Professor Andrew Nicholas
Professor in Physical Geography
A.P.Nicholas@exeter.ac.uk
3338
Amory C413
Amory Building, University of Exeter, Rennes Drive, Exeter, EX4 4RJ , UK
Overview
Andrew Nicholas completed a BSc in Geography at Leeds University after which he undertook a PhD at Exeter. Between 1994 and 1996 he spent two years as a postdoctoral Fellow at Leeds before taking up a lectureship in Physical Geography at Exeter. He received the British Geomorphology Research Group Gordon Warwick Award in 2002.
Broad research specialisms:
Fluvial Geomorphology and Numerical Modelling
Qualifications
BSc (Leeds),
PhD (Exeter)
Research group links
Research
Research interests
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My research interests are in river and floodplain processes, with a particular focus on hydrology (river hydraulics and flooding) and geomorphology (sediment transport, erosion and deposition, river migration, floodplain construction and alluvial deposits). My past work has involved studies of gravel-bed rivers in the UK, Iceland and New Zealand. My recent and ongoing work focuses on large sand-bed rivers, including some of the World’s largest (such as the Amazon, Mekong, Brahmaputra, and Beni). Methodologically, much of my work involves mathematical modelling, with a strong emphasis on the integration of theoretical and empirical approaches (using remote sensing and field measurements). I use these approaches to understand the factors that control the diversity of river and floodplain morphology and behaviour found in nature, and to investigate how rivers respond to past and future environmental changes. |
Research projects
Grants:
NERC Large grant NE/S015612/1, 2021-2025: The evolution of global flood hazard and risk (EVOFLOOD)
NERC grant NE/T007478/1, 2020-23: Propagation of hydro-geomorphic disturbances through continental-scale river basins
Leverhulme Trust project grant, 2020-23: Hidden Depths: The environmental and social impacts of river sand mining
NERC grant NE/P014704/1, 2017-2019: The resilience and sustainability of the Mekong delta to changes in water and sediment fluxes
BBSRC grant BB/P022693/1, 2017-2019: Sustainable Intensification of Rice Agriculture in Vulnerable Mega-Deltas: A Global Challenge
NERC grant NE/L00738X/1, 2015-2017: Modelling how sediment suspension controls the morphology and evolution of sand-bed rivers
NERC grant NE/J021571/1, 2012-2016: Climatic and autogenic controls on the morphodynamics of mega-rivers: modelling sediment flux in the alluvial transfer zone
NERC grant NE/I023120/1, 2012-2016: The sedimentology of fluvial megascours
NERC grant NE/H009108/1, 2010-2014: Do floods matter? Bridging the gap between fluvial morphodynamics and alluvial architecture
NERC grant NE/H006524/1, 2010-2013: Morphodynamics and sedimentology of the tidally influenced fluvial zone
NERC grant NE/E014798/1, 2008-2010: Dynamics and deposits of braid-bars in the World's largest rivers: processes, morphology and subsurface sedimentology
NERC grant NE/E011713/1, 2007-2010: Impacts of climate change on erosion, sediment transport and soil carbon in the UK and Europe
Publications
Journal articles
Nicholas A, Aalto R, Bruckner M (In Press). Bank strength variability and its impact on the system-scale morphodynamics of the upper Amazon River in Brazil. Geology
Sandbach S, Nicholas AP, Ashworth P, Best J, Keevil C, Parsons D, Prokocki E, Simpson C (In Press). Hydrodynamic modeling of tidal-fluvial flows in a large river estuary. Estuarine, Coastal and Shelf Science
