Emergency swing dam at Soo Locks

Stereoscopic cyanotype photograph of a test of the newly built Emergency Swing Dam at the head of the canal above the Weitzel and State Locks.  This photograph had to have been taken between 1881 (when the Weitzel Lock opened) and 1888 (when the International (Railroad) Bridge was built). The dam would be used if an accident in one of the locks called for draining the canal.
Abstract/Description: Stereoscopic cyanotype photograph of a test of the newly built Emergency Swing Dam at the head of the canal above the Weitzel and State Locks. This photograph had to have been taken between 1881 (when the Weitzel Lock opened) and 1888 (when the International (Railroad) Bridge was built). The dam would be used if an accident in one of the locks called for draining the canal.
Subject(s): Boats and boating
Soo Locks (Mich.)
Date Created: 1881-1887 (approximate)