Caption from book:
<p>"Although <a rel="nofollow" class="external text" href="http://www.louisvilleghs.com/LGHS_MASTER/SUB/Legends/Captains_Tomb/captians_tomb.html">Frank McHarry</a> [stonemason and owner of Tarascon Mill, a former flour mill which then made high-quality hydraulic cement] and Shippingport residents opposed it, this pivot bridge replaced the stone arch bridge across the canal at Eighteenth Street in 1856."
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</p><p>Looking NW (downstream)
</p><p>When this pivot bridge was built in 1856 (replacing a stone-arch bridge which had opened in 1829), the Portland Canal was only 64 feet wide.
</p><p>By 1871, the canal had been widened to 85 feet and this bridge would have been replaced by a longer pivot bridge. So the photo would have been taken some time between 1856 and 1871.
</p><p>When the canal was widened to 200 feet in 1917, a new lift span was installed, using the pivot pier (at left) of the old bridge as its south pier.
(All the excavating was done on the north side of the canal).
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</p><p>Photo from <i>Triumph at the Falls: The Louisville and Portland Canal</i>, p. 98.
by Leland R. Johnson and Charles E. Parrish.
Louisville District.
U.S. Army Corps of Engineers.
Louisville, Kentucky.
2007.
Library of Congress Control Number: 2005931890.
(Download a <a rel="nofollow" class="external text" href="https://www.lrl.usace.army.mil/Portals/64/docs/Ops/Navigation/TriumphAtTheFalls.pdf">13 MB PDF file of this book</a>)
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The book's version of this photo (as well as other photos) seems to be elongated in the horizontal dimension.
</p>
I have shortened the horizontal dimension to make the photo closer to the correct aspect ratio
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/70020260@N04">William Alden</a> from Louisville, Kentucky, USA
CC BY-SA 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/bill_alden/8365088759/">99e020 supplement 1: Old 18th St. Bridge over Portland Canal (built 1856)</a>