Bussi G, Darby S, Whitehead P, Jin L, Dadson S, Voepel E, Vasilopoulos G, Hackney C, Hutton C, Berchoux T, et al (In Press). Impact of dams and climate change on suspended sediment flux to the Mekong Delta. Science of the Total Environment
Unsworth C, Nicholas A, Ashworth P, Best J, Lane S, Parsons D, Sambrook Smith G, Simpson C, Strick R (In Press). Influence of dunes on channel-scale flow and sediment transport in a sand-bed braided river. Journal of Geophysical Research
Schwendel A, Nicholas AP, Aalto R, Sambrook Smith GH, Buckley S (In Press). Interaction between meander dynamics and floodplain heterogeneity in a large tropical sand-bed river: the Rio Beni, Bolivian Amazon. Earth Surface Processes and Landforms
Schwendel A, Nicholas AP, Aalto R, Sambrook Smith G, Buckley S (In Press). Interaction between meander dynamics and floodplain heterogeneity in a large tropical sand-bed river: the Rio Beni, Bolivian Amazon. Earth Surface Processes and Landforms
Nicholas A (In Press). MORPHODYNAMICS AND DEPOSITIONAL ARCHITECTURE OF MID-CHANNEL BARS IN LARGE AMAZONIAN RIVERS. Sedimentology
Nicholas AP (In Press). Morphodynamic diversity of the world's largest rivers. Geology
Nicholas AP, Ashworth PJ, Sambrook Smith GH, Sandbach SD (In Press). Numerical simulation of bar and island morphodynamics in anabranching mega-rivers. Journal of Geophysical Research
Hutton CJ, Nicholas AN, Brazier RE, Nearing MA (In Press). On the effects of improved cross-section representation in 1D flow routing models applied to ephemeral rivers. Water Resources Research
Hackney C, Darby S, Parsons D, Leyland J, Best J, Aalto R, Nicholas A, Houseago R (In Press). River bank instability from unsustainable sand mining in the lower Mekong River. Nature Sustainability
Gebrechorkos S, Leyland J, Slater L, Wortmann M, Ashworth PJ, Bennett GL, Boothroyd R, Cloke H, Delorme P, Griffith H, et al (2023). A high-resolution daily global dataset of statistically downscaled CMIP6 models for climate impact analyses. Sci Data, 10(1). Abstract. Author URL.
Mancini D, Dietze M, Müller T, Jenkin M, Miesen F, Roncoroni M, Nicholas AP, Lane SN (2023). Filtering of the Signal of Sediment Export from a Glacier by its Proglacial Forefield. Geophysical Research Letters, 50(21). Abstract.
Vasilopoulos G, Quan QL, Parsons DR, Darby SE, Tri VPD, Hung NN, Haigh ID, Voepel HE, Nicholas AP, Aalto R, et al (2021). Establishing sustainable sediment budgets is critical for climate-resilient mega-deltas. ENVIRONMENTAL RESEARCH LETTERS, 16(6). Author URL.
Prokocki EW, Best JL, Ashworth PJ, Sambrook Smith GH, Nicholas AP, Parsons DR, Simpson CJ (2020). Alluvial architecture of mid-channel fluvial-tidal barforms: the mesotidal Lower Columbia River, Oregon/Washington, USA. SEDIMENTOLOGY, 67(7), 3533-3566. Author URL.
Darby SE, Langdon PG, Best JL, Leyland J, Hackney CR, Marti M, Morgan PR, Ben S, Aalto R, Parsons DR, et al (2020). Drainage and erosion of Cambodia's great lake in the middle-late Holocene: the combined role of climatic drying, base-level fall and river capture. Quaternary Science Reviews, 236 Abstract.
Nicholas AP, Aalto RE, Sambrook Smith GH, Schwendel AC (2018). Hydrodynamic controls on alluvial ridge construction and avulsion likelihood in meandering river floodplains. Geology, 46(7), 639-642.
Strick R, Ashworth P, Sambrook Smith G, Nicholas AP, Best J, Lane S, Parsons D, Simpson C, Unsworth C, Dale J, et al (2018). Quantification of bedform dynamics and bedload sediment
flux in sandy braided rivers from airborne and satellite
imagery. Earth Surface Processes and Landforms, 44(4), 953-972.
