City Council Meeting Date: November 19, 2024
To: Mayor and City Council
City Administrator
From: Justin Wagner, Utilities Manager
David Bennett, P.E., Public Works Director/City Engineer
Title
Presentation on Infrastructure Planning for Northwest Industrial Development Area for Water and Sewer.
Body
Action Requested:
The Northfield City Council is to receive a presentation on infrastructure planning for the northwest industrial development area for water and sewer.
Summary Report:
The City has been planning for growth in the Northwest Area since the mid-2000 with the Comprehensive Sewer and Water Plan. With more recent and planned growth in the area, staff along with Bolton and Menk, Inc. conducted a study on how to serve the northwest industrial development area with water and sewer. Currently, water and sewer infrastructure end at the entrance to the hospital on North Avenue. The study looked at how water and sewer infrastructure could be brought to the northwest industrial area based on different development and demand needs.
The sewer review included flow monitoring of existing infrastructure to determine capacity of the system. Quality flow monitoring data was received based on high rainfall in June 2024 while the flow monitoring equipment was in place. The current sewer capacity is around 1,300 gallons per minute. From there, costs for improving the existing infrastructure were estimated as well as costs for running a new trunk sewer line to serve the area to obtain larger sewer capacities based on different development options included in the City’s Comprehensive Plan and AUAR. The improvements cost ranges from ~$20,000,000 to ~$30,000,000 depending on the route and how much capacity the development would need.
The water study looked at different flow needs to the Northwest Area and how the City could meet those needs. Currently, the existing booster station has the capacity to support an additional 500 gallons per minute. Three different alternatives were looked at to achieve a capacity of 700-5,700 gallons per minute. The higher end of the water use is typically driven by the fire flow demand. The alternatives were upsizing the existing pumps at the booster station, construction of a new 1,000,000-gallon water tower, and construction of a new booster station with water main near the St. Olaf campus entrance on TH19. The improvements cost ranged from $600,000 to $14,000,000 depending on the water demand.
Financial Impacts:
Summary in presentation
Tentative Timelines:
Currently, the water tower is scheduled in the Capital Improvement Plan for 2026, however, that date is planned to continue to move back until development drives the need for the water tower. Additionally, the TH19 watermain is scheduled in 2027 to coincide with the TH19 road project. None of the sewer improvements are programed in the Capital Improvement Plan.