Sonoma County Water Agency’s Stream Maintenance Program

Project Summary

Montrose (Formerly Horizon Water and Environment) helped Sonoma County Water Agency (Sonoma Water) develop its Stream Maintenance Program (SMP). The SMP involves annual sediment removal, vegetation removal and thinning, and bank stabilization activities to maintain flow conveyance capacity in county flood control channels. Previously, maintenance projects were permitted individually, leading to project uncertainty, delays, and high permitting costs. Montrose developed a comprehensive approach to secure long-term (10-year and 15-year) permits with multiple regulatory agencies.

Our Role

We led developing the SMP by:

Preparing an award-winning SMP Manual that describes program activities, resources, and impact avoidance and minimization approaches.
Successfully obtaining more than 35 interim permits from regulatory agencies for individual maintenance projects while the program was under development.
Successfully obtaining all long-term regulatory permits.
Developing a flexible mitigation program that includes on-site restoration and off-site watershed projects with partner agencies, landowners, and non-profit organizations.
Preparing a Program Environmental Impact Report (EIR) for CEQA compliance.
Conducting several technical studies, including riparian vegetation mapping, wetlands inventory, cultural resources assessment, and sensitive species and habitat mapping to support permitting processes.
Developing treatment design templates for sediment removal, bank stabilization, and vegetation management activities.

Challenges

We worked closely with Sonoma Water to navigate the complex regulatory landscape and ensure environmental compliance. This involved:

Developing strategies for working with regulatory agencies.
Ensuring all environmental constraints were considered during project planning.
Addressing various environmental considerations and compliance requirements.

Outcome

Sonoma Water’s SMP won the 2009 Project Award of Excellence by the Floodplain Management Association (FMA) and the 2011 Outstanding Environmental Resource Document from the California Association of Environmental Professionals. Since the publication of the 2009 SMP Manual, we have helped Sonoma Water conduct sediment quality testing to comply with Regional Water Quality Control Board permit requirements and is currently updating the program. All program regulatory permits have been successfully renewed since the original authorizations.