CER Surface Processes Group

Flow regulation and climate change impacts on river systems

Flow regulation through dams and diversions can significantly impact downstream flow hydrographs, channel morphology, sediment mobility, and aquatic ecosystems. We are using laboratory experiments, as well as hydraulic and aquatic habitat modeling to better understand and potentially mitigate for these impacts. Some questions we are investigating include:

the influence of hydrograph shape on sediment transport rates and hysteresis
flow regulation and climate change impacts on riparian ecosystems, in-stream habitat, and channel morphology

Some example publications on this topic:

Pelletier et al., 2015 (PDF), Neupane and Yager, 2013 (PDF), Benjankar et al., 2012 (link), Benjankar et al., 2015 (link), Duffin et al., 2023 (link)

Vegetation and geomorphology

Vegetation can partly control many geomorphic processes and is often used in river restoration projects to increase habitat, decrease stream temperatures, and provide bank stability. However, many complex feedback mechanisms exist between vegetation and river channels, which complicates predictions of geomorphic change and river restoration success. We use models and laboratory experiments with real and simulated vegetation to investigate:

vegetation impacts on flow turbulence, sediment transport rates, and channel morphology
vegetation succession and cottonwood recruitment

Some example publications on this topic:

Yager and Schmeeckle, 2013 (PDF), Benjankar et al., 2014 (link), Tranmer et al., 2024 (link)

Interactions between salmon and channel processes

Many studies have shown that salmon habitat is partly controlled by the flow and grain sizes present in river systems. We are investigating the reverse question, which is how salmon impact their own environment as well as the long term evolution of landscapes. We use laboratory experiments and numerical models to answer the following:

how do salmon influence the onset of sediment motion, channel bed structure, and sediment transport rates
the effects of salmon on nutrient exchange in rivers
the role of salmon spawning on river profile evolution over millions of years

Photo from BLM

Some example publications on this topic:

Buxton et al., 2015a (PDF), Fremier et al., 2018 (link), Buxton et al., 2015b (link), Duffin et al., 2021 (link)