The Russian River Estuary may close at any time of the year as a result of a sandbar forming at the mouth of the Russian River. The sandbar usually closes from the spring through the fall when river flows are relatively low and long period waves transport sand landward, rebuilding the beach that was removed by winter waves and river outflows.
Closures result in the formation of a lagoon in the Russian River behind the sandbar and water level increases in the estuary. Natural breaching events occur when estuary water surface levels exceed the sandbar height and overtop the sandbar, scouring an outlet channel, or when ocean wave conditions erode the barrier beach. Public agencies have been involved in breaching the sandbar since at least the 1960s. Sonoma Water became responsible for breaching activities in 1994.
Sonoma Water staff mechanically breach the sandbar to minimize the potential flood risk of low-lying shoreline properties along the estuary. Sonoma Water holds permits from the U.S. Army Corps of Engineers, National Marine Fisheries Service, California State Parks, North Coast Regional Water Quality Control Board, California Department of Fish and Wildlife, California State Lands Commission, and the California Coastal Commission for the breaching activities. Beginning in Summer 2010, Sonoma Water began implementing a new way of breaching the estuary, described in the annual adaptive beach management plans, below.
Sonoma Water contacts State Parks lifeguards within 24 hours prior to management activities to minimize potential hazards to beach visitors. Signs are also posted for 24 hours prior to and after events to warn beach visitors of the hazards of the management area and to be aware of seals hauled out on the beach.
Goat Rock State Park Beach is a haul-out spot for migratory species, including California sea lions, northern elephant seals and northern fur seals. Harbor seals are a resident species of marine mammal that have been observed at the Russian River estuary since 1974. These marine mammals (also known as pinnipeds) use the protected area of the Russian River outlet and sandy barrier beach for resting and refuge. Sonoma Water works closely with Stewards of the Coast and Redwoods to monitor pinnipeds at the Goat Rock State Beach haulout near Jenner. Sonoma Water's Estuary Management activities are authorized under a Marine Mammal Protection Act Letter of Authorization.
Several biological and physical studies have been conducted in the Russian River estuary to assist in management decisions. These studies began in the early 1990s and many studies are ongoing. Listed below in chronological order are estuary reports. The Annual Biological Opinion reports provide the results of the annual fisheries, invertebrate, seining and downstream migrant trapping work conducted in the estuary.
Russian River Estuary Study, 1992-1993
The Russian River Estuary Study, 1992-1993, was prepared for the Sonoma County Department of Public Works to evaluate the physical processes associated with sandbar closure, the changes to water quality and biological conditions following sandbar closure and breaching, the flooding impacts of sandbar closure, and develop a management plan for the estuary. The current management plan, which specifies breaching the sandbar when the water surface level in the estuary is between 4.5 and 7 feet NGVD was a result of this plan.
Biological and Water Quality Monitoring, 1996-2000
Sonoma Water evaluated the impact of artificially breaching the sandbar at the mouth of the Russian River on water quality, pinnipeds, nekton, and fisheries from 1996 through 2000. Monitoring included continuous sampling and observations before, during and following sandbar breaching.
Russian River estuary fish and macro-invertebrate monitoring
This monitoring evaluates the distribution and abundance of aquatic species in the Russian River estuary during late spring through early fall beginning in 2003. Over 50 fish species have been inventoried, including juvenile steelhead and Chinook salmon. Also, juvenile Dungeness crab rear in the estuary. This monitoring effort has since been incorporated into the current sandbar breaching monitoring plan.
Hydrography of the Russian River estuary: 2009-2011
This report, compiled by John Largier & Dane Behrens, Bodega Marine Laboratory, University of California Davis, is preceded by a data report (Behrens & Largier 2010), in which all field data are plotted and details are provided on instrument deployments. In this report, core sections address (i) water budget and seepage analysis, (ii) tidal and diurnal currents, (iii) hydrographic structure – salinity, temperature, dissolved oxygen, (iv) stratification and water column stability, (v) salt and dissolved oxygen budgets.
Estuary water quality data
As a part of the State Water Resources Control Board Temporary Urgency Change Petitions, Sonoma Water monitored the Russian River and the Estuary for Bacteria and Nutrient levels.