Ecological Status as the Basis for the Holistic Environmental Flow Assessment of a Tropical Highland River in Ethiopia

Round 1

Reviewer 1 Report

The manuscript investigates the potential effect of flows on macroinvertebrates,  vegetation and ecosystem services. The manuscript is potentially interesting but it needs intensive and serious editing and English corrections. All these errors are so distracting. I suggest that the authors ask a professional proofreader to correct these aspects. I also suggest that the authors shorten the text (excluding the references) into 17-18 pages (if possible into 15 pages) by removing some Tables and moving them in the supporting information, maybe some figures and by writing concisely.

The international relevance of the study is also missing. Add this in the introduction. Furthermore, I miss a broader perspective of the manuscript in the Discussion. Please add a broader perspective of the study. The discussion is mainly discussing the results and sometimes speculating. Probably, this is because the manuscript is complexly structured and not well-focused. I suggest that the authors move parts that are not so crucial in the supporting information and put the main results in the main text. The main results that I refer are those results that support the conclusions and aims of the study and the main storyline of the paper. This is to make the paper more straightforward and sharp. I suggest that the authors sit down together and think of what is the key message of the paper, then based on this key message, only include the results supporting these key message in the main text and the other (extra) information be placed in the supporting information.   

• The title is too long. I suggest shortening it and make it only two lines max. The study is mainly assessing the impact of flows on ecology, macroinvertebrates, fish, vegetation and ecosystem services so I suggest building the title around those aspects. I would remove connected wetlands and put wetlands (or connected wetlands) in the keywords.
• Line 28: change into: and finally linking ecological and hydrological components
• Line 30: on March 2020
• Line 31: what trend are the authors referring to? Decreasing trend over the years or decreasing trend at the mouth of the river?
• Line 33: was observed in….
• Line 34: from upstream,
• What was the expectation and why was there an expectation.
• Line 37: small letter N for negatively – how did the authors come to this conclusion that NDVI negatively influences the density of fish etc.?
• Line 38: delete to continue
• Keywords: spell out SWAT, NDVI, remove NMDS

• Line 47: remove “,” after human being. This punctuation is not correctly used in this sentence
• Line 49: what do the authors refer to as “timing” in this sentence. Timing of what?
• Line 61: during the dry season
• Line 64: …event also impact water quality [5].
• Line 69: change like into “such as”; “like” is colloquial
• Line 69-74: simplify this sentence, by rephrasing and shortening. Also, there is no good flow of thoughts from the previous sentences. It is not well connected with the 1^st and 2^nd sentences in this paragraph. The same is true with the remaining sentences. I suggest that the authors rewrite paragraph 66-81 so that there is a connectedness between sentences and a good flow of thoughts.
• Sentences in Line 87 and 89: the connection between these sentences is not well-established. Does farm encroachment affects environmental flows?
• Line 96: the aim of the study is vague. What is even an ecological foundation? Rephrase aim and indicate what is exactly being investigated in the paper.
• The specific aims are clear so they are ok.
• Line 106 km², check this elsewhere in the manuscript as there are also other parts of the manuscript with such an error.
• Rephrase the sentence in line 106-107. Strange sentence
• Line 108: m a.s.l.; is draining
• Line 111: correct the error.
• Line 117: urban is not a soil type, it is a land use. It is strange to include this in the list
• Line 119-1230: please fix this sentence
• Line 126-127: Strange sentence. Fix this sentence.
• Line 132-133: Fix this sentence
• Line 139: fix this Error of reference and elsewhere in the manuscript
• Table 1. I would put this in the supporting information.
• Figure 1: adapt the figure caption. Make these into good sentences
• Lines 150-158: Not clear what data was calibrated with SWAT, what data was validated. Is there observed station data? For the temperature, rain, etc. data, how does the author know that the data is accurate? They did not include observed data? For this paragraph please provide more information about the calibration, validation and uncertainty analyses of the SWAT model. Which data were used? This additional information is preferably be placed in the supporting information.
• Fix Figure 2 caption into proper sentence
• When were the samples collected?
• Line 178-180: fix these sentences
• Be consistent with the tenses in the methods. Use past tense
• Line 194 – 199: what exactly was collected/surveyed? Which ecosystem services? Did the authors obtain ethical compliance documents for conducting surveys?
• Line 200: Data Analysis and Interpretation
• Line 209: “;” not appropriate here
• Information in Line 202-215 should be integrated into the previous section together with Flow data
• Information in Line 217-223 should be integrated also in the previous section together with Physico-chemical data
• Likewise for lines 224-261. The authors can integrate this information in the previous section and please make it concise. Don’t put all sentences as it can be repetitive. The same is true for previous remarks. Line 238-247 can stay in this Section. I suggest that Section 2.3 be named Data Collection and Processing. In this way, most information in Section 2.4 can be integrated into Section 2.3 and the authors don’t repeat aspects in Section 2.4. that are found in Section 2.3. Also, this makes Section 2.3 more holistic, not missing some information, which is found in Section 2.4.
• Line 267-269: not clear what was done here. Expound but be concise.
• Line 276: R², and everywhere else
• Line 280: m³s^-1, please correct these units and elsewhere in the manuscript!
• Line 280-283: please fix this sentence to have better flow by adding proper conjunctions
• I would put Table 2 in the supporting information
• Line 308: incorrect use of “;”
• What is a weedy watercourse? Do authors mean eutrophic?
• Improve resolution of Figure 4. Fix figure caption also incorrect use of “;” and elsewhere in the manuscript. Please fix these
• Table 3: add 0 in the values such that it becomes 0.35, where are the other physico-chemical variables?
• Figure 5: Legends are overlapping with map. Fix this. Also which macroinvertebrate-based index or water quality index was used for this? Indicate this in the legend instead of writing macroinvertebrate-based or water quality-based.
• Line 332: macroinvertebrate: one word not hyphenated, and elsewhere in the manuscript
• Shesher 01 is the name of the wetland?
• Line 339: Figure S4
• Line 339: Globally, - what is globally? Or authors refer to Generally?
• Figure 6: Please improve the resolution of the figure
• Line 349: incorrect use of ‘;” and elsewhere in the manuscript!
• Line 397-398: space within a parenthesis? And elsewhere in the manuscript!
• Line 417: incorrect use of “:”
• Line 427-428: scientific names should be italicized
• Line 430: what does this mean: but the exotic tree species are being expanded through government agricultural/forestry extension system? The government is planting exotic tree species?
• Line 437: were identified. Be consistent with your tenses in both methods and results in the manuscript
• Line 440: rephrase this phrase into a formal tone: and you can find them in fewer places nowadays as informed by the inter-440 viewed riparian community.
• Line 442: rephrase sentence: The degradation is potentially due to the less flooding and drying out of the river during the rainy season and dry season, respectively, because of unwise use.
• Line 444: strange to end the paragraph with this sentence
• Line 450: (i.e. Sensawuha….)
• Line 454-456: this sentence can be improved by rephrasing
• Figure 8: Legend is overlapping with the bar. Please adjust
• Line 515: Figure S8 and elsewhere in the manuscript
• Figure 11, please improve figure resolution and improve figure caption
• Line 547: should be Authors et al. [3]
• Line 550: rephrase the sentence, not correctly formulated
• Line 577: not clear what the authors meant. Please rephrase the sentence.
• Table 4: Decreased aquatic habitat. Impacts of livelihoods
• Table 4. Why is the third column has a different font size compared to the other columns? The Table is also difficult to understand. Does the first row of column 1 relate to the first rows of column 2 and 3? Or all rows in column 1 relates to all rows in column 2 and 3? I think rows in column 1 are related to the same row number in column 2 and 3. Please clarify this Table. Alternatively, the authors can also put arrows on which row is connected to which rows in the next column. The rows in each column are also of different lines in the Table that’s why it becomes confusing.
• Line 588-592: is this a result of your study? But the authors did not collect data on waterfowls.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

