Historically, the American River, like many other rivers in California, were modified by the dams of beavers, until European trappers removed many of the beavers from their native habitat for their fur.
Since the California Gold Rush was centered in an area that included the American River basin, it was one of the earlier California rivers to be populated, beginning at Leidesdorff Ranch, owned by William Leidesdorff.
Water was used to drive grist mills.
Gold miners dredged the riverbed and constructed diversion dams for hydraulic mining.
Mining activity caused sediment and mercury waste to accumulate in the rivers.
The Natoma Company completed its Folsom Powerhouse in 1895 and began delivering power 22 miles (35 km) away to the city of Sacramento to power a streetcar system.

Major flooding of the Sacramento area led to calls for a large dam on the American River by the late 19th century.
During the 20th century, the American River was extensively developed for flood control, hydroelectricity production and irrigation.
Folsom Dam is the primary flood-control facility for Sacramento.
The numerous hydroelectric dams upstream on the Middle and South Forks are not constrained by flood control requirements; rather, the needs of electricity and water supply govern their operation.
Historically, the American River, like many other rivers in California, were modified by the dams of beavers, until European trappers removed many of the beavers from their native habitat for their fur. Since the California Gold Rush was centered in an area that included the American River basin, it was one of the earlier California rivers to be populated, beginning at Leidesdorff Ranch, owned by William Leidesdorff. Water was used to drive grist mills. Gold miners dredged the riverbed and constructed diversion dams for hydraulic mining. Mining activity caused sediment and mercury waste to accumulate in the rivers. The Natoma Company completed its Folsom Powerhouse in 1895 and began delivering power 22 miles (35 km) away to the city of Sacramento to power a streetcar system.
Major flooding of the Sacramento area led to calls for a large dam on the American River by the late 19th century. During the 20th century, the American River was extensively developed for flood control, hydroelectricity production and irrigation. Folsom Dam is the primary flood-control facility for Sacramento. The numerous hydroelectric dams upstream on the Middle and South Forks are not constrained by flood control requirements; rather, the needs of electricity and water supply govern their operation.
American River