In the 1840s, canal operations at Yellow Bank Creek featured the twin arch aqueduct, a bridge that carried the canal over the creek, and Lock 21, the Yellow Bank Lock, which raised boats from ground level on one side of the creek to the top of the aqueduct before they continued toward Metamora. Lock 21 had a lift of over 12 feet and was the deepest lock on this section of the canal, though nearly 4 feet of accumulated sediment and debris now cover its floor. In the 1940s, state plans for the Whitewater Canal Memorial intended to preserve both structures, but after the aqueduct had survived for more than 100 years, work on Project No. 31 was halted in November 1946 because of financial and engineering problems elsewhere in the project. Earth fill and face stone were removed from the aqueduct, with some stone intended for use at the Metamora Aqueduct, and the dirt taken from the arches, canal channel, and towpath was piled at the east end of the aqueduct, blocking Lock 21. That pile of dirt at the far end of the lock is all that remains of the Twin Arch Aqueduct.