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Reader’s report of Tucker and Hancock, 2010: Modelling landscape evolution. Earth Surface Processes and Landforms, 35(1): 28-50

Reader: Arnaud Temme

This paper was part of ESPL’s State of the Science issue in the beginning of 2010. This means that it is supposed to review, reframe and reformulate our current understanding of key geomorphological questions – landscape evolution modelling in this case.

After reading, I’d probably go for reformulate as the main achievement. In what they describe as a review of basic modelling elements, Tucker and Hancock give answers to the questions that each of us has (or should have) asked themselves when working with or developing such models. The answers are ordered along the lines of the geomorphic system – from weathering to hillslope processes and fluvial activity. This order felt very natural, although I would have preferred to deal with discretization schemes and flow routing (of any flow) before dealing with the different transport processes. All in all, this is a fine paper, and one of the few that I have at hand on my desk in paper form.

Liked:

I particularly liked the part that presents flow routing considerations. This was the first text where I found the various elements of this explained in language that is easy to understand.

The conclusions and future issues-section is pleasantly long and detailed and is a must-read for anyone looking for creative ideas for new research in the field.

Left to be desired:

I certainly missed our Wageningen landscape evolution model (www.lapsusmodel.nl) in the list in Table I, but that is a minor issue.

My main concern is the ease with which the authors accept geomorphology’s self- (and field-)defined processes as starting points for numerical analysis. What works for a field-based linking of landforms to processes (form-process relations), does not necessarily work for model-based analysis (which must explain formation of forms through the interaction of multiple processes). The authors only hint at the topic: “.. this must drive the landscape modelling community toward not just new numerical methods but also new methods for describing and quantifying landforms” (p42).

I also missed a discussion of how to deal (or not to deal) with sinks and depressions in landscape evolution models.