Parameterization of river incision models requires accounting for environmental heterogeneity: insights from the tropical Andes
<p>Landscape evolution models can be used to assess the impact of rainfall variability on bedrock river incision over millennial timescales. However, isolating the role of rainfall variability remains difficult in natural environments, in part because environmental controls on river incision s...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-06-01
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| Series: | Earth Surface Dynamics |
| Online Access: | https://www.earth-surf-dynam.net/8/447/2020/esurf-8-447-2020.pdf |
| _version_ | 1818576952499372032 |
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| author | B. Campforts B. Campforts B. Campforts V. Vanacker F. Herman M. Vanmaercke W. Schwanghart G. E. Tenorio G. E. Tenorio P. Willems G. Govers |
| author_facet | B. Campforts B. Campforts B. Campforts V. Vanacker F. Herman M. Vanmaercke W. Schwanghart G. E. Tenorio G. E. Tenorio P. Willems G. Govers |
| author_sort | B. Campforts |
| collection | DOAJ |
| description | <p>Landscape evolution models can be used to assess the impact of
rainfall variability on bedrock river incision over millennial timescales.
However, isolating the role of rainfall variability remains difficult in
natural environments, in part because environmental controls on river
incision such as lithological heterogeneity are poorly constrained. In this
study, we explore spatial differences in the rate of bedrock river incision
in the Ecuadorian Andes using three different stream power models. A
pronounced rainfall gradient due to orographic precipitation and high
lithological heterogeneity enable us to explore the relative roles of
these controls. First, we use an area-based stream power model to scrutinize
the role of lithological heterogeneity in river incision rates. We show that
lithological heterogeneity is key to predicting the spatial patterns of incision
rates. Accounting for lithological heterogeneity reveals a nonlinear
relationship between river steepness, a proxy for river incision, and
denudation rates derived from cosmogenic radionuclide (CRNs). Second, we explore
this nonlinearity using runoff-based and stochastic-threshold stream power
models, combined with a hydrological dataset, to calculate spatial and
temporal runoff variability. Statistical modeling suggests that the
nonlinear relationship between river steepness and denudation rates can be
attributed to a spatial runoff gradient and incision thresholds. Our
findings have two main implications for the overall interpretation of
CRN-derived denudation rates and the use of river incision models: (i)
applying sophisticated stream power models to explain denudation rates at
the landscape scale is only relevant when accounting for the confounding
role of environmental factors such as lithology, and (ii) spatial patterns in
runoff due to orographic precipitation in combination with incision
thresholds explain part of the nonlinearity between river steepness and
CRN-derived denudation rates. Our methodology can be used as a framework to
study the coupling between river incision, lithological heterogeneity and
climate at regional to continental scales.</p> |
| first_indexed | 2024-12-16T06:22:11Z |
| format | Article |
| id | doaj.art-998a8a26e91f4974b6e90af214fb12ee |
| institution | Directory Open Access Journal |
| issn | 2196-6311 2196-632X |
| language | English |
| last_indexed | 2024-12-16T06:22:11Z |
| publishDate | 2020-06-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Earth Surface Dynamics |
| spelling | doaj.art-998a8a26e91f4974b6e90af214fb12ee2022-12-21T22:41:06ZengCopernicus PublicationsEarth Surface Dynamics2196-63112196-632X2020-06-01844747010.5194/esurf-8-447-2020Parameterization of river incision models requires accounting for environmental heterogeneity: insights from the tropical AndesB. Campforts0B. Campforts1B. Campforts2V. Vanacker3F. Herman4M. Vanmaercke5W. Schwanghart6G. E. Tenorio7G. E. Tenorio8P. Willems9G. Govers10Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, GermanyCSDMS, Institute for Arctic and Alpine Research, University of Colorado at Boulder, Boulder, CO, USAResearch Foundation Flanders (FWO), Egmontstraat 5, 1000 Brussels, BelgiumEarth and Life Institute, Georges Lemaître Centre for Earth and Climate Research, University of Louvain, Place Louis Pasteur 3, 1348 Louvain-la-Neuve, BelgiumInstitute of Earth Surface Dynamics, University of Lausanne, 1015 Lausanne, SwitzerlandUniversity of Liege, UR SPHERES, Department of Geography, Clos Mercator 3, 4000 Liège, BelgiumInstitute of Environmental Science and Geography, University of Potsdam, GermanyFacultad de Ciencias Agropecuarias, Universidad de Cuenca, Campus Yanuncay, Cuenca, EcuadorDepartment of Earth and Environmental Sciences, KU Leuven, Celestijnenlaan 200E, 3001 Leuven, BelgiumDepartment of Civil Engineering – Hydraulics Section, KU Leuven, Kasteelpark 40 box 2448, 3001 Leuven, BelgiumDepartment of Earth and Environmental Sciences, KU Leuven, Celestijnenlaan 200E, 3001 Leuven, Belgium<p>Landscape evolution models can be used to assess the impact of rainfall variability on bedrock river incision over millennial timescales. However, isolating the role of rainfall variability remains difficult in natural environments, in part because environmental controls on river incision such as lithological heterogeneity are poorly constrained. In this study, we explore spatial differences in the rate of bedrock river incision in the Ecuadorian Andes using three different stream power models. A pronounced rainfall gradient due to orographic precipitation and high lithological heterogeneity enable us to explore the relative roles of these controls. First, we use an area-based stream power model to scrutinize the role of lithological heterogeneity in river incision rates. We show that lithological heterogeneity is key to predicting the spatial patterns of incision rates. Accounting for lithological heterogeneity reveals a nonlinear relationship between river steepness, a proxy for river incision, and denudation rates derived from cosmogenic radionuclide (CRNs). Second, we explore this nonlinearity using runoff-based and stochastic-threshold stream power models, combined with a hydrological dataset, to calculate spatial and temporal runoff variability. Statistical modeling suggests that the nonlinear relationship between river steepness and denudation rates can be attributed to a spatial runoff gradient and incision thresholds. Our findings have two main implications for the overall interpretation of CRN-derived denudation rates and the use of river incision models: (i) applying sophisticated stream power models to explain denudation rates at the landscape scale is only relevant when accounting for the confounding role of environmental factors such as lithology, and (ii) spatial patterns in runoff due to orographic precipitation in combination with incision thresholds explain part of the nonlinearity between river steepness and CRN-derived denudation rates. Our methodology can be used as a framework to study the coupling between river incision, lithological heterogeneity and climate at regional to continental scales.</p>https://www.earth-surf-dynam.net/8/447/2020/esurf-8-447-2020.pdf |
| spellingShingle | B. Campforts B. Campforts B. Campforts V. Vanacker F. Herman M. Vanmaercke W. Schwanghart G. E. Tenorio G. E. Tenorio P. Willems G. Govers Parameterization of river incision models requires accounting for environmental heterogeneity: insights from the tropical Andes Earth Surface Dynamics |
| title | Parameterization of river incision models requires accounting for environmental heterogeneity: insights from the tropical Andes |
| title_full | Parameterization of river incision models requires accounting for environmental heterogeneity: insights from the tropical Andes |
| title_fullStr | Parameterization of river incision models requires accounting for environmental heterogeneity: insights from the tropical Andes |
| title_full_unstemmed | Parameterization of river incision models requires accounting for environmental heterogeneity: insights from the tropical Andes |
| title_short | Parameterization of river incision models requires accounting for environmental heterogeneity: insights from the tropical Andes |
| title_sort | parameterization of river incision models requires accounting for environmental heterogeneity insights from the tropical andes |
| url | https://www.earth-surf-dynam.net/8/447/2020/esurf-8-447-2020.pdf |
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