The reviewed manuscript addresses very important and topical issues. What is worth emphasizing it has the interdisciplinary nature. The authors collected a very extensive hydrological database and performed numerous analyzes of biological samples. It seems that the problem of Authors’ is to present the results in a condensed and legible form. The manuscript`s is too long.  It contains information that can be found in other works (e.g. the exact characteristics of the research area), and sentences containing repetitions and truisms. (e. g. "Water quality variability can be specifically related to the water source, flow variability, and aquatic processes" and "Changes in the timing of extreme flow events have also impact on water quality"). In my opinion some sentences are "long-winded" e.g. the paragraph “The demand for agricultural water has been rapidly increasing in the Lake Tana basin. If uncontrolled, the establishment of dams for agricultural expansion through irrigation will highly affect the lake and the surrounding environment. For instance, the construction of a dam in Ribb river and unregulated pump irrigation in the Gumara river avoids rivers flooding into the wetlands and disconnects with Lake Tana which is critical for the existence of ecologically important wetlands [3, 12, 15].” I am definitely sure that the most important information including in this paragraph could be expressed by two short sentences.

Despite that introduction section is long, and introduce to the issue of the interaction between ecological and hydrological processes as well as the meaning of water resources for human and environment, there is lack in manuscript the clear, precise definition of the concept of environmental water. The term “environmental water” is used in literature in several different meanings. I suggest to better explain the context.   

Since English is not my native language, it is difficult for me to express my opinion on the linguistic issue, but I have doubts about some terms, style and consistency of times. I strongly recommend the proofreading of the manuscript by a professional company dealing with the verification of scientific texts.

The way of writing units should be corrected, there is no superscripts and subscripts.

Species and genera names should be italicized.

More detailed comments:

Line 47 Remove the comma

Line 102 “based on 1st and 2nd level data” Could You explain what data do You mean?

Line 111 “(Error! Reference source not found.).” It should be delate.

Lines 115-117 Is it necessary information? I Think it could be omitted.

Lines 122-128 In my opinion, a paragraph is too long. I would consider shortening to 2 or 3 sentences and possibly moving to an introductory section i. e. after line 96. Information on natural values of studied area is rather an argument for undertaking research than a methodological issue.

Lines 130-132  Are references really necessary here? Cite figure 1.

Table 1 and Figure 1 ID of sites are different, they should be unify.

Line 139-140, 153, 169 etc. …..Please, correct these errors.

Figure 2 I recommend delate the photos. The photos fit rather an academic textbook than a scientific publication.

Line 232 Are you sure that the given bibliography is correct? I don`t know these references but titles don`t suit subject.  Moreover, I suppose one citation is enough.

Table 1 and Table 2 Please compare tables 1 and 2, the same code appears in columns with different headings. In table 1 it is "site" in table 2 "reach". I would also consider delating the first column  in Table 2. Additional codes may have been helpful during the analysis, but are probably unnecessary (and too long!) in the publication.

Line 315 “doubtful pollution status” I would avoid making such judgmental statements

Figure 5 The key for macroinvertebrate classification is too extensive. Please give inormaion about ecological status classes in methods section. I would give only “high”, “good”….. In addition, the map does not seem to be legible. Could the number of colors be limited? For example, leave the studied area in black and white and mark only the condition assessments with colors?

Lines 397-398 unnecessary parentheses? The same line 576.

Figure 9 The symbols in the figure and the legend are different. It also seems that the legend for the sites is not necessary in this case.

Table 4 I believe it would be better give in the title full names and year of publication of sours of data.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Congratulations to the authors for the thorough investigation of the effects of environmental flows on the ecology and ecosystem-dependent livelihoods. The paper is interesting after all. The manuscript was adapted well.

Below are the remaining minor comments.

The specific objectives are: to 1) characterize the ecological condition (fish, macroinvertebrate, riparian vegetation

Line 105-107: “The Gumara River basin was divided into three reaches: - should be “:” instead of “;”

Line 196-201: macroinvertebrate is without “-“

Line 235-237: DO was very high in almost all sites, indicating

I saw some incorrect uses of “;”, the authors can check out https://www.niu.edu/writingtutorial/punctuation/semicolon.shtml to correct this punctuation.

Line 283-287: seems the font size or type is not the same as the majority of the text.

Line 301: include:

Table 1: should be NH₄⁺-N, PO₄^-3-P

Figure 7. Italicized scientific names

 Figure 8: Can the author enlarge the axis labels and axis values such as -0.5, -0.25. The values are too microscopic.

Table 2: Decreased aquatic habitat for fish….: capital letter D for decreased.

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.docx