4.5. Conclusion
The results of this study indicate that the addition of large amounts of sediment to the lower SRR at Cottonwood Wash facilitated the occlusion of the main river channel, encouraged bank destabilization, promoted beaver dam building, allowed for channel avulsion and aided in riparian wetland expansion across the entire valley bottom that resulted in complex habitat that has benefitted native and imperiled fishes (Remiszewski, 2022). We also suggest that an increased area of inundation has enhanced the capacity of this riverscape to retain water for periods longer than expected during extended drought. Traditional stream restoration approaches are typically too expensive and small in size to match what has taken place naturally on the SRR (Skidmore & Wheaton, 2022). This realization has led us to believe that in order to promote large-scale, habitat-forming and ecologically beneficial restoration in desert river tributaries, there needs to be an increased emphasis on large-scale, process-based approaches to restoration (Wohl, 2019; Ciotti, Mckee, Pope, Kondolf, & Pollock, 2021; Skidmore & Wheaton, 2022). If intentional process-based restoration actions were taken on the scale of channel occlusions and valley plugs, we would likely see the creation and maintenance of additional complex habitat, further improving the recruitment and persistence of the native and endangered fishes of the Upper CRB, and contributing to resiliency and refugia in the face of worsening climate change (Fairfax & Whittle, 2020).