Estuary Subwatershed Study Assessment of the Physical and Biological Condition of the Santa Clara River Estuary, Ventura County, California. Final Synthesis Report and the Environmental Effects of the City of Ventura Wastewater Reclamation Facility Discharge to the Santa Clara River Estuary

The Santa Clara River Estuary (SCRE) is a seasonally closed estuary. In general, the estuary opens during the wet season when high river flow and ocean waves breach the sand barrier, and then closes in spring when river flow is reduced and ocean waves rebuild the sand barrier. The alternating open and closed conditions of the estuary are essential characteristics for the ecology of the SCRE ecosystem. The natural breaching regime for the estuary is not known (although there is currently a study of the historical ecology of the Santa Clara River that will provide important information about this and related dynamics via the Historical Ecology of Southern California Wetlands under the umbrella of the Southern California Coastal Water Resource Project). In particular, the amount of water (both surface and subsurface) delivered to the estuary during the dry season is not well quantified. This is a critical aspect of the hydrology because it determines the volume of water in the estuary when it is closed, its salinity, and whether it would breach over the summer. As noted below, all of these aspects of the estuary have important consequences for the species living in it.