Simulation and Prediction of the Impact of Climate Change Scenarios on Runoff of Typical Watersheds in Changbai Mountains, China

Round 1

Reviewer 1 Report

Paper is a typical application work with limited new research. It is just another case study and very local.  It could be published after a major review.

Please improve the quality of all figures.

Row 48. I agree that lots of research and simulation in this field are still undergoing. But, I suggest finding a few current references.  Only one reference is from 2017, other are rather old.

Row 150. I thought that you have rainfall data and runoff from 10 stations. But, when I take a look at table 1, rainfall data is only for 4 stations and run-on for 6 stations. Please make it more clear in this row.

Row 151. Could you explain more precisely how you understand the uniform distribution of rainfall in your case?  

Row 161-162 sounds like a part of the manual. Please improve your English.

Row 163 This sentence seems not finished.

Table 1 . How important is a station code for your calculation? It will be more clear for a reader if you indicate the position of these stations somewhere in figure 1 or 2.

Row 183 R² not R2

Row 193 “The average DC average of…”?

Row 194. What do you mean by writing “qualified years”? Is the value of 0,701 of parameter CD good or not. Could you put somewhere in row 183 how to understand those values?

Row 198-200. It is hard to judge based on figures because what you have on figures depends on how you draw them. For example, for me, for the year 2006, you have a very bad simulation of peak flow. Based on the figure, it looks like an overestimation of about 75 m3/s for the date 7/1. When you have a total measure peak flow of 250 m3/s, 75m3/s is a very big mistake. Please judge only based on data and measures.

Table 2. What do you mean by “rate regular” for a period of time? Please add a line in this table after the year 2011 for the separation of calibration and verification period.

Row 229 …. value of )? Sentence not clear.

Row 236. Flood season? What is a flood season? Please explain.

Row 240 may be “the change in trend”?  You do not have a trend line in figure 5.

Row 249. “Compared with s …”? Wat do you mean.  

Row 257. What is the average concentration of flow? It is not clear for me please explain.

Row 278-279. It is not clear. More accurately than what?

Chapter 4 looks more like a conclusion than results and dissection. Chapter 3 is also results.

Row 286 It is not good to speculate in a scientific paper. Just do not put in the paper unchecked information. You do not calculate flood probability here.

The subchapter discussion is strange. It is in the wrong place in the article. Some part of it is actually an introduction and some part looks like an abstract (last paragraph). It should be rewritten and the text should be split into another part of the article. 

Author Response

Thank you very much for your valuable comments, we have made changes as requested. Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

The research topic is rather important for reader, scientists and practitioners. The study is relatively well written but a lot of editing issues are present in this version (look for instance at line 74, line 193 or line 227).

In the abstract, clarify what typical watershed runoff means (line 17).

Sentence starting at Line 19 should be rephrased.

The paper is organized in the following sections:

1 – Introduction

Where the subjected is presented and some similar studies are referred. Authors may look into more relevant references. The results of the reports from the IPCC should be highlighted.

In line 48, the reference to “scholars at home and abroad” seems irrelevant.

Authors present a lot of studies dealing with glaciers but then in the results/analysis nothing is said about that. It seems incoherent.

Rephrase sentence starting at line 74.

2 – Materials and Methods

The location of the stations should be presented in the map.

The concentration time (equation and results per watershed) should be presented.

How did the authors divide the total watershed in sub-basins. Did the authors consider uniform and homogeneous sub-basins? The size of these sub-basins seems too high.

3 – Results and analysis

The results of the simulation with HEC-HMS (in table 2 and Figure 4) do not seem accurately calibrated. Isn’t it possible to achieve better results (for instance, by reducing the size of the sub-basins or change the calibrated parameters).

The main input data for the subject are the precipitation pattern for the 2 scenarios. These data needs to be characterized in detail. The information given in line 221 should be complemented. How are the scenarios characterized? Who and how this data was obtained? How did the authors produce the downscaling of these data?

Results should be presented in detail and more analysis could be made.

Author Response

Thank you very much for your valuable comments, we have made changes as requested. Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

1. Runoff (water discharge) forecasting is done not only based on precipitation forecast but also temperature. This is especially important for forecasting snowmelt-induced floods. Nothing was written about this in the Discussion. Moreover, it is fundamentally important to consider the snow water equivalent and the depth of soil freezing for forecasting snowmelt runoff. These critical variables were not analyzed in any way in the manuscript. For this reason, I do not consider the obtained results to be of scientific and practical importance. They are very superficial. Science is not done that way.
2. The results obtained are not considered in the context of the numerous forecasts that have been made in recent years for many river basins in China. How do these findings compare with these predictions? The authors have studied this issue very poorly. This is evidenced by a small list of references.
3. Figure 5. The authors did not do any statistical analysis of the obtained trends to write about them confidently. What is their statistical significance? Why are they not compared to probable forecast errors? This is one of the major flaws of the study.
4. In the methodological part of the manuscript, information on the initial hydrometeorological data is insufficient.

In addition:

5. There is no topographic (elevation) map of the study area in the manuscript.
6. The content of Figure 3 is incomprehensible in context. Moreover, it is hard to read. What is "reach" in the context of your map?
7. The section “3. Results and Analysis” and section “4. Results and Discussion”. Do you think this is logical?
8. In the manuscript, there is no decoding of the abbreviation "HEC-HMS hydrological model" anywhere.
9. Line 66. 8.7×108 m3 and 10.8×108 m3.
10. Line 128. The terrain has a large drop. Maybe “a large amplitude”?
11. Figure 1. The map of the studied river basin (bottom right map) is highly uninformative. There are no river names. The positions of the studied meteorological and hydrological stations are not shown on the map.
12. Figure 2. The readability of the soil map legend needs to be improved.
13. Lines 148-149. “… HEC-HMS model comes from the China Hydrological Yearbook over the years.”. It is necessary to provide complete information about this source(s) in References. If there is an Internet resource for this source, it should also be provided.
14. Line 157. The hydrological rainfall station information… What did you mean?
15. Table 1. Station type: Hydrology, Rainfall… It is not correct. Did you mean "Hydrological, Meteorological"?
16. Changbai Mountain? Maybe Changbai Mountains?

