Large woody debris and boulders are in place along Rock Creek, to test juvenile coho salmon population response to large scale habitat enhancements. Approximately 125 woody debris pieces and 250 boulders were placed along the channel to promote pool formation, and create habitat complexity and overwintering habitat for juvenile coho salmon populations in the North Umpqua basin. Various configurations are being used to determine which will provide the greatest benefit to juvenile coho salmon production. The results of this study will guide future habitat enhancements in the basin.
A photographic base map using low elevation aerial photography (LEAP) was used to map and assess existing habitat, as well as determine locations for enhancements. The study reach has been seeded with coho salmon eggs in artificial redds for the past three years to assess current carrying capacity and establish pre-treatment conditions.
Post-project monitoring will begin after the reach has received a two-year recurrence interval peak flow, to allow woody debris to become functional within the channel. Compliance monitoring will be conducted to ensure that enhancements were implemented and are functioning as intended, while effectiveness monitoring will assess the extent to which the project actually increases coho salmon production. These habitat enhancements are provisions of the renewed license for the North Umpqua Hydroelectric Project.
Large woody debris is a crucial habitat requirement for juvenile coho salmon during their freshwater residency and low-velocity refuge habitat can often be a limiting factor in small streams in forested regions.View the gallery