City Council Meeting Date: March 1, 2022
To: Mayor and City Council
City Administrator
From: Cole Johnson, Water Quality Technician
Sean M. Simonson, Engineering Division Manager
David E. Bennett, Public Works Director/City Engineer
Subject:
TITLE
Consider Approving Plans and Specifications and Order Advertisement for Bids for Prairie Hills 1 and Hidden Valley Park Pond Dredging Project (STRM2022-K30).
BODY
Action Requested:
The City Council considers approval of the attached Resolution approving the plans and specifications and authorizing the advertisement for bids for the Prairie Hills 1 and Hidden Valley Park Pond Dredging Project (STRM2022-K30).
Summary Report:
In 2017, the City of Northfield performed a Stormwater Pond Assessment on 56 ponds within the City of Northfield. Out of this pond assessment project, eight ponds were isolated for further assessment due to the total sediment accumulation discovered during the pond assessment. These eight ponds were then ranked one to eight based on their percent full of sediment. Prairie Hills #1 and Hidden Valley Park Pond were ranked number three and number five respectively. The location of these ponds are show in Attachment 2.
The City began the dredging process of the first three ponds identified in the 2017 Assessment (Golf Course Pond, Parmeadow 1 and Parmeadow 3 ponds) in 2020 and concluded in 2021. The Prairie Hills #1 and Hidden Valley Park Pond is phase two of the dredging projects identified in the report and included in the adopted 2022-2026 Capital Improvement Program (CIP).
This pond dredging project includes dewatering, excavating, and disposing of the accumulated sediment in the ponds. All of the ponds had the sediment tested for hazardous substances or petroleum products, specifically carcinogenic and noncarcinogenic Polycyclic Aromatic Hydrocarbons (cPAH/PAH), copper, or arsenic which may have been disposed or released into the ponds. The Minnesota Pollution Control Agency (MPCA) requires sediment testing for the aforementioned contaminants so their guidance and practices were followed when completing the testing. The testing indicated that Prairie Hills #1 was Management Level 2 and Hidden Valley Park Pond was Management Level 3. Management Level 2 allows for fill and use on industrial sites and Management Level 3 requires the sediment to be disposed of at a Municipal Solid Waste landfill. Due to the small size of Prairie Hills #1 and difficulty to find an acceptable Industrial site, it was determined that sediment from both Ponds will be disposed of at a Municipal Solid Waste landfill.
In addition to the sediment removal, miscellaneous slope re-grading, storm pipe repair, and pond buffer restoration is proposed with the dredging project.
Unlike the Golf Course and Parmeadow Pond Dredging Project, no additional permitting will be required from the DNR since these ponds are not associated with a public waterbody.
With the current schedule for the project (Attachment 3), the bids are scheduled to be opened on March 31, 2022, and the contract is scheduled to be awarded at the April 19, 2022 City Council meeting.
Alternative Options:
The City Council could delay this project; however, staff would not recommend that option.
Financial Impacts:
Below are the estimated total project costs, and the estimated total project funding.
Tentative Timelines:
The bids will be received on March 31, 2022 and awarded April 19, 2022. Construction is scheduled to be completed during the fall/winter of 2022/2023, with final completion in the spring of 2023.