May 2017 – Phase One Rock Dam Modernization Construction Update
Construction divided into two phases to stabilize east bank and manage breach
The Big Pine Lake Association (BPLA) Board is pleased to report recent progress in addressing both the Pine River Fish Passage Project and current lake levels. Funding for the project is coming from a Conservation Partners Legacy Grant. The approach and implementation planned for the grant-funded project has changed, but the design is the same.
In a recent meeting between three BPLA Board members and SWCD’s Project Manager and Engineer, it was decided that a two-phased approach could address both short- and long-term needs of constituents and stakeholders.
Phase One will immediately focus on protecting the eroding east bank made worse by the breach. The area will be rip-rapped at a stable angle and height to stop erosion. The gap left between the existing dam will be closed using a temporary treatment until Phase Two construction begins. The proposed start date for Phase One construction is early June, but depends on many variables including contractor availability, weather, and pricing.
In Phase Two, a series of arch riffle structures, will be built with the precise placement of boulders and large rocks. The new structure will control water flow and reconnect aquatic communities to up and downstream habitat. A hydrological model of the reach between Big Pine Lake and the new structures will provide information needed to finalize Phase Two. Project cost estimates for Phase Two are well above Phase One and will require following the public bidding process per MN State Statute. This process can take up to three months.
The breach and on-going erosion of the east bank has impacted timing of the original fish passage project plan, but it must be dealt with as soon as possible. We are trying to minimize the impacts on the project schedule and cost by simultaneously building the required section of the new structure, stopping further east bank erosion, restoring lake water levels, and continuing progress on Phase Two design finalization and contractor bidding/selection. Inherent schedule risks and cost exposures remain, but the BPLA Board feels strongly that this is our best overall option, so we appreciate everyone’s patience, understanding, and on-going support.