Economic Analysis of Flood Risk Applied to the Rehabilitation of Drainage Networks

Round 1

Reviewer 1 Report

Papers presents an optimization analysis for rehabilitation of drainage networks to combat flood risk. It builds upon previous work of the author team with respect to both the network/flood modeling as well as the optimization scheme, but advances the objective function formulation to examine probabilistic assessment of the flood risk.

Overall paper is well written and informative. Grammar and flow should be improved but that can be handled at the editing stage.

More importantly,  some clarifications need to be made with respect to the probabilistic aspects of the problem formulation.  

1) Authors confuse probability and annual exceedance rate. More care is needed on these two concepts becasue they are not the same. For example frequently, and even in figures authors equate probability p (which is unitless) with return rate 1/T which has units 1/years. This seems to imply that probability can be larger than 1 (it T<1). I suggest revisiting the concepts of annual exceedance rate and probability [actually all discussions should be framed with respect annual exceedance rate and remove references to probaiblity]. 

2) Rephrase lines 106107. They give the impression that EAD for a specific return period is necessarily from a single event, but that is not true (it is annual). 

3) Concepts in lines 113-115 are global truths for any probabilistic assessment, but authors make it sound like this came from comparing different methods for estimating flood risk in urban areas. Rephrase sentence appropriately.

4) Lines 141-142. Genetic algorithms can handle continuous variables. Simply the specific GA the authors use needs discrete variables. Do not pose this as a general requirement of GAs. 

5) I felt that some version of Figures S2/S4 belongs in the main paper (and not supplementary material) since they pertain to advancements of this study compared to previous ones, but will leave it up to the authors to decide on optimal placement.  

 

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

1-Add "Economic Analysis" in Keywords.

2-Include the assumption of SWMM model

3-Add the "Limitation of the Study" in Introduction.

4-The use of genetic algorithms has been stated as one of the most suitable alternatives  to find solutions to this type of problem, but it does not compare with other optimization methods.

5-Compare the results with previous works extensively.

6-Maps should have North Direction and Scale.

7-What about sensitivity analysis of the model?

8-What about climate change impact on the results?

9-Add the below reference:

Cantos, J. O.,  Hernández, M., Morote, A. F. and Eslamian, S.,, 2022, Reducing flood risk in Spain: The Role of Spatial planning, Ch. 12 in Flood Handbook, Vol. 3: Flood Impact and Management, Ed. by  Eslamian, S., and Eslamian, F., Taylor and Francis, CRC Group, USA.

Author Response

Please see the attachment

Author Response File: Author Response.pdf