Which dam is located on the American River?

Folsom Dam is located on the American River, making it the correct choice. This dam plays a crucial role in water management, flood control, and providing storage for irrigation and municipal use within the region. It was built primarily for flood control and to regulate the flow of the American River, which is essential for maintaining ecological balance and supporting recreation activities.

In contrast, the other dams mentioned serve different rivers or are located elsewhere. Shasta Dam is on the Sacramento River, Oroville Dam is situated on the Feather River, and New Melones Dam is on the Stanislaus River. Their respective functions and locations emphasize the importance of understanding the specific geography and purpose of each dam when discussing water management in California.