Continuous measurements of valley floor width in mountainous landscapes

Clubb, Fiona J.; Weir, Eliot F.; Mudd, Simon M.

doi:https://doi.org/10.5194/esurf-10-437-2022

Articles | Volume 10, issue 3

https://doi.org/10.5194/esurf-10-437-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/esurf-10-437-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 10, issue 3

Research article

|

31 May 2022

Research article |

| 31 May 2022

Continuous measurements of valley floor width in mountainous landscapes

Fiona J. Clubb, Eliot F. Weir, and Simon M. Mudd

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Final revised paper (published on 31 May 2022)
Supplement to the final revised paper
Preprint (discussion started on 01 Feb 2022)
Supplement to the preprint

Interactive discussion

Status: closed

RC1:
'Comment on esurf-2022-2', Helen Beeson, 04 Mar 2022

This manuscript presents a new tool for automated extraction of valley width that is a contribution to an open-source toolbox for topographic analysis – LSDTopoTools. They test the tool via comparison with geological maps in three river basins with varying conditions, then apply the tool to numerous small subbasins as well as continental-scale rivers in the Appalachian Plateau to investigate the relationships between valley width and drainage area across a tectonically stable region where disturbances to this relationship should be minimal.

In the automated tool, a valley mask is first defined by user input slope and elevation thresholds. Then, a centerline is computed and widths are continuously measured orthogonal to this centerline. For three river systems, they compare automated width measurements between 1) valleys defined using slope and elevation thresholds and 2) valleys defined by previously mapped alluvium, terraces, and glacial deposits. They find good agreement between the two methods and in cases where the automated valley-defining algorithm is off, they provide good evidence that the automated method actually better reflects the true valley floor. Furthermore, the measurements from the Appalachian Plateau show power law exponents that are in line with previously published values.

This is a really useful, well-tested tool that will greatly facilitate research on bedrock valley widths, from tectonic geomorphology to ecological implications. I sure wish I had it during my masters research! The manuscript is clear, organized, well-written and has beautiful, clear figures.

Line/figure comments:

393 or explore what drives the variability in valley width! Can’t help noticing the order of magnitude variability in width over miniscule changes in drainage area (fig 12)!

Fig 7: probably should add the note about line colors and rolling averages you have in the other figure captions in case someone jumps to this figure.

Citation: https://doi.org/10.5194/esurf-2022-2-RC1
- AC1: 'Reply to RC1', Fiona Clubb, 08 Mar 2022
  
  Dear Helen,
  Thank you very much for your positive review of our manuscript and kind words! We agree with the changes you have suggested and will implement them in a revised manuscript.
  All the best,
  
  Fiona, on behalf of all authors.
  
  Citation: https://doi.org/10.5194/esurf-2022-2-AC1
RC2: 'Comment on esurf-2022-2', Matthew Morriss, 14 Mar 2022

Comments are in attached PDF

Citation: https://doi.org/10.5194/esurf-2022-2-RC2

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload

AR by Fiona Clubb on behalf of the Authors (22 Apr 2022) Author's response Author's tracked changes Manuscript

EF by Una Miškovic (23 Apr 2022)

EF by Una Miškovic (23 Apr 2022) Supplement

ED: Publish subject to minor revisions (review by editor) (02 May 2022) by Wolfgang Schwanghart

Dear Fiona and coauthors,

thanks for responding to the referees' comments and for submitting a revised version of your manuscript. Both referees have been very positive about your study and the method that you have developed. Moreover, you have fully accounted for all issues that have been raised by the referees.

I also think that your study represents an important and timely contribution to geomorphometry which provides fluvial and tectonic geomorphologists a tool to study a much overlooked property of fluvial systems. To this end, I just have a few minor issues (see below) that should be addressed before the paper can finally be accepted.

Best regards, Wolfgang

Minor comments

I am quite pleased to see a paper that deviates from the standard heading-scheme: Introduction, Methods, etc. , although this makes it a bit harder to quickly navigate the manuscript at first sight. However, in the guidelines (https://www.earth-surface-dynamics.net/submission.html#manuscriptcomposition) we ask our authors to provide sections titled Introduction and Conclusions. While you have the former, I need to ask you to rename the last section to Conclusions.

369: Really, the D8 flow routed channel was already and always in the valley centre? This is actually hard to believe looking at e.g. the Cumberland River and how it freely meanders in a relatively wide floodplain.

Fig. 12: All regression lines should have confidence bounds associated with them. These could be bootstrapped if autocorrelation in valley floor width is a problem. It will be interesting, however, whether any significant changes between the different creeks can be observed once you account for the uncertainties of the fits.

394: The units of K_v reported here is strange.

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AR by Fiona Clubb on behalf of the Authors (04 May 2022) Author's response Author's tracked changes Manuscript

EF by Mika Burghoff (06 May 2022) Supplement

ED: Publish as is (06 May 2022) by Wolfgang Schwanghart

ED: Publish as is (10 May 2022) by Tom Coulthard (Editor)

AR by Fiona Clubb on behalf of the Authors (10 May 2022) Manuscript

Short summary

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.