Use of Holistic Environmental Flow Assessment for the Alijanchay River, Azerbaijan

Comment

Response

1) I consider the layout of the article as inappropriate. To increase clarity of reception, please reformat the current layout with standard chapters-especially the Results chapter. In addition, chapter 3 Materials and methods (Line 171), 4 Materials and methods (Line 241) appear twice. This is incorrect and needs to be corrected.

We appreciate the reviewer’s comments, and have revised Section 4 by renaming to “4. Results and discussion”

Discussion

2) Importantly, the article lacks a Discussion chapter. This is the basis of scientific papers, where one should confront one's own research results against the existing state of knowledge. This provides an opportunity for progress in the discipline. It should be noted that the analyzed topic is common in the literature.

Section 4 has been renamed to 4.Results and discussion

3) The text in Figures 2 and 3 is illegible. Consider describing the individual colors in the legend.

Both figures are updated and generated so that the text is more legible.

4) Please provide a broader background of climatic conditions (precipitation, air temperature) during the period of analysis against the background of a longer period.

Unfortunately, detailed climatic records are  unavailable. Although there is an Ogus meteorological observation point in Alijanchay basin these data are not available in open sources. Ministry of Ecology and Natural Resources provides these information at a very high cost.

5) How the results obtained can provide a basis for the management of water resources and water quality of the analyzed river. Currently there is a lack of application guidance.

The proposed holistic approach can be used as more modern method during preparation of application guide for ecology flow assessment in Azerbaijan and similar landscapes. We have added this to the conclusions.

Conclusions

6) The conclusions chapter should be more synthetic in nature. What limitations do the authors note? What are the prospects, if any, for further research?

Below sentence is added to line 498:

In Azerbaijan, the proposed holistic method can be only be applied in 2 river basins – Alijanchay and Shamkirchay. At present hydrobiology monitoring of all rivers in Azerbaijan is planned for near future. There is information about water discharge for other rivers and corresponding calculation can be done. Therefore, water discharge can be calculated and summarized during holistic approach for other regions.

7) ...”Overall, this assessment shows the quality of this important tributary decreases from upstream to downstream”... (Line 439-440). This is an obvious statement, and not only in the case of the analyzed river. Outside mountainous areas, human economic activity is increasing and, consequently, water quality is declining.

We appreciate the reviewer’s comment, but are unsure how to modify this observation.

Comment

Response

Introduction

- Include much more literature to engage an international audience.

- Consider adding a "Literature Review" section in the introduction. This section should discuss relevant studies and provide a summary to highlight the study's importance.

- Expand on the diverse factors influencing EFLOW, such as climatic, human, and natural factors in the introduction.

- Before stating the objective, provide a synopsis of previous research and highlight key aspects of the research discourse to enhance emphasis.

- The introduction lacks details regarding the novelty of the study.

- In the concluding part of the introduction, we will discuss the significant deficiencies identified in the literature and explicitly state the study's objectives.

Additional literature is added to engage the audience.

Literature review is provided within 1.Introduction section

Target of article’s research is described in lines 123-127. Literature review and current hydrology situation in Azerbaijan is described before it and objectives are stated.

It is the first time such modern and complex research was carried in Azerbaijan. We applied our own methodic approach during research works and summarizing results.

It is mentioned that (line 93-94) only hydrology methods are developed and used till now in Azerbaijan. The disadvantage of hydrology methods is absence of hydromorphology, hydrochemical and hydrobiological properties. Holistic method includes all above mentioned.

Study area and Methodology

- Provide numerical data on discharge values, station establishment year or statistical period, low-flow and high-flow periods in a comparative table.

- There are duplicate headings titled "Materials and methods" that need to be revised.

- Explain the estimation methods for Eflow presented in Table 9 in the Methodology section.

- Provide additional explanation in the text regarding the difference between "Environmental flow" and "Survival flow."

- Figure 2 and other similar figures lack the necessary quality and need to be presented with better quality.

Table 1 with discharge data is added (line 186)

-This was a typographical mistake. Section 4 is renamed to 4.Results and discussion

-Methods description is added to method section (line 188-221)

-Below additional information is added in line 224.

Survival flow is the critical, extreme low flow recommended during a designated drought period.

-Figure 2 is updated.

Results:

- It is preferable that the results of Eflow estimation presented in Table 9 be provided on a monthly basis for all months of the year.

- The results of Eflow estimation in Table 9 should be presented in terms of discharge values instead of volume (volume per unit time), as allocating Eflow without considering timing may not effectively sustain river ecosystems.

- Have the figures presented in Figure 3 been plotted based on average daily discharges for all years, or are they specific to a selected year?

- The station name "Khalkhal" in Figure 5 needs correction.

