Modelling Flash Floods Driven by Rain-on-Snow Events Using Rain-on-Grid Technique in the Hydrodynamic Model TELEMAC-2D

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The main question addressed in the following study is the significance of incorporating snowmelt in runoff modeling and routing to analyze flash floods triggered by heavy rainfall, snowmelt contributions, and rain-on-snow events in Norway.

 

I consider the topic original relevant in the field of hydrological modelling. The idea of combining two different types of models is intristing.

 

The presented study focuses on a single watershed and a short observation period. I believe this is the reason for the strong agreement of the statistical results.

 

It would be appropriate to test the model's sensitivity to changes in the CN curves.

 

Figure 2: In the legend you need, describe the data time step - daily? Hourly?

Author Response

Thank you so much for taking your time and sharing your suggestions on the manuscript. Our response to your comments is as follows:

Comment: It would be appropriate to test the model's sensitivity to changes in the CN curves.

REPLY: The present study is based on our previous study (Godara et al., 2023) where we have done the sensitivity analyses for the changes in CN values along with the other parameters such as antecedent moisture conditions, roughness and mesh resolutions. This study uses the previous study as a basis to analyze Rain-on-Snow events and to show how to integrate snowmelt modelling into the rain-on-grid modelling. This is an important event in cold climates and our main objective is to show how snowmelt can be integrated in the rain on grid model. We have added a sentence referencing the sensitivity analysis in the current manuscript (line 378-385).

Comment: In the legend you need, describe the data time step - daily? Hourly?

REPLY: We have added in the figure caption that the series has an hourly temporal resolution.

 

References:

Godara, N., Bruland, O., & Alfredsen, K. (2023). Simulation of flash flood peaks in a small and steep catchment using rain-on-grid technique. Journal of Flood Risk Management. https://doi.org/https://doi.org/10.1111/jfr3.12898

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

After carefully reading your manuscript several times, my top suggestions are:

1. In my humble opinion its main objective has been only partially achieved and should be clearly underline.

2. I strongly suggest including in detail, but briefly, how the models used are constituted. I am referring to what are the main methods used to model production and routing functions (please include the main equations and conceptual model).

3. Furthermore, what are the set of information necessary to implement these models and their availability for this basin? These should include information on bathymetry, pixel resolution, rain gauge stations, quality assessment of precipitation and flow data, etc.

4. On the other hand, it is well known that the CN parameter is very sensitive. In fact, a very small change in this CN value generates a significant change in the basin hydrograph. However, the series of events to be simulated has a specific calibration so it would not be possible to use the proposed models to predict future events. Consequently, this is a very big limitation of the manuscript under evaluation and goes against the objective pursued, reducing its level of achievement.

5. I suggest the authors try to propose a model to represent the change of the CN parameter taking into account the various meteorological conditions present for each flow peak.

6. Table 1 can be simplified without repeating values that are the same for all events.

Comments on the Quality of English Language

Minor English corrections needed. I think the editorial team will be able to correct the style and some technical words.

Author Response

Thank you so much for taking your time and sharing very relevant and helpful suggestions on the manuscripts. We have tried our best to include your suggestions in the manuscript. The corresponding revisions are highlighted and also tracked in the revised manuscript.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you for taking into account all my suggestions and comments made about your manuscript.