The County of Santa Cruz asked Balance Hydrologics, Inc. to assist in managing public safety, salmonid habitat, and riparian corridors in the Corralitos and upper Soquel Creek watersheds following the Summit Fire of May 2008.  The Summit Fire burned approximately 4,270 acres in the headwaters of the Corralitos and Soquel watersheds, as well as the Uvas Creek watershed in Santa Clara County, threatening to introduce potentially large and persistent sediment loads into the channel systems.

Beginning in winter 2009, Balance staff identified 10 sites (including 1 each in the Browns and East Fork Upper Soquel Creek systems) to conduct both pre- and post-rainy season monitoring of channel bed conditions and bed elevation, along with sediment transport measurements during storms.  Some monitoring locations are reoccupations of sites selected for almost identical assessment following the catastrophic January 4-5, 1982 storm, thus enabling a comparison between post-fire response in 2009 with the only other major episodic watershed disturbance in the past 50-60 years.

Flooding risk was assessed via bedload and suspended load transport measurements and calculations during storm events, coupled with cross-section surveys that identified detectable bed elevation change at key locations along the creek corridors.  Senior geomorphic and engineering staff worked with County Flood Control managers to identify likely locations subject to flooding along Corralitos Creek and assisted in evaluating conveyance capacity.  Salmonid habitat was assessed through repeated cross-section surveys that identified scour or filling of representative habitat features (pools, glides, or riffles), along with repeated bed condition measurements consisting of a modified pebble count and habitat element survey at select locations.  In this rare but necessary and exceedingly important approach, Balance assisted the County in forging a coalition between floodplain management and salmonid habitat interests to respond to the potential hazards posed by the Summit Fire.

Santa Cruz County, CA
Santa Cruz County
Corralitos Creek
Climate Change, Post-fire, Water Quality
Geomorphology, Monitoring & Gaging