Behind the moored steamboat Gila, a bridge used by the Southern Pacific Railroad spans the Colorado River at Yuma in a photo from the late 1870s or early 1880s. In the 1920s, a new railroad bridge was built in a less flood-prone location; it’s still in use today, right next to the Ocean-to-Ocean Highway Bridge. | THE BANCROFT LIBRARY, UNIVERSITY OF CALIFORNIA, BERKELEY

Behind the moored steamboat Gila, a bridge used by the Southern Pacific Railroad spans the Colorado River at Yuma in a photo from the late 1870s or early 1880s. In the 1920s, a new railroad bridge was built in a less flood-prone location; it’s still in use today, right next to the Ocean-to-Ocean Highway Bridge. | THE BANCROFT LIBRARY, UNIVERSITY OF CALIFORNIA, BERKELEY

 

Captain Isaac Polhamus pilots a steamboat on the river around 1890. A New York native and son of a Hudson River boat captain, Polhamus arrived in Yuma County in 1856 and helmed the Colorado, the Mojave and other boats during a river career that spanned half a century. | THE HUNTINGTON LIBRARY

Captain Isaac Polhamus pilots a steamboat on the river around 1890. A New York native and son of a Hudson River boat captain, Polhamus arrived in Yuma County in 1856 and helmed the Colorado, the Mojave and other boats during a river career that spanned half a century. | THE HUNTINGTON LIBRARY

 

Boats including the Gila (foreground) and the Cocopah wait near hay bales at the Yuma Quartermaster Depot, a U.S. Army installation, in 1876. The depot site is now part of Colorado River State Historic Park. | THE HUNTINGTON LIBRARY

Boats including the Gila (foreground) and the Cocopah wait near hay bales at the Yuma Quartermaster Depot, a U.S. Army installation, in 1876. The depot site is now part of Colorado River State Historic Park. | THE HUNTINGTON LIBRARY

 

The Gila might also be the steamboat visible in this 1878 photo of the Colorado Steam Navigation Co.’s facility in Yuma. In the background, a train can be seen crossing the original railroad bridge. | THE HUNTINGTON LIBRARY

The Gila might also be the steamboat visible in this 1878 photo of the Colorado Steam Navigation Co.’s facility in Yuma. In the background, a train can be seen crossing the original railroad bridge. | THE HUNTINGTON LIBRARY

 

Stern-wheel boats, or “sternwheelers,” came in all shapes and sizes on the Colorado. In this photo from the late 1890s, a man and a boy pose for a photo on a small ferry in Yuma. | UNIVERSITY OF SOUTHERN CALIFORNIA DIGITAL LIBRARY, CALIFORNIA HISTORICAL SOCIETY COLLECTION

Stern-wheel boats, or “sternwheelers,” came in all shapes and sizes on the Colorado. In this photo from the late 1890s, a man and a boy pose for a photo on a small ferry in Yuma. | UNIVERSITY OF SOUTHERN CALIFORNIA DIGITAL LIBRARY, CALIFORNIA HISTORICAL SOCIETY COLLECTION

 

The crew of the steamer St. Vallier takes a break on the river somewhere above Yuma. Built by the Santa Ana Mining Co., the St. Vallier began operating around 1900. | THE HUNTINGTON LIBRARY

The crew of the steamer St. Vallier takes a break on the river somewhere above Yuma. Built by the Santa Ana Mining Co., the St. Vallier began operating around 1900. | THE HUNTINGTON LIBRARY

 

The 135-foot Cochan, the last stern-wheel steamboat built for the Colorado Steam Navigation Co., ran the river from 1900 to 1909. Another steamer, the Searchlight, is visible at far right. | THE HUNTINGTON LIBRARY

The 135-foot Cochan, the last stern-wheel steamboat built for the Colorado Steam Navigation Co., ran the river from 1900 to 1909. Another steamer, the Searchlight, is visible at far right. | THE HUNTINGTON LIBRARY

 

The gas-powered riverboat Aztec passes through a movable bridge at Yuma in 1902. The Aztec moved cargo on the Colorado River between Yuma and Needles, California, until 1905, when a severe sandstorm caused it to wreck a few miles downstream from Needles. | THE HUNTINGTON LIBRARY

The gas-powered riverboat Aztec passes through a movable bridge at Yuma in 1902. The Aztec moved cargo on the Colorado River between Yuma and Needles, California, until 1905, when a severe sandstorm caused it to wreck a few miles downstream from Needles. | THE HUNTINGTON LIBRARY