The Russian River estuary opens with self breach
The barrier beach at the mouth of the Russian River breached late in the afternoon on Thursday, January 7, 2021.
Sonoma Water did not artificially breach the barrier beach. The maximum water surface elevation measured at the USGS Hwy 1 stage gage was 10.23 feet. This would likely be approximately 10.4 feet at the Jenner gage.
It took a few hours, but water levels began to decline overnight and the water elevation is currently at 3.33 ft at the USGS Hwy 1 stage gage.
A few clarifications:
Barrier beach, beach berm – The sand ridge that separates the Russian River estuary from the Pacific Ocean. Sometimes shortened to just ‘beach’. The Russian River Biological Opinion uses ‘sandbar’ as a synonym.
Breaching – Removal of sand from the barrier beach that forms a channel for water to flow between the estuary and ocean. ‘Natural’ refers to breaches that occur without human intervention and ‘artificial’ to describe breaches that are the result of human sand excavation. ‘Self-breach’ refers to breaches caused by the estuary’s own rising water levels that scour the beach open.
The Russian River Estuary closes throughout the year as a result of a sandbar forming at the mouth of the Russian River. The sandbar usually closes during the spring, summer, and 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 ponding of the Russian River behind the sandbar and water level increases in the Estuary.
In the past, Sonoma Water mechanically breached the sandbar to alleviate potential flooding of low-lying shoreline properties near the town of Jenner. Beginning in Summer 2010, Sonoma Water began implementing a new way of breaching the estuary to enhance rearing habitat for juvenile salmonids (particularly steelhead during the summer), while still managing estuary water levels to minimize flood hazards.
About the Russian River Estuary
Russian River EstuaryThe Russian River Estuary closes throughout the year as a result of a sandbar forming at the mouth of the Russian River. The sandbar usually closes during the spring, summer, and 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 ponding of 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. 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 alleviate potential flooding of low-lying shoreline properties near the town of Jenner. Sonoma Water holds permits from the U.S. Army Corps of Engineers, National Marine Fisheries Service, California State Parks and Recreation, North Coast Regional Water Quality Control Board, California Department of Fish and Game, 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.
Russian River Estuary Adaptive Management Facts:
THE RUSSIAN RIVER ESTUARY
An estuary is where a river meets the ocean. The mix of freshwater from the river and saltwater from the sea creates a dynamic environment that supports a broad array of fish, wildlife, and invertebrate and plant species. Salmon and steelhead use estuaries to adapt to saline conditions prior to entering the ocean and to adapt to freshwater before migrating upstream to their spawning grounds.
THE PROBLEM
During the summer, tidal action forms a sandbar at the mouth of the Russian River near the town of Jenner. The sandbar often becomes high enough to prevent the river from entering the sea. The result is a lagoon that occasionally threatens to flood low-lying properties from Jenner to Duncans Mills. For many years private citizens would breach the sandbar, enabling the river to flow into the ocean and eliminating the threat of flooding. In the early 1950s, the Sonoma County Public Works Department took over the job, using heavy equipment to breach the sandbar. In the mid1990s, the task was turned over to the Sonoma County Water Agency (Water Agency) during a county reorganization. Scientists with the National Marine Fisheries Service (NMFS) believe that the large volume of saltwater that enters the estuary when the sandbar is opened creates a less-thanoptimal environment for young steelhead to grow before entering the ocean.
THE SOLUTION
NMFS biologists believe that a summertime freshwater lagoon would create a healthier nursery for young steelhead. In other California rivers, the formation of similar “perched” lagoons has improved conditions for steelhead during the summer months.
THE IMPLEMENTATION
The Russian River Biological Opinion outlines a two-pronged strategy for creating a summertime freshwater lagoon. Part one of the strategy is to reduce the flow of water in the Russian River during the summer (May 15 - October 15). Less water in the river reduces the likelihood of the lagoon flooding nearby properties. Part two of the strategy requires the Water Agency to adopt adaptive management practices in the estuary that involve the following:
• Instead of employing traditional breaching methods creating an outlet channel when the sandbar closes, the plan allows river water to flow out while preventing ocean water from entering the lagoon (see conceptual illustration below).
• Studying the effects of the jetty at Goat Rock State Beach on the estuary and evaluating alternatives that include removing or notching the jetty (study is currently underway).
• If the new method of creating a perched lagoon isn’t successful in reducing flood risks, evaluating the possibility of elevating structures in danger of flooding when the sandbar closes. The plan also requires extensive biological, physical, and water-quality monitoring to help determine whether a closed summertime lagoon is better for salmon. An Environmental Impact Report (EIR) of the project was certified in 2011.
