4/25/2013 3:46:00 PM $7.2 million Byllesby Dam project to begin in May
by Ken Haggerty
A $7.2 million construction project that will build a new spillway for the Byllesby Dam on the Cannon River between Cannon Falls and Randolph is set to begin in May. The project will also take out an earthen "fuse plug" dam.
The project is scheduled to be completed in August of 2014. No lake level impact will be seen during construction, as the new spillway will be built below the existing dam. The new spillway will not change how the lake level is managed daily and seasonally, but it will allow the dam to better manage flow and pass more water during high water situations.
Josh Peterson, Dakota County Senior Water Resources Engineer, briefed the Cannon Falls city council on the project April 16. Peterson said the new spillway will feature two steel crest gates that are each 65 feet wide and 14 feet tall. The gates weigh about 40 tons a piece. They are hydraulically operated to allow varying flows, with the four hydraulic cylinders each weighing 3 tons.
There are two contractors. Steel-Fab, Fitchburg, MA, will assemble and truck the gates in by sections and then bolt and weld them on-site. Edward Kraemer and Sons, Plain, WI, will handle general site construction and installation.
The plan calls for the gates to be delivered in November 2013 and to be ready for wet testing in Spring of 2014,
The fuse plug dam is the earthen area to the far south of the concrete dam (Goodhue County side). It is designed to give way in the case of a huge flood, but new Federal regulations are calling for the elimination of such designs.
The Minnesota DNR, in a separate but somewhat coordinated project, is also planning on construction this year of a bicycle and pedestrian bridge below the existing dam that will span the high river gorge bluff to bluff. The DNR wants to link the Dakota County and Goodhue County Parks with the bridge and eventually have bike trails that will connect to Cannon Falls and to Northfield. Some land acquisition on the Goodhue County side for Trail use has begun.
The Byllesby Dam project has been in the works for seven years, since the Federal Energy Regulatory Commission upgraded standards on dams and dykes in the wake of the Hurricane Katrina disasters in New Orleans.
The project is being funded with $2.9 million from DNR money designated for dam safety projects and by past and future revenues from the lease of the dam to the third party hydraulic power operators. The lease was renegotiated recently, with Goodhue County bowing out of the dam operation. Goodhue and Dakota County were given the dam in 1969 by Northern States Power (now Xcel Energy). It was unused until 1977. It was upgraded and repaired and began operation again in 1985. The dam was built in 1911 by NSP and named after company President Henry Byllesby.