Redridge Dam

The Keweenaw needed a constant and dependable source of water to quench this industrial thirst. In order to meet that need, dozens of dams were built all over the copper country, blocking up streams and creeks along the way. Most of these were small endeavors, made from earth, timbers, or masonry. There was however a few dams that were a bit more ambitious. In the copper country two of these immense structures remain – Victoria and Redridge.

After reading the marker, we take a trail that moved further into the woods. As we followed it we hoped that it would bring us to the dam. Instead, it brought us to another trail, this one apparently an old rail grade. Knowing a rail line once topped the dam, we followed it instead. Our assumptions were proved correct as we soon found ourselves face to face with a makeshift fence, built out of barbed wire and old rails. Ahead of us an old railroad trestle spanned the ravine.

Steel dams were an experiment in dam construction that had a very short life in the United States. Steel dams work under the premise that steel construction offers substantial savings in material and labor costs compared to concrete or masonry construction. The Redridge dam was relatively cheap to build, costing only $150,000. The dam also took very little time to build, construction lasting only a year. A standard type dam on this river would have cost more to build and taken much longer to complete.

As we quickly dropped down into the river gorge the roar of the river ( and the rumble under our feet ) became more pronounced. The light of the day disappeared as we arrived at the bottom, and as we walked forwards we could see why. The trees parted in front of us and we were assaulted by a rising wall of steel. We peered up towards it’s apex, some thirty feet above our head. Its oppressive bulk managed to block out most of the sun from above, leaving a dark and mysterious labyrinth of steel in its shadow – which we hastily entered.

There are actually two dams built on the Salmon Trout River. When there was but one stamp mill on the red-ridged shores of Lake Superior, a smaller and less technically advanced structure was used to dam the river. When the newer dam was built years later, the old dam was submerged under the waters of the newly formed reservoir, and subsequently forgotten. It wasn’t until a good forty years later when Copper Range compromised the steel dam by cutting holes in its superstructure that the original dam was once again revealed.

There are in actuality two dams on the Salmon Trout River. The first and older dam was built before the turn of the century, and was a classical style of dam construction used heavily up to the time. The second dam – the steel one currently in place – was built after the turn of the century and showcased a new and emergent technology.

The Redridge Steel Dam was built not to supply power, but to supply water. The Atlantic and Baltic stamp mills that relied on the dam required over 25 million gallons of water each day to operate. The reservoir created by the dam held over 600 million gallons of water, enough water to feed the two mills for a month. Getting that water to the mills, some 2000 feet downstream, required the use of a combination of wooden launders and a steel pipeline – two things we were looking for on our most recent exploration.

The dangers that a spring thaw once meant for the Redridge dam included the possibility of a dangerous over-topping. The water level in the reservoir would get so high as to flow over the top of the superstructure itself, spilling down onto the dam’s foundation and threatening to wash away the entire structure. When this same scenario happened in the 60’s, the owners of the dam cut large holes into it in order to keep this from happening again. In the process however, they managed to make the situation just as bad.

Flood waters pose a serious threat to most dams steel or otherwise. Dams are built with a specific load limit and water height in mind, and once that is exceeded the dams fate becomes perilous. The other steel dams of its time were designed so that those flood waters would simply flow off the top of the dam (over-topping), but Redridge was different. The builders added a separate weir and spillway some distance up stream from the main dam. A weir is a small dam designed to allow water to to flow over it’s top.

By 1900 the wood crib dam that had been built on the Salmon Trout River to supply water to the nearby Atlantic Mill had proved inadequate in performing the same function to both it and the new Baltic Mill. A new larger dam was needed – and fast. This time constraint together with a lack of conventional materials nearby, the decision was made to try a different approach. The Wisconsin Bridge and Iron Company would build a new steel dam at Redridge – under the direction of engineer J.F. Jackson.