Articles | Volume 14, issue 1
https://doi.org/10.5194/esurf-14-95-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/esurf-14-95-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Investigating controls on fluvial grain sizes in post-glacial landscapes using citizen science
Anya H. Towers
CORRESPONDING AUTHOR
School of GeoSciences, University of Edinburgh, Edinburgh, UK
Mikael Attal
School of GeoSciences, University of Edinburgh, Edinburgh, UK
Simon M. Mudd
School of GeoSciences, University of Edinburgh, Edinburgh, UK
Fiona J. Clubb
Department of Geography, Durham University, Durham, UK
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Earth Surf. Dynam., 12, 515–536, https://doi.org/10.5194/esurf-12-515-2024, https://doi.org/10.5194/esurf-12-515-2024, 2024
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Pebbles become increasingly rounded during downstream transport in rivers due to abrasion. This study quantifies pebble roundness along the length of two Himalayan rivers. We demonstrate that roundness increases with downstream distance and that the rates are dependent on rock type. We apply this to reconstructing travel distances and hence the size of ancient Himalaya. Results show that the ancient river network was larger than the modern one, indicating that there has been river capture.
Emma L. S. Graf, Hugh D. Sinclair, Mikaël Attal, Boris Gailleton, Basanta Raj Adhikari, and Bishnu Raj Baral
Earth Surf. Dynam., 12, 135–161, https://doi.org/10.5194/esurf-12-135-2024, https://doi.org/10.5194/esurf-12-135-2024, 2024
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Using satellite images, we show that, unlike other examples of earthquake-affected rivers, the rivers of central Nepal experienced little increase in sedimentation following the 2015 Gorkha earthquake. Instead, a catastrophic flood occurred in 2021 that buried towns and agricultural land under up to 10 m of sediment. We show that intense storms remobilised glacial sediment from high elevations causing much a greater impact than flushing of earthquake-induced landslides.
Fiona J. Clubb, Eliot F. Weir, and Simon M. Mudd
Earth Surf. Dynam., 10, 437–456, https://doi.org/10.5194/esurf-10-437-2022, https://doi.org/10.5194/esurf-10-437-2022, 2022
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River valleys are important components of mountain systems: they are the most fertile part of landscapes and store sediment which is transported from mountains to surrounding basins. Our knowledge of the location and shape of valleys is hindered by our ability to measure them over large areas. We present a new method for measuring the width of mountain valleys continuously along river channels from digital topography and show that our method can be used to test common models of river widening.
Cited articles
Abeshu, G. W., Li, H.-Y., Zhu, Z., Tan, Z., and Leung, L. R.: Median bed-material sediment particle size across rivers in the contiguous US, Earth System Science Data, 14, 929–942, https://doi.org/10.5194/essd-14-929-2022, 2022. a, b
Attal, M. and Lavé, J.: Changes of bedload characteristics along the Marsyandi River (central Nepal): Implications for understanding hillslope sediment supply, sediment load evolution along fluvial networks, and denudation in active orogenic belts, Special Paper of the Geological Society of America, 398, 143–171, https://doi.org/10.1130/2006.2398(09), 2006. a, b, c, d, e, f, g
Attal, M. and Lavé, J.: Pebble abrasion during fluvial transport: Experimental results and implications for the evolution of the sediment load along rivers, Journal of Geophysical Research: Earth Surface, 114, https://doi.org/10.1029/2009JF001328, 2009. a
Attal, M., Mudd, S. M., Hurst, M. D., Weinman, B., Yoo, K., and Naylor, M.: Impact of change in erosion rate and landscape steepness on hillslope and fluvial sediments grain size in the Feather River basin (Sierra Nevada, California), Earth Surface Dynamics, 3, 201–222, https://doi.org/10.5194/esurf-3-201-2015, 2015. a, b, c, d, e, f, g, h, i, j, k, l, m
