Determination of Environmental Flows in Data-Poor Estuaries—Wami River Estuary in Saadani National Park, Tanzania

Round 1

Reviewer 1 Report (New Reviewer)

References need to be reviewed as some references are not mentioned in the list of references.

The order of the Figures is incorrect as it mentioned Figure 5 before 3

The discussion part needs improvement with a comparison to others' work

Comments for author File: Comments.pdf

Author Response

Dear Reviewer, firstly thank you very much for taking the time to review this manuscript.

I have gone through your .pdf, and accepted all the suggestions that improve grammar and readability ( eg. comments F 1-6). Comments on missing references have also been looked at. Indeed, I went in and reformatted the references as per journal requirements, and in the process eliminated a set of unused references.

Figure 2 has been inserted after the two paragraphs.

re: your comment about how Figures 5 and 6 appear before Fig 3 and 4 in the text,  its actually Figures 5 and 6 in SUPPLEMENTARY INFORMATION that is being referred to here. I have gone in and made that clearer. In addtion, they have been UPDATED to Figures 2 and 3, Supplementary Information.

I have added the analysis of another method ( The Tennant or Montana method) to the paper, and have compared our EF results with the Tennant method.  I have also expanded the Introduction to mention other prevailing methods of determining EFs in both rivers and estuaries, along with the main limitations of these methods, primarily that each method is specific to the area where it has been developed ( flow-ecosystem links).

Thank you very much again.  Best regards, Amartya

Reviewer 2 Report (New Reviewer)

The manuscript developed a relatively complete freshwater inflow guideline for the Wami Estuary and performed a detailed Environmental Flows Assessment based on the Building Blocks Methodology. Although the topic of the paper is meaningful, the manuscript is rather weak for several reasons. It is more like a survey report than a scientific manuscript.

Comment 1: Most references in this paper were written more than a decade ago. The author is recommended to update them and follow the latest studies.

Comment 2: The latitude marks in Figure 1 are missing, as well as the longitude on the top of the right picture. It is recommended to be redrawn.

Comment 3: The legend in Figure 5 is too vague. And the legend of Figure 6 can be labeled with just one.

Comment 4: Figure 8 shows the vegetation map of Wami Estuary, but it is difficult to identify the different vegetation types from the map. It is recommended that different tree species are indicated by different colors.

Comment 5: The figure serial number in this paper is wrong since page 26.

Comment 6: The coordinate axis labels of the figures on pages 26 and 27 are obscured by the vertical coordinates. It is hard to recognize the 1-2 peak events from the red circles on these two figures.

Comment 7: This paper recommended minimum freshwater flow guidelines based on the BBM at Gama Gate for normal rainfall years and below-normal rainfall years. A brief comparison between the minimum freshwater flow results based on the BBM and other methodologies such as the Montana method is recommended to make the results more reliable.

Comment 8: The conclusion section of the paper is too rough and fails to show the highlights and the core results.

Author Response

Dear Reviewer,

firstly I thank you for taking the effort and time to review, and for your constructive suggestions, that I have incorporated. i think that greatly enhances the overall readability of the manuscript.  Below are my responses to your points , prefixed with an arrow (-->)

The manuscript developed a relatively complete freshwater inflow guideline for the Wami Estuary and performed a detailed Environmental Flows Assessment based on the Building Blocks Methodology. Although the topic of the paper is meaningful, the manuscript is rather weak for several reasons. It is more like a survey report than a scientific manuscript.

--> agreed. The intention of stating the obvious basics in the paper (like the socioeconomic and ecological importance of tropical estuaries) is to address the lack of awareness of this subject amongst authorities in these countries (from authors experience). And being an open access paper, its available to water managers, researchers and students in these countries, and the aim is to explain the basics as well - which may be common knowledge in more 'developed' countries where policies and programs are already underway to restore estuarine environments. Such is not the case in much of the developing world, where not only there is a lack of awareness amongst government departments on the management of coastal and estuarine systems.Also, I had intended this paper to be part of the Special Issue on Aquatic Ecosystems and Water Resources, which has to be useful for actual management. Hence the paper addresses both scientific aspects of flows determination, as well as explanation of basics to allow non-scientists to also grasp the importance of the need for EFs. 

That being said, I do think the manuscript has become more scientific with the addition of the Tennant method, improvements to figures and other changes.

