Project Abstract

Change in Sediment Dynamics: Post-Grazing Restoration of Quemada Creek, Santa Rosa Island, Channel Islands, California

            Excessive grazing degrades watershed efficiency including decreased channel stabilization, reduced function of riparian habitat, terracette formation and accelerated bank erosion. This is shown to reduce water infiltration rates and escalate surface runoff and erosion rates.  This research explores post-grazing channel characteristics of Quemada Creek Watershed on Santa Rosa Island, Channel Islands, California.  Stream channel morphology is impacted by ungulates through soil compaction, and the prevention of floodplain development.  We re-surveyed ten stream channel cross-sections fifteen years after the restoration attempt began in 1999 to determine restoration success, watershed health and functionality. This report presents the survey data obtained in October and November of 2014 and compares it with the cross sections taken in 1999 and 2002. The objective of this research is to determine if removing cattle, elk and deer had a positive effect of the functioning of Quemada Creek.  We found the non-functioning watershed returning to pre-grazing conditions with increases in native vegetation and floodplain development.  Baseline data was established in two additional watersheds on the island for a future comparative study to determine rates of watershed recovery based on factors including different bedrock and geologic features.

Ho: Quemada Creek Watershed shows post-grazing bank stabilization and recovering riparian corridor functioning.