Options Defined for Diversion Project Improvements
Members of the Flood Diversion Authority are considering a list of options for changes to the Fargo-Moorhead Area Diversion Project that would save several million dollars in project costs, reduce upstream impacts and reduce risk of summer time project operation. The technical options are a result of value engineering and other studies as part of the U.S. Army Corps of Engineers design process. The Diversion Authority also led other studies to evaluate its potential to benefit the project.
The option studies that were led by the Corps are:
1. Value Engineering #13: Option A (Cost savings compared to Federally Recommended Plan: $53 million)
The option studies that were led by the Diversion Authority are:
1. North of the Wild Rice/Red River Confluence (Cost savings compared to Federally Recommended Plan: $6 million)
A map illustration of the options is available here.
A thorough technical evaluation of the options was conducted by the Corps of Engineers, local consultants, technical staff, and the program management consultant. These options, detailed to the Authority and in two public meetings on Sept. 13, come after several potential alignment adjustments were developed and reviewed.
The technical evaluation included ranking the options against seven factors, including: technical risks (length and height of embankment, number of structures requiring human intervention, etc.), the ability to implement the project, the number of structures, environmental impacts, number of acres impacted, floodplain impacts, and transportation impacts.
All of the alignment options include maintaining the 200,000 acre-feet of upstream retention to mitigate downstream impacts, as determined to be required during the feasibility study.
The Top-Ranking Option: VE13-A
The southern alignment refinement option for the diversion channel upstream of the Sheyenne River, which ranked highest by the Corps and the other members of the evaluation team, is titled “Value Engineering #13: Option A”. VE13-A includes an improved southern alignment, increasing Red River flows through Fargo-Moorhead during times of severe flooding, and a gated inlet structure.
VE13-A offers numerous advantages over the former Federally Recommended Plan. These advantages include:
1. The elimination of the Wolverton Creek Hydraulic Structure and Storage Area 1, which reduces the cost to the project;
VE13-A has the lowest risk, the lowest cost, and is expected to be the most acceptable under the federal review process for the project.
VE13-A, along with increased flows through town and the gated inlet control structure, results in an estimated cost savings of $53 million. However, the new southern alignment will impact approximately 35 new residential structures. Specific property impacts will be defined in the coming months and shared with property owners. Also, the communities of Oxbow, Hickson and Bakke remain a buyout under this option.
Increased River Flows through Fargo-Moorhead
It was concluded early in the analysis that allowing more flow through the cities than originally determined in the Corps feasibility study would cause the proposed diversion project to operate less frequently, reduce how long the water is staged, improve fish passage mitigation requirements, and reduce the risks to crops.
Allowing a flow up to a stage of 35 feet through town will reduce the frequency of operating the diversion project and staging area from once every three or four years to once every 10 years. In addition, allowing a stage of 35 feet through town will greatly reduce the chances of summer floods requiring project operation, which will greatly reduce the risk of staging water on growing crops upstream.
In recognition that every flood event is different, it was concluded that a gated control structure on the inlet to the diversion channel will improve the operational flexibility of the project and enable reducing upstream impacts during flood events.
The other options studied would also operate in concert with increased river flows through Fargo-Moorhead but did not rank as high in the technical evaluation for several reasons. Option VE13-C, located to the north of VE13-A and ranked by the research team at #2 in the list of options, offers many similar advantages to VE13-A. However, it would impact 87 new structures, compared to 35 additional structures under VE13-A.
The North of Wild Rice Confluence alignment was ranked by the research team at #3 in the list of options. It would impact 251 new residential structures, would not eliminate impacts to the Oxbow area and would increase overall project risk. The Oxbow area would see a reduction in staged water depth under this alignment option but would have still require ring levees around the urban area and relocation of nearly half of the structures in Oxbow.
The current Federally Recommended plan was ranked by the research team at #4.
The South of Oxbow alignment option was ranked at #5 and is the most expensive of the four options. The research team found the option is not implementable because of restrictive permitting requirements and various hydraulic and physical issues. Also, under this option, the impacts to Richland and Wilkin counties were much more significant. The analysis verified the findings contained within the Corps Environmental Impact Statement.
The Diversion Authority is scheduled to vote on which technical option to recommend at its Oct. 11, 2012, meeting. In the meantime, the Diversion Authority will collect public comment on the options.
Anyone who wishes to comment on the technical options may do so by talking with their elected officials, or leaving a comment here.
Also, according to the Corps of Engineers, a decision on the proposed changes is not final until the required National Environmental Policy Act, or NEPA, process is completed. The NEPA process includes a public comment period, and will begin in November.
The presentations given at the September 13 public meetings regarding the alignment options and other support materials are available in the Technical Documents section. Maps from the presentations are available in the Maps section. In addition, videos from the Sept. 13 7:00pm public meeting, outlining the options, are posted in the Video Library.
The northern and southern alignments are very close to being finalized. The exact location of the western alignment of the diversion between the Maple and Sheyenne rivers is yet to be determined.
Assuming the project is authorized and funded by Congress and a Project Partnership Agreement is executed, construction could begin no sooner than the summer of 2013. Under ideal conditions, the project would be operable in spring 2021, although benefits would be enjoyed by the partial project much earlier. An 8.5 year construction period has been estimated based on a $240 million per year funding stream, which is subject to change based on congressional decision making.