Ballantyne, C. K.: A general model of paraglacial landscape response, Holocene, 12, 371–376, https://doi.org/10.1191/0959683602hl553fa, 2002. a
Ballantyne, C. K.: After the ice: Holocene geomorphic activity in the Scottish Highlands, vol. 124, ISBN 1470254080230, https://doi.org/10.1080/14702540802300167, 2008. a, b
Ballantyne, C. K.: After the ice: Lateglacial and holocene landforms and landscape evolution in Scotland, Earth and Environmental Science Transactions of the Royal Society of Edinburgh, 110, 133–171, https://doi.org/10.1017/S175569101800004X, 2019. a, b, c, d
Baynes, E. R., Lague, D., Steer, P., Bonnet, S., and Illien, L.: Sediment flux-driven channel geometry adjustment of bedrock and mixed gravel–bedrock rivers, Earth Surface Processes and Landforms, 45, 3714–3731, https://doi.org/10.1002/esp.4996, 2020. a, b
Bradley, S. A., Ely, J. E., Clark, C. H., Edwards, R. O., and Shennan, I.: Reconstruction of the palaeo-sea level of Britain and Ireland arising from empirical constraints of ice extent: implications for regional sea level forecasts and North American ice sheet volume, Journal of Quaternary Science, 38, 791–805, https://doi.org/10.1002/jqs.3523, 2023. a
Brasington, J., Vericat, D., and Rychkov, I.: Modeling river bed morphology, roughness, and surface sedimentology using high resolution terrestrial laser scanning, Water Resources Research, 48, 1–18, https://doi.org/10.1029/2012WR012223, 2012. a
Breiman, L.: Random Forests, Tech. rep., https://doi.org/10.1023/A:1010933404324, 2001. a
Buffington, J. M. and Montgomery, D. R.: A systematic analysis of eight decades of incipient motion studies, with special reference to gravel-bedded rivers, Water Resources Research, 33, 1993–2029, https://doi.org/10.1029/96WR03190, 1997. a
Bunte, K. and Abt, S. R.: Sampling surface and subsurface particle-size distributions in wadable gravel-and cobble-bed streams for analyses in sediment transport, hydraulics, and streambed monitoring, Gen. Tech. Rep. RMRS-GTR-74, US Department of Agriculture, Forest Service, p. 428, https://doi.org/10.2737/rmrs-gtr-74, 2001. a, b
Campforts, B., Vanacker, V., Herman, F., Vanmaercke, M., Schwanghart, W., Tenorio, G. E., Willems, P., and Govers, G.: Parameterization of river incision models requires accounting for environmental heterogeneity: insights from the tropical Andes, Earth Surface Dynamics, 8, 447–470, https://doi.org/10.5194/esurf-8-447-2020, 2020. a, b, c
Chardon, V., Piasny, G., and Schmitt, L.: Comparison of software accuracy to estimate the bed grain size distribution from digital images: A test performed along the Rhine River, River Research and Applications, 38, 358–367, https://doi.org/10.1002/rra.3910, 2022. a
Clark, C. D., Ely, J. C., Greenwood, S. L., Hughes, A. L., Meehan, R., Barr, I. D., Bateman, M. D., Bradwell, T., Doole, J., Evans, D. J., Jordan, C. J., Monteys, X., Pellicer, X. M., and Sheehy, M.: BRITICE Glacial Map, version 2: a map and GIS database of glacial landforms of the last British–Irish Ice Sheet, Boreas, 47, 11–e8, https://doi.org/10.1111/bor.12273, 2018. a
Clubb, F. J., Mudd, S. M., Schildgen, T. F., van der Beek, P. A., Devrani, R., and Sinclair, H. D.: Himalayan valley-floor widths controlled by tectonically driven exhumation, Nature Geoscience, 16, 739–746, https://doi.org/10.1038/s41561-023-01238-8, 2023. a, b
Detert, M. and Weitbrecht, V.: User guide to gravelometric image analysis by BASEGRAIN, Advances in Science and Research, 1789–1796, https://doi.org/10.5905/ethz-1007-347, 2013. a
Egholm, D. L., Knudsen, M. F., and Sandiford, M.: Lifespan of mountain ranges scaled by feedbacks between landsliding and erosion by rivers, Nature, 498, 475–478, https://doi.org/10.1038/nature12218, 2013. a
