June 15—ROCHESTER — The next steps in the plan to dredge Silver Lake and replace the existing dam will be presented Monday.
With plans nearly one-third complete, Rochester City Council will be asked to sign a nearly $800,000 contract with WHKS and Co. to complete the final designs and manage the project until 2025.
Councilors will also be asked at their regular meeting Monday at 6 p.m. in the council chambers of the city government center to authorize staff to request construction bids for the project once the design is complete.
“Ultimately the city would have to accept the bids, but we would like to be allowed to submit bids once we have the final design to see where the final project costs will be,” said Aaron Luckstein, Rochester’s deputy director of Public Works. during a recent council study session.
During the discussion earlier this week, councilors at various levels expressed their support and opposition to the proposed dam changes.
Councilor Shaun Palmer raised questions about the cost and need for the changes, while Councilor Patrick Keane said he is prepared to support the project after years of discussion.
The dredging portion of the project is underway under a 2016 WHKS contract, with the possibility of changing the dam location in 2019. From there, a concept was developed to take advantage of plans to lower the lake level for dredging.
Although the lake will need to be lowered to allow for dredging next year, Rochester project development manager Matt Crawford said the water level change won’t be permanent even if the dam replacement is approved.
“There will be no change in assessments,” he said of the long-term effects of the proposed dam change. “It will suit the current circumstances.”
The concept calls for creating a new dam structure approximately 700 feet east of the existing dam, keeping the remaining lake at its current level.
“We’re trying to preserve 85%, or at least 85%, of the lake,” Luckstein said, acknowledging the community’s concerns about the lake’s future.
The new dam structure will allow year-round upstream passage of fish, with the opportunity for recreational pools for kayaking if enough water flows through the system.
“As the water rises, it starts to flow through the wave pools,” Rochester project development manager Matt Crawford told the council. “As we have more water, the wave pools are more active.”
With more design work to be done, Luckstein says the city needs to be able to show the Minnesota Department of Natural Resources and the U.S. Army Corps of Engineers that the new dam structure will not send more water downstream than is already flowing in that direction.
Although the dam is not considered part of the water retention portion of the city’s flood control system, it works in conjunction with the dredged channel through Silver Lake to help move potential floodwaters through the city.
Crawford said water is held in reservoirs around the city, and the river and lake channel water to reduce flooding in the city and downstream, but the dam’s only function is to create a recreational lake.
He said the proposed work is intended to enhance the recreational function, while also providing the opportunity for additional dredging work to extend the benefits.
The original proposal, with an estimate of $5.5 million for dam replacement and at least $4 million for necessary dredging work, also includes preparation for a possible trail extension on the north side of Silver Lake, which would allow passage bidding under the North Broadway Avenue bridge.
Luckstein said currently available funds will not be enough to complete the trail, or a proposed pedestrian bridge and south trail, but additional funding sources are being studied.
Completion of the north trails is estimated to cost another $500,000, with $1 million needed for a south trail under the Broadway Bridge and nearly $2.2 million for the proposed pedestrian bridge.
If the council approves the efforts to move forward, city staff will also seek permission to negotiate details related to accepting a nearly $2.4 million state grant for the dam project, which would require future council approval necessary for acceptance.
An additional $2 million is expected to be requested through Rochester Public Utilities, which would achieve a similar cost savings by avoiding a nearly $1.2 million major overhaul of the gates at the top of the current dam, as well as future maintenance costs .
“If the council doesn’t take action, I think this is the direction for the RPU to spend the $1.2 million to overhaul the wing gates, which essentially means leaving the dam in place,” Luckstein said.
If the replacement is approved, about $1.1 million in additional city funds will be needed, and Luckstein said Public Works staff will present proposed options Monday.
“We are evaluating financing options,” he said.
While the city cannot use money from the recent sales tax expansion for the dam project, it does have flood control reserves from the 1989 sales tax approval and stormwater funds that can be used with council approval.
Luckstein said many details will remain in the works as design efforts continue, with plans to collaborate with lake neighbors and hold additional public input sessions as plans are nearly one-third complete.
