Minnesota Water Resources Conference - Water Resources Center ...

BOOK OF ABSTRACTS
Tuesday, October 28
Concurrent Sessions VI 3:00–4:30
Track D: Flood Reduction and Riverine Habitat
Impoundments—An Integral Part of the Overall Flood Damage Reduction Strategy in the Flood Prone
Red River of the North Basin
Nate Dalager, HDR Engineering, Inc., nate.dalager@hdrinc.com
Covering thousands of square miles, the Northwest Minnesota portion of the Red River of the North basin has
some of the most fertile farmland in the nation, yet is often flooded. Many of the communities are also flood
prone.
A system of ditches running east to west was constructed almost every mile around the early 1900s to settle and
farm the area. Most of these ditches are undersized for their respective drainage areas and the farmland that
was opened up over the last century. A typical ditch has the capacity to handle runoff from a 1-2 year frequency
event (~2 inches in 24 hours). Because of the low capacity, flooding and crop losses occur on an almost annual
basis in many areas.
The Red River Watershed Management Board (RRWMB), a local governmental unit with water management
responsibilities in the region, is pursuing flood damage reduction goals using structural and non-structural
measures, but primarily through the construction of gated impoundment floodwater storage, incorporating an
environmentally friendly systems approach. The RRWMB has developed an objective project evaluation system
that quantifies a project’s flood damage reduction effectiveness locally and on the main stem of the Red River.
In addition, the State of Minnesota and RRWMB coordinate these projects using a “Mediation Agreement”,
whereby all relevant parties are involved in all phases of project planning, design, and implementation.
Ultimately, the process is intended to yield projects that are acceptable to all interests, including private
landowners and State and Federal permit agencies.
Goals, objectives and benefits:
■■
Provide 100-year protection to urban areas
■■
Protect flood prone farmland, roads, and structures from a 10-year frequency storm event (~3.5 inches in 24
hours) through the development of flood storage
■■
Prevent erosion damages to land, reduce turbidity downstream, and increase fish and wildlife habitat
81 Minnesota Water Resources Conference, October 27–28, 2008