Study on the Evaporation Suppression Efficiency and Optimal Diameter of Plain Reservoirs Covered by EPS Floating Balls in Arid Areas

Round 1

Reviewer 1 Report

The manuscript is focused of the Evaporation Suppression Efficiency (ESE) of the EPS floating balls (of different diameters, 10-150 mm) in arid areas (experimental study from the Xinjiang province in China). The ESE of the EPS floating balls has been estimated by the experimental way in evaporators with diameter of 1.2 m. The main goal of the study has been to find the optimal diameter of the EPS balls as well as optimal economy efficiency. The main results have been focused on the diameter and wind influence on the ESE values. The experimental methodology has been suitable to obtain the relevant results, but the diameter of 1.2 m (evaporators) is too low to study the wind speed influence higher than 2.5-3 m.s^-1 due to different water waves structures in real lakes/dams than in small evaporators. Therefore I strongly recommend to add the discussion part focused on the limitations of the evaporators diameter related to wind speed influence on the ESE values. I can accept the results for wind speed lower than 3 m.s^-1 as well as partly the conclusions.

Author Response

Dear Reviewer，

Thank you for your valuable comments on the manuscript. I have made the following modifications：

1.Added at the end of Section 4.2：

What needs to be added is that the specification of evaporator was limited, the side wall of the evaporator weakened the influence of wind speed and wave on the internal floating balls. If the ambient wind speed is greater than 3 m/s, it is necessary to further prove the anti-evaporation effect of the floating ball on the water surface by using a larger evaporator or in the actual project when applying the floating ball to reduce evaporation in small sized water.

Changes have been marked in red fonts, please review it again. Looking forward to your reply. Thank you again for your careful review. Looking forward to your reply.

Best wishes，

Buzhi.Wang

Author Response File: Author Response.pdf

Reviewer 2 Report

Review of “Study on the Evaporation Suppression Efficiency and Optimal Diameter of Plain Reservoirs Covered by EPS Floating Balls in Arid Areas.”

 The article describes two sets of experiments designed to evaluate the evaporation suppression potential of expanded polystyrene (EPS) floating balls of different diameters, under normal evaporative conditions, and under a wave and wind test.  The results indicate that in both tests, floating balls with diameters in the 40 – 80 mm range outperformed those with larger or smaller diameters, and that EPS presents a viable material option for evaporation control projects.  The authors consider factors such as cost and material durability as well as environmental impacts, in addition to evaporation suppression.  All factors appear to align around the use of 40-80 mm EPS floating balls in plain reservoirs.

The study is well-designed and the analyses are convincing.  I have only minor comments, which I provide below.

1)  Page 2, paragraph beginning “Currently, the problems brought on by….” contains several statements of specific fact, but zero citations to references.  For example: the statement “…the proportion of farmland water-saving irrigation area is far from meeting the requirements of efficient water conservation,” is a quantitative statement.  I think a reference is required here and elsewhere in the paragraph.

2)  Page 2, Section 1.2 “Research Status”

     This section appears to be a literature review, and begins that way.  But halfway through the second paragraph of the section it shifts directly to stating the objectives of the current study.  This was confusing to me as there was no transition from literature review to objectives.  Simply moving the objectives to a newly-added section 1.3 “Research Objectives” would solve this.

Also in this section, in the fifth line of “Research Status,” the authors refer to “remote and ‘backward’ arid areas.”  I’m not sure which definition of the word “backward” is being used here, as no reversal of anything has been reported or implied.  Rather, it reads as a pejorative term.  I suggest that “remote arid areas” is sufficient information on this point.

3) Page 6, Figure 3: Among the main factors influencing evaporation rates is a box containing only a series of dots (…..).  If this is intentional, it should be addressed in the figure caption, as there is no other interpretive guidance provided.

4) Page 6, Section 3.1, fourth line:  the authors name two instruments used to observe evaporation, along with “other instruments.”  What other instruments?  If I wanted to replicate the study, I would need this information.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer，

Thank you for your comments on the manuscript. I have accepted all comments and made the following changes: 

1.Add three references in  Page 

2.Add Section 1.3 and adjust relevant contents

3.Delete the word "backward"

3.Add a description for "..." in the Figure 8

4.Adjust statements to disambiguate

Changes have been marked in red fonts, please review it again. Looking forward to your reply

Best wishes，

Buzhi.Wang

Author Response File: Author Response.pdf