Finnegan, N. J., Roe, G., Montgomery, D. R., and Hallet, B.: Controls on the channel width of rivers: Implications for modeling fluvial incision of bedrock, Geology, 33, 229–232, https://doi.org/10.1130/G21171.1, 2005. a
Firth, C. R. and Stewart, I. S.: Postglacial tectonics of the Scottish glacio-isostatic uplift centre, Quaternary Science Reviews, 19, 1469–1493, https://doi.org/10.1016/S0277-3791(00)00074-3, 2000. a
Gomez, B., Rosser, B. J., Peacock, D. H., Hicks, D. M., and Palmer, J. A.: Downstream fining in a rapidly aggrading gravel bed river, Water Resources Research, 37, 1813–1823, https://doi.org/10.1029/2001WR900007, 2001. a
Haddadchi, A., Booker, D. J., and Measures, R. J.: Predicting river bed substrate cover proportions across New Zealand, Catena, 163, 130–146, https://doi.org/10.1016/j.catena.2017.12.014, 2018. a, b
Harvey, E. L., Hales, T. C., Hobley, D. E., Liu, J., and Fan, X.: Measuring the grain-size distributions of mass movement deposits, Earth Surface Processes and Landforms, 47, 1599–1614, https://doi.org/10.1002/esp.5337, 2022. a
Jansen, J. D., Codilean, A. T., Bishop, P., and Hoey, T. B.: Scale dependence of lithological control on topography: Bedrock channel geometry and catchment morphometry in western Scotland, Journal of Geology, 118, 223–246, https://doi.org/10.1086/651273, 2010. a
Johnson, S. E., Swallom, M. L., Thigpen, R., McGlue, M., Dortch, J. M., Gallen, S., Woolery, E., and Yeager, K. M.: The influence of glacial topography on fluvial efficiency in the Teton Range, Wyoming (USA), Earth and Planetary Science Letters, 592, https://doi.org/10.1016/j.epsl.2022.117643, 2022. a
Lai, L. S.-H., Roering, J. J., Finnegan, N. J., Dorsey, R. J., and Yen, J.-Y.: Coarse sediment supply sets the slope of bedrock channels in rapidly uplifting terrain: Field and topographic evidence from eastern Taiwan, Earth Surface Processes and Landforms, 46, 2671–2689, 2021. a
Lehner, B. and Grill, G.: Global river hydrography and network routing: Baseline data and new approaches to study the world's large river systems, Hydrological Processes, 27, 2171–2186, https://doi.org/10.1002/hyp.9740, 2013. a, b
Li, T., Fuller, T. K., Sklar, L. S., Gran, K. B., and Venditti, J. G.: A Mechanistic Model for Lateral Erosion of Bedrock Channel Banks by Bedload Particle Impacts, Journal of Geophysical Research: Earth Surface, 125, https://doi.org/10.1029/2019JF005509, 2020a. a
Li, T., Fuller, T. K., Sklar, L. S., Gran, K. B., and Venditti, J. G.: A Mechanistic Model for Lateral Erosion of Bedrock Channel Banks by Bedload Particle Impacts, Journal of Geophysical Research: Earth Surface, 125, https://doi.org/10.1029/2019JF005509, 2020b. a
Mason, R. J. and Polvi, L. E.: Unravelling fluvial versus glacial legacy controls on boulder-bed river geomorphology for semi-alluvial rivers in Fennoscandia, Earth Surface Processes and Landforms, 48, 2900–2919, https://doi.org/10.1002/esp.5666, 2023. a, b
Matthews, B., Naylor, M., Sinclair, H., Black, A., Williams, R., Cuthill, C., Gervais, M., Dietze, M., and Smith, A.: Sounding out the river: Seismic and hydroacoustic monitoring of bedload transport, Earth Surface Processes and Landforms, https://doi.org/10.1002/esp.5940, 2024. a
Messager, M. L., Lehner, B., Grill, G., Nedeva, I., and Schmitt, O.: Estimating the volume and age of water stored in global lakes using a geo-statistical approach, Nature Communications, 7, 1–11, https://doi.org/10.1038/ncomms13603, 2016. a, b
Miazza, R., Pascal, I., and Ancey, C.: Automated grain sizing from uncrewed aerial vehicles imagery of a gravel‐bed river: Benchmarking of three object‐based methods, Earth Surface Processes and Landforms, https://doi.org/10.1002/esp.5782, 2024. a
Moussavi-Harami, R., Mahboubi, A., and Khanehbad, M.: Analysis of controls on downstream fining along three gravel-bed rivers in the Band-e-Golestan drainage basin NE Iran, Geomorphology, 61, 143–153, https://doi.org/10.1016/j.geomorph.2003.12.005, 2004. a
