In the fall of 1905, representatives of the New York State Barge Canal visited Europe on a fact finding tour to see how the new dams (weirs) were working along the canals and river navigation. A stop was made to see the newly built bridge dam at Mirowitz on the Moldau, or today known as Mirejovice on the Vitava River. The engineers were interested in the Vitava as it was very similar to the Mohawk River, and they felt that it would offer a nice comparison to what New York wished to accomplish.
The bridge dam, or what the French called the “barrage mobiles a pont”, was a relatively new system of elevating the weir works above the river channel. Prior to this development, mobile or movable dams were of the trestle type which were attached to a sill in the river channel. By elevating the dam over the river, it was hoped that any floods or ice flows would not damage the structure.
So in 1905 the New York contingent visited Mirejovice to see this new weir. Interestingly, this dam is a mix of the old and new. The five-span-bridge was built to accommodate vehicles and to support the weir works that can be seen in the middle of the span. But to each side you can see the older trestle style needle dam. And in the other photos, you can see the group walking on the heavily stoned river bottom. The group watches from this bank as the weir is deployed.
The other dams along the Vitava were of the trestle type. The only reason that the bridge weir was built was due to the bend in the river and the fear that boats would not be able to line up for the lock while avoiding the piers of the road bridge that had to be built there. So it was decided to combine the two into one.
The Mirejovice weir was heavily promoted in New York during the construction of the Barge Canal as an example of modern construction. It is interesting that today the weir has been replaced while the bridge dams along the Mohawk remain in use 115 years later.
In the collection was a photo of the Horin Lock, which looks like it hasn’t aged a bit over the years.
These photos are from the New York State Archives, Barge Canal Collection 11833.