Laguna Watershed Knowledgebase

The Sonoma County Water Agency has responsibility for flood protection and stream maintenance in the Laguna de Santa Rosa area and is a local sponsor for a federal study of sedimentation and flood protection in the Laguna. The agency’s efforts centers on providing the best level of flood protection we can while sustaining a healthy, thriving ecosystem that supports viable salmon and steelhead populations.

The importance of having healthy and vital Laguna de Santa Rosa cannot be over estimated. The Laguna serves as an essential ecosystem, a critically important flood relief system providing more flood protection than Lake Sonoma, a spawning area for endangered and threatened salmon and a recreational resource for the people of Sonoma County. It forms an important component of the larger Russian River watershed and is the second largest freshwater wetland in Northern California. The Laguna provides habitat to over 200 species of birds, fish and mammals.

Existing climate models do not provide specific indication of changes to be expected in the Laguna area due to global warming. However, statewide models generally predict rising average temperatures and increased occurrence of high temperature extremes. Ocean warming and changes in coastal upwelling will impact salmon and steelhead that spawn in the Laguna. Rainfall patterns will change with increasing intensity of storms and shifts in timing of rainfall. If recent trends are an indication we can expect more dry springs, warmer conditions and more intense flooding events.

Success in adaptation to these changes will require science-based decision making that is founded on solid scientific research and long range, regional planning. Completion of the federal study on sedimentation and flood protection in the Laguna would be of great value in establishing current conditions and tracking changes over time. Success will also require planning in a watershed context so that larger goals like protection of endangered species and improved water quality can be met. Salmon may be the indicator of our success in adaptation.

Adaptation alternatives available to us now include design of flood retention systems that capture floodwater and debris upstream shaving the peak floods, reducing sedimentation and possibly supplying water for aquifer recharge. State mandated flow levels in the Russian River Watershed will have to be change to face the new reality about water availability. An effort is now underway to start that process. Adaptation will also require that we continue the battle against invasive species and lead in the effort to restore and improve habitat for listed species.