The Spillway
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. At Redridge this wood and steel structure was used to control the level of the reservoir, allowing excess flood waters to flow over the top and continue down a man-made spillway past the dam and into the river.
Since the dam was compromised, the lake level lowered and this spillway was no longer used. The lake now sits an eternity away, and the remains of the weir sit silently in the woods - slowly being overrun by trees and brush. The site is so overgrown that during our previous trip to the dam during the summer we couldn’t find any sign of it. Now in the nakedness of spring, the metal frames and concrete walls are easily discovered.
This photo was taken from the perspective of the reservoir. Once the lake level would of been above my head a good foot here, lapping up against the top of the concrete wall across the way. The weir consisted of a series of panels that were supported by these metal frames, forming a wall. When water got to a certain height (most likely to the top of the previously mentioned walls) the excess would flow over the top of the wall and down into the spillway. The “floor” of the spillway’s artificial channel can be seen below the metal frames, just above the puddle.
There are five metal frames placed about 6 feet apart across the spillway’s entrance. Each is identical, standing a good ten feet and capped with a wooden post on the downstream side. The upstream side (to the left in the photo) is braced by a triangle piece of metal. The whole thing is bolted down into the concrete floor of the spillway, which now is buried by about an inch of dirt and debris.
These frames supported a line of wooden panels which stretched across the channel entrance. I don’t believe they were designed to move or be lifted, although they probably could of been. Photos of the weir in operation always show water flowing over it’s top, so the panels most likely were permanently held in place.
A close up detail of where the panels were attached to the metal supports. A metal channel runs halfway up the frames, about two inches in thickness. The wood panels were probably held in place here. If thats true, it means that the boards only ran half way up the spillway. This might be the actually “top” of the weir.
Its hard to see but this metal band is attached to a large piece of wood (the moss covered thing in the foreground). This might of been a piece of one of the panels. It sat on the ground next to one of the metal supports.
Here the artificial channel was strengthened by concrete walls on each end. These walls extend a good 20-30 feet back down the spillway. From that point on the channel is formed by earthen banks, until is comes to a railroad trestle further downstream. The channel is 50 feet wide at this point, and tapers down to 30 feet at the start of the wooden launder. The entire length of the channel from here to the launder is 250 feet.
An interesting design detail along the channel walls. Here at the front of the wall (where the channel meats the lake) the wall has been gracefully rounded over. Most likely this was to cut down on turbulence or backwash from the weir. Either way its a nice touch.
A total of three bridges crossed the spillway. The first was a wooden timber bridge for trains running over the dam. All that remains of that bridge are the concrete footings in the channel itself. A third bridge allowed cars to cross the channel on the way to Freda. A second bridge - shown here - allowed trains to head down to the Baltic Mill on the lake. This trestle is made of a steel truss, covered by wooden ties.
Looking down from the trestle down into the spillway and the channel walls. This is the end of the spillway as it exists today. Just a few yards from here the road commission filled in the channel to build a new road to Feda, and further down the original wooden launder was destroyed by a flood and never replaced. Now only a narrow gorge remains.
This spillway - or “waste weir” as it was called - was completely destroyed in a disastrous spring thaw near Easter in 1941. Debris had blocked the weir dam and had forced the flood waters to overtop the steel dam for hours. While the steel dam managed to survive, the clog eventually gave way and succeeded in destroying the weir, spillway, and launder.
What’s unclear is whether the weir and spillway were ever rebuilt or put into use again. There is some evidence that the weir and spillway were abandoned long before the holes were cut in the steel dam. The road which now blocks the spillway was built in 1980, one year after the holes were cut in the dam. Without the road, the waste weir should still have been usable and would keep the dam from over-topping a second time (which Copper Range feared). Yet they cut the holes anyway, as if there was no other way for flood water to exit the reservoir. My guess is that the waste weir was never rebuilt after the disastrous Easter flood. Of course someone that grew up around the dam might know the real story. (hint, hint)
explorer | March 29, 2007
I have some information on the Redridge dam. The information is from the August 15 1901 issue of Engineering News.
The main dam support is made up of 8,000 cubic yards of cement. The abutments and “core wall” contains 2,000 cubic yards of cement. The cement test weighted approximately 165 pounds per cubic foot. Using the weight of the cement and converting cubic yards to cubic feet and multiplying the result, 270,000 cubic feet, times 165 lbs comes out to approximately 44,550,000 pounds of concrete in the structure of the dam. The concrete was made using Atlas Portland cement, stamp sand and broken trap rock. The concrete was mixed at the dam using small platform on which the dry ingredients were measured out. The mixer was made using an inclined trough that had blades and pins. The materials were shoveled into the trough without any manual mixing. As the dry material went down the trough water was introduced into the trough. At the bottom the mixed concrete was loaded into wheelbarrows and dump where needed.
There was a concrete “head wall” whose sill was six feet below the crest of the dam. On top of the headwall are “steel standards” carrying “flashboards” which were used to keep the reservoir full. If there was a danger of flooding these could be used to prevent topping of the dam.
The flume discharged into the Salmon Trout river about 750 feet northwest measured from the face of the dam. The flume was built in layers so that the layer directly to the water could be repaired or replaced without disturbing the water proof construction of the flume.
