The Aliso Creek Watershed covers 30.4 square miles and includes portions of the cities of Aliso Viejo, Dana Point, Laguna Niguel, Laguna Woods, Laguna Beach, and Lake Forest. Its main tributary, Aliso Creek, originates in the Santa Ana Mountains inside the boundaries of Cleveland National Forest. Smaller tributaries include Wood Canyon, Sulphur Creek, the Aliso Hills Channel, and English Channel.

A comprehensive watershed management study for the Aliso Creek Watershed has been underway for several years. The U.S. Army Corps of Engineers completed the Reconnaissance Report in February 1997. The Feasibility Study phase began in January of 1998 and a draft of the final Feasibility Study report was circulated in November 2001.