Fulfilling a decades old community dream, IRWD and The Irvine Company restored 150 acres of the San Joaquin Marsh. The plan was devised over 10 years in consultation with the City of Irvine and numerous regulatory and environmental organizations.

Adjacent to UCI, and bounded by the San Diego Creek, Michelson, and Carlson Drives, the 500-acre marsh is the largest coastal freshwater wetlands in Southern California. The marsh slowly degraded over a number of years as a result of dry farming, use by private duck clubs, and the San Diego Creek realignment which diverted a large portion of its water supply. The restoration project reestablished a water supply for the Marsh, the enhanced marsh will provide a significantly better nesting and feeding environment, as well as a migratory stopover, for more than 200 species of waterfowl, shorebirds, and other birds.

IRWD owns approximately 300 acres of the marsh, of which 150 acres were restored and enhanced. University of California Natural Reserve System owns the remaining 200 acres, west of Campus Drive, on which it is sponsoring its own restoration project.