Study on the Contribution of Groundwater Nitrogen Pollution Sources in a Typical Section of the Wei River in China

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Thanks for inviting to review the manuscript entitled “Study on the contribution of groundwater nitrogen pollution sources in a typical section of the Wei River in the riverine area.” This study is very important for the study area; therefore, some comments are given to improve the quality of the paper.

·       The title should be precise and informative.

·       Consider editing the long sentences in the abstract, for example, the 1^st sentence of the abstract in 7 line long, into several sentences.

·       Moreover, the abstract should containing the following points- background of the study, problem statement, objectives and respective methods to achieve the results, major contribution from this study, and recommendation based on the results.

·       Literature review should be updated with more information such as (i) source and impacts of nitrogen pollution in the study area as well as similar places around the world, (ii) why the Hydrus-1D model has been chosen among many models for this study and provide some benefits of using this model based on the comparisons with other models. For example, the following article (https://doi.org/10.1007/s10653-020-00571-w) can be refer to show the model comparisons. Most importantly, the authors should justify why they have conducted this research along with the aim of this study at the end of the introduction section.

·       Write a section in method part about the suitability of data and validation results.

·       Provide the uncertainty of results presented in Table 5 to show the reliability and accuracy of the results.   

 

·       Add the recommendation for further studies in the conclusion part. 

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

 This paper describes a simulation process carried out at Weihe River, China, substituting points for surfaces, calculating the amount of water and nitrogen concentration of the leaching water at the bottom of the aeration zone and inputting them into numerical model to realize the integration of simulation calculations between the surface, the aeration zone and the aquifer system.

 The manuscript’s strengths are an integrated approach, where Hydrus-1D and Visual Modflow were used and the contribution rate of different groundwater nitrogen pollution sources was calculated through the equilibrium formula by combining the groundwater nitrogen test results.

 The weakness is the scarcity of contaminants (only 3, ammonia, nitrite and nitrate), and effective groundwater pollution prevention and control measures proposed are too vague.

Abstract – the information given is adequate and concise.

1.Introduction – The aim of paper is adequately exploited.

Lines 43/44 – correct the name of the places cited in this paper, it is Alvalade and Mitra.

2. Methods

2.1 Study area overview – adequate

How were samples collected?

How were these N-parameters determined? Cite the methods used.

Water quality categories (class III, IV and V) should be explained as well as the standard values cited (lines 91-93).

2.2. Vertical infiltration simulation of surface nitrogen pollution

Line 104 – it is Table 2 and not table 1

Line 114-118 - poor spelling and difficult to understand. Rewrite this sentence.

Table 3 – insert labels for the Soil moisture characteristics parameters (what is θr, θs ….)

Fig.4 – Represent what are the axis x and y.

3.Results and discussion

Adequate discussion well documented by tables and figures.

 Lines 271-272 should be deleted.

4. Conclusions - Adequate

 Effective groundwater pollution prevention and control measures proposed are too vague. If you know the sources and fate you should propose more specific measures to mitigate this problem.

 

The paper is suitable for publication with major revisions.

 

Comments on the Quality of English Language

Some minor corrections to be made.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Thanks for addressing all the comments. 

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript has been sufficiently improved to warrant publication in Water. All the recommendations were addressed in the revised version, so the paper is acceptable in the present form.