Mudd, S., Clubb, F., Grieve, S., Milodowski, D., Gailleton, B., Hurst, M., Valters, D., Wickert, A., and Hutton, E.: LSDtopotools/LSDTopoTools2: LSDTopoTools2 v0.8, Zenodo [code], https://doi.org/10.5281/ZENODO.7892465, 2023. a, b
Mueller, E. R. and Pitlick, J.: Sediment supply and channel morphology in mountain river systems: 1. Relative importance of lithology, topography, and climate, Journal of Geophysical Research: Earth Surface, 118, 2325–2342, https://doi.org/10.1002/2013JF002843, 2013. a
Mueller, E. R. and Pitlick, J.: Sediment supply and channel morphology in mountain river systems: 2. Single thread to braided transitions, Journal of Geophysical Research: Earth Surface, 119, 1516–1541, https://doi.org/10.1002/2013JF003045, 2014. a
Mugodo, J., Kennard, M., Liston, P., Nichols, S., Linke, S., Norris, R. H., and Lintermans, M.: Local stream habitat variables predicted from catchment scale characteristics are useful for predicting fish distribution, Hydrobiologia, 572, 59–70, https://doi.org/10.1007/s10750-006-0252-7, 2006. a, b
Neely, A. B. and DiBiase, R. A.: Drainage area, bedrock fracture spacing, and weathering controls on landscape-scale patterns in surface sediment grain size, Earth and Space Science Open Archive [preprint], 1–22, https://doi.org/10.1002/essoar.10502617.1, 2020. a
Parker, G.: Selective Sorting and Abrasion of River Gravel. I: Theory, Journal of Hydraulic Engineering, 117, 131–147, 1991. a
Prasicek, G., Larsen, I. J., and Montgomery, D. R.: Tectonic control on the persistence of glacially sculpted topography, Nature Communications, 6, https://doi.org/10.1038/ncomms9028, 2015. a
Purinton, B. and Bookhagen, B.: PebbleCounts: a Python grain-sizing algorithm for gravel-bed river imagery. V. 1.0, GFZ Data Services, https://doi.org/10.5880/fidgeo.2019.007 (last access: 30 January 2024), 2019b. a
Purinton, B. and Bookhagen, B.: Tracking downstream variability in large grain‐size distributions in the south‐central Andes, Journal of Geophysical Research: Earth Surface, 1–29, https://doi.org/10.1029/2021jf006260, 2021. a, b
Reid, D. A., Hassan, M. A., and McCleary, R.: Glacial landscape configuration influences channel response to flooding, Earth Surface Processes and Landforms, 47, 209–227, https://doi.org/10.1002/esp.5240, 2022. a, b
Rice, S. and Church, M.: Grain size along two gravel-bed rivers: Statistical variation, spatial pattern and sedimentary links, Earth Surface Processes and Landforms, 23, 345–363, https://doi.org/10.1002/(SICI)1096-9837(199804)23:4<345::AID-ESP850>3.0.CO;2-B, 1998. a
Shennan, I., Milne, G., and Bradley, S.: Late Holocene relative land- and sea-level changes: Providing information for stakeholders, GSA Today, 19, 52–53, https://doi.org/10.1130/GSATG50GW.1, 2009. a
Shields, A.: Application of similarity principles and turbulence research for bed-load movement, Mitteilungen der preussischen Versuchsanstalt für Wasserbau und Schiffbuar, https://resolver.tudelft.nl/uuid:a66ea380-ffa3-449b-b59f-38a35b2c6658 (last access: 3 February 2026), 1936. a
Sklar, D. W.: Sediment and rock strength controls on river incision into bedrock, Geology, 29, 1087–1090, https://doi.org/10.1130/0091-7613(2001)029<1087:SARSCO>2.0.CO, 2001. a
Sklar, L. S.: Grain Size in Landscapes, Annu. Rev. Earth Planet. Sc., 52, https://doi.org/10.1146/annurev-earth-052623-075856, 2024. a, b
Sklar, L. S. and Dietrich, W. E.: A mechanistic model for river incision into bedrock by saltating bed load, Water Resources Research, 40, 1–22, https://doi.org/10.1029/2003WR002496, 2004. a
Sklar, L. S., Dietrich, W. E., Foufoula-Georgiou, E., Lashermes, B., and Bellugi, D.: Do gravel bed river size distributions record channel network structure?, Water Resources Research, 42, 1–22, https://doi.org/10.1029/2006WR005035, 2006. a, b, c, d
