Predicting Compound Coastal Flooding in Embayment-Backed Urban Catchments: Seawall and Storm Drain Implications

Round 1

Reviewer 1 Report

Based on a numerical modeling approach, the paper presents a sound and relevant work about coastal floods caused by compound (sea level and precipitation) events.

 

Some minor improvements to the manuscript are suggested:

 

- Figure 1: Insert lat long coordinates

- Line 146: Correct “… full non-linear nonlinear shallow…”

- Line 157: Use Delft3D-FM to distinguish from the Delft3D software

- Line 176: A figure with the mesh/grid and open boundaries location will improve the model's description. Seawalls and sink/source points location will also improve the description.

- Lines 189-190: The authors should clarify their affirmation “It is notable that all model roughness coefficients correspond to physical values for a given land cover. No calibration was performed.”

- Lines 199-200: The authors should further justify the implications of using precipitation data from a gauge station 12 km from the study site.

- Lines 220-222: RBR pressure sensor measured data has to be processed to obtain water levels. The procedure should be further detailed, including used surface pressure data, water density, and eventual sea level rise during the measurement period.

- Equations (1) and (2): The authors should detail how they were implemented in Delft3D-FM or indicate that they were used before considering the sink discharge in the model.

- Figure 9: Insert A to F labels

- Line 442: Correct “when tide values are closed” values should be valves

- Line 492: The authors only mention and consider pumping scenarios in the conclusions paper section. They should say why this was not an option for the simulated scenarios along the seawall rising.

- References should be numbered

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

This manuscript aims to develop an integrated modeling approach to simultaneously deal with infrastructure and multi-pathway flood processes that can be used to quantitatively characterize flood risk on an urbanized coastline. 

This manuscript fits well in the context of a case study rather than a research article, as it does not offer groundbreaking scientific content or relevant methodological novelty. This is evidenced by the extensive list of references, and many more could be added.

The list of references is (unnecessarily) extensive, but the Introduction/state-of-art on the topic is very targeted and therefore limited. Indeed, the issue addressed in this manuscript has been the subject of discussion, and different solutions have been tested and implemented in many countries with extensive coastal zones.

In order for this manuscript to be of sufficiently convincing and useful interest to those less familiar with the Delft3D model, consider providing essential details of the mathematical model and the numerical method of resolution, eventually providing a flowchart showing the workflow process. 

To resolve multiple-source flood processes basically solutions based on seawalls and maneuvering of tide valves are analyzed and discussed in the case study. That's ok, however, the Discussion section should be broader, and not limited to complementary analyzes that may be included in the Results section. Note that flooding hazards can be mitigated by implementing other (or complementary) measures.

Why not discuss other types of measures, such as small to medium dams/reservoirs with suitable locations and dimensions and the various types of vegetation in upstream areas to reduce surface runoff and increase infiltration? 

The Discussion may also consider other possible methodologies, or complementary to the previous ones, such as hybrid solutions on the coastline composed of different layers, such as sand dunes, channels with casuarinas, creepers, retaining walls, casuarinas, coconuts,...

Also note that a Research Article in a scientific journal should not be intended as a repository or reminder of material already published in numerous publications, as in this case with 125 unnecessary and repetitive references (4.5 pages).

Other specific issues that should be duly checked are:

- Abbreviations/acronyms should be defined at first mention and used consistently thereafter. The List of Abbreviations should be greatly expanded.

- Enter the date of the photo in the Figure 4 caption.

- Table 3 is not mentioned throughout the manuscript.

- Check the punctuation on line 329. 

- Check the “Inundation Volume” column of Table 6; commas are missing.

- Figure 9 must be redrawn; the letters A, B, C, D, E, and F are missing and the horizontal axis must be named and include units (h). 

- Avoid using keywords that already exist in the title, such as "storm drain" and "seawall".  

The English language and style are fine; just a minor spell check, especially punctuation is advised. 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The new version of the manuscript is basically identical to the previous one, limiting itself to clarifying specific details, improving some figures (some still with insufficient graphical resolution), and correcting gaps reported by the reviewers. Nothing significantly relevant is added to the core content. 

Indeed, regarding most of the scientific weaknesses pointed out in the previous review, the authors devalued them, understanding that they should not be addressed.

The Delft3D model is used to obtain and discuss the presented results; however, the authors assume that details about the model are unnecessary and that its calibration is also not necessary.

Regarding a broader discussion on other (or complementary) measures to mitigate flooding hazards, the authors mention that they "are beyond the scope of this paper". It is accepted that the core content of the manuscript is limited to the key topic; however, it is clear that having a more comprehensive Discussion section would improve the manuscript, making it more useful to a wider audience and more appropriate for a Review Article.

A special note for the 125 references, including 6 by the authors themselves, most of them unnecessary and repetitive. This is only acceptable in the context of a Review Article, and even then, in this case, it remains unnecessary overkill, as most of them do not contribute to improve the quality of the manuscript.

In short, this manuscript is acceptable for possible publication as a Review Article or Case Study, but could significantly improve and be more useful to the reader if the above points were addressed.

The English language and style are fine; just a minor spell check, especially punctuation is advised.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf