In dry years, the mouth of Porter Creek—a salmon and steelhead bearing tributary to the Russian River—becomes disconnected during the coho salmon smolt migration season, preventing smolts from accessing the river and, ultimately, the ocean. The property owner, E & J Gallo Winery, offered to release water from a nearby water storage pond into the creek annually, as needed, to reconnect the outmigration corridor. California Sea Grant placed temporary fish tracking equipment near the mouth of Porter Creek after the stream disconnected in April 2015 and provided evidence that two pulsed releases allowed passage of over 200 smolts that otherwise would have remained trapped.
The first phase of the Porter Creek Flow Augmentation project—a 2017-2019 collaboration between the Sonoma Resource Conservation District, Trout Unlimited, E & J Gallo and California Sea Grant—was launched in order to determine how to most effectively manage flow releases. Streamflow data collected by Trout Unlimited was compared to footage from a trail camera in order to determine the date and time of stream disconnection from the Russian River, and Sea Grant continued monitoring fish passage in relation to stream drying and augmentation.
Although 2018 was the only study year in which spring flows were low enough to warrant a flow release, 25% of the Porter Creek smolt run was allowed passage as a result of a flow release of approximately 0.9 ft3/s for five days that May. Study results demonstrated that spring flow augmentation can have a significant benefit to outmigrating coho salmon smolts and that even if the migration corridor can be kept open for a few extra days during the peak of the smolt outmigration, it has the potential to greatly improve the chances that a cohort of fish will be successful at completing their life cycle. Learn more in this summary report and slideshow.