Abstract Johnstown, Pennsylvania, has long been associated with flooding due to major floods in 1889, 1936, and 1977. The most famous of these floods, the Johnstown Flood of 1889, led to more than 2200 deaths and was the result of the catastrophic collapse of the South Fork Dam. This privately owned dam was located on the South Fork of the Little Conemaugh River, ~14 mi (23 km) upstream of Johnstown. The dam changed ownership multiple times since its initial construction and had been improperly rebuilt and maintained after partial breaches. It was the final failure after a wet spring and heavy rainfall that resulted in death and devastation along the Little Conemaugh River valley from South Fork to Johnstown. This field guide presents the history of the South Fork Dam and incorporates recent studies that examined the timing of the flood and failure of the dam itself. The field trip begins at the origin of the flood at the South Fork Dam and largely follows the path of the flood down the valley to Johnstown with stops at sites impacted by the flood wave, as well as sites that demonstrate a response to the flood.

Abstract The Allegheny Portage Railroad, just one leg of the Pennsylvania Mainline Canal system, was the first railroad over the Allegheny Mountains, an imposing physiographic barrier to westward migration in the early 1800s. Construction of the canal system began in 1826 and continued until ca. 1840 without interruption. The Allegheny Portage Railroad began construction in 1831 and opened for business in 1834. This astonishing engineering feat took less than four years for completion, despite the necessity of 10 inclined planes and the use of the new-fangled railroad locomotives. Construction made use of many of the natural resources occurring along and adjacent to the right-of-way, especially the Pennsylvanian-aged sandstones used for the “sleepers” that held the rails in place. Travel occurred in sectional canal boats, boats that were built in two or three pieces that could be easily loaded onto rail cars. Passengers and goods were loaded onto the boat sections in Philadelphia, which were then hauled by horse or locomotive to the Susquehanna River west of Lancaster. The boats traveled north on the Susquehanna River canal to the mouth of the Juniata River north of Harrisburg, then along the Juniata River canal to Hollidaysburg near the foot of Allegheny Mountain. There, the boats were taken from the water, loaded onto rail cars, and hauled over the mountain on the Allegheny Portage Railroad to Johnstown where they were unloaded into the Conemaugh River canal for the journey to Pittsburgh. A New Allegheny Portage Railroad was built in the 1850s to bypass the inclined planes. It was no sooner built, however, when the state sold the entire canal system to the Pennsylvania Railroad for less than half the cost of construction. The Pennsylvania Railroad promptly dismantled the Allegheny Portage Railroad and filled in the canals. Today, the Allegheny Portage Railroad National Historic Site oversees and administers the preservation of the few remaining aspects of the old railroad.