Comment 1: Most references in this paper were written more than a decade ago. The author is recommended to update them and follow the latest studies.
--> I have included some recent references now. for eg Sinclair et al 2021, Arthington et al 2018, Alfieri et al 2017, Mligo 2017, Burgess et al 2013, Barbier et al 2011. At the same time, while there are many recent pubs on estuarine ecosystems in other parts of the world, its harder to find recent pubs for Tanzania/East African coastal regions in international journals. Hence many references are from decades ago, that too in the form of reports or books at times. 

Comment 2: The latitude marks in Figure 1 are missing, as well as the longitude on the top of the right picture. It is recommended to be redrawn. 
--> This has been redrawn. Indeed, the first map has been expanded in scale to include the entire Wami basin with topography, to include a regional aspect as well as show the large area of the basin where activities can affect the inflow into the estuary. The second map shows the estuary and stations, along with a label that indicates the approximate location of the frehswater-saltwater interface. 

Comment 3: The legend in Figure 5 is too vague. And the legend of Figure 6 can be labeled with just one. 
--> Figure 5 has been redrawn with larger legible legends, axes and axis titles. 
- For Figure 6,  i feel its better to include the legend in every figure, for convenience of referring to a legend that is adjacent -- if the scale is close by its easier to observe shades of blue to understand the salinity in the river. I agree that its superfluous to add the same legend in each picture - if you strongly feel its better to have just one legend, i can recreate this figure panel - it would take some time as I would need to access a computer with a valid ArcGIS license, or use a graphic program. I have also added in HIGH TIDE and LOW TIDE to the figure, to allow one to grasp it quicker.

Comment 4: Figure 8 shows the vegetation map of Wami Estuary, but it is difficult to identify the different vegetation types from the map. It is recommended that different tree species are indicated by different colors.
--> a great suggestion. I have put in colored circles for different species, as using different colors for letters was not very visible, given the colored background of the image. I hope adding colored circles makes it easier for the reader to quickly see where different species were encountered. 

Comment 5: The figure serial number in this paper is wrong since page 26.

--> thank you for bringing this to our attention.  This has been corrected.

Comment 6: The coordinate axis labels of the figures on pages 26 and 27 are obscured by the vertical coordinates. It is hard to recognize the 1-2 peak events from the red circles on these two figures.

-->figures 8-10 have been redrawn with larger titles, units and axis titles properly aligned.  I have taken out the red circles for peak flows, as i see that they can be confusing, and instead, explained in the figure as well as text that the magnitude of the 1-2 peak flow events should be around the max flow amounts in the graph.

Comment 7: This paper recommended minimum freshwater flow guidelines based on the BBM at Gama Gate for normal rainfall years and below-normal rainfall years. A brief comparison between the minimum freshwater flow results based on the BBM and other methodologies such as the Montana method is recommended to make the results more reliable.

-->This is again a great suggestion, and for the latest manuscript, I included an analysis of EFs via the Montana method (Table 7) using the mean annual flow data from Gama Gate  - also expanded the Intro to include references to other older established methods, as well as their limitations while applying them to other geographical areas.

Comment 8: The conclusion section of the paper is too rough and fails to show the highlights and the core results.
-> I have expanded this section as well to be a standalone section, with the main points, yet to not have overlap with the Discussion.

Thank you again,

best regards,

Amartya

Reviewer 3 Report (New Reviewer)

The Authors apply an interesting interdisciplinary approach to develop an Environmental Flows (EF) assessment for the management of freshwater inflow in data-poor tropical estuaries, as the Wami River estuary in Tanzania, combining scarce river flow data, hydrological modeling, inferring natural salinity regime from vegetation zonation and investigating freshwater requirements of people/wildlife. The Wami River is the only perennial source of water for both terrestrial and aquatic wildlife in Saadani National Park in Tanzania, apart from a few pools constructed by the Park Authority.

The Authors rightly state that maintaining an adequate freshwater inflow regime is thus critical for maintaining the plant and animal ecosystem and surrounding connected environments. Moreover they observe that often terminating minimum river inflows for management guidelines is hampered by lack of ecosystem flow link data.

The Authors analyze available historical flow data (since the 1950s) of the Wami River into the  estuary, carry out field measurements, setting up a hydrological model of the river channel to relate water depth to flow/depth at the upriver end of the estuary and observing riparian vegetation zonation, water quality, channel geomorphology and surveys of wildlife.

The Authors describe the study site, collect hydrology and water quality data, and estimate the Flow duration curves (FDCs). In particular, they carry out field discharge measurements collecting hydraulic data at each EFA site including cross-section geometry, reach lengths, water surface profile elevations, streamflow, flow velocity and roughness conditions. Moreover, they calibrate and apply HEC-RAS model, observed and measure backwater tidal effects at freshwater end of estuary, carry out water quality measurements, reporte riparian vegetation zonation from earlier reports.

At the end, the Authors carry out a fisheries and terrestrial wildlife surveys,  identifing the flows necessary for different ecosystem processes. Therefore, the Authors characterize the state of the eco system and its link with hydrology.

Analysis of historical and field data of Wami River inflows to the estuary indicate the existence of a well-defined peak in Wami river flow during the wet season and low flows during the dry period, namely July to October.

The Authors observe that the results of the hydraulic modeling resent that it has been validated with low flow season data.

Moreover, the Authors point out that salinity is the main water quality parameter required for understanding freshwater and seawater dynamics. During the sampling period, the lower estuary (5 km from mouth upriver) was mainly freshwater-dominated, but in times of very low freshwater flows particularly in October salinity intrusion can be a problem for water supply, and vegetation and fish survey.

The Authors propose an interesting team effort, involving experts for the evaluation of  the current state of ecosystem components. The experts point out numerous problems and propose a path to improve some of the ecosystem components, describing the restoration goals.

Particularly interesting are the evaluation of minimum discharges and minimum water depths required at Gama Gate for the 6 different hydrological conditions to avoid ecosystem collapse and the analysis of environmental Flows at Gama Gate.

The global and interdisciplinary approach proposed by the Authors is interesting and very current, and can be applied to other environmental contexts, modulating the components to be considered.

I suggest the Authors improve their conclusions, based on the work they have done.

Author Response

Dear Reviewer,

thank you for taking the time to review and for your succint summary.

In line with what you suggest, I have modified the Conclusion section to state the essence of the study, as well as suggest an alternative approach of using an established method like Tennant (1976) that is widely used to get an initial EF guideline, but with the caveat that the local flow-ecology relationships need to be determined via fieldwork, and then used for modifying the EFs.

I have made some additional changes, like including an analysis (Tennant method) for comparative purposes, improving figures. formatting references as per journal standards, removing spurious references, that I believe has made the manuscript tighter and more readable.

With  regards,

Amartya

Round 2

Reviewer 2 Report (New Reviewer)

The author has well revised the manuscript. It can be accepted.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The manuscript deals with an important problem of justifying ecological runoff.

Remarks.

1. The manuscript contains a description of the problem, but there are no methods for quantifying the parameters of the water regime.

2. There are no predictions of ecosystem change with allowable water withdrawals.

3. There is no assessment of the changes in the hydrological regime of the river as a result of economic activity.

4. The description of the animal is very detailed, but there are no formulations of restrictions on the water regime. Text can be shortened.

5. Some figures can be shortened.

6. There is no discussion about quantitative assessments of environmental runoff.

The manuscript needs to be substantially finalized.

Author Response

Dear Reviewer,

firstly thank you for taking the time and effort to review this manuscript, and for the comments, addressing which has hopefully made the paper clearer to a diverse audience. Our responses are added below each point below, preceded with ---.

"The manuscript deals with an important problem of justifying ecological runoff." ---Yes, the main objective is to determine a range of freshwater inflows into Wami Estuary, that are necessary to maintain essential estuarine ecosystem health and services.

Remarks.

1. "The manuscript contains a description of the problem, but there are no methods for quantifying the parameters of the water regime." ---We have written the methods more clearly to describe how river flowspeed and channel profiles were obtained. In this study, given the scarcity and gaps of longterm hydrological data, we added in hydrological modeling to understand and estimate channel discharge as a function of water level. The methods section elaborates upon this ( Section 2; also note that we refer to Valimba (2007) who has detailed the method used to reconstruct missing data from 1955-1984. The other objective was to quantify the salinity regime in the entire estuary in both wet and dry seasons, and thereby relate that to riparian ecosystems ( vegetation, wildlife) and socioeconomic activities. Lastly, as a guide, a set of minimum freshwater inflows in wet/normal/drought years is included, and methods explained in a little more detail.
2. "There are no predictions of ecosystem change with allowable water withdrawals." - While the introduction mentions threats of diminished freshwater inflows on estuarine ecosystems and the services they provide, we have expanded in a little bit more detail on likely ecosystem change under a scenario of increasing water withdrawal. The discussion also mentions existing situation of increasing salinization of coastal wells in Bagamoyo and Pangani district (Sotthewes).
3. "There is no assessment of the changes in the hydrological regime of the river as a result of economic activity." That assessment is beyond the scope of the present study, as explained, partly because of the lack of longterm hydrological data. Also, our objective here is to determine the range of freshwater inflow to maintain the estuarine ecosystem, to inform water management in the river.
4. "The description of the animal is very detailed, but there are no formulations of restrictions on the water regime. Text can be shortened." Yes, We have shortened the section on wildlife, moving some of that to Supplementary Material. Wildlife is a critical part of the ecosystem - estuarine and the surrounding forests of the Sadaani National Park, that is an important source of tourism revenue for Tanzania. This study has gathered together a subset of available data and publications to enable scientists and managers understand the freshwater - salinity - wildlife link better, so as to sustainably manage the ecosystem and water resources in the wider upstream basin. Hence we would like to keep this information, in Supplemental Material. Also, another reviewer has suggested the opposite, to bring in some supplementary material on wildlife and socioeconomic aspects to the main manuscript, so you can see that this is a subjective matter. We have tried to take both opposing points of view and include enough material in the main paper, with pointers to supplemental data/info.
5. "Some figures can be shortened." ---Can you give more specific details as to which figures and to what extent ?
6. "There is no discussion about quantitative assessments of environmental runoff." Runoff (sediment, agrochemical) from within the estuary was not a major threat, as the Sadaani National Park is a protected area. We did measure turbidity as an analog for sediment pollution. However, analyzing water quality for upstream-sourced agrochemical pollution was not part of the study.  We are aware that the Wami basin faces increasing amount of commercial agriculture and deforestation that are increasing agrochemical and sediment loadings to the river ( Kiwango 2011, 2018).

"The manuscript needs to be substantially finalized." - We have added in details in the Discussion addressing your suggestions, while simultaneously intending this paper to be useful to multiple audiences. Thank you again.

Reviewer 2 Report

This study investigates the Environmental Flows in Wami River Estuary in Sadaani National Park, Tanzania. The authors studied mentioned estuary from several points of view and tried to comprehensively discuss the current situation there to provide better insight. The manuscript includes some points that should be revised or improved to be considered as a scientific paper. Therefore, as a reviewer, I suggest that the manuscript can be accepted after major revision. Comments and suggestions for improvement are presented below:

(1)         Please check the references and referencing methods, I can see several typos and errors as below:

·       Line 108: reference is not in correct format as well as it is missing in the referencing part. Please make sure that all the references are properly mentioned in the paper.

·       If you adapt Table 1 from a previous literatures, you have to provide reference for this table.

·       Line 599: if Kiwango’s PhD study available online you can mention it where other scholars could make use of it, otherwise, you have to substitute with other reliable sources.

·       You have to provide proper reference for water requirements for wildlife such as elephants (line 761).

·       Referencing system (line 1185) should be unified. Please check the font type and size as well as spacing. Line 299 through 318 has also different font size which should be adjusted.

(2)         In general, please provide figures with better quality. Also, you are mentioning two villages (line 425) which one of them is available in the figure 1. Please provide the location of both villages in that figure.

(3)         Please provide a table including statistical summary of the historical data for the section 2.2.

(4)         I would suggest discussing more about anthropogenic activities in the paper. There are some discussions in the supplementary file, use them in the main paper rather than supplementary document.    

(5)         There are several good tables and figures which should be used in the paper directly. By moving the below mentioned material to the main paper you can support your arguments appropriately.  

·       Table 2: Summary of measured discharges at three locations in August 2015

·       Figure 5: Wami Estuary Channel bathymetry up to freshwater vegetation section.

·       Table 8: Water quality parameters

·       Figure 10: Catch composition of fish species at different locations in the Wami River estuary and within 2 kilometers offshore (Chanyungu). Numbers indicate number of individual fish species caught.

·       Figure 12: Water required per population of terrestrial wildlife species in Sadaani National Park

Also, there are several titles without any figures in the end of the supplementary document, please provide the required materials or remove the titles.

Author Response

Dear Reviewer, firstly thank you very for your time and helpful suggestions; we have accepted many of these that makes the paper read better and be more scientifically formatted. Please find our responses below each point prefixed with ---

• Please check the references and referencing methods, I can see several typos and errors as below:
  • Line 108: reference is not in correct format as well as it is missing in the referencing part. Please make sure that all the references are properly mentioned in the paper. ---done
  • If you adapt Table 1 from a previous literatures, you have to provide reference for this table. ---done - this was adapted from King et al 2000.
  • Line 599: if Kiwango’s PhD study available online you can mention it where other scholars could make use of it, otherwise, you have to substitute with other reliable sources. ---done, replaced with KIwango's publication in 2011.
  • You have to provide proper reference for water requirements for wildlife such as elephants (line 761). done - Young (1970) was used for savanna wildlife water requirement estimates.
  • Referencing system (line 1185) should be unified. Please check the font type and size as well as spacing. Line 299 through 318 has also different font size which should be adjusted. ---done
• In general, please provide figures with better quality. Also, you are mentioning two villages (line 425) which one of them is available in the figure 1. Please provide the location of both villages in that figure.
• Please provide a table including statistical summary of the historical data for the section 2.2. ---historical data has been provided in the Supplemental Section, else the paper gets to an unwieldly length.
• I would suggest discussing more about anthropogenic activities in the paper. There are some discussions in the supplementary file, use them in the main paper rather than supplementary document.  --- this was a hard decision, and indeed another reviewer has suggested taking out some of the wildlife and anthropogenic activities to Supp Data. The paper already is very long, given the multiple areas of research involved in estimating the Building Blocks.
• There are several good tables and figures which should be used in the paper directly. By moving the below mentioned material to the main paper you can support your arguments appropriately.
  • Table 2: Summary of measured discharges at three locations in August 2015
  • Figure 5: Wami Estuary Channel bathymetry up to freshwater vegetation section.
  • Table 8: Water quality parameters
  • Figure 10: Catch composition of fish species at different locations in the Wami River estuary and within 2 kilometers offshore (Chanyungu). Numbers indicate number of individual fish species caught.
  • Figure 12: Water required per population of terrestrial wildlife species in Sadaani National Park
  • --- thank you - again the same argument about making an already long paper even longer. However we have advertised the Supplementary Data section better in the paper, with specific references to the figures and tables, as well as some text explaining them within the main paper.

Also, there are several titles without any figures in the end of the supplementary document, please provide the required materials or remove the titles. --- yes, we are cleaning that up.

Thank you again.

Reviewer 3 Report

Comments on the hydraulic modelling:

1) are the sections employed by the HR model the ones shown in the supplementary? please comment on their choice (location and number)

2) how is then possible to predict salt wedge intrusion into the river bed with the proposed procedure. The authors should make the reader aware that there exist modern approaches which are able to accurately simulate salt wedge distributions in the river bed, for complex geometries and time varying boundary conditions (tides and fresh water discharge). See reference [a] and other works therein cited.

3) it is not clear how the hydraulic models exchanges data with the other methods. Maybe a flow chart would clarify.

Author Response

Dear Reviewer,

firstly, we thank you very much for your time and attention to the paper, and for your helpful comments, addressing which improves the paper. Please find our responses in line below, prefixed with ---

Comments on the hydraulic modelling:

1) are the sections employed by the HR model the ones shown in the supplementary? please comment on their choice (location and number) ---yes, Fig 2 in main paper shows the 4 channel sections at each site (Matipwili and Gama Gate), and the actual channel cross-sections are shown in Fig 2, 3 Supplemental Info. It would have been good to include these in the main paper, however has been relegated to Supplemental Info, in view of the long length of the paper.  The reasons for choice of Matipwili and Gama Gate has been explained in sections 2.2.1 and 2.2.2; also some transects had better results than others, and were chosen - this is mentioned in Results 3.2, and all the results included in Table 7 Supplemental Info document.

2) how is then possible to predict salt wedge intrusion into the river bed with the proposed procedure. The authors should make the reader aware that there exist modern approaches which are able to accurately simulate salt wedge distributions in the river bed, for complex geometries and time varying boundary conditions (tides and fresh water discharge). See reference [a] and other works therein cited. --- in this study, salinity measurements were done on the surface, 1m and 2m depth over different high and low tide conditions in August, that is in between the dry and wet seasons. Salinity varied widely with tide conditions. Ideally noting the salinity over a year at different locations along the estuary would provide adequate data to estimate the salinity wedge distribution and extent with season and tide. However this level of daily monitoring for a year was out of the scope of the study. Hence we used the mangrove zonation as a comprehensive indicator of the salinity conditions prevailing in the estuary over the past several decades, the reason being that different mangrove species vary intheir tolerances to salinity, and in the dry season, high tide conditions create the highest salinity that can stress those mangrove species that are not tolerant of full marine salinity. We also do not refer the reader to modern approaches for modeling salinity distribution in complex estuaries because that requires high resolution spatiotemporal salinity data, which was out of the scope of this study. This study was a demonstration of how to determine freshwater inflows in data-poor estuaries, where it is urgent to have some scientific inputs for management in a situation where water is fast becoming scarce.

3) it is not clear how the hydraulic models exchanges data with the other methods. Maybe a flow chart would clarify. --- we are writing this clearer, both in the end of the introduction, as well as in the methods section ( 2.5) - Steps 1-7 list the entire EFA process with how the minimum stage requirements for diff communities are determined, and the hydrological model used to get the inflow for a corresponding stage value. The hydrological part is described fully in 2.5.2

Reviewer 4 Report

Comments for author File: Comments.pdf

Author Response

Dear Reviewer, thank you very much for taking the time and effort to review this paper. We have responded to your comments below ( in-line, prefixed with ---), and have revised the manuscript taking most of them into consideration.

Greetings, Editor thank you for providing me with the opportunity to review the article. I reviewed the article with ID=hydrology-1770619. The article topic is intriguing and promising in the area. Overall, the article structure and content are suitable for the journal. I am pleased to send you minor-level comments, there are some flaws which need to be corrected before publication. Please consider these suggestions as listed below.

1. The title seems good, but the abstract seems to be wired. Please add one more introductory line of your objective in the beginning of the abstract. --- Done
2. Research gap should be delivered in a clearer way with the directed necessity for future research work. –-- Good suggestion, we have expanded on the need for future research in the last paragraph of the Discussion.
3. Introduction section must be written in a more quality way, i.e., more up-to-date references addressed. Please target the specific gap. –- Here the challenge is that there is a lack of scientific publications addressing flow-ecosystem links in this part of Africa, and such is the case in many parts of Africa, Asia and Latin America. There may be Government reports that describe the current status of the environment, but these are not always available online. We have provided scientific references for basic estuarine ecology-flow linkages, but there are very few in Tanzania.
4. The novelty of the work must be clearly addressed and discussed, compare previous research with existing research findings and highlight novelty. –-- The novelty here is to develop science-based management guidelines where no data exists and hence natural resource management has little scientific ecological and environmental guidance. As such, this paper details a scientific study to inform managers about the minimum freshwater flows to be maintained in the Wami River estuary; it is the first study of its kind for the specific area.
5. What is the main challenge? Please highlight this in the introduction part. –-we have tried to do this better.
6. Please check the abbreviations of words throughout the article. All should be consistent. – Thanks we are paying attention to that.
7. Please provide space between numbers and units. Please revise your paper accordingly since some issue occurs on several spots in the paper.

---Yes

8. The main objective of the work must be written in the clearer and more concise way at the end of the introduction section.

--yes, we have revised the abstract, introduction and discussion substantially, as well as methods and results sections to make these more evident.

9. Regarding the replications, authors confirmed that replications of experiment were carried out. However, these results are not shown in the manuscript, how many replicated were carried out by experiment? Results seem to be related to a unique experiment. Please, clarify whether the results of this document are from a single experiment or from an average resulting from replications. If replicated were carried out, the use of average data is required as well as the standard deviation in the results and figures shown throughout the manuscript. In case of showing only one replicate explain why only one is shown and include the standard deviations.

--> replications were carried out in both wet and dry seasons, and additionally, in each season, measurements were carried out on 3-4 consecutive days, to capture tidal conditions with replicates. We are writing this more clearly in the methods. Also this is not an experiment, rather, its gathering data on ecohydrology, wilfdlife and social needs.

10. Why few sentence are in bold form in section 4.1.

---Have changed that – these sentences stress how critical it is to note that EF recommendations are based on the very minimum flows as a compromise in a situation of competing water demands, and that in reality the ecosystem has evolved with the entire flow and not a subset.

11. Section 5 should be added and named by Conclusion and Future perspectives. Conclusion section is missing some perspective related to the future research work, quantify main research findings, highlight relevance of the work with respect to the field aspect.

---thank you for the suggestion.

12. To avoid grammar and linguistic mistakes, Major level English language should be thoroughly checked. Please revise your paper accordingly since several language issue occurs on several spots in the paper. –- -we are proof-reading the paper thoroughly. Some of us are native English speakers as well.
13. Reference formatting need carefully revision. All must be consistent in one formate. Please follow the journal guidelines. – thanks, we are paying attention to that.

Round 2

Reviewer 2 Report

The manuscript has improved a lot since the last time; therefore, I recommend accepting the manuscript. However, I still believe that the anthropogenic activities which was discussed in supplementary is very important and useful section and should move to main paper.

Reviewer 3 Report

none