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Planning Assistance to States (PAS): Red River Basin Long Term Flood Study

Published March 22, 2019
Updated: April 8, 2020
 
Purpose

The purpose of this study is to investigate the effectiveness of tributary flood storage basin-wide to reduce main stem peak flows by 20 percent for the larger rare events such as the 0.5 (200-year) and 0.2 (500-year) percent chance of exceedance floods.

Location

The Red River of the North rises in Lake Traverse near Wheaton, Minnesota and flows north towards Canada and ultimately to Lake Winnipeg. This is a basin-wide study in Minnesota and North Dakota.

Description

The Red River Basin Commission (RRBC) produced the Long Term Flood Study (LTFS) in 2011 after the 2009 flood. Minnesota and North Dakota expressed the need for a coordinated, comprehensive, proactive plan that responds to and mitigates flooding and flood damages throughout the Red River Watershed. The 2011 LTFS report provided 48 recommendations ranging from immediate needs and critical risks to long term studies. A 2015 status report showed that substantial progress had been made for about 20 percent of the recommendations, but that limited or no progress had been made for about 50 percent of the recommendations. The focus of the study will be on the 0.5 (200-year) and 0.2 (500-year) percent chance of exceedance floods. Study tasks include updating hydrology models with sensitivity to climate variability and other factors like storage, impacts of changed hydrology on levee certification, analysis of risk reduction goals, effectiveness of flood plain regulations, and storm water management.

Status

A partnership agreement was executed between the U.S. Army Corps of Engineers and the sponsor (RRBC) in November 2018. The sponsor will meet all or a portion of their cost share requirement through work-in-kind efforts.

Phases 1 and 2:

  • Hydrologic data for floods in the range of the 0.5 to 0.2 percent chance exceedance events are being developed.
  • Impacts of flood storage are being investigated. The study is scheduled to be completed in fall 2020.
  • An addendum will be added, if approved, for potential storage effects downstream of Halstad.
Authority

Section 22 of the Water Resources Development Act of 1974 (Public Law 93‒251), as amended. The study is being conducted under the Corps’ Planning Assistance to States (PAS) program, following the 50/50 cost share formula with the non-federal sponsor. The sponsor may contribute additional funds beyond this formula.

Funding

The following is a summary of the funds required for the Red River Basin LTFS PAS Project:

Total Study Cost Phases 1 and 2                      $650,000
Total Study Cost Addendum 1                          $382,250
Total Federal Funds Allocated to Date            $150,000