The English language of the manuscript needs improvement.

Author Response

Thank you very much for your valuable comments, we have made changes as requested. Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Some small additional remarks:

row 267, 268, 273 etc. "m3/s" should be "m³/s". 

I suggest putting an equation of trend line into fig.5

I still completely do not understand why you have a conclusion first and then a discussion. Should be the opposite. First, you have a discussion and at the end conclusions. 

Author Response

Dear Reviewer 1：

   Thank you for your comments on my paper, which has been revised, see the attachment and article for details.

Author Response File: Author Response.docx

Reviewer 2 Report

•    Correct typing error in line 16
•    Correct typing error in line 63
•    Authors should clarify if changes in temperature are important for their system. If not, this should be explained in the text.
•    The location of the stations in Table 1 is not important as this information is presented in figure 1.
•    The name of HEC-HMS should appear the first time (line 147). 
•    The explanation starting in line 156 is rather important for this paper but it needs to be rewritten. As it is, it is quite confusing and it does not answer my previous doubts (“The main input data for the subject are the precipitation pattern for the 2 scenarios. These data needs to be characterized in detail. The information given in line 221 should be complemented. How are the scenarios characterized? Who and how this data was obtained? How did the authors produce the downscaling of these data?”)
•    The explanation starting in line 200 is rather important for this paper but it needs to be rewritten. As it is, it is quite confusing. What does e "Hydrological Information Forecast Specification" (GB/T 22482-2008) stand for? It is not in the reference list.
•    I cannot understand this sentence in the conclusions “The HEC-HMS hydrological model is mainly driven by precipitation. So the greater the precipitation, the greater the contribution of the surface runoff process to the entire water cycle, and the model's interpretation of runoff flow is more accurate.” The paper should be about the physical processes that should be incorporated in the model. As it is it seems that reality should be changed to fit the model!
Despite my previous comment on the concentration time (equation and results per watershed), this characteristic was not presented in this version (authors said they have corrected that).
•    I still think that the sub-basins should be smaller in order to obtain better accuracy. The reason presented by the authors (“The sub-basins are divided by the model combined with ArcGIS according to the tributaries, and then artificially merge the redundant parts according to the hydrological characteristics and topographic conditions of the Erdao Songhua River Basin”) does not justify this division. 

Author Response

Dear Reviewer2:

   Thank you for your comments on my paper, which has been revised, see the attachment and article for details.

Author Response File: Author Response.docx

Reviewer 3 Report

1. In the revised manuscript, I did not find an answer to my previous second comment. The authors replied that they took this comment into account. But I didn't see any progress. I reiterate this comment: “The results obtained are not considered in the context of the numerous forecasts that have been made in recent years for many river basins in China. How do these findings compare with these predictions? The authors have studied this issue very poorly. This is evidenced by a small list of references.”
2. "4. Conclusion and Discussion"? In all my practice as a reviewer, I see a manuscript where the conclusions of the work are ahead of the discussion for the first time.
3. Line 266 and Figure 5. I still cannot understand the statistical significance of the identified trends. To what extent can they be trusted? If there is no statistical significance in the series, why do the authors pay so much attention to these trends in the manuscript?
4. My earlier additional comment: "Figure 3. What is "reach" in the context of your map?". The authors have answered me: "Reach” represents the flow of the river." I didn't understand much. Why can't you just write the word "river"?
5. The bottom right map of Figure 1. You have modified the map to show relief. Ok. But where is the elevation scale? On the other maps of this figure, the names of the rivers refer to areal objects, but not linear ones? How can this be? This is geographically incorrect.
6. The English language of the manuscript needs improvement.

Author Response

Dear reviewer3: 

    Thank you for your comments on my paper, which has been revised, see the attachment and article for details.

Author Response File: Author Response.docx

Round 3

Reviewer 2 Report

• When asked to clarify if changes in temperature are important for their system, authors argue that HEC-HMS hydrological model does not take into account temperature. I would like to see an explanation why temperature is not important in this case and therefore Hec-HMS can be used. As it is, it seems that as Hec-HMS does not account for temperature, it is not important.
• Isn’t there the influence of temperature for snow?
• Remove reference to table 1 in line 191
• Sub-basin concentration time and lag time should be presented.
• Correct Tyson (!) method in line 232

Author Response

I am very grateful to the reviewers for their comments on my article. For specific responses, see the uploaded document.

Author Response File: Author Response.docx

Reviewer 3 Report

My final recommendations.

1. Neither the title of the manuscript nor the Abstract contains the name of the country to which the Changbai Mountains belong. For the international reader, the location of these mountains is most likely not known. In the title of the manuscript, it is necessary to add "... in Changbai Mountains, China". It is desirable to do the same in the Abstract.
2. The word "Data" is a plural noun (“a datum” is singular of data). Therefore, it must correctly correlate with verb forms (“data are …” but not “data is …”). According to the English language rules, check the manuscript text and correct the verb forms associated with this word.

Author Response

I am very grateful to the reviewers for their comments on my article. For specific responses, see the uploaded document.

Author Response File: Author Response.docx