Water Resource Collections and Archives

Restoration Site and Water-Quality Monitoring in Sonoma Valley

Organization: Sonoma Ecology Center
2005 Grant Recipient - Sonoma County

Purpose

The purpose of San Francisco Foundation Bay Fund Grant titled “Restoration Site and Water-Quality Monitoring in Sonoma Valley” was to monitor and evaluate water quality and stream changes at five restoration sites in Sonoma Valley. The five boulder-and-log installations the Center assessed were constructed in Sonoma Creek and tributaries in 2003 by the Sonoma Ecology Center and Sonoma County Roads and Maintenance Department. Monitoring the installation sites over two years for changes in geomorphology, habitat structures, and water quality provided them with important information about how the watershed's stream channels respond to designed restoration structures.

Geomorphic changes in the streambeds and banks from our restoration efforts were captured when comparing pre- and post-restoration cross sections and longitudinal profiles. The San Francisco Foundation Bay Fund grant allowed them to update cross sections and long profiles at Sonoma Creek, Graham Creek, and Calabazas Creek. Through this process they were able to discern geomorphic differences in the stream bed after the work. All sites displayed significant bed and bank erosion over the monitoring period, which included the December 30, 2005, flood of record, which flowed at twice the discharge of previous estimates of the 100-year event. Four out of five sites displayed cross-sections with a deeper and wider thalweg after the period of monitoring. The remaining site showed a later significant shift in thalweg location.

Re-surveys of cross-sections also revealed the increasing role installed structures play over time in terms of impact on channel roughness and micro-topography. In general, geomorphic assessments showed that while restoration sites created scour that produced sediment movement or trapping, channel complexity was increased throughout to improved habitat and reduced erosivity of flows. In addition, the majority of restoration sites helped trap coarse sediments that were immediately put to use by fish for spawning.

2012 Update

The San Francisco Foundation Bay Fund grant built a foundation for continued understanding about what can be expected both spatially and through time at restoration sites.

Documents

• Restoration Site and Water-Quality Monitoring in Sonoma Valley. Rebecca Lawton. June 2012. These attachments show project-success monitoring locations throughout Sonoma Valley, channel cross section changes and survey results, water quality data and analysis, erosion pin monitoring photographs, a capsule description, and the final project narrative.__________________.
  • Cross Section Survey Data Sheets from 2003 and 2006 (9 pp.)
  • Volunteer Monitoring of Turbidity and SSC Concentrations Sonoma Creek Watershed, Sonoma Creek, California (13 pp.)
  • Document 3
  • Document 4

Contact for the Project

Rebecca Lawton
Geologist, Director of Programs
Sonoma Ecology Center
Phone: 707-996-0712 x116
Email: Becca@SonomaEcologyCenter.org