The Impact of Meteorological and Hydrological Memory on Compound Peak Flows in the Rhine River Basin

Round 1

Reviewer 1 Report

This study investigates the effects of soil moisture and precipitation in regulating peak flows in Rhine river basin through numerical simulations. Overall, the paper is well written and some results are interesting. The following comments have to be addressed before the paper can be considered for publication.

My major concern is on the use of climate model simulations for driving the hydrological model. I am wondering why not use the observed climate data, which is available in the study period? The climate model simulations can not be treated as observations, even if they are bias-corrected to certain extent.

In addition, more descriptions are required for the SPHY model, e.g. runoff scheme, soil moisture scheme. And it is unclear whether only temperature and precipitation are required for driving the model.

It is good to see authors mentioned the potential caveats of the SPHY in the discussion section. Several nice studies have improved our understandings on the diverse behaviours of various hydrological models. I suggest authors add the following literatures to make their discussions on hydrological model uncertainty more insightful.

Hattermann, F. F., et al. "Cross‐scale intercomparison of climate change impacts simulated by regional and global hydrological models in eleven large river basins." Climatic Change 141.3 (2017): 561-576.

Zhao, F., et al. "The critical role of the routing scheme in simulating peak river discharge in global hydrological models." Environmental Research Letters 12.7 (2017): 075003.

Zaherpour, J., et al. "Worldwide evaluation of mean and extreme runoff from six global-scale hydrological models that account for human impacts." Environmental Research Letters 13.6 (2018): 065015.

Author Response

Dear Reviewer 1,

Thanks for your constructive remarks. The clarification of your comments has been uploaded here in the word document.

Best,

Authors

Author Response File: Author Response.docx

Reviewer 2 Report

The paper was well written. Analysis appear to be thorough. However, the conclusions are not very revealing in my view. Most findings are already well-known:

- The soil moisture content is a relevant factor for generating high discharges

- High peaks in the rain are caused by multiple days of rainfall

- Most extreme events in the Rhine are a combination of high rainfall in combination with substantial snow melt

I don't feel a climate model and/or a hydrological model is required to come to these conclusions, historical data will lead to the same conclusions. Moreover, I's rather base the conclusions on historical data than on a climate model with substantial bias corrections and a hydrological model with all its uncertainties/simplifications. The fact that the combination of the two models resulted in a peak discharge of 26.000 m3/s, twice as high as the highest observed event, make me rather skeptical of the model suite. I would at least have expected that this event was further investigated, ie a deeper analysis of (the credibility of) the synthetic rainfall and snow melt that lead to this peak discharge.

Author Response

Dear Reviewer 2,

Thanks for your constructive remarks. The clarification of your comments has been uploaded here in the word document.

Best,

Authors

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors have well addressed my concerns. I recommend publication of the revised manuscript.