The East Branch takes water from Tehachapi Afterbay along the north side of the San Gabriel Mountains and San Bernardino Mountains to the Silverwood Lake reservoir, which can hold . From here it passes through a tunnel under the San Bernardino Mountains to the Devil Canyon Powerplant, the largest recovery plant, or aqueduct power plant, of the SWP system. The water then flows through the Santa Ana Tunnel to Lake Perris, which can store up to .