Study on Characteristics of the Water Diversion Ratio and Impact of the Diversion Dyke at South and North Ports of the Minjiang River During Wet Season

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript employs the MIKE 21 hydrodynamic module to establish a two-dimensional hydrodynamic model of the lower Minjiang River, conducting numerical simulations to analyze the impact of the diversion dyke's length and angle on the water diversion ratio (WDR) during the wet season. The methodology is scientifically sound, and the conclusions are clear, providing valuable reference for engineering practice. Overall, the manuscript is well-written. However, some minor modifications are recommended to further enhance the quality of the manuscript before acceptance.

 

1. In line 14 of the abstract, there is a duplication of the definite article "the the South and North Ports". One "the" should be deleted. Additionally, it is recommended to change "at a tidal cycle scale" to "on a tidal cycle scale ", as "on" is more appropriate for describing periodic processes.
2. In line 28 of the introduction, the term "water diversion ratio" is defined and its abbreviation is provided. However, inconsistent variations of this term appear in several sections, such as "flow diversion ratios" in line 48 and "diversion ratios" in lines 51 and 55. It is recommended to standardize the terminology throughout the manuscript to avoid confusion.
3. The introduction provides a comprehensive description of the research background; however, the explanation of the research motivation is relatively weak. It is recommended to further emphasize the significance of the current study or clearly highlight the research objectives.
4. In line 98 of Section 2.1, the text mentions that the bifurcation of the lower Minjiang River occurs at "Houguan", while Figure 1 labels the bifurcation point as "Huaiankou". It is recommended to revise either the text or the figure to ensure consistency. Additionally, it is suggested to add the key landmark "Nantai Island" in the figure for better clarity.
5. In Figure 1, the color used for the flow velocity and direction monitoring stations is too similar to the background topography color, making it difficult to distinguish. It is recommended to adjust the color scheme to provide more contrasting colors and improve the readability of the figure.
6. In lines 114–127 of Section 2.1, some reference numbers appearing in the text do not correspond to any entries in the reference list. Similar inconsistencies are also present in other parts of the manuscript, indicating potential citation errors. It is recommended to thoroughly review and verify all references to ensure completeness and accuracy.
7. In section 2.4, equations (4) and (5) use the same symbol to represent different expressions, which is unreasonable. Please revise and differentiate them.
8. In section 2.4, the method for calculating the WDR is introduced, but the variable "Average WDR" is used multiple times later in the text without a detailed explanation of the corresponding calculation formula. It is recommended to add this information.
9. The formatting should place the figures and tables closer to the text. For example, in line 237 of section 3.1, Figure 6 is already mentioned, but Figure 6 is placed at the end of the section. To ensure readability, it is recommended to adjust the positions of Figures 4, 5, 6, and Table 1.
10. It is recommended to modify "Figure 6" in line 237 of section 3.1 to "Figure 6 (a)".
11. Although the article presents the hourly variations of the WDR of the South and North Ports during spring and neap tides in Figures 4 and 6, it lacks specific data to support the findings. It is recommended to add this information.

 

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This study focuses on the lower MinJiang River. It employs a MIKE 21-based two-dimensional hydrodynamic model to quantify the WDR variations between the South and North Ports at a tidal cycle scale during the wet season and to reveal the regulatory effects of diversion dyke length and angles. The results indicate that the WDR of the North Port exhibits distinct variation under different tidal stages. The WDR of the North Port increases with the length of the diversion dyke. However, here are some comments and suggestions that need to be improved before it is published.

 

1. In Abstract on Line 14, “ between the the South” should be “ between the South”.
2. Keywords on Lines 24 and 25 suggest to reduce below five.
3. The measurement locations of velocity and water level in Figure 1 are not easy to read. It suggests using the arrow to point out each location.
4. There are four tidal cycle data of velocity within 24 hours in Figure 3. However, it should be two tidal cycles within 24 hours in a normal condition. How can It be?
5. In addition, why are all velocity values positive? The velocity values and directions should be affected by tidal in Figure 3.
6. What is the definition of flow direction in Figure 3, and why is there a fixed direction during specific durations?
7. The sediment transport will affect topographic conditions and hydraulic flow patterns under different tidal conditions. Therefore, what are the effects of sediment transport in the study area? Can Mike 21 simulate such a sediment transport condition?
8. What is Mike 21's simulated mesh sizes, delta t, and calibrated parameters? Please list them and point out the accuracy of model calibration.
9. The flow field in Figure 5 is unclear. Does it present the flow field on the water surface?