Cressey EL, Dungait JAJ, Jones DL, Nicholas AP, Quine TA (2018). Soil microbial populations in deep floodplain soils are adapted to infrequent but regular carbon substrate addition. Soil Biology and Biochemistry, 122, 60-70. Abstract.
Dixon SJ, Sambrook Smith GH, Best JL, Nicholas AP, Bull JM, Vardy ME, Sarker MH, Goodbred S (2018). The planform mobility of river channel confluences: Insights from analysis of remotely sensed imagery. Earth-Science Reviews, 176, 1-18. Abstract.
Sambrook Smith GH, Nicholas AP, Best JL, Bull JM, Dixon SJ, Goodbred S, Sarker MH, Vardy ME (2018). The sedimentology of river confluences. Sedimentology, 66(2), 391-407. Abstract.
Janes VJJ, Nicholas AP, Collins AL, Quine TA (2017). Analysis of fundamental physical factors influencing channel bank erosion: results for contrasting catchments in England and Wales. Environmental Earth Sciences, 76(7). Abstract.
Hackney CR, Darby SE, Parsons DR, Leyland J, Aalto R, Nicholas AP, Best JL (2017). The influence of flow discharge variations on the morphodynamics of a diffluence–confluence unit on a large river. Earth Surface Processes and Landforms, 43(2), 349-362. Abstract.
Leyland J, Hackney C, Darby S, Parsons D, Best J, Nicholas AP, Aalto R, Lague D (2016). Extreme flood-driven bank erosion and sediment transport on a mega-river: Direct process measurements using integrated Mobile Laser Scanning (MLS) and hydro-acoustic techniques. Earth Surface Processes and Landforms
Darby SE, Hackney CR, Leyland J, Kummu M, Lauri H, Parsons DR, Best JL, Nicholas AP, Aalto R (2016). Fluvial sediment supply to a mega-delta reduced by shifting tropical-cyclone activity. Nature, 539(7628), 276-279. Abstract. Author URL.
Nicholas AP, Sambrook Smith GH, Amsler ML, Ashworth PJ, Best JL, Hardy RJ, Lane SN, Orfeo O, Parsonsm DR, Reesink AJH, et al (2016). The role of discharge variability in determining alluvial stratigraphy. Geology, 44(1), 3-6. Abstract.
Hackney C, Best J, Leyland J, Darby SE, Parsons D, Aalto R, Nicholas A (2015). Modulation of outer bank erosion by slump blocks: Disentangling the protective and destructive role of failed material on the three-dimensional flow structure. Geophysical Research Letters Abstract.
Grenfell MC, Nicholas AP, Aalto R (2014). Mediative adjustment of river dynamics: the role of chute channels in tropical sand-bed meandering rivers. Sedimentary Geology, 301, 93-106. Abstract.
Reesink AJH, Ashworth PJ, Sambrook Smith GH, Best JL, Parsons DR, Amsler ML, Hardy RJ, Lane SN, Nicholas AP, Orfeo O, et al (2014). Scales and causes of heterogeneity in bars in a large multi-channel river: Río Paraná, Argentina. Sedimentology, 61(4), 1055-1085. Abstract.
Reesink AJH, Ashworth PJ, Sambrook Smith GH, Best JL, Parsons DR, Amsler ML, Hardy RJ, Lane SN, Nicholas AP, Orfeo O, et al (2014). Scales and causes of heterogeneity in bars in a large multi-channel river: Río paraná, argentina. Sedimentology
Hutton C, Nicholas A, Brazier R (2014). Sub-grid scale parameterization of hillslope runoff and erosion processes for catchment-scale models of semi-arid landscapes. Hydrological Processes, 28(4), 1713-1721. Abstract.
Nicholas AP (2013). Modelling the continuum of river channel patterns. Earth Surface Processes and Landforms, 38(10), 1187-1196. Abstract.
Sandbach SD, Lane SN, Hardy RJ, Amsler ML, Ashworth PJ, Best JL, Nicholas AP, Orfeo O, Parsons DR, Reesink AJH, et al (2012). Application of a roughness-length representation to parameterize energy loss in 3-D numerical simulations of large rivers. Water Resources Research, 48(12). Abstract.
Nicholas AP, Sandbach SD, Ashworth PJ, Amsler ML, Best JL, Hardy RJ, Lane SN, Orfeo O, Parsons DR, Reesink AJH, et al (2012). Modelling hydrodynamics in the Rio Paraná, Argentina: an evaluation and inter-comparison of reduced-complexity and physics based models applied to a large sand-bed river. Geomorphology, 169-170, 192-211. Abstract.
Nicholas AP, Sandbach SD, Ashworth PJ, Amsler ML, Best JL, Hardy RJ, Lane SN, Orfeo O, Parsons DR, Reesink AJH, et al (2012). Modelling hydrodynamics in the Rio Paraná, Argentina: an evaluation and inter-comparison of reduced-complexity and physics based models applied to a large sand-bed river. Geomorphology
Grenfell MC, Aalto RE, Nicholas AP (2011). Chute channel dynamics in large, sand-bed meandering rivers. Earth Surface Processes and Landforms Abstract.
Clarke L, Quine TA, Nicholas AP (2010). An Experimental investigation of autogenic behaviour during alluvial fan evolution. Geomorphology, 115, 278-285.
Nicholas AP, Quine TA (2010). Quantitative assessment of landform equifinality and palaeoenvironmental reconstruction using geomorphic models. Geomorphology, 121(3-4), 167-183.
Nicholas AP (2010). Reduced-complexity modelling of free bar morphodynamics in alluvial channels. Journal of Geophysical Research - Earth Surface, doi:10.1029/2010JF001774.
Nicholas AP, Clarke L, Quine TA (2009). A numerical modelling and experimental study of flow width dynamics on alluvial fans. Earth Surface Processes and Landforms, 34, 1985-1993.
Clarke L, Quine TA, Nicholas AP (2009). An experimental investigation of autogenic behaviour during alluvial fan evolution. Geomorphology, 115, 278-285.
Nicholas AP (2009). Reduced-complexity flow routing models for sinuous single-thread channels: intercomparison with a physically-based shallow-water equation model. Earth Surface Processes and Landforms, 34, 641-653.
Thomas R, Nicholas AP, Quine TA (2007). Cellular modelling as a tool for interpreting historic braided river evolution. Geomorphology, 90(3-4), 302-317. Abstract.
Nicholas AP, Quine TA (2007). Crossing the divide: Representation of channels and processes in reduced-complexity river models at reach and landscape scales. Geomorphology, 90(3-4), 318-339.
Nicholas AP, Quine TA (2007). Modelling alluvial landform change in the absence of external environmental forcing. Geology, 35(6), 527-530.
Nicholas AP, Fang X, Sweet RJ, Walling DE (2006). Development and evaluation of a new catchment-scale model of floodplain sedimentation . Water Resources Research, 42(10).
Walling, D.E. Sweet, R.J. Fang, X. (2006). New strategies for upscaling high-resolution flow and overbank sedimentation models to quantify floodplain sediment storage at the catchment scale. Journal of Hydrology, 329(3-4), 577-594.
Nicholas AP (2005). Cellular modelling in fluvial geomorphology. Earth Surface Processes and Landforms, 30(5), 645-649. Abstract.
Sambrook-Smith, G.H. (2005). Effect on flow structure of sand deposition on a gravel bed: results from a two-dimensional flume experiment. Water Resources Research, 41(10), 1-12.
Nicholas AP, McLelland SJ (2004). Computational fluid dynamics modelling of three-dimensional processes on natural river floodplains. Journal of Hydraulic Research, 42(2), 131-143.
