WORTHINGTON — Construction workers were busily welding pieces together and making progress on renovations to the Lake Ocheda outlet dam this week south of Worthington.
Land Pride Construction of Paynesville began work on the project Nov. 19, building coffer dams north and south of the dam, which was originally constructed in 1941. A diversion channel was dug around the east side of the dam to redirect water from the lake into the stream that flows to Peterson Slough.
With colder temperatures in the forecast, the plan is to pour concrete on the north side of the dam to support new steel I-beams next week. The beams will support a new overhead catwalk, stop log bays and a fish barrier. Colder weather is needed to freeze the ground hard enough to bring in the cement trucks.
Les Morgenstern, construction manager for Ducks Unlimited, which is overseeing the project, said if the concrete work is done next week, he anticipates the project will be 90% to 95% complete by next Friday.
The Okabena-Ocheda Watershed District began removing stop logs from the dam in August to begin a lake drawdown. Administrator Dan Livdahl said the lake dropped to its lowest level of the season in late September, but had risen again due to precipitation since then.
“It has raised a couple of tenths since we started construction,” said Morgenstern, noting that neither water levels nor wintry weather has impeded workers as they retrofit the outlet dam.
The retrofits are necessary to achieve water quality goals for Lake Ocheda. The maneuverability of the new stop logs will allow the watershed district to more easily conduct lake drawdowns in the future, and the fish barrier will work to keep roughfish from reentering the lake after they’ve traveled downstream to spawn in Peterson Slough.
Lake Ocheda’s high levels of roughfish have degraded water quality, and it's hoped that conducting a wintertime drawdown will freeze out the fish population. Once carp numbers have been reduced to a reasonable level, the Minnesota Department of Natural Resources will restock the lake with gamefish and panfish known to feed on carp eggs to keep roughfish levels controlled.
“The fish barrier is a management tool,” Morgenstern said. “That’s a real bonus here for the watershed district and the DNR — to manage water levels and manage some of the roughfish coming back upstream into Lake Ocheda.”
While the fish barriers will be installed yet this fall, the stop logs won’t be put into place until early next spring. The hope is that the natural drawdown continues, but Livdahl told Okabena-Ocheda Watershed District managers at their Tuesday meeting that “extraordinarily cold conditions” will be needed to get a fish kill this winter.
Livdahl's update on the Lake Ocheda project was one of several items discussed during the meeting.
In other business, the board:
Approved a 3% salary increase for Livdahl, bringing his annual compensation to $60,760 in 2020.
Adopted the Missouri River Watershed comprehensive watershed management plan and authorized signing the Joint Powers Agreement for its implementation. Once all 14 entities (six counties and their Soil and Water Conservation District boards, plus two watersheds) adopt the plan and sign the joint powers, the group will receive $1.32 million to fund conservation practices for the next two years.
Delayed action on the 2020 budget until January. With work ongoing on the Lake Ocheda dam project, payments that need to be made on the Prairie View project and outstanding revenues including the last 10% of the state grant for the Prairie View project — as well as the FEMA reimbursement for damages there and at the Lake Bella spillway — Livdahl was uncertain if those expenses and revenues would be part of the 2019 budget or 2020.