Dave Freeze | March 30, 2007
Dave - Once again great information. One thing that made the Redridge dam unique (even among other steel dams) was the size of the concrete base. J.F. Jackson, the engineer in charge of the project, knew that the brittle sandstone below the dam could not support the structure adequately. He decided on a large foundation to carry most of the load of the dam and water - and not so much the steel truss-work.
This decision cost him in the short term, diminishing some of the cost advantage of the steel design. (the base itself cost $90,000 of the $150,000 price tag) But his decision also allowed him to increase the angle of the steel structure to the reservoir, raising it from a typical 45 degrees to a more steep 55 degrees. This saved him money in reducing the amount of steel plating required.
Stay tuned because next week I got a multi-part series taking a much closer look at the design of the dam as well as its construction.
explorer | March 31, 2007
I should have known that Explorer had already found and visited the “waste water” spillway at Redridge steel dam. By now where ain’t he been? I had my little tent pitched on the RR grade next to the bridge where he took the photo. It was a nice protected spot; just the kind I always look for.
I ran across something else about J.F. Jackson, the engineer for Wis. Bridge and Iron Works that built Redridge dam. Remember I mentioned that Bill Harley worked at the Bridge and Iron Works around 1908? Get this, Jackson and other guys from the firm later started up their own motorcycle company in Milwaukee c1912-1914. It was called the Feilbach Motor Co. and Jackson was vice-president, and I’ll bet the other officers were guys from the Bridge and Iron Works. It was a big heavy V-twin motorcycle called the “Feilbach Limited” and it had shaft-drive in 1914. Very advanced! Just a footnote, perhaps, but it shows that Jackson was a live wire, and it would be a nice detail to include in any future writeup of the steel dam.
Herb from Wis.
Herb | June 30, 2008
Sorry Herb, I didn’t mean to steel your thunder. Since you had mentioned the spillway I thought I’d show other people what you were talking about. (and no, I haven’t been everwhere. Just about though). About J.F. Jackson, thats interesting. It reminds me of how I always read about these people back in the day who accomplished great things, they seem to have done a little bit of everything. First they build bridges then move on to making motorcycles. Just like Agassiz from Calumet, the man ran a successful enterprise, was a worthy engineer, and became a naturalist in his later years. Now-a-days everyone seems to just specialize in one thing and that their entire legacy. Back in the day people did lots of stuff and gain notoriety for all of it. Reading about these people make my life seem very dull and uninspired. I guess they don’t raise them like they use to.
explorer | June 30, 2008
The other day, I was trying to identify specific Copper Country sites which I’ve seen, but not Mike. Other than something like “the inside of my house,” I’m not sure there are any!
I’ve considered challenging Mike to identify different locations based on photos I’ve taken. Sounds like it might be a fun game.
dcclark | June 30, 2008
Perhaps a stump the explorer feature is in order?
Just for the record I haven’t been everywhere. I can think of at least a half-dozen places that I have yet to get to. But after that I draw a blank. Over the last few years I’ve spend probably a dozen hours a week just walking and driving all about the peninsula and have seen alot, probably more then I should. A lot of locals, who’ve lived here all their lives, haven’t heard of half the place’s I’ve been too. (but of course mine ruins are an acquired taste) But the great thing about the Keweenaw is that there’s always more to discover, even for me.
And dcclark, I just might of been inside your house. You never know..
explorer | July 1, 2008
The blog postings are coming from INSIDE THE HOUSE! RUN!!
dcclark | July 1, 2008
No problem, Explorer, you’re the guy we look to to blaze the trail over the ruins of the lost Keweenaw Copper Empire and you do it well. Your mentioning the waste spillway got me over there to read it, which I must have missed the first time around.
As to new places, not as exciting, perhaps, as the South Range to Copper Harbor segment of the Copper Country, there is also the Ontonagon District to explore, that has it’s own peculiar and unique history and a few ruins.
Another interesting feature up there are the old copper country graveyards. Have you done a study on those yet?
Stump the Explorer sounds kidn of fun!
And yes, many of those early guys had their fingers into several pies at once. Everything was growing and developing and everything must have seemed possible to them. This part of the world was a real happening place back then, unlike the “ghost towns” they are now, and that’s true of places like Milwaukee and Detroit too, a mere shadow their former industrial greatness.
Herb | July 1, 2008
Herb speaks the truth! I never would have known about a lot of amazing sites around the copper country if not for your footwork, Mike. And yeah, I’d love to try and stump you!
dcclark | July 1, 2008
Thanks, you guys are too kind. I think I’ll set up a thread on the forum: “Can You Stump the Explorer?”. People can throw some pictures my way and I’ll try to identify them. I have a feeling that I’d get a lot of close up’s of rock piles and rock walls however.
dcclark - “blog post from inside the house” … loved it. I actually laughed out loud over here. But I did live in a fair amount of houses and visited a good deal of other peoples houses as well during my five years at Tech….
explorer | July 1, 2008
Explorer… I’ve got one all lined up for you. No close-ups of poor rock for you, this one’s just fun!
dcclark | July 1, 2008
This picture shows the operation of the spill gates. they were movable.
http://www.geocities.com/Athens/Aegean/2272/weir3.jpg
South range guy | December 11, 2008
I wonder if the spill gates were removed or were destroyed in that spring flood that resulted in the dam’s over-topping. There seems to be no evidence of them today, but since they were probably made of wood I doubt they would of survived this long. That photo sure provides evidence of the powerful force that water could be - its amazing they survived at all during the spring thaws.
explorer | December 12, 2008