The Sonoma County Water Agency (SCWA) is responsible for the operation and maintenance (O&M) of channel works and other facilities installed along the Russian River and Dry Creek by the U.S. Army Corps of Engineers (USACE) following the construction of Lake Mendocino and Lake Sonoma upstream. The USACE built pilot channels and various forms of erosion protection including anchored steel jacks, flexible fences, revetments and pervious erosion check dams. The condition of much of the original erosion control features has declined over the years due to natural fluvial process (e.g., erosion, sedimentation), other environmental stressors (e.g., direct precipitation, sunlight), and human alterations (e.g., replacement with riprap, mining activities).
On behalf of SCWA, Horizon Water and Environment (Horizon) is working with the USACE to update the outdated river works O&M Manuals and inspection procedures. The revised O&M Manuals will address the current condition of the channel stabilization works, and provide O&M procedures that are compatible with current environmental regulations and river management practices.
The SCWA also acts as the local sponsor for administering the Public Law 84-99, which authorizes the federal government to assist in the rehabilitation and inspection of private levees. The USACE has recently updated their policies for maintenance and management of vegetation on levees. Horizon is assisting SCWA with communicating these new requirements to private levee owners and developing solutions that meet the objectives of all parties.