Sklar, L. S., Riebe, C. S., Marshall, J. A., Genetti, J., Leclere, S., Lukens, C. L., and Merces, V.: The problem of predicting the size distribution of sediment supplied by hillslopes to rivers, Geomorphology, 277, 31–49, https://doi.org/10.1016/j.geomorph.2016.05.005, 2017. a, b, c
Sklar, L. S., Riebe, C. S., Genetti, J., Leclere, S., and Lukens, C. E.: Downvalley fining of hillslope sediment in an alpine catchment: implications for downstream fining of sediment flux in mountain rivers, Earth Surface Processes and Landforms, 45, 1828–1845, https://doi.org/10.1002/esp.4849, 2020. a
Sternberg, H.: Untersuchungen uber langen-und Querprofil geschiebefuhrender flusse, Zeitshrift fur Bauwesen, 25, 483–506, https://cir.nii.ac.jp/crid/1572824500838774016 (last access: 1 May 2025), 1875. a
Towers, A. H., Mudd, S. M., Attal, M., Clubb, F. J., Binnie, S. A., Dunai, T. J., and Haghipour, N.: Denudation rates and Holocene sediment storage dynamics inferred from in situ 14C concentrations in the Feshie basin, Scotland, Earth Surface Processes and Landforms, 50, e70043, https://doi.org/10.1002%2Fesp.70043, 2025. a, b, c, d, e, f, g
Wells, T., Hancock, G., and Fryer, J.: Weathering rates of sandstone in a semi-arid environment (Hunter Valley, Australia), Environmental Geology, 54, 1047–1057, https://doi.org/10.1007/s00254-007-0871-y, 2008. a
Westoby, M. J., Dunning, S. A., Woodward, J., Hein, A. S., Marrero, S. M., Winter, K., and Sugden, D. E.: Instruments and methods: Sedimentological characterization of Antarctic moraines using uavs and Structure-from-Motion photogrammetry, Journal of Glaciology, 61, 1088–1102, https://doi.org/10.3189/2015JoG15J086, 2015. a
Whitbread, K., Thomas, C., and Finlayson, A.: The influence of bedrock faulting and fracturing on sediment availability and Quaternary slope systems, Talla, Southern Uplands, Scotland, UK, Proceedings of the Geologists' Association, 135, 61–77, https://doi.org/10.1016/j.pgeola.2023.11.003, 2024. a
Whittaker, A. C.: How do landscapes record tectonics and climate?, Lithosphere, 4, 160–164, https://doi.org/10.1130/RF.L003.1, 2012. a
Whittaker, A. C., Attal, M., and Allen, P. A.: Characterising the origin, nature and fate of sediment exported from catchments perturbed by active tectonics, Basin Research, 22, 809–828, https://doi.org/10.1111/j.1365-2117.2009.00447.x, 2010. a, b, c
Wolman, M. G.: A method of sampling coarse river‐bed material, Eos, Transactions American Geophysical Union, 35, 951–956, https://doi.org/10.1029/TR035i006p00951, 1954. a
Zomer, R. J., Xu, J., and Trabucco, A.: Version 3 of the Global Aridity Index and Potential Evapotranspiration Database, Scientific Data, 9, 1–15, https://doi.org/10.1038/s41597-022-01493-1, 2022. a, b
Editor
How does grainsize vary along rivers, and what are the controls? Based on an extensive dataset compiled in a citizen-science survey across Scotland, Towers et al. find that in post-glacial landscapes commonly used global environmental factors provide little explanation. Instead, the local sediment input from glacially sculpted landforms and emplaced deposits largely determine the high spatial variability of grainsizes.
How does grainsize vary along rivers, and what are the controls? Based on an extensive dataset...
Short summary
We explore controls on channel sediment characteristics in post-glacial landscapes. In contrast to other studies that have focused on landscapes with little glacial influence, we find no apparent controls. We propose that Scotland's post-glacial legacy drives the lack of sedimentological trends, and that changes in landscape morphology and sediment sources caused by glacial processes lead to a decoupling between fluvial sediment grain size and environmental variables.
We explore controls on channel sediment characteristics in post-glacial landscapes. In contrast...