Comments on the Quality of English Language

No.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

General Comments

• The abstract section contains a lot of the most difficult words that are not technical. Either remove them or replace them with the relevant simple and easy technical language.
• Introduction lacks the background of dyke, which is main focus of the current research. But there is no proper research background about it.
• Please restructure the manuscript by improving the grammatical mistakes.
• Finally, please provide a thoroughly revised manuscript along with a point-by-point response addressing both general and specific comments. For the point-by-point response, use a different text color to highlight the changes. It is not sufficient to merely modify the text; you must specifically explain how each issue was addressed or changed by giving response under each comment with the same name as given in this file.

 

Specific Comments

Abstract

Line 14

"the the South and North Ports" → "the South and North Ports" (remove repeated "the")

Line 12

“it is the first time in history” what do you mean ?? without mentioning the discharge quantity, and any loss, how can you mention that this is the first time in history. If you want to write this please mention some reasons or destruction.

Line 14

The phrase "at a tidal cycle scale" → could be clearer as "on the scale of a tidal cycle"

Line 16

Consider rephrasing "distinct variation under different tidal stages" as "significant variation with tidal stages"

Introduction

Line 31

There should be space after full stop.

Line 32

Instead of “mirror” use some technical word.

Line 37

Planimetric characteristics ?????

Line 39

Bifurcation patterns ?????

Line 39

Anabranching ???

Line 57-58

“Alomari et al. [12] systematically quantified” are you sure ?? please check it again.

Line 61

Please check it again.

Line 62

"critical discharge ratios" should be "critical discharge conditions"

Line 94

"in estuarine environments." should be "within estuarine environments."

Comment

There are no research background about the dikes. Could you please add some updated references?? For example,

“An Experimental Investigation on Dike Stabilization against Floods”

“A state-of-the-art review of normal and extreme flow interaction with spur dikes and its failure mechanism”

 

Methodology

Line 164

“The model grid was constructed” is wrong. Please mention the total number of nodes ? did you check the mesh sensitivity ? please add one figure to confirm that model is mesh independent. Moreover, provide one table that defines the boundary conditions.  

 

Line 169-170

"The upstream boundary condition used an average discharge..." should be "An average discharge was applied as the upstream boundary condition..."

Line 170

"at Zhuqi Station." should be "(upstream boundary at Zhuqi Station)"

Line 174

How did you maintain CFL 0.8? Please explain it in detail.

Line 186

although some discrepancies occurred at certain times" should be "although minor discrepancies occurred occasionally"

Line 188

“Alomari et al. [12] systematically quantified” are you sure ?? please check it again. Moreover, add some statistical indicators, as they play a crucial role in evaluating the performance of numerical predictions by comparing them with the data observed through experiments

Line 247

"close to 20%." Consider explicitly mentioning accuracy comparison clearly as: "close to 20%, indicating strong agreement between simulation and observed data."

 

Results and Discussion

Line 255-256

"during the flooding and ebbing rush tides" should be "during flood and ebb tidal surges"

Line 261

"first decreasing, then increasing, and then decreasing again" should be "initially decreasing, subsequently increasing, and then decreasing again"

Line 324

"Operational condition de-scription" should be "Operational condition description" (line break issue, should be corrected)

Line 355-356

"variation characteristics" should be simpler as "variations" or "variation patterns"

Conclusion

Line 360

Clarify the statement "regardless of the tide type" should be "regardless of tidal conditions"

Comments for author File: Comments.pdf

Comments on the Quality of English Language

English should be improved.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The reviewer’s comments have been answered, and the manuscript has been improved. However, some minor comments and suggestions must be mentioned before acceptance.

 

1. As replied in comment 7, the current MIKE 21 model primarily focuses on hydrodynamic processes, concentrating on studying the bifurcation ratio variations at the tidal cycle scale without using the sediment transport module. The authors recognize that sediment transport-induced long-term adjustments in river morphology are key drivers of bifurcation ratio evolution. Therefore, in the future, the advanced study will explore the impact of sediment transport on bifurcation ratio changes through coupling sediment-hydrodynamic models. I suggest adding this condition and limitation in the conclusion paragraph to address the study criteria.
2. What is the simulated velocity error and accuracy in comment 8?

Comments on the Quality of English Language

No.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

I don’t have any further comments.

Author Response

Thank you for your review.