Ash Fork Steel Dam Evaluation


The Ashfork-Bainbridge Steel Dam was designed by Francis H. Bainbridge and built in 1898 by the Atchison, Topeka, and Santa Fe Railway Co. The Steel Dam was the first large steel dam in the United States. The dam is located on Johnson Canyon Creek in the Kaibab National Forest, about 40 miles west of Flagstaff, Arizona.

Location of Ashfork-Bainbridge Steel Dam (AutoCAD/Bing Maps)

The Dam was built in order to supply the railway company with a constant stock of water, however its use was discontinued. The town of Ashfork also used the water, which it pumped through a 4” pipe. Today, the reservoir is no longer used except to provide water to livestock and wildlife.
The height of the steel dam is about 46 feet, total crest length is about 300 feet and the elevation of dam is 5,402 feet (AzSCE). The dam was supported with a series of 24 triangular bents having a slope of 45 degrees facing upstream. It was designed as a cantilever truss with anchorage at the upstream toe. Rear anchors bolts are two-inch diameter and anchored at right angles to the steel face and two feet into the rock. The bottom plate is anchored to the left abutment. The upstream face is composed of 3/8-inch thick cylindrically curved steel plates riveted to outer flanges of the bent’s I-beams. The top is fitted with curved crest plates, projecting on the downstream side. The flexibility of the curved plates will take up any movement by bending, acting as a suspension system. Expansion joints were provided in the lateral bracing by means of round and slotted holes, with bolts, at connections. Also, the dam has a drainage area of 26 square miles and a gross capacity of 400 acre-feet (Chanson). For additional structural information please see Figure below.

Original drawing of Ashfork-Bainbridge Dam (Bureau of Reclamation)

The goal of the project is to evaluate the potential failure modes of the Ashfork- Bainbridge Steel Dam in order to classify the current hazard potential of the dam. To ensure accuracy of this project, the dam will be analyzed by hydraulic, geotechnical, seismic, and structural means.


The National Forest Service owns and maintains the Steel Dam, which it acquired
in 1993. More information see National Forest Service Website:

DWP Team Information

Technical advisors

  • Robin Tuchscherer
    Position: Assistant Professor
    Phone: 928-523-8080