Statistical and Water Management Assessment of the Impact of Climate Change in the Reservoir Basin of the Volga–Kama Cascade on the Environmental Safety of the Lower Volga Ecosystem

Round 1

Reviewer 1 Report

In principle, the manuscript is acceptable with minor changes. The authors provided a precise and clear description of the methods and an understandable presentation of the results. The research topic tends to be very important given that water resources are greatly affected by climate change, while the hydrological regimes of many rivers have been redistributed. The focus of the study is the use of several methods for determining the state of inflows, then the use of methods for the analysis of non-stationary hydrological time series, and the method of water resources calculation (WRC). The authors generally concluded that the inflow into the VKC reservoirs increased, while there was a change in the structure of the river inflow with its redistribution in favor of low water inflows. The results of the optimization of the water resources calculation clearly indicate that the requirements of water users obtained from the hydrological series 1916-1978 were violated for almost all of the mentioned criteria. The authors successfully determined that climate change significantly changed the hydrological regimes at the studied locations in the VKC reservoirs, indicating that extreme flows (floods) did not show significant changes.

Author Response

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Reviewer 2 Report

This paper “Statistical and water management assessment of the impact of climate change in the reservoir basin of the Volga-Kama cascade on the environmental safety of the Lower Volga ecosystem” determined the reliability for water users in the Basin of the Volga-Kama Cascade reservoirs in connection with climate change. It is important to determine the nature and indicators of changes in the hydrological regime, calculate quantitative estimates of these indicators, ranges of acceptable values, and develop release rules that ensure compliance with these ranges with a given probability. This paper search trade-offs solutions in the favor of different water users (Ecology, Agriculture and Fisheries, Water Supply, Hydropower, Navigation and etc.). The search method is based on multi-criteria optimization methods and the trade-offs theory. The application of this paper is interesting, but those flaws should be fixed before a proper review. My comments are as follows.

 

Moderate English improvements are required before the paper can be considered for publication. What follows below is a sample, and the list is not exhaustive.

 

Line 42: The structure of Introduction is a little disorder. There are too many paragraphs. Many paragraphs can be merged into one paragraph. Authors can raise one problem with possible solutions with background and related literatures in one paragraph.

 

Line 143: “the reliability of two types” should be reframed.

 

Line 186: duplicate caption of “2.1 Initial data of observed inflow and processing methods

”

 

Line 194: In figure 2 and figure 3, the trending line of the annual and seasonal inflow - Kuibyshev reservoir is not clear. Readers may be confused by gridlines. Authors can delete the background gridlines.

 

Line 356 2.3.2 “Indices, notations and definitions” and 2.2.3 can be merge into one section. Indices, notations and definitions should be

 

Line 479: In figure 4, the y-axis caption should be English.

 

Line 506: In figure 5, The frame of the figure should not be duplicate. The following figures should be changed too.

 

Line 531: Figure 6 should be figure 7. The following figures should be changed too.

 

Line 578: the resolution of the figure 8 should be improved.

 

Line 580: the resolution of the figure 9 should be improved.

 

Comments for author File: Comments.pdf

Author Response

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Reviewer 3 Report

Dear Author/s

This manuscript needs a general revision. 

1- In lines 26 to 32 (abstract) a series of information is stated in a summary form, but no information is provided regarding the type of test that was used.

2- Information about the research results is not provided in the abstract. Most of the abstract is dedicated to the introduction. It seems that the abstract should be more concise and present the research results.

3- The number of keywords is high.

4- In the introduction, the necessity of conducting research is not well stated. The purpose is not clearly presented and the innovation of the research is not stated. On the other hand, the difference between the present research and other researchers has not been stated.

  5- What is meant by CPD in line 28?

6- As you know, there is a difference between homogeneity and Stationary. Stationary is usually checked with methods such as ADF or KPSS. Why did you use homogeneity instead of stationary?

7- What is meant by "year" in table 3? Why is the "year" parameter included in the calculations?

8- What are the X and Y axis titles in Figure 5? Also, Figure 6

9- The quality and resolution of the figures is very low.

10- What was the method of calculating the changing point? Has the Pettitte test been used?

11- But the important research question is how climate change has been seen in the study? Have climate change scenarios been used? Has the change process been investigated? You mentioned climate change in the title of the manuscript.

12- It seems that it is better to use a flowchart to understand the research steps.

Author Response

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Round 2

Reviewer 3 Report

Dear Authors

The manuscript is well corrected, which is understandable for the readers.

With respect