Dear authors,
my apologies for the delayed handling of your manuscript.
I am glad to inform you that I accept your paper as is. You have addressed all comments of the reviewers which has improved the manuscript considerably. I think that, together with the two companion papers, this manuscript is a valuable addition to the way how water movement through landscapes is computed and modelled.
Thanks for submitting to ESURF and kind regards,
Wolfgang Schwanghart

Dear authors,

I am pleased to confirm acceptance of your paper for publication in esurf, based on the careful review and recommendation of the 2 reviewers and the Associate Editor. Thank you for your thorough and thoughtful response to the reviewer comments, particularly the detailed comments from Reviewer #2 — and for choosing to publish this set of papers in e-surf.

I have some very minor suggestions, mostly related to the discussion, which are not obligatory but which you might consider. You could make these now, before uploading your final files for type-setting, or during proof-reading (or you can ignore them). These comments are listed below.

In addition, I had a look at your code on GitHub (thank you for making this available). While the procedure for compiling and installing seem clear, it is harder to see how someone not familiar with your code would go about applying it to a given DEM. I wonder if it might help make your code more useful if you provide some additional details on GitHub, such as (1) the expected format of the elevation data, etc., (2) some clues about how to pass the data file when calling the executable, and (3) what output to expect — as well as any general tips for things to avoid, etc. I don't consider these changes to be pre-requisites for publication of your paper, but I share the comments here because I do expect they would make your work more widely accessible.

My final comment is just to apologize for how long the handling of this manuscript has taken. As you may imagine during this time, many of us are stretched thin, and there have been delays at each stage of handling your paper that has led to a longer-than-expected overall timeline. Please accept my apologies — and thank you again for choosing esurf for this work!

Josh


Minor suggestions:

p. 18, line 462: "the latter algorithm is significantly slower" (add latter to be clearer)
p. 18, line 462: "LiDAR DEM from the..." (add "from the")
p. 18, line 462: "reduction in wall-time using FSM." (add "using FSM" the be clearer)
p. 18, line 491: "our FSM results" (add FSM)
p. 18, line 491: "from those" is repeated, so delete one
Table 2: I think it could help to have units in the column headers here; although you say seconds in the caption, the speed-up is presumably a multiplicative factor, and this is not spelled out (though one could infer it from the caption)
Figures 7 and 8: I am curious (1) why you used such different starting depth of runoff (were these scaled to expected regional hydrology?) and (2) why the differences between the methods seem largest at the moderate starting depths, with less difference at the extreme low and extreme high starting values in each case. As above, you needn't address these questions before publication unless you want to do so.