California Flooding: Salinas Valley

Last week, California got its greatest dose of rain in years.  Some parts of the state got hit worse than others, and thankfully the Salinas Valley was one of the luckier spots ("Salinas escapes weekend major flooding").

While the Salinas River's watershed received much less rain that some other areas in Northern and Central California, there have been other developments in the Salinas Valley that could have contributed to the River's ability to pass this series of storms without a major flooding incident. Beginning in 2014, landowners in the Salinas Valley have been engaging in a new Stream Maintenance Program ("Salinas River Stream Program could help prevent floods") to help reduce flood risk.

The new Stream Maintenance Program was a unique collaborative effort between landowners, a local agricultural association, the Monterey County Water Resources Agency, and The Nature Conservancy (TNC) that broke a long-term stalemate between environmentalists wanting to preserve Salinas River habitats and landowners wanting to remove in-channel vegetation to reduce flood risk.  Landowners had not been able to secure permits to remove vegetation from the river over concerns these actions would harm riparian habitat needed by migratory fish and other wildlife.

TNC enlisted FlowWest's help in 2012 to study the way the Salinas River worked and see if there wasn't a better way forward for all parties that would conserve or enhance habitat while reducing flood risk at the same time.  Between 2012 and 2015, FlowWest developed a sophisticated computer model of the Salinas Valley that helped all stakeholders better understand where, how, and why the Salinas River would flood under different sizes of storms.

FlowWest's computer model was able to answer questions about Salinas River flooding that weren't possible before.

FlowWest's computer model was able to answer questions about Salinas River flooding that weren't possible before.

Armed with this information, and in collaboration with other TNC experts in biology and environmental permitting, FlowWest and the TNC team designed a series of vegetation removal zones along the River called secondary channels. These secondary channels were able to maximize flood carrying capacity of the River while minimizing impacts to habitat. Even more, these secondary channels are helping return the River to a more natural, "braided" form that it took historically. This new plan was accepted by both landowners and environmental regulators.

FlowWest presenting its findings to Salinas Valley stakeholders.

FlowWest presenting its findings to Salinas Valley stakeholders.

In 2014 the first pilot sites of this new Stream Maintenance Program were completed, and in late 2016, similar work began in parts of the rest of the Valley.  While we know that this program cannot prevent all future floods, it should reduce the frequency of floods and reduce damage when flooding occurs.  A group of stakeholders historically at odds with each other were brought a bit closer together to work toward a common goal, and everyone learned more about the River in the process.

CompleteD Salinas River secondary channel during dry period.

CompleteD Salinas River secondary channel during dry period.

FlowWest is proud to have been part of this effort!