Helmut Schmidt, Published May 14 2010
Long-term flood protection: Higher risk for higher water
But a corps study has also determined that 100-year and 500-year floods are much bigger than once thought for the F-M area.
That means the current local flood protection choice – a $1.3 billion North Dakota 35,000-cfs diversion – won’t protect the area to a 500-year level.
In fact, rather than bringing 500-year floods down to a manageable 36 feet, the best either the Minnesota or North Dakota channels can do is a 40-foot flood stage, corps’ project co-manager Aaron Snyder said.
Corps’ studies have determined that a 100-year flood hits 42.6 feet in Fargo, and a 500-year flood is at a 46.7-foot flood stage. The highest recorded in Fargo was 40.84 feet in 2009.
In a day mixing good news with bad, members of the Metro Flood Study Work Group were told that the Minnesota diversion is the new National Economic Development plan. Studies show it provides
$90 million in net benefits annually, and it could garner $170 million more in federal funding.
However, Snyder told the work group they must quickly decide whether to accept less protection or to opt for a bigger diversion.
Without quick decisions, Snyder said the project could miss important deadlines and not be considered by Congress this year.
The corps is also in a time crunch. It must study Minnesota 40,000-cfs and 45,000-cfs diversions to be sure those channels aren’t the true NED plan. Those studies will take a couple of weeks to complete, Snyder said.
The NED plan nearly doubled in size after a new analysis found annual damages from flooding jumped from $77 million to $177 million, Snyder said.
That pushed the Minnesota diversion’s benefit-to-cost ratio to 2.37 and makes it a good candidate to make it into the president’s budget, Snyder said.
In a related issue, the corps found that the route of the North Dakota diversion has poor soils for construction. That will mean at least $100 million in added construction costs, Snyder said.
Work Group Co-chairman Kevin Campbell said the bigger NED plan is good news, in that $170 million more in federal money could go toward a North Dakota diversion.
Even with another $100 million in work needed in North Dakota, Campbell said the federal funding boost gives local taxpayers a $70 million break over what they would have paid before.
In other business:
- The work group voted to have local governments provide another $770,000 to pay for needed studies because federal cost share funds have not been freed up.
- Officials must still determine who will be the North Dakota sponsor for the project – Fargo or Cass County.
The corps would like one government sponsor from each side of the Red to be chosen by July 15.
County Commission Chairman Darrell Vanyo asked the work group if it was possible to speed the creation of a joint powers agreement so decisions could be made by a group representing all of the parties at the table.
- A revised analysis of the downstream effects of the diversions should be ready by June, Snyder estimated.
- Snyder also said it may be possible to move the diversion farther west of the Sheyenne Diversion during the design phase of the project. Both West Fargo and Horace officials have said they want the North Dakota channel to run farther to the west.
- The work group’s next meeting is 3:30 p.m. May 26.
Readers can reach Forum reporter Helmut Schmidt at (701) 241-5583