Nicholas AP (2003). Investigation of spatially distributed braided river flows using a two-dimensional hydraulic model. Earth Surface Processes and Landforms, 28(6), 655-674. Abstract.
Nicholas AP, Mitchell CA (2003). Numerical simulation of overbank processes in topographically complex floodplain environments. Hydrological Processes, 17(4), 727-746. Abstract.
Quine TA, Basher LR, Nicholas AP (2003). Tillage erosion intensity in the South Canterbury Downlands, New Zealand. Australian Journal of Soil Research, 41(4), 789-807. Abstract.
Thomas, R. (2002). Simulation of braided river flow using a new cellular routing scheme. Geomorphology, 43(3-4), 179-195.
Nicholas AP (2001). Computational fluid dynamics modelling of boundary roughness in gravel-bed rivers: an investigation of the effects of random variability in bed elevation. Earth Surface Processes and Landforms, 26(4), 345-362. Abstract.
McLelland SJ, Nicholas AP (2000). A new method for evaluating errors in high-frequency ADV measurements. Hydrological Processes, 14(2), 351-366. Abstract.
Nicholas AP (2000). Modelling bedload yield braided gravel bed rivers. Geomorphology, 36(1-2), 89-106. Abstract.
Nicholas AP, Smith GHS (1999). Numerical simulation of three-dimensional flow hydraulics in a braided channel. Hydrological Processes, 13(6), 913-929. Abstract.
Nicholas AP, Walling DE (1998). Numerical modelling of floodplain hydraulics and suspended sediment transport and deposition. Hydrological Processes, 12(8), 1339-1355. Abstract.
Nicholas AP, Sambrook Smith GH (1998). Relationships between flow hydraulics, sediment supply, bedload transport and channel stability in the proglacial Virkisa River, Iceland. Geografiska Annaler, Series A: Physical Geography, 80(2), 111-122. Abstract.
Nicholas AP, Smith GHS (1998). Relationships between flow hydraulics, sediment supply, bedload transport and channel stability in the proglacial Virkisa River, Iceland. GEOGRAFISKA ANNALER SERIES A-PHYSICAL GEOGRAPHY, 80A(2), 111-122. Author URL.
Nicholas AP, Walling DE (1997). Investigating spatial patterns of medium-term overbank sedimentation on floodplains: a combined numerical modelling and radiocaesium-based approach. Geomorphology, 19(1-2), 133-150. Abstract.
Sambrook Smith GH, Nicholas AP, Ferguson RI (1997). Measuring and defining bimodal sediments: Problems and implications. Water Resources Research, 33(5), 1179-1185. Abstract.
Nicholas AP, Walling DE (1997). Modelling flood hydraulics and overbank deposition on river floodplains. Earth Surface Processes and Landforms, 22(1), 59-77. Abstract.
Nicholas AP, Walling DE (1996). The significance of particle aggregation in the overbank deposition of suspended sediment on river floodplains. Journal of Hydrology, 186(1-4), 275-293. Abstract.
Nicholas AP, Ashworth PJ, Kirkby MK, Macklin MG, Murray T (1995). Sediment slugs: large-scale fluctuations in fluvial sediment transport rates and storage volumes. Progress in Physical Geography, 19, 500-519.
Chapters
Prokocki EW, Best JL, Ashworth PJ, Parsons DR, Smith GHS, Nicholas AP, Simpson CJ, Wang H, Sandbach SD, Keevil CE, et al (2015). Mid to late Holocene geomorphological and sedimentological evolution of the fluvial-tidal zone. Lower Columbia River, WA/OR, USA. In (Ed) Developments in Sedimentology, 193-226. Abstract.
Nicholas AP, Thomas R, Quine TA (2006). Cellular modelling of braided river form and process. In Smith S, GH, Best, J, Bristow, Petts C, GE (Eds.) Braided Rivers, Blackwell, 136-150.
