March 26, 2023 – We visited Roosevelt Dam, which was the first and largest dam built on the Salt River. Without a doubt, it is an impressive structure. We were amazed standing downstream and looking up at this monolith holding back the waters of the Salt River in the narrow, steep canyon where Tonto Creek and the Salt River meet. It resembles the much larger Hoover Dam on the Colorado River, but its smaller stature does not diminish it in any way.
Construction of Roosevelt began in 1908 and concluded in 1911, a year before Arizona statehood. Originally constructed as a rubble-masonry dam, it was built from giant stone blocks mortared together with cement. The first course of blocks was laid 32 feet deep into the bedrock. When completed, it was the largest masonry dam in the world, standing 280 feet high and 723 feet long. The dam formed Roosevelt Lake, which for a time was the world’s largest artificial reservoir.
Between 1989 and 1996, Roosevelt Dam underwent a major expansion and renovation that raised its current height and length to 357 feet and 1,210 feet, respectively. As part of the expansion and renovation, the dam was completely encased in concrete, drastically altering its original appearance. In conjunction with the dam upgrade, Roosevelt Bridge was constructed to provide vehicular access across the Salt River while the dam was being modernized. Roosevelt Bridge is the longest two-lane, single-span, steel-arch bridge in North America according to the American Consulting Engineers Council.
More than any other public works, Roosevelt Dam is responsible for the growth and development of the Salt River Valley and the Phoenix metropolitan area. Prior to the construction of the dam, the Salt River Valley was subject to natural desert processes that included periodic droughts and floods. So harsh was this environment that from the time of the first inhabitants around 450 CE humans struggled to sustain themselves in it. It was only with the construction of Roosevelt Dam that the Salt River finally provided a consistent source of irrigation water and flood control necessary for modern economic development to occur.
Much was gained; yet much was lost. The dam drastically altered the natural ecosystem and flooded untold archaeological and cultural resources. No longer was the Salt a free-flowing river and the impact on the native flora and fauna cannot be underestimated. Likewise, the rising waters of Roosevelt Lake likely covered hundreds of archeological sites according to field studies by the Bureau of Reclamation.
Roosevelt Dam stands as a prime example of the central question of this website: How do we balance the natural environment and the built world, which are both necessary for modern life but often opposed to each other?