- Regarding the results presented in Table 11, they should be formatted to clearly indicate the significance of correlation values (significant at 95% or 99% confidence levels). Using terms like "bold-strong correlation (r > 0.9)" in the table caption is not particularly logical.

- The percentages presented in Table 10 should be explained in textual form and removed from the table.

- Similar to Figure 4, flow duration curves for all sampling stations should be plotted and presented.

We revised this table as recommended using annual data in order to make it simpler and more presentable.

-Figure 3 has been plotted on based of information of 10 years 2001-2010.

-Done

-Coefficients with strong correlations (r>0.9) are marked bold. The sentence is paraphrased and added into bottom of column.

-Done

-There were 12 water discharge measurement for each 4 sample points. Unfortunately, 12 water discharge data is not enough for plotting flow duration curve. As it is mentioned above the curve on picture 3 is plotted on 10 years data.

Conclusions

- The classification of WQI values into categories such as "good," "very good," etc., serves what purpose? Is it for drinking water, agricultural use, or environmental monitoring?

- If the holistic approach is not feasible, which alternative methods are recommended?

- Explain the practical implications of the research conducted.

- In the conclusion section, it would be more appropriate to address the limitations of the research, particularly regarding regionalization, application in similar areas.

There are notes in line 236 and in line 261 (new added) and 308 indicating that WQI values are calculated for drinking water purposes.

-Hydrological method is used currently whenever the holistic method cannot be applied.

-The advanced holistic approach is applied the first time in Azerbaijan. It is observed that application of holistic approach is more practical for water reserves management and security.

-Below sentence is added to line 498:

Currently holistic method can be applied only for 2 rivers – Alijanchay and Shamkirchay. It is not possible to arrange expensive hydrobiology monitoring of all rivers in Azerbaijan in near future. There is information about water discharge for other rivers and corresponding calculation can be done. Therefore, water discharge can be calculated and summarized during holistic approach for other regions.

The English proficiency of the manuscript is satisfactory, but minor revisions are required

We have revised English and checked spelling throughout.

Comments

Response

Abstract

1. The abstract mentions that six hydrological methods were used, but it doesn't specify what these methods are. Mentioning the methodologies or general approach would improve the abstract's information value.

We have added a sentence at line 188 specifying the method sources.

2. "Further degradation... is likely" is the abstract's concluding line, however, it doesn't explain what this means, what to do with the information, or suggest, what more to investigate.

The value of suggested ecological flow must be used during action plan for usage of Alijanchay river basin water reserves (line 30)

Introduction:

1. The introduction discusses environmental flow assessment broadly, but it lacks specific background information on the Alijanchay River, which is the subject of the study. Details about the river's characteristics, current ecological status, existing water management practices etc. are missing.

These details are given in Section 2. Study site

2. A few small typos exist, like the repeated use of "the" in line 50. These need to be fixed.

These are corrected.

Materials and Methods:

1. The selection of specific physico-chemical parameters (e.g., BOD5, COD, nutrients) and ecological indicators (e.g., benthic species, hydromorphological state) lacks a clear justification. The section should justify why these particular indicators were chosen.

These parameters are the most pollutants of river waters and widely used by most of authors for calculation of WQI (line 234).

Results:

1. Pearson's correlation matrix is presented, but the text does not clearly explain the significance of these correlations or how they relate to the overall water quality assessment. Additionally, there is a mention of "winter results for correlation" (in line 397) without clarification on why winter data were specifically chosen for this analysis.

The matrix is very good tool to see the strength of linear relations between 2 different values. The correlation can be positive or negative. The higher the value the stronger the relationship (line 446-448).

Winter results are used because we got stable results during winter (line 452)

2. There is insufficient discussion about the results of this study. A separate section of discussion would benefit from a more detailed explanation.

It was typo mistake. Section 4 is renamed to 4.Results and discussion

Conclusion:

1. The conclusions section does not provide actionable recommendations based on the study's findings. It is important to include specific recommendations for river management, policy improvements, or further research to guide practical applications of the study's results.

Below sentence is added to line 498:

Currently holistic method can be applied only for 2 rivers – Alijanchay and Shamkirchay. It is not possible to arrange expensive hydrobiology monitoring of all rivers in Azerbaijan in near future. There is information about water discharge for other rivers and corresponding calculation can be done. Therefore, water discharge can be calculated and summarized during holistic approach for other regions.

Others:

1. Tables 8 and 9 need to be cited in the text.

We have cited the tables in the text.

Reviewer’s Decision Comment: The academic article was written very carefully. This might be useful once things have calmed down, but I highly recommend running a few quick tests first.

We appreciate these encouraging comments and below the corrections have greatly improved this article.