PWAT-D-22-00017

A Google Earth-GIS based approach to examine the potential of the current rainwater harvesting practices to meet water demands in Mityana district, Uganda.

PLOS Water

Dear Dr. Nanteza,

Thank you for submitting your manuscript to PLOS Water. After careful consideration, we feel that it has merit but does not fully meet PLOS Water's publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

The manuscript entitled "A Google Earth-GIS based approach to examine the potential 1 of the current rainwater harvesting practices to meet water demands in Mityana district, Uganda." investigated the application of simple google earth tool for estimating the rainwater harvesting potential to satisfy the present needs in the study area. The topic is of interest and fits the scope of the journal. However, the paper is more inclined towards calculations rather than some scientific findings. The drawn conclusion and recommendation about cost and economics of the water tank storage capacity is not supported by data. Statement and interpretation about cost is inappropriate and unjustified. It is suggested to incorporate more details about economics aspects. These concluding facts about cost is not contributing any scientific finding.

Moreover, It is becoming difficult to understand about the under size of the RWH system to meet the demand while rainfall is distributed over entire year. The detailed comments of the reviewers are provided that need to be addressed in the revised manuscript.

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Kind regards,

Muhammad Jehanzeb Masud Cheema

Academic Editor

PLOS Water

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Additional Editor Comments (if provided):

The manuscript entitled "A Google Earth-GIS based approach to examine the potential 1 of the current rainwater harvesting practices to meet water demands in Mityana district, Uganda." investigated the application of simple google earth tool for estimating the rainwater harvesting potential to satisfy the present needs in the study area. The topic is of interest and fits the scope of the journal. However, the paper is more inclined towards calculations rather than some scientific findings. The drawn conclusion and recommendation about cost and economics of the water tank storage capacity is not supported by data. Statement and interpretation about cost is inappropriate and unjustified. It is suggested to incorporate more details about economics aspects. These concluding facts about cost is not contributing any scientific finding.

Moreover, It is becoming difficult to understand about the under size of the RWH system to meet the demand while rainfall is distributed over entire year. The detailed comments of the reviewers are attached that need to be addressed in the revised manuscript. Also double check the reference list.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Does this manuscript meet PLOS Water’s publication criteria? Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe methodologically and ethically rigorous research with conclusions that are appropriately drawn based on the data presented.

Reviewer #1: Partly

Reviewer #2: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: No

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Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The manuscript entitled "A Google Earth-GIS based approach to examine the potential 1 of the current rainwater harvesting practices to meet water demands in Mityana district, Uganda." investigated the application of simple google earth tool for estimating the rainwater harvesting potential to satisfy the present needs in the study area. The topic is of interest and fits the scope of the journal. However, the paper is more inclined towards calculations rather than some scientific findings. It is becoming difficult to understand about the under size of the RWH system to meet the demand while rainfall is distributed over entire year.There are some major points that require to perform as described below, where also specific recommendations and comments are provided.

Abstract:-The abstract needs to be more concise as some findings are repeated in different ways.

1. Line 21: The unit of water volume l/c/d is not defined.

2. Line 28-31: The sentence “Most of the tanks …………..20,000 litres” is to be modified as it is giving the information that tanks with storage capacity< 20K are not meeting the demand.

3. Line 34: The words like lumpsum should be avoided in support of the findings.

4. Line 36-38: The generalized statements may be avoided.

Introduction: The authors have not discussed much about the background of the proposed study in connection with interest of other readers worldwide. Why the design parameters have not been adopted while construction of these RWH tanks. Authors are supposed to discuss more about the importance for inception of the work by adding some more relevant review of literature. Objectives of the proposed study are very general in nature rather to inclined towards scientific findings.

Material Methods: It is not mentioned in the methodology about that the RWH tanks are being continuously filled by the rainwater. How it is possible to define that the size of the tanks is not sufficient, while the tanks are receiving water continuously. This needs to be included in the methodology.How the continuous utilization of harvested water and inflows are managed.

1. Line 138: The location of the study area is not showing that Mityana district belongs to which country. The back lines mentioned in the map are not defined in legend (Fig.1). What is the relevance of showing the Shallow well and deep bore holes over location map?

2. Line 148: why the course resolution rainfall data is used, while the finer resolution data is available works wide. This has the problem to have no coverage in border areas (Fig. 3).

3. Pattern of scale is not followed uniform across all the figures.

4. Fig. 4, it is hard to understand the decimal values of persons/ house hold. It should be some integer values.

5. Line-160 & 166, the mentioned fig.4 has the different information. I think Fig.4 & 5 needs to interchanged.

6. Line 173: see comment-5

7. Line 178: While average no. of persons/ house hold is considered then, it was linked with the varied capacity of tanks. It may be useful for total demand and total capacity not for individual house hold and individual tanks. In case of average house hold data of population, it is hard to understand the capacity of tanks is surplus or not satisfy the needs of a household.

8. 183-185: How it is possible to separate more than one adjacent roof tops within the periphery of 200m, out of them only one roof top is feeding to RWH tank.

9. Line 206-207: Reference for standard runoff coefficient is not given. It will better to estimate this coefficient with some actual data of rainfall and storage volume on sample basis.

10. Line 235: The term dry days is not clear while, it is being reported about the rainfall during entire year (Fig. 2).

11. Line 234: The dry day needs to be defined clearly.

12. Line 235: From where number of user per tank is taken. In section 2.4 it is mentioned that average no. of persons/ house hold are taken from population data. Again it is the question of linking of all population data with the data of house hold population which is having tanks.

13. Line 246-249: The economic analysis has the assumptions only and defined in one sentence only. It needs to be elaborated about the selection of size of storage tank during construction and what are the economic benefits or losses through utilization of harvested water since the construction.

Results: The discussion about the results is superficial and just elaboration of calculated results. It needs to be added some scientific angle to attract readers. The most of the information provided in the Table or Figures is just repeated in the text.

1. Line (table 2): What is the meaning of rooftop area of 0 (in 0-99), I think zero can’t be a minimum area. How the interconnected roof area is handled during digitization.

2. Line 263 & 273: While average RWHP is 200,000 lit/ roof area and storage capacity is about 20000 lit, then how 5% tanks have storage capacity more than RWHP. Comparative figure for the same may be added for more clarifications. How many times the situation when the storage tanks are full or empty during rainfall.

3. Line 283 (Table 3): Most of the tanks are not meeting the demands for 180- days, the continuous supply of rainfall during the given period is considered or not, this will add in the storage capacity of the tank after emptying and then filling again. This need to be clarified that about 400 mm rainfall is happening during this dry period of 180 days (Dec-Feb and Jun-Aug)

4. Line 283-289: The discussed information is already mentioned in Table 3.

5. Section 3.4: In Fig 8 & 9, the information of RWHP/ Dry period potential inflow to the tanks may be added for more clarification. The situation of tanks (whether it is completely filed or partially filled) is also not clear before initiation and during ending of dry period.

6. Line 324-328: How the information provided in Table3 and Fig. 10 is different? The finding of the estimated gap in demand is not discussed scientifically, rather presenting only calculated data so far. One Table may be added to estimate the demand gap in support of the economic analysis.

Reviewer #2: Author’s made a good attempt to examine the potential of current rainwater harvesting to meet water demands.

Abstract is well written and describing the research question with clear statement.

However, drawn conclusion and recommendation about cost and economics (lines 34 to 38) of the water tank storage capacity is not supported by data. Statement and interpretation about cost is inappropriate and unjustified. It is suggested to authors, incorporate more details about economics aspects. These concluding facts about cost is not contributing any scientific finding.

Methodology section is described well in text. Information and procedure about google-earth GIS based approach is described in few lines only section 2.5.1. Some more information about tools, techniques, equation applied for area estimation should be described. It would be more supportive to readers if conceptual flow chart of methodology added to describe the sequence of calculations and estimations.

Statistical analysis is missing in methodology as well as in results. Only frequency and percent distribution is analyzed. It’s suggested some more statistical analysis should be added.

A reasonable correction/improvement is required in cited references. In some references information about publisher/journal name and page details is missing or incomplete. It will be better if authors add doi number of references and update the reference list. Minor mistakes are noticed in citations, it’s recommended a uniform pattern should be followed for citation.

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Reviewer #1: Yes: Sanjay Kumar, College of Forestry, Banda University of Agriculture and Technology, Banda (India)

Reviewer #2: No

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A Google Earth-GIS based approach to examine the potential of the current rainwater harvesting practices to meet water demands in Mityana district, Uganda.

PWAT-D-22-00017R1

Dear Dr Nanteza,

We are pleased to inform you that your manuscript 'A Google Earth-GIS based approach to examine the potential of the current rainwater harvesting practices to meet water demands in Mityana district, Uganda.' has been provisionally accepted for publication in PLOS Water.

Before your manuscript can be formally accepted you will need to complete some formatting changes, which you will receive in a follow-up email from a member of our team. 

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Thank you again for supporting Open Access publishing; we are looking forward to publishing your work in PLOS Water.

Best regards,

MJM Cheema, PhD

Academic Editor

PLOS Water

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Reviewer Comments (if any, and for reference):