[6] The Cuyama River's source is in San Emigdio Mountains, within the Chumash Wilderness area of the Los Padres National Forest at an altitude above 8,000 feet (2,400 m).

After leaving the national forest the river enters Santa Barbara County and flows through the 45-mile-long (72 km) Cuyama Valley, which lies between the Caliente Range and the Sierra Madre Mountains.

The joined streams are called the Santa Maria River, which flows about 20 miles (32 km) to the Pacific Ocean.

The dam provides flood control and allows water to be released gradually, so that as much of it as possible will seep into the soil and recharge the groundwater aquifer.

The water is released as quickly as possible while still allowing it to percolate into the ground, so the reservoir is often empty.