Nicholas, A.P. (2005). Roughness parameterization in CFD modeling of gravel-bed rivers. In Bates PD, Lane SN, Ferguson RI (Eds.) Computational Fluid Dynamics: Applications in Environmental Hydraulics, Wiley, 329-355.
Walling DE, He Q, Nicholas AP (1996). River floodplains as suspended sediment sinks. In Anderson MG, Walling DE, Bates PD (Eds.) Floodplain Processes, Wiley, 399-440.
Conferences
Unsworth CA, Nicholas AP, Ashworth PJ, Simpson CJ, Best JL, Lane SN, Parsons DR, Sambrook Smith GH (2016). Using bedform migration and orientation to infer sediment transport pathways in a sandy braided river. Abstract.
Parsons DR, Amsler ML, Szupiany RN, Ashworth PJ, Best JL, Hardy RJ, Lane SN, Nicholas AP, Orfeo O, Sambrook Smith GH, et al (2010). Process-product relationships in a large multi-channel river: the Río Paraná, Argentina. 6th IAHR Symposium on River, Coastal and Estuarine Morphodynamics: RCEM 2009.
Sandbach SD, Hardy RJ, Lane SN, Parsons DR, Best JL, Ashworth PJ, Reesink AJH, Amsler ML, Szupiany RN, Nicholas AP, et al (2010). Three-dimensional modelling of a very large river; the Rio Parana. IAHR International Conference on Fluvial Hydraulics, River Flow 2010.
Hutton CJ, Nicholas AP, Nearing MA, Brazier RB (2009). Ephemeral channel modelling at historic timescales in semi-arid environments. Advances in Studies on Desertification.
Clarke L, Quine TA, Nicholas AP (2008). An evaluation of the role of physical models in exploring form-process feedbacks in alluvial fans. Sediment Dynamics in Changing Environments.
Walling DE, Fang D, Nicholas AP, Sweet RJ (2006). River flood plains as carbon sinks. Abstract.
Sutton RI, Nicholas AP, Walling DE (2004). Monitoring and modelling flow and suspended sediment transport processes in alluvial cutoffs. Abstract.
Walling DE, Fang D, Nicholas AP, Sweet RJ (2004). The grain size characteristics of overbank deposits on the flood plains of British lowland rivers. Abstract.
Nicholas AP (2003). Modelling and monitoring flow and suspended sediment transport in lowland river flood plain environments. Abstract.
Sweet RJ, Nicholas AP, Walling DE, Fang X (2003). Morphological controls on medium-term sedimentation rates on British lowland river floodplains. Abstract.
Thomas R, Nicholas AP, Quine TA (2002). Development and application of a cellular model to simulate braided river process-form interactions and morphological change. River Flow 2002.
Nicholas AP (2002). Modelling flood hydraulics in topographically-complex lowland floodplain environments. River Flow 2002.
Nicholas AP, Mclelland SJ (1999). Hydrodynamics of a floodplain recirculation zone investigated by field monitoring and numerical simulation. Abstract.
Nicholas AP, Woodward JC, Christopoulos G, Macklin MG (1999). Modelling and monitoring river response to environmental change: the impact of dam construction and alluvial gravel extraction on bank erosion rates in the Lower Alfios Basin, Greece. Author URL.
NICHOLAS AP, WALLING DE (1995). Modelling contemporary overbank sedimentation on floodplains: Some preliminary results. Author URL.
Walling DW, Woodward JC, Nicholas AP (1993). A multi-parameter approach to fingerprinting suspended-sediment sources. Abstract.
External Engagement and Impact
Committee/panel activities
Member of the NERC peer review college
Teaching
Office hours:
Week 1 : Tue 26th Sept (9:30-10:30) & Thur 28th Sept (9:30-10:30)
Other weeks in Term 1: Mon (9:30-10:30) & Wed (11:00-12:00)
Modules
2023/24
- GEO2233 - Landscape Response to Environmental Change: from Source to Sink
- GEO3321 - BSc Dissertation
- GEO3322 - BSc Dissertation
