• The POT event declustering is quite simplistic and doesn't count for the varying speed of response of the flow to rainfall at each location.
• The reference to "high" and "low" return periods from line 330 onwards needs to be more specific. The exact choice of cutoff is not important, but stating what it is and sticking to it is important.
• Using high numbers of different copulas and distributions can make it hard to compare results, especially between sites. Using more general distributions (e.g. kappa) or more general copulas and sticking to one overall best choice may make it easier to interpret.

• The heavy use of abbreviations does make this harder to read, consider sometimes switching back to fully spelling out terms like rainfall.
• Check your references in the main body match those in the bibliography.
• Some paragraphs could be swapped for tables (paragraph around line 168, paragraph around line 330
• line 252: numbered lists should be presented as such, with a new line for each for readability.
• Figure 4: It is unclear what is exactly meant by "natural variability", and how it differs from the significance shown by the red circles.
• Figures 7 and 8 are very busy. Consider splitting into more figures, or remove elements of the figures which do not directly contribute to your conclusions.

This paper is well-written and scientifically sound. I would like to see more discussion on the following topics:

[1] you end up with results for RF and NTR. Please recommend how to combine these results in a flood risk analysis

[2] the isolines method has some shortcomings in my view. The paper hints that these can be used to define a single event (the one on the isoline with the highest probability density), However, in most compound flood risk analysis there is no single "most representative event". In coastal zone there are locations close to the coastline for which the main flood driver is the peak sea level (surge) and there are locations more inland for which the rainfall is the dominant flood river. For the former, an event with extreme NTR  and moderate RF is the most relevant, for the latter an event with extreme RF and moderate NTR is the most relevant. 

furthermore some minor comments in the attached document

I would like to compliment the authors for a well-written paper. The research gap this paper aims to fill is clear and relevant. Here are some minor comments to consider

• Consider adjusting the title to speak to a larger audience. Currently, the term ‘mixed populations’ does not speak for itself. Instead, it would be good to focus on the fact that you look at different storm types that can drive compound flooding
  1. As a follow-up, the term ‘populations’ is never clearly defined.
• As RC1 and RC2 have highlighted there are some limitations and uncertainties in the methods that you have used. In the paper, I am missing a proper discussion of these limitations and how to overcome them in the discussion/conclusion