2025/04/01 by Philip Roni, Jake Kvistad, Shelby Burgess +4 · 1 voice
Agricultural and Biological Sciences · Environmental Science · #Hydrology and Sediment Transport Processes #Hydrology and Watershed Management Studies #Soil erosion and sediment transport
paper · doi:10.1093/najfmt/vqaf001
openalex publication_date 2025/04/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/06/23
ABSTRACT Objective River restoration efforts continue to grow in spatial extent and complexity, though conventional monitoring methods are not designed to monitor effectiveness at broad scales. The Middle Entiat Restoration Project, implemented in 2019 and 2020, represented a unique opportunity to monitor physical and biological responses to a large restoration project (∼8 km) and evaluate new and efficient project effectiveness monitoring techniques. Methods Using a before–after study design, we examined whether placement of more than 140 logjams and construction of side channels led to measurable improvements in floodplain condition (e.g., width, complexity, side-channel metrics, morphological quality), instream habitat (pool metrics, diversity, large wood), and salmonid response (habitat suitability, capacity, and juvenile abundance). Results Comparison of instream habitat survey data before and 2 to 3 years after restoration demonstrated that most pool and habitat metrics increased by 20% to 40%. Floodplain and geomorphic metrics calculated primarily from remotely sensed data and hydraulic model outputs also showed that bank-full area (84%), bank-full width (31%), flood-prone width and area (10%), sinuosity (21%), river complexity index (47%), and length and area of side channels at high flows (79% and 40%, respectively) increased following restoration. Juvenile Chinook Salmon Oncorhynchus tshawytscha and steelhead O. mykiss abundance increased from 573 to 2,782 and 80 to 544 fish before and after restoration, respectively. Juvenile Chinook Salmon and steelhead habitat capacity increased 32% and 26%, respectively. Habitat suitability modeling indicated that total weighted usable area increased for juvenile and spawning Chinook Salmon and steelhead at base, 2-year, and spawning flows. Most logjams met their design objectives, though perennial side channels and some seasonal side channels were only meeting their high-flow design objectives. Conclusions Our study demonstrated that before–after monitoring using remotely sensed data, coupled with targeted field data collection, can be used to evaluate not only the physical and biological success of large floodplain projects but also individual design elements.