Alluvial Fans and Salmonid Habitat: The Forgotten and Challenging Landscape In-Between
Although fisheries habitat on alluvial fans is may not provide the highest quality, the processes occurring on them is commonly essential to maintaining high quality habitats at their proximal and distal margins. When functioning, they can store and meter sediment loads, recharge groundwater, produce cold water springs and seeps at their base, and support rich and vibrant wetland ecosystems at their distal end. When these systems are perturbed, the geomorphic responses are often extreme, sometimes resulting in deeply incised channels or alternatively, aggrading channels and splays of sediment deposited across working landscapes.
Alluvial fans are often critical zones for salmon and steelhead migration to holding, spawning and rearing habitats located in upstream reaches. The dynamic network of channels and often complex surface and groundwater interactions creates unique challenges to fish passage, especially where water diversions may limit flow availability and alter sediment transport. This session will focus on the hydraulic and geomorphic processes occurring within alluvial fans relative to fisheries habitat and fisheries access to upstream habitat, the causes and responses of dysfunctional alluvial fan systems, and the importance of restoring these processes to create desirable habitats for salmonid recovery.
The Benefits of Restoring Alluvial Fan Processes after a Century of Neglect
Michael Love, Michael Love & Associates, Inc.
Alluvial Fan Construction in the Pacific Northwest
Paul Powers. US Forest Services
Managing Fish Passage Across the Antelope Creek Alluvial Fan
Jay Stallman, Stillwater Sciences
Debris Basins in Southern Santa Barbara County; Their History and Exciting Future
Seth Shank and Andrew Raaf, Santa Barbara County Flood Control and Water Conservation District
Expect the Unexpected – Monitoring Geomorphic Changes and Evaluating Overall Effectiveness in Highly Dynamic Alluvial Fan Environments – The Hansen Creek Story
Ian Mostrenko. Herrera Environmental Consultants
Salmonid Habitat Use of the Goodell Alluvial Fan: Would Removal of Anthropogenic Features Increase Fish Numbers?
Rick Hartson, Upper Skagit Indian Tribe