The manuscript by Rach et al. presents a new approach to assessing palaeo-hydrology changes using the co-registered stable hydrogen isotope signatures of “aquatic” and “terrestrial” n-alkanes. The authors formulate a model whereby changes in relative humidity can be isolated from the sedimentary record, using a combination of the stable isotope data and a plant modelling approach. Overall the reviewers are positive about the new insights which can be gained from the approach proposed here. A number of concerns have been raised across the three reviews, however, which indicate that revisions are required to ensure that the practical steps and assumptions made by the authors are clarified, and that the interpretations are robust as a result.

In most instances, the authors have indicated in their reply that they can address the concerns of the reviewers. Of key importance is that the uncertainties of the approach are discussed in more detail (perhaps splitting the current section 3 into 3.1 Uncertainties and 3.2 Sensitivity tests). I agree with the reviewers that there are uncertainties that are also difficult to quantify (e.g. transport of the lipids), but which likely increase the errors on the reconstructions. But these should still be clearly stated. The authors note that many uncertainties have been accounted for or minimised given the particular location of the lake being studied here: it is also critical that such information is more clearly outlined. In addition to the comments provided by the Reviewers, I am keen to see a note in the section on sensitivity tests (currently lines 239-244) giving some indication of whether these tested variations in each value are considered realistic/feasible, or are they at the upper/lower end of feasibility? (are they specific to this site?) This would help the reader to understand whether the sensitivity tests are giving an over- or under-estimation of the errors. Drawing on the information given by Reviewer 3, it is also important that the universal applicability of this study (or not) is more clearly highlighted: does MFM provide such a special case that this is a unique record? If such an approach was to be applied elsewhere, what information would be required?

I disagree with the authors replies in a couple of instances, and would like them to consider these comments in their revised manuscript:
1) Display of the original n-alkane d2H data in figure 2. This is the first step towards generating the rh output, and I think it is important that the reader can see how this data developed. As the manuscript currently stands, it has to be read with Rach et al. (2014) open at the same time. It does no harm (and makes life easier) to show some the key data in its original form. Likewise, I encourage the authors to show the chironomid data on either figure 2 or figure 3, especially if it is this data which supports their inference that temperature did not fall below 15*C (see page C10 of reply to reviewer 1). The chironomid data is part of the input to the model, and given the discussions about the resolution and age uncertainties it is important for this to be directly compared against the rh model output.

2) Reviewer 1 asked for some information about the palaeo-hydrology of the Younger Dryas event here (comment 6). I disagree that nothing can be said about this here: a short paragraph which notes the main patterns of hydrological change would provide a valuable rationale for why this event was targeted. MFM is a key site for this time interval, and this could be emphasised. Since the new results seem to support the existing interpretations of changing humidity, a detailed discussion and interpretation of the climate drivers is not required.

On page 2 there is a discussion about how the stable isotope approach has developed and been applied to understand palaeo-hydrology. I missed a note to the peatland work of Nichols, who has also combined aquatic and higher plant deuterium/hydrogen ratios as a way of understanding bog hydrology (e.g. Nichols et al. 2009 Quantitative assessment of precipitation seasonality and summer surface wetness using ombrotrophic sediments from an Arctic Norwegian peatland. Quaternary Research)

Minor typos or corrections:
Line 57: and thus allow the extraction of quantitative..
Line 67: terrestrial plants
Line 70: organisms
Lines 162-164, lines 173-175: where are the values provided in the equations sourced from? No references are given.
Lines 200-201: we did not, however, …
Line 291: since no paleotemperature…
Line 412: italicise n- of n-alkanes
Line 420: hypothesis would imply that leaf
Line 426: move ‘also’ to after ‘would’ (before ‘underestimate’)
Line 451: ‘place’ rather than ‘level’?
Line 459: but a lack of mechanistic understanding
Figure 3: is the Younger Dryas the area shaded in grey?
Line 483: drier conditions
Line 484: remove comma and formulate citation into one set of brackets

Dear authors,
Thank you for your thorough and careful consideration of the comments by the reviewers and the editor. I am satisfied that you have responded to the comments and concerns. I attach here an annotated pdf with some final minor corrections (mostly typos).