How Many Ways Can You Cross a River?

Part of the joy of working with historical photos at the SDSHS Press is when you find something that doesn’t seem to “fit,” and it sends you on a quest to make sense of what you see. Here’s an example from the SDSHS Archives, which also appears in the forthcoming Summer 2011 issue of South Dakota History. This seems deceptively simple. All the description says is “Chamberlain.” Now, to denizens of Chamberlain, all the following may be well known (or maybe you’ll be surprised too). But as for the rest of us…

Bridges at Chamberlain

Like many South Dakotans, I frequently cross the Missouri on I-90. Looking upstream, I see a truss road bridge at the end of a long causeway—but I’ve never actually driven across it. Downstream there’s a railroad bridge for the old CMSt.P&P.

So when I looked at this photo I immediately thought, okay, the piers on the right are for the familiar interstate bridge, which in this picture is under construction. The truss bridge in the center is the old road bridge. The truss bridge on the far left looks like an old railroad bridge that must have been replaced at some point by the railroad bridge downstream. I just dismissed the earthen causeway running most of the way across the river as “construction” and didn’t give any thought to its implications.

Only one thing bothered me about this photograph and made me question my interpretation, and it wasn’t the narrowness of the river. I correctly assumed that the photograph was taken before the creation of the Fort Randall Dam (and that should have given me a clue). What bothered me was this: the bridge piers on the right (my “interstate bridge”) are way too close to the bridge in the middle. The two current highway bridges are much farther apart than that. That’s when I went to my favorite toy, Google Maps.

You’ll notice two things. First, yes, the two modern road bridges are farther apart than the two in the photograph (and they cross the river at two different angles, unlike the two in the photograph, which run parallel to each other). Second, zoom in and look closely: the truss bridge is double-barreled, which is a pseudo-technical term for a bridge in which each span is made up of two structures side-by-side.

Now I was really curious, because the truss bridge in the photograph is manifestly not double-barreled. Also, it’s four spans long. The modern bridge, as you can see in the satellite image, is five spans. What happened?

Here’s the real story behind this photograph. In 1925, the original Chamberlain highway bridge was completed as part of a plan that also included similar structures at Mobridge, Forest City, Pierre, and Wheeler (between Geddes and Bonesteel, S.Dak.). It comprised four 336-foot spans. That’s the bridge in the middle of the picture. The engineer in charge of the project dreamed that these bridges might do their job for five hundred years, but scarcely a quarter-century later they were nearing the end of their service. Two things had changed. First, their width was inconvenient for heavier, wider postwar truck traffic. Second and more importantly, the river was about to rise quite a bit along much of its course in South Dakota due to the construction of the dams that have so preoccupied the thoughts of people in Pierre, Dakota Dunes, Omaha, etc. in the last few weeks. Fort Randall Dam, which transformed the river in the areas of Chamberlain and Wheeler into Lake Francis Case, was completed in 1956.

Before the water rose, bridge engineers once again got busy. In 1953, they built a new railroad bridge to replace the 1923 structure that you see on the left of the photograph. If you look closely at the satellite map, you can follow the old railroad grade as it runs up the gulch just north of town (visible as a dark, wooded area in the photograph) and eventually meets the railway’s present course.

In the same year, the new truss highway bridge was completed. And it was completed in a way that should make resource-conscious people proud: to get the ten spans necessary for a five-span double-barreled bridge, they reused the four 336-foot spans from the original bridge and five of the six 256-foot spans from the bridge at Wheeler (which, unlike its four sibling bridges, was never replaced), moving them all onto the new piers you see on the right side of the photograph. I’d love to know how this was accomplished. Only one 256-foot span was built new. You can also see the five piers of the 1925 bridge, still sticking up out of the water—but not by much.

So our photograph shows us the state of the project after the new piers had been built but before the spans had been moved on top of them. Meanwhile, at the bottom of the frame, the causeway that will carry traffic to the west end of the bridge, halfway across the yet-unformed Lake Francis Case, is taking shape. The photo was taken in 1952 or 1953, shortly after the last great Missouri River flood episode.

And, as for the earth causeway, it was a transportation stopgap. Before engineers dismantled the 1925 bridge, a Bailey Bridge, a portable truss bridge originally designed for military use during World War II, so that traffic could keep rolling, spanned the gap in this causeway. Apparently, it was washed out the day that the new bridge opened.

The present I-90 bridge at Chamberlain opened in 1974. So, I was twenty years off. In South Dakota history, twenty years is kind of a big deal. But the most fun in history is finding out that you’re wrong, that there’s more to discover. Of course, you hope that this happens before you publish.

For more on the double-barreled truss bridge, including some photographs, see the website of bridge enthusiast John Weeks. The history of the five sibling 1920s highway bridges, plus the Meridian bridge at Yankton, can be read in a National Register documentation form for “Historic Bridges in South Dakota, 1893–1943,” online.