaning that it only holds water during floods, allowing farmers to continue using pasture and cropland behind the dam.

Key Project Facts

• Year Completed: 2015
• Watershed (drainage) area – 58 square miles
• Surface Area – 20,000 acres in Steele, Barnes, and Cass Counties
• Maximum height – 35 feet
• Width at top of dam – 20 feet

Maple River Dam: Cass County, North Dakota

Flooding along the Maple River in Cass County North Dakota has long been thought of as a way of life. The Communities of Mapleton, West Fargo, and Harwood are directly impacted by pervasive Maple River breakout flows.

To find a regional solution that would benefit multiple communities, the Cass County Joint Water Resource District relied on Moore Engineering. A regional floodwater impoundment on the mainstem of the Maple River was soon identified as the most practical solution. Up against environmental, cultural, and right-of-way challenges requiring significant time and expense, Moore coordinated all necessary items related to the permitting process. This included habitat mitigation, cultural resource surveys, and other items related to the Environmental Impact Statement, as well as right-of way acquisition.

Constructed over two years, the Maple River Dam stands 73 feet high and controls a drainage area of 902 square miles. This Cass County Joint Water Resource District facility is a dry dam that stores 60,000 acre-feet of floodwater. As a result of the project, the frequency, depth, and duration of downstream flooding is significantly reduced. Since completion of the project, Moore has served as the land manager and trusted advisor for ongoing operation and maintenance, repairs and upgrades, and regulatory compliance related to habitat and wetland mitigation.

Key Project Facts

• Year Completed: 2006
• Watershed (drainage) area – 902 square miles
• Surface Area – 2,800 acres
• Maximum height – 73 feet
• Width at top of dam – 25 feet