Using an Intensively Monitored Watershed to Answer the Question, “Does Stream Restoration Increase Freshwater Production of Steelhead?”

As part of the recovery planning for steelhead and salmon, Intensively Monitored Watershed (IMW) designs are being implemented throughout the Pacific Northwest. A primary goal of IMW projects is to determine the effectiveness of specific restoration actions on increasing salmonid production. The Asotin Creek Watershed in southeast Washington was selected by the Snake River Salmon Recovery Board’s Regional Technical Team (RTT) to monitor fish response to habitat restoration activities, focusing on increasing the density of large woody debris and percent pools in the short-term, and restoration of riparian function in the long-term. A hierarchical staircase experimental and monitoring design has been implemented and power analysis and statistical modeling indicates that the experiment has sufficient power to detect change in steelhead abundance (i.e., 75% power to detect a 25% change). Preliminary estimates indicate that approximately a 160% increase in pool habitat (e.g., an additional 65 pools/km) is required to increase the abundance of juvenile steelhead by 25%. We provide descriptions of the experimental and monitoring designs and lessons learned during the development phase of the IMW in the hopes that future designs will benefit from our experiences.