Middletown Hydraulic opened in 1852, supplying water power for shops and mills. Middletown leaders authorized its construction in April 1852. Heading the project were John W. Erwin, Thomas Sherlock, J. B. Oglesby, Richard H. Hendrickson and Joseph Cooper. Erwin, an engineer, had also designed the Hamilton Hydraulic, which opened in 1845. The two-mile Middletown Hydraulic drew water from the Great Miami River north of the town, starting near the site of the present Miami River Preserve along Ohio 73. The hydraulic ran parallel to the Miami-Erie Canal (now Verity Parkway) before turning west and returning to the river at the west end of Fourth Street. "The building of the hydraulic laid the foundation for the prosperity of Middletown," said the 1882 county history. John W. Erwin also built two paper mills in Middletown, including one on the hydraulic while the waterway was under construction.
That mill later became the Sorg Paper Company. Erwin, who died at his residence in Hamilton April 17, 1889, also built hydraulic systems in Franklin and Troy in Ohio; Goshen, Elkhart and Bristol in Indiana; and in Constantine, Michigan. The native of New Castle, Delaware, was a resident engineer on the Miami-Erie Canal from 1837 until 1879.