Assessment of a Smartphone App for Open Channel Flow Measurement in Data Scarce Irrigation Schemes

Round 1

Reviewer 1 Report

The manuscript reports information about an interesting topic and results are supported by several measurements and analysis.

Author Response

Dear Reviewer 1

Thank you very much for your useful and constructive comments. In the revised version, we have tried to address all comments provided by you if there are any. We made all changes with red texts and track changes in the responses attached. The revised manuscript is also attached as part of the responses.  

Author Response File: Author Response.pdf

Reviewer 2 Report

This paper evaluated the applicability and accuracy of using DischargeApp mobile image flow measurement software to measure the flow of irrigation channels. Taking the flow measurement data of V Notch Weir method as a reference。the paper analyzes the errors of DischargeApp flow measurement and builds a correction method to correct the flow measurement results. The accuracy of flow measurement was improved. However, there are some problems in the whole paper, such as unclear expression of experimental materials and methods and insufficient data analysis. Specific problems are as follows:

 

1. "2.2. Data Collection" introduces the selection of 6 blocks as the test section. The basic information of the test section needs to be further explained, such as width, depth, channel shape, etc.

2. in "2.2. Data Collection", the layout of V Notch Weir should be explained in the form of pictures or photos.

3. V Notch Weir was used as a reference method to verify the accuracy of APP. However, the V Notch Weir method itself also has certain errors in measuring traffic, which need to be explained.

4. Figure 2 shows that the channel for the experiment is unlined, and the status quo of the channel is irregular. Then, whether the measurement results are consistent under the condition of irregular shape of the channel and what is the consistency of the measurement results at different positions of the channel?

5. Water level is an important factor affecting measurement accuracy. In the experiment introduced in this paper, how to obtain water level needs to be explained in detail.

6. The expression in Table 1(should be table 2) is not clear, the content in the table is not explained, and the data accuracy is inconsistent with "257.875" (line-218)

7. In Figure 5. (b), errors of different measurement times are compared, and the figure shows that there are obvious differences in measurement errors of different times. What accounts for the differences in time measurements?

8. Further analysis of the measured data is needed in the discussion.Whether shadow, dazzle light, water wave caused by the wind, has influence on velocity measurement accuracy of flow.

9. The method used in this paper has a good application effect in near qualitative measurement such as flood monitoring. In precision irrigation, whether it can still be used under the condition of high accuracy of flow measurement needs further discussion.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer 2

Thank you very much for your useful and constructive comments. In the revised version, we have tried to address all comments provided by you. All edits are shown with red texts and track changes in the responses and manuscripts attached below in the system.

Author Response File: Author Response.pdf

Reviewer 3 Report

General comments

The paper under evaluation is not formally well structured.  Thus, for example, the conclusions are very similar to the abstract. In addition, the conclusions should respond to the objectives and they do not. Likewise, the "Discussion" section has paragraphs that are conclusions and, on the other hand, discussion is also made in the "Results" section. The "Material and Methods" section does not adequately describe the channels in which the measurements are made.

Specific comments

- Line 133: Figure 1 is not cited in the text.

- Equation (1): indicate how equation (1) is obtained.

- Line 162: A drawing showing the installation of the 90º V-notch weir and the location of the Discharge-App and the distance between them would be necessary.

- Line 165: What is Manning's coefficient used for? They do not indicate anything in the text.

- Line 170: the 18 experimental sites are not described, are they the same, does the section vary?

- Lines 190-194: although the use of the Discharge-App is not expensive, the authors indicate that many citizens would not be able to afford to pay for it or take data, therefore, with this device. Then, what is the point of doing this work if this device will not be usable in the region?

- Line 214: Since the MAE and MAPE coefficients are not going to be used, it is better not to quote them.

- Line 247: Errors of 25% are very large.

- Line 268: the sizes of the channels on which the measurements were made are unknown.

- Line 270-2: The sentence is not understood by looking at Figure 6.

- Line 282: Table 2 is not understood. It should be explained what each term means

- Line 290: RMSE and MAE errors have not been previously defined in the paper.

- Line 303: why do the flow rate values of both devices coincide especially in the measurements made in April?

- Lines 305-313: This paragraph is not a discussion of results.

- Lines 313-5: Where in the text is this result shown?

- Lines 324-6: Where in the text is this result shown?

- Lines 329-334: This is conclusions.

 

Author Response

Dear Reviewer 3

Thank you very much for your useful and constructive comments. In the revised manuscript, we have tried to address all comments provided by you. All edits are shown with red texts and track changes in the responses provided below. In addition, the manuscript is attached with the responses.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The author modified the main problems in the paper, such as providing pictures of v-notch weir, modifying Table 2, adding necessary instructions in the experimental method, etc., and explaining the questions raised about applicability and accuracy. This paper provides a great reference for the application prospect of 'DischargeApp' in the monitoring of irrigation channel flow, but there are still some problems in the writing specification that need further modification.

1. Pay attention to the writing specification of variables in the formula. For example, in formula 2, the subscript should be used; for example, Qapp should be changed to Qapp.

2. "Figure 6. (a). App discharge plotted against V-notch weir discharge, and Qvn and Qapp 'are the v-notch weir and the recalculated app discharge measurements in l/s respectively. And QVN and Qapp' are the V-notch weir and the recalculated app discharge measurements in L /s respectively.” “Qapp’ ” did not appear in Figure 6. (a).

3. Necessary explanations should be added to the picture. For example, What are the meanings of points “o” and “×” in Figure 7 respectively?

Author Response

Dear Reviewer and Editors,

We appreciate you and the reviewers again for your efforts and insightful comments to improve the manuscript. The detailed responses are provided below (with red-colored). The manuscript has been modified, and all changes have been made in tracked changes in the manuscript.

Author Response File: Author Response.docx

Reviewer 3 Report

The authors have satisfactorily answered all the questions raised by adding new graphics and more in-depth explanations. Likewise, they have redrafted the "Discussion" section, making it more understandable.

Author Response

Dear Reviewer and Editors,

We appreciate you and the reviewers again for your efforts and insightful comments to improve the manuscript. The detailed responses are provided below (with red-colored). The manuscript has been modified, and all changes have been made in tracked changes in the manuscript.

 

Comment: The authors have satisfactorily answered all the questions raised by adding new graphics and more in-depth explanations. Likewise, they have redrafted the "Discussion" section, making it more understandable.

Response: Dear reviewer, we sincerely appreciate your valuable comments and suggestions that led us to improve the quality of the manuscript.