Extensive Green Roofs: Different Time Approaches to Runoff Coefficient Determination
Round 1
Reviewer 1 Report
The manuscript of the authors from Portugal is concerned "EXTENSIVE GREEN ROOFS: DIFFERENT TIME APPROACHES TO RUNOFF COEFFICIENT DETERMINATION”.
Thank you for the opportunity to review this useful and actual research study.
The manuscript presents the suitability of a previously developed model for green roofs runoff coefficient determination assessed, using experimental data, which is fundamental to assessing their hydraulic performance and designing the drainage systems downstream.
This submitted article could be with the aim and scope of the MDPI journal Water.
• Abstract & introduction: These two parts are focused on the paper's main aim and the new contributions of authors to the state of the art.
The abstract with keywords very effectively summarizes the manuscript.
The key objective for the authors is the assessment of different time scales for runoff coefficient determination as a major contