Sedimentary Basin Water and Energy Storage: A Low Environmental Impact Option for the Bananal Basin

Round 1

Reviewer 1 Report

It is a very well presented article, its argumentation is good and presents an interesting contribution between the hydrological, geomorphological and energetic relationship.

However, I think it is necessary to expand the results of steps 1 and 2 proposed in the methodology, since they are not the support for the other steps. 

Author Response

1) It is a very well presented article, its argumentation is good and presents an interesting contribution between the hydrological, geomorphological and energetic relationship.    

We would like to thank you for your significant contributions to the paper.

2) However, I think it is necessary to expand the results of steps 1 and 2 proposed in the methodology, since they are not the support for the other steps.  

Thanks for this. We have revised and expanded the results section related to steps 1 and 2.

Author Response File: Author Response.docx

Reviewer 2 Report

This manuscript aims to analyze the water and energy storage, costs and benefits of two proposed water management solutions of constructing the dredged canal and dam for hydropower generation at Bananal sedimentary basin before developing the projects. The goal of two water management solutions is to improve the water and energy storage and to reduce the vulnerability of floodplains to global warming and changes in climate. The impacts of three proposals (adding dam, adding dam and a shallow canal, adding dam and a deep canal) on the environment and society during the wet and dry seasons are investigated. This analysis is interesting, and it could help with the project planning. I have some minor comments.

I suggest adding one figure of the simplified sketch of the spatial distribution of the rivers and cascade dams. Line 97: where is the location of the Tucuruí dam? You can also add two proposed water management solutions of dredged canal and low head dam in this figure to help readers to understand. Figure 11 could help. You may consider how to combine them.

The first highlight needs to be clearer for the number 42.3 km3.

The figure numbers should be revised following the occurring sequence of figures. Figure 3 occurs earlier than figure 2 in the current manuscript.

Line 196: typo “do” changed to “to”

Author Response

1) This manuscript aims to analyze the water and energy storage, costs and benefits of two proposed water management solutions of constructing the dredged canal and dam for hydropower generation at Bananal sedimentary basin before developing the projects. The goal of two water management solutions is to improve the water and energy storage and to reduce the vulnerability of floodplains to global warming and changes in climate. The impacts of three proposals (adding dam, adding dam and a shallow canal, adding dam and a deep canal) on the environment and society during the wet and dry seasons are investigated. This analysis is interesting, and it could help with the project planning. I have some minor comments.    

We would like to thank you for your significant contributions to the paper.

2) I suggest adding one figure of the simplified sketch of the spatial distribution of the rivers and cascade dams. Line 97: where is the location of the Tucuruí dam? You can also add two proposed water management solutions of dredged canal and low head dam in this figure to help readers to understand. Figure 11 could help. You may consider how to combine them.    

We added a map showing the location of the proposed dams to Figure 11.

3) The first highlight needs to be clearer for the number 42.3 km3.    

We realised energies paper do not have highlights. We deleted the highlights.

4) The figure numbers should be revised following the occurring sequence of figures. Figure 3 occurs earlier than figure 2 in the current manuscript.    

You are right. Thanks for spotting this. We corrected the order of the figures.

5) Line 196: typo “do” changed to “to”    

“São Felix do Araguaia” is the Brazilian name of the location. To avoid confusion, we removed “do Araguaia”.

Author Response File: Author Response.docx

Reviewer 3 Report

Dear authors,
The article raises important issues related to the protection of water resources. On this point, however, the authors could describe the whole situation in more detail. While reading the article, I saw a certain dissatisfaction. In my opinion, the job could be much better and better. I have included my thoughts in the remarks and comments.

Comments for author File: Comments.pdf

Author Response

1) Dear authors, The article raises important issues related to the protection of water resources. On this point, however, the authors could describe the whole situation in more detail. While reading the article, I saw a certain dissatisfaction. In my opinion, the job could be much better and better. I have included my thoughts in the remarks and comments. peer-review-19258927.v1.pdf    

We would like to thank you for your significant contributions to the paper.

2) What authors mean? If we want to keep water in sediment basin we need to flood them. So why it is said that no flooding will be required? Maybe expected would sounds better.    

Thanks for spotting this error. We changed to: “A significantly smaller reservoir area is expected, as the water will be stored as groundwater in the sedimentary basin”.

3) Too general. What is the relation between the unit cost of energy versus the cost of a battery? I do not get it, explain it, please.    

We agree that it is not a reasonable comparison. We also checked that the Energies journal does not publish the highlights of the paper. Thus, we decided to delete the highlights section.

4) We usually name such areas as polders even if it isn't lay in depression.    

Thanks! We changed the text to: “Sedimentary basins store a significant amount of water and are also called wetlands or polders”.

5) Where are these points? Please show them at the map.    

The maps in the paper do not show all the hydrological locations analysed in the paper. However, Figure 11 does. So we added: “These points are shown in Figure 11”.

6) Where are these points?    

We added: “(Figure 11)”. Add a legend to figure 7. Show what kind of particular colors means.    We added the legend to Figure 7. We only added the description of the relevant soil to the proposed solution presented in the paper. We also added: “The legend describes the soil relevant to the proposed solution presented in the paper”.

7) To be more precisely the ground water storage capacity should be counted by using weighted arithmetic mean.    

We agree with you. However, unfortunately we do not have enough information from the basin to make a more precise ground water estimation. Thus, we decided to apply a simplified approach.

8) Add a legend to figure 9.    

Added the legend to Figure 9.

9) What kind of water level is shown in this histogram? Maximum, average, minimum?    

We changed the figure and caption, and added a better description of the data. We also corrected the main text description of Figure 10.

10) Would you explain the inadequacies in this description? In figure 11 you show 4 proposals for dams. In this text, you describe 3 of them without showing which one is and omitting one of them. Please explain it.    

We re-wrote the paragraph: “Figure 12 presents three proposed operations for the Bananal sedimentary basin storage. The three proposed operations include the São José, Santa Isabel and Marabá dams described in Figure 11. The first proposal (P1) adds the Sedimentary basin storage dam, which controls the water exiting the basin and allows the water to remain for a longer time in the sedimentary basin. The second proposal (P2) adds the Sedimentary basin storage dam and involves the construction of a shallow canal, which allows more water to be extracted from the basin during the dry period and, thus, more water can be stored in the basin. The third proposal (P3) adds the Sedimentary basin storage dam and involves the construction of a deep canal, which allows even more water to be stored in the basin.”.

11) First of all, you should explain what we can gain by building turbines, which will be need huge engines and will be work only for a few days in whole year. Economically your concept is unjustified.    

Thanks for spotting this. We added the utilization factor (capacity factor) of the turbines to the table, and added a discussion in the paragraph. “The capacity factor the proposed dams without the Bananal sedimentary basin reservoir is low are small (50-60%). However, with the P3 scenario, the capacity factor increases to (70-80%), which significantly increases the viability of the proposed dams.”.

12) Flooding or even waterlogging sounds better then spillage.    

There is a misunderstanding here. By spillage, I mean the water that flows through the spillways of the existing and proposed dams. When the reservoir is full and the hydropower turbines do not have the capacity to discharge all the water that enters the reservoir, the spillway has to be used. This result in water passing through the dam without generating electricity. The water flow that passes through the spillway in a dam is spillage.

13) To be more precisely you should add information about river section with brown colour.    

We have changed the information about the river section with brown.

14) Write how it was counted or give the source.    

We added: “assuming a battery cost of 150 USD/kWh [46]”.

Author Response File: Author Response.docx

Reviewer 4 Report

Dear Authors

Greetings. Your submitted work is acceptable in its current form.

Best regards,

MAA

Author Response

1) Dear Authors. Greetings. Your submitted work is acceptable in its current form. Best regards, MAA.    

We would like to thank you for your interest in the research and positive feedback.

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

Dear Authors,
I get acquainted with your improvements and from my point of view, I think that your article now sounds much better. I will be recommending it to be published.