17 million gallons of sewage spills into ocean; beaches between El Segundo, Dockweiler closed By Mary Stringini Aerial photo from SkyFOX over the Hyperion Water Reclamation Plant near Dockweiler State Beach. LOS ANGELES - Approximately 17 million gallons of untreated sewage discharged into the ocean on Sunday night, prompting the closure of beaches between El Segundo and the Dockweiler RV Park, Los Angeles County Supervisor Janice Hahn said Monday. How did this happen? The sewage discharge was a result of excessive debris which caused a backup Sunday night at the Hyperion Treatment Plant. According to a statement from Timeyin Dafeta, Hyperion Executive Plant Manager, the plant became inundated with overwhelming quantities of debris, causing backup of the headworks facilities. This caused the plant's relief system to be triggered and "sewage flows were controlled through the plant's one-mile outfall and discharge of untreated sewage into Santa Monica Bay".