2015 Dam Maintenance
Four BPLA Officers met with Crow Wing County (CWC) Engineer, Tim Bray, and Assistant County Engineer, Rob Hall, on June 11th to discuss the current maintenance needs and future replacement plans for the rock dam at Big Pine Lake (BPL). It was a productive meeting in which agreements were reached on moving forward in both areas. Unbeknownst to CWC, the Minnesota Department of Natural Resources (DNR), and most of our lake residents prior to last summer, the rock dam has not been restored/maintained to the originally permitted elevations for many years. This condition has resulted in unacceptably low water conditions for some lake residents for much of each summer. In addition, the natural process of erosion and the on-going pilfering of rocks from the west end of the dam have resulted in sections of the dam being over one foot lower than the DNR specified elevations. We are confident that CWC now has sufficient maintenance funds available in our BPL SSD (Subordinate Service District) account (over $31,000) to proceed with a rock dam maintenance project.
Rob Hall recently developed and issued an RFP (Request for Proposals) for the purpose of restoring the top of dam elevation and spillway configuration to the original DNR permit elevations approved for the initial construction of the rock dam in 1970. Five contractor responses to CWC’s RFP were received and evaluated. In addition to cost, each bidder’s ability to complete the project quickly (assuming low water conditions continue to allow the construction) were also a selection factor. CWC and BPLA’s mutual goal is to get the project completed quickly in order to restore usable lake elevations for the future, including the rest of this fall. Holmvig Excavation was deemed the lowest bidder and is ready to mobilize for construction shortly after a Notice to Proceed (NTP) is received by CWC, who is currently awaiting a signed maintenance permit from the DNR.
Recent inspections of our rock dam have confirmed the need for both remedial and preventative maintenance actions. Although there have been no high-water events since last summer to cause major damage to the structure, repair of previous erosion to the spillway and west end of the dam is needed. In addition, material fill may be required to reduce leakage through several channels undercutting the eastern half of the structure. Both of these actions will reduce our exposure to very low lake levels without increasing high water level exposure. Lake levels must be low with minimal flow over the dam for these repairs to be made. Up to $20,000 is currently available in the BPL SSD Dam Maintenance account to pay for necessary repairs although a specific cost estimate has not yet been determined.