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Robert Ferguson's Outputs (53)

Flow Resistance and Hydraulic Geometry in Gravel‐And Boulder‐Bed Rivers (2025)
Journal Article
Ferguson, R., & Recking, A. (2025). Flow Resistance and Hydraulic Geometry in Gravel‐And Boulder‐Bed Rivers. Water Resources Research, 61(3), Article e2024WR038852. https://doi.org/10.1029/2024wr038852

The frictional resistance of river beds affects how water discharge is partitioned between depth and velocity, which is important in many aspects of hydrology, geomorphology, and aquatic ecology. Many of the most widely‐used resistance equations pred... Read More about Flow Resistance and Hydraulic Geometry in Gravel‐And Boulder‐Bed Rivers.

Predicting flow resistance in rough‐bed rivers from topographic roughness: Review and open questions (2024)
Journal Article
Ferguson, R. I., Hardy, R. J., Hodge, R. A., Houseago, R. C., Yager, E. M., & Yamasaki, T. N. (online). Predicting flow resistance in rough‐bed rivers from topographic roughness: Review and open questions. Earth Surface Processes and Landforms, https://doi.org/10.1002/esp.6016

Most ways of predicting flow resistance in shallow rivers with a partial or complete cover of coarse sediment use a bed‐sediment grain diameter as a roughness length scale. However, beds with the same grain size distribution differ in roughness and f... Read More about Predicting flow resistance in rough‐bed rivers from topographic roughness: Review and open questions.

Fluvial processes and landforms (2022)
Journal Article
Ferguson, R. I., Lewin, J., & Hardy, R. J. (2022). Fluvial processes and landforms. Memoirs, 58(1), 257-270. https://doi.org/10.1144/m58-2021-18

The period 1965–2000 saw a sustained increase in research and publications on fluvial processes and landforms. The trend towards generalization and/or mechanistic understanding, rather than site-specific history, continued. Research was multidiscipli... Read More about Fluvial processes and landforms.

Roughness Calibration to Improve Flow Predictions in Coarse‐Bed Streams (2021)
Journal Article
Ferguson, R. I. (2021). Roughness Calibration to Improve Flow Predictions in Coarse‐Bed Streams. Water Resources Research, 57(6), Article e2021WR029979. https://doi.org/10.1029/2021wr029979

Logarithmic and variable-power equations that use the bed D84 grain size as a roughness metric reproduce the general trend of flow resistance in streams with coarse beds, but they are unreliable for predictions in individual reaches. For site-specifi... Read More about Roughness Calibration to Improve Flow Predictions in Coarse‐Bed Streams.

Limits to scale invariance in alluvial rivers (2020)
Journal Article
Ferguson, R. (2021). Limits to scale invariance in alluvial rivers. Earth Surface Processes and Landforms, 46(1), 173-187. https://doi.org/10.1002/esp.5006

Assumptions about fluvial processes and process–form relations are made in general models and in many site‐specific applications. Many standard assumptions about reach‐scale flow resistance, bed‐material entrainment thresholds and transport rates, an... Read More about Limits to scale invariance in alluvial rivers.

Flow resistance and hydraulic geometry in bedrock rivers with multiple roughness length scales (2019)
Journal Article
Ferguson, R., Hardy, R., & Hodge, R. (2019). Flow resistance and hydraulic geometry in bedrock rivers with multiple roughness length scales. Earth Surface Processes and Landforms, 44(12), 2437-2449. https://doi.org/10.1002/esp.4673

Many models of incision by bedrock rivers predict water depth and shear stress from discharge; conversely, palaeoflood discharge is sometimes reconstructed from flow depth markers in rock gorges. In both cases assumptions are made about flow resistan... Read More about Flow resistance and hydraulic geometry in bedrock rivers with multiple roughness length scales.

Advance, Retreat, and Halt of Abrupt Gravel-Sand Transitions in Alluvial Rivers (2017)
Journal Article
Blom, A., Chavarrías, V., Ferguson, R. I., & Viparelli, E. (2017). Advance, Retreat, and Halt of Abrupt Gravel-Sand Transitions in Alluvial Rivers. Geophysical Research Letters, 44(19), 9751-9760. https://doi.org/10.1002/2017gl074231

Downstream fining of bed sediment in alluvial rivers is usually gradual, but often an abrupt decrease in characteristic grain size occurs from about 10 to 1 mm, i.e., a gravel-sand transition (GST) or gravel front. Here we present an analytical model... Read More about Advance, Retreat, and Halt of Abrupt Gravel-Sand Transitions in Alluvial Rivers.

Bed load tracer mobility in a mixed bedrock/alluvial channel (2017)
Journal Article
Ferguson, R., Sharma, B., Hodge, R., Hardy, R., & Warburton, J. (2017). Bed load tracer mobility in a mixed bedrock/alluvial channel. Journal of Geophysical Research: Earth Surface, 122(4), 807-822. https://doi.org/10.1002/2016jf003946

The presence of bare or partially-covered rock in an otherwise alluvial river implies a downstream change in transport capacity relative to supply. Field investigations of this change and what causes it are lacking. We used two sets of magnet-tagged... Read More about Bed load tracer mobility in a mixed bedrock/alluvial channel.

