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).