Earth Notes: Ash Fork Steel Dam

Dec 18, 2019

A steel dam near Ash Fork in Arizona’s high desert still holds water after more than a century. It’s a relic of a short-lived era in American history, when dam builders thought steel could replace stone.

The steel dam near Ash Fork
Credit Kaibab National Forest

The Santa Fe Pacific Railroad constructed the dam in 1897 to supply water to its steam boilers. A Chicago engineer named F.H. Bainbridge proposed it be made of steel—the first of its kind in the nation. Bainbridge believed steel could make dams cheaper and more efficient. Prices had dropped to an all-time low, and prefabricated beams and plates could be easily hauled to rugged locations.

Workers constructed the nearly 50-foot-high dam in Johnson Canyon. Overlapping steel plates curved upstream, so the weight of the water would help keep the foundation stable.

A four-mile-long pipeline brought the water from the 36-million-gallon reservoir to Ash Fork. It supplied not only the railroad company but also the town’s fire hydrants.  

It seemed like the start of a new era in dam building. Steel dams went up in Michigan and Montana. But Montana’s dam broke after just one year due to a faulty foundation, and engineers began to fear the structures wouldn’t last. They had a frail, flimsy appearance compared to massive masonry dams.

In the end, tradition triumphed over innovation. No more steel dams went up after 1910. But the Ash Fork Dam is still in use by ranchers today. It proved, too late, that steel could stand the test of time. Hikers can find it at the end of the Stone to Steel Trail on the Kaibab National Forest.