Flow resistance and hydraulic geometry in contrasting reaches of a bedrock channel (2017)
Journal Article
Ferguson, R., Sharma, B., Hardy, R., Hodge, R., & Warburton, J. (2017). Flow resistance and hydraulic geometry in contrasting reaches of a bedrock channel. Water Resources Research, 53(3), 2278-2293. https://doi.org/10.1002/2016wr020233

Assumptions about flow resistance in bedrock channels have to be made for mechanistic modeling of river incision, paleoflood estimation, flood routing, and river engineering. Field data on bedrock flow resistance are very limited and calculations gen... Read More about Flow resistance and hydraulic geometry in contrasting reaches of a bedrock channel.

Erosion of organic carbon from the Andes and its affects on ecosystem carbon dioxide balance (2017)
Journal Article
Clark, K., Hilton, R., West, A., Robles Caceres, A., Grocke, D., Marthews, T., …Malhi, Y. (2017). Erosion of organic carbon from the Andes and its affects on ecosystem carbon dioxide balance. Journal of Geophysical Research: Biogeosciences, 122(3), 449-469. https://doi.org/10.1002/2016jg003615

Productive forests of the Andes are subject to high erosion rates that supply to the Amazon River sediment and carbon from both recently photosynthesized biomass and geological sources. Despite this recognition, the source and discharge of particulat... Read More about Erosion of organic carbon from the Andes and its affects on ecosystem carbon dioxide balance.

The cause of advective slowdown of tracer pebbles in rivers: Implementation of Exner-Based Master Equation for coevolving streamwise and vertical dispersion (2016)
Journal Article
Pelosi, A., Schumer, R., Parker, G., & Ferguson, R. (2016). The cause of advective slowdown of tracer pebbles in rivers: Implementation of Exner-Based Master Equation for coevolving streamwise and vertical dispersion. Journal of Geophysical Research: Earth Surface, 121(3), 623-637. https://doi.org/10.1002/2015jf003497

Tracer pebbles are often used to study bed load transport processes in gravel bed rivers. Models have been proposed for their downstream dispersion, and also for vertical dispersion, but not for the combined effects of downstream and vertical movemen... Read More about The cause of advective slowdown of tracer pebbles in rivers: Implementation of Exner-Based Master Equation for coevolving streamwise and vertical dispersion.

River channel slope, flow resistance, and gravel entrainment thresholds (2012)
Journal Article
Ferguson, R. (2012). River channel slope, flow resistance, and gravel entrainment thresholds. Water Resources Research, 48(5), Article W05517. https://doi.org/10.1029/2011wr010850

[1] River beds are traditionally assumed to become mobile at a fixed value of nondimensional shear stress, but several flume and field studies have found that the critical value is higher in steep shallow flows. Explanations for this have been propos... Read More about River channel slope, flow resistance, and gravel entrainment thresholds.

A coupled sediment routing and lateral migration model for gravel-bed rivers (2011)
Journal Article
Raven, E., Ferguson, R., & Lane, S. (2011). A coupled sediment routing and lateral migration model for gravel-bed rivers. Hydrological Processes, 25(12), 1887-1898. https://doi.org/10.1002/hyp.7945

We describe additions made to a multi-size sediment routing model enabling it to simulate width adjustment simultaneously alongside bed aggradation/incision and fining/coarsening. The model is intended for use in single thread gravel-bed rivers over... Read More about A coupled sediment routing and lateral migration model for gravel-bed rivers.

Implications of climate change in the twenty-first century for simulated magnitude and frequency of bed-material transport in tributaries of the Saint-Lawrence River (2011)
Journal Article
Verhaar, P., Biron, P., Ferguson, R., & Hoey, T. (2011). Implications of climate change in the twenty-first century for simulated magnitude and frequency of bed-material transport in tributaries of the Saint-Lawrence River. Hydrological Processes, 25(10), 1558-1573. https://doi.org/10.1002/hyp.7918

More frequent extreme flood events are likely to occur in many areas in the twenty-first century due to climate change. The impacts of these changes on sediment transport are examined at the event scale using a 1D morphodynamic model (SEDROUT4-M) for... Read More about Implications of climate change in the twenty-first century for simulated magnitude and frequency of bed-material transport in tributaries of the Saint-Lawrence River.

Evolution of an advancing gravel front: observations from Vedder Canal, British Columbia (2011)
Journal Article
Ferguson, R., Bloomer, D., & Church, M. (2011). Evolution of an advancing gravel front: observations from Vedder Canal, British Columbia. Earth Surface Processes and Landforms, 36(9), 1172-1182. https://doi.org/10.1002/esp.2142

Channelization of the lowermost part of Vedder River in 1922 initiated a natural experiment relevant to the unresolved question of how abrupt gravel–sand transitions develop along rivers. The new channel (Vedder Canal) had a fine bed and a much lower... Read More about Evolution of an advancing gravel front: observations from Vedder Canal, British Columbia.