Members of the Minot City Council were left to digest the discouraging news about the minimal cost savings in a scaled-back flood control plan after a meeting with a design engineer Tuesday.
The council's Finance and Improvements Committee heard from Ryan Ackerman with Ackerman-Estvold Engineering and Management Consulting, who will be delivering the same message to the Public Works and Safety Committee today. The message is that scaling back flood protection from 27,400 cubic feet of river flow per second to just 10,000 cfs would save about $30.7 million, or less than 6 percent of the $543 million estimated cost of a proposed control plan.
The reason for the small difference, Ackerman explained, is that the city council desires to keep the same project footprint. Keeping the same footprint will enable the project to eventually be built to 27,400 cfs, the 2011 flood of record. That means foundations of nine miles of levees and 2.2 miles of flood walls must be built to the 27,400 cfs standard to accommodate the future construction. The $87 million in land acquisition and easement costs would not change, either.
"Are you shocked like I am that there's such a minuscule difference in the cost between 27,000 (cfs) or 10,000 (cfs)?" council member Dean Frantsvog asked Ackerman.
"Based on the assumptions that were made, no, I am not surprised. I am not shocked," Ackerman responded. "Just looking at where the costs of the project lie and that really only about 25 percent of the overall project cost is in the levees and flood walls that you are scaling down I am not surprised by that, especially when we are going to design foundations for the bigger event."
Ackerman shared information regarding the flood-protection planning in Grand Forks after the 1997 flood. Projections at that time showed scaling back protection from a 210-year event to a 50-event only cut costs from $256 million to $213 million. Grand Forks built for a 250-year event.
The design change from 27,000 cfs to 10,000 cfs is a 65 percent reduction in flood protection for Minot.
"We would give up 65 percent of public safety for a cost savings of 6 percent," council member Bob Miller said, questioning the wisdom of that action.
Ackerman clarified that that the permanent protection would decline 65 percent, but the city would retain the ability to add to the levees in emergencies.
Ackerman said he will present the council with a plan for the sequential construction of the project in about three weeks. Ackerman-Estvold Engineering is a subcontractor to the primary engineering firm, Barr Engineering.
The finance committee also voted to recommend the council spend an estimated $98,750 to cover continuing work on the flood protection plan, including technical support, financial modeling and phasing of the project.
The State Water Commission agreed to 100 percent of the initial cost but only 50 percent of costs being incurred with the additional work desired by the city. The other 50 percent would come from Minot through the Souris River Joint Board, which is the entity working with the water commission.
Minot's share would come from a sales tax infrastructure fund created when voters approved the tax in June 2011.