Fundamental Study on the Development of an Inexpensive Velocity Meter for River Floods Using Stagnation Points

Round 1

Reviewer 1 Report (Previous Reviewer 4)

The artice is well prepare and deals with the development of an inexpensive velocity meter. It is useful gor hydrologist science, reduce the cost and present a modern technology in hydrology. I believe that worth publication in the current form.

Author Response

Dear Reviewer 1

Thank you very much for providing important comments. We are thankful for the time and energy you expended. 

Thank you for your positive review of our paper.

 

Reviewer 2 Report (New Reviewer)

The authors experimentally measured the flow velocity based on the simple physical phenomenon of afflux due to increased pressure at the stagnation point. They measured the flow velocity from photographs taken by residents of floodwaters raised by utility poles. The results are very useful to the current scenario. The paper is suitable for publication after incorporating the following comments.

 1. The Abstract should contain the following things: Why is it important to study this problem? What methods were used? What are the important results? What conclusions can be drawn from the results? Please include specific and quantitative results in your Abstract, while ensuring that it is suitable for a broad audience.

 

2. What is the novelty of the work and where does it go beyond previous efforts in the literature?, particularly, from Ref. [29]

3. Give the limitations in the study.

4. Add all the assumptions in the study.

5. Why the authors chose the cylinder diameter 40, 120, 200 mm only. Is there any specific reason?

6. Give reference(s) for Equation (7) if possible.

7. Conclusion is too long. It should be concise and brief.

Moderate editing is required.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report (New Reviewer)

In this study, experimental studies are conducted using a method of measuring the flow velocity based on the simple physical phenomenon of afflux due to increased pressure at the stagnation point. The experimental results demonstrate the effectiveness of the proposed method. However, some weaknesses should be addressed, especially the introduction and experiment.

1) The introduction section needs further supplementation. Current literature analysis is not enough to fully explain the significance of this study. For example, at present, the introduction mainly introduces the research status of relevant background in Japan. The current research status in more places also needs further introduction. In addition, some literature on target location and detection in other fields should also be introduced. I suggest that the authors combine the introduction with relevant work and supplement relevant literature, such as

[1] Super-Resolution Mapping Based on Spatial-Spectral Correlation for Spectral Imagery [J]. IEEE Transactions on Geoscience and Remote Sensing, 2021, 59(3): 2256-2268.

[2] Target-Constrained Interference-Minimized Band Selection for Hyperspectral Target Detection, IEEE Transactions on Geoscience and Remote Sensing, 2021, 59(7): 6044-6064.

2) The experimental part needs further improvement. The current testing scenario is still relatively single, as many factors in the water area may affect the performance of the equipment. For example, the surrounding temperature, the degree of turbidity in the water body, etc. It is recommended that the authors discuss some factors that affect device performance.

3) Can the method proposed by the authors be compared with more advanced methods to highlight the performance of the method.

4) There are some grammatical errors in the article, which need further careful proofreading.

There are some grammatical errors in the article, which need further careful proofreading. For example, some fonts are red. The formula in Figure 3 should have a serial number

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report (New Reviewer)

I hove no other problems. Thanks

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Abstract should better present  contribution of this study.

Physical and theoretical interpretation of the results has been presented in the text weakly.   The novelty of this work for the journal readers is not sufficient. In fact, this manuscript makes no progress in practical and theoretical considerations. Also, scatter in velocity data and underestimation in measured data show that more advanced methods are required for new studies.

The superiority of this instrument and method is not clear in comparison to existing ones.

The literature review is not critical and pertinent regarding the existing methods and tools to measure flow velocity. The authors only use a few data to present their method. This may not be justified without clarifying the strong and weak points for readers. The authors should present more profound investigation around their method, and clarify its key limitations. How can one use this method for 2D and 3D flows?  After three centuries Pitot tube method or Bernoulli  equation do work in the laboratory very well, so more novelty is required to measure velocity especially in coarse-bed rivers in flood conditions. The reliability of data near the bed and water surface should be discussed.

What is the range of flow depth to collect data?

What are the key assumptions to use this method?

What are the correction coefficients to adjust the measured velocity? A simple regression may not be justified to present a new method or instrument.

 

Abstract and conclusions need to be rewritten by revealing the novelty and contribution of this study.

How can the authors manage the limitations of their instrument?

There is no information regarding the reliability of data for non-clear water during floods in rivers.

What is the sampling duration in each point?

 

Why has the velocity profile been plotted inversely in Fig. 10? The velocity increases toward upstream.

Author Response

Author Response File: Author Response.docx

Reviewer 2 Report

This study has obvious appeal due to its simplicity and applicability to real flood monitoring problems. It is the basis for a good example of so-called 'citizen science' and therefore of potential value to readers. Nevertheless in its present form it has significant shortcomings, essentially related to the novelty/applicability to other systems and recommendations made. A major point seems missing from the work, in terms of what this might mean for how such devices could be used in a flood monitoring situation. Would they be put in fixed positions immediately before the arrival of a flood? Would they be deployed by volunteers? How can we assure the accuracy and reliability of the data obtained?

The language used in paper can be confusing and needs a thorough edit from an  independent experienced author. Abstract in particular is not at all clear and the impact of the work may be lost especially for an international audience. 

Overall I would say the submission contains too many figures and these need to be reduced to maximise impact and focus in on the major points to help readers.

Given that we are dealing with quite well established technology, the focus of the paper needs to be on how the technology can be applied in a novel and useful way for the benefit of mankind, as part of a flood risk management process.

The structure should be revised so that Section one contains the background and aims of the study, for which a much clearer statement should be provided. Contents of Section 2 should be combined with Section 1.

Fig.1 is not clear and should be omitted. Maybe replace it with a clearer version or some sort of sketch.

The term 'rising water surface elevation' is used widely and is not clear. This is because 'rising water' could be taken to relate to the situation when the water level is rising, i.e. during the first few hours of a storm hydrograph. I suggest a term such as 'afflux' for clarity.

In Fig.3 the caption should contain more information about where and when these results were obtained, what the points on the graph signify, and the basis of the straight lines used.

Fig.4 needs re-drafting. It must be original, and not copied from an internet source.

Fig.6 Readers will need more details including diameter of nozzle and justification of the selection of tube diameters used, materials, methods of fixing in position etc.

Fig.8 more details required, same comment as Fig.3

The remainder of the figures suffer from the same lack of clarity as mentioned above and I think further information is needed in all captions, to help readers. I also think further justification is needed for the use of velocity squared on the horizontal axis, perhaps by referring back to the fundamental equations.

 

 

 

Author Response

Author Response File: Author Response.docx

Reviewer 3 Report

I recommend revising the work methodology and placing emphasis on more rigorous experimental verification of results with a greater number of repetitions and better theoretical background of the proposed measurement methods.

Author Response

Author Response File: Author Response.docx

Reviewer 4 Report

This study aims on the development of an inexpensive velocity meter for river floods using stagnation points. The article is interesting and well-structure; however, some parts need to be revised.

Line 36. Why only estimations from the RCP2.6 climate change scenario were presented? What about the others?

Line 51. The importance of targeted management and NbS solution for flood mitigations has raise the concern of scientific community especially where critical infrastructure exposed in flood zones as mentioned in a recent national scale approach (https://doi.org/10.3390/hydrology9080145).

Which is the difference in cost between the proposed methods and the installation of a hydrometeorological station (gauged station). Also, any evidence for the difference in the results accuracy?

Discussion part is missing. Authors should discuss the results and how they can be interpreted in perspective of previous studies and of the working hypotheses. The findings and their implications should be discussed in the broadest context possible and limitations of the work highlighted. Future research directions may also be mentioned.

 

Author Response

Author Response File: Author Response.docx