This paper explains that the Johnstown Flood of 1889 was due to poor construction of the dam. The writer states that there will never be another flood like this again due to laws passed in the state of Pennsylvania.
From the Paper:
"The Johnstown Flood was caused due to the poor construction of the South Fork Dam. In 1839, the Pennsylvania commonwealth began building a dam. The dam was to be used in times of drought for the canal basin in Johnstown, Pennsylvania. Fourteen years later the South Fork dam was completed. Diann Olsen stated that the dam took so long to build that the canal system became obsolete by the Pennsylvania Railroad. The Pennsylvania Railroad bought the dam and the canal in 1857. The dam broke in the summer of 1862 while under the ownership of the Pennsylvania Railroad (Olsen, 3). The lake was only halfway full and it was a dry summer, so the dam did not cause much damage."