Review Reports

Round 1

Reviewer 1 Report

Abstract should be rewritten show its potential, main results as well as the novel

References should be discussed not only enumerated (eg., line 33, line 39, line 43) Please review all document and citations and the authors have to discuss them

The authors should develop a best approach to the methodology. They should develop a flowchart in which they explain each one of the different steps of the research.

The different indexes to calibrate were defined in some research. The authors should add a table in which define the goodness range as a function of BIAS, Nash, RMSE (the authors can use the following classification of the goodness, which used these indexes (Calibrating a flow model in an irrigation network: Case study in Alicante, Spain¸https://doi.org/10.5424/sjar/2017151-10144, who used the hydrologic model to define this goodness)

Figure 6 and 7 should be discussed better and compared with other researches. Maybe the authors can use the used references, but they must discuss it and compare between them not only enumerate

Conclusions should show the main novel and the main difference with other published models

Author Response

Please see the attachment for reply to comments to both reviewers

Author Response File: Author Response.docx

Reviewer 2 Report

Dear authors,
thanks for your contribution firstly.
The paper provides a study to develop an integrated, variable-scale system dynamics model for water quantity and quality (including stream temperature; dissolved oxygen; macronutrients) applied to a small low-land catchment located on Sjaelland, 25 km north of Copenhagen, Denmark .
The abstract is well written, it briefly summarizes the purpose of the paper and the results obtained and also the English language is fine.
The bibliography of this manuscript is very rich, but in some cases even a little dated for this reason I suggest you prefer more recent research (perhaps from the last 5 years); in this regard, on the topic of water quality, I suggest a recent publication (https://doi.org/10.3390/w13070934), which addresses the problem of optimizing the position of water quality sensors in sewer networks as their quality, in fact, it has effects not only on the sewer and purification system but also on the receiving water bodies in the event of a combined sewer overflow, thus constituting an environmental problem. These reflections can be useful to you in a short paragraph, perhaps positioned in the introduction, which deals with the importance of water quality in general (not strictly related to your study).
Overall, I believe that the paper includes solid content, but some aspects need improvement, if so this manuscript can have its own value and impact.
I hope that these recommendations are helpful to the authors and wish good luck for the further reviewing process.

Author Response

Please see the attachment for reply to the comments from both reviewers

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors clarified the developed suggestions

Reviewer 2 Report

Dear Authors,

in my opinion, the paper is ready for the pubblication.