City Council Meeting Date: May 16, 2023
To: Mayor and City Council
City Administrator
From: David Bennett, Public Works Director/City Engineer
Title
Discuss Downtown Flood Study Phase 2 - FEMA Benefit Cost Analysis.
Body
Action Requested:
The Northfield City Council Discusses Downtown Flood Study Phase 2 - FEMA Benefit Cost Analysis.
Summary Report:
The City, over the last 10 years, has had numerous flooding events of the Cannon River causing damages to properties and public infrastructure. Due to this, City Council approved an Advanced Assistance Grant with the State of MN Homeland and Emergency Management. Barr Engineering is performing the study for the City.
There are three phases to the project study, only Phase 1 study was completed and accepted by Council on May 3, 2022. Tonight, we will be reviewing the proposed flood mitigation projects, benefit cost analysis, and climate change modeling. On May 3, 2022 Council directed that the flood mitigation project below get moved to Phase 2.
Area 1 - West side North of 4th Street Bridge (301 Water St., 207 Water St., 205 Water St.)
• Recommendation is to move the Alt 1-2 Floodwall Extension to Phase 2
Area 2 - East side North of 4th Street Bridge (11 Bridge Square, 13 Bridge Square)
• Recommendation is to move the Alt 2-2 Dry Floodproofing to Phase 2
Area 3 - South of Fifth St. - East side (500 Water St., 516 Water St., 630 Water St.,)
• Recommendation is to move the Alt 3-2 Dry Floodproofing to Phase 2
The City was able secure additional funding from the state for the Phase 2 study along with studying the Carleton Stadium, West Gym, and practice fields that flood.
The timeline/phases of the Downtown Flood Study are below:
Phase 1 - Completed - Study and Identify Downtown Flood Improvement Options and identify costs for the improvements.
Phase 2 - Underway, FEMA Benefit Cost Analysis, climate change modeling, and include Carleton Properties.
Phase 2A - Pursue Funding - Explore grants and hazard mitigation funding.
Phase 3 - Design Permitting/Construction.
On April 26, 2023, Barr Engineering presented that draft recommendation in the Phase 2 study to property owners. Not all property owners were present but the following input was received.
Area 1 - West side North of 4th Street Bridge (301 Water St., 207 Water St., 205 Water St.)
The property owners were generally supportive of the West Floodwall.
Area 2 - East side North of 4th Street Bridge (11 Bridge Square, 13 Bridge Square)
Not in attendance of the meeting, staff is following up with them.
Area 3 - South of Fifth St. - East side (500 Water St., 516 Water St., 630 Water St.,)
Not in attendance, the benefit cost ratio and potential flood impacts doesn’t support moving Dry Floodproofing forward.
Carleton - Stadium floodwall, West Gym Closure, Practice Field Berms
Carleton projects benefit cost ratio don’t strongly support the other area recommendation but also don’t really hurt the other projects benefit cost ratio if a joint project was completed. Understanding this Carleton is open to moving to the next phase once more details related to the funding, property restrictions are known.
Alternative Options:
NA
Financial Impacts:
$4.1 - $7.2 Million
Tentative Timelines:
ü Sharing of Draft Report March 15 - April 15, 2022
ü City Council Considers Phase 1 Report and Authorized Phase 2 May 3, 2022
• Phase 2 Study Discussion with Council May 16, 2023
• Council Accepts Phase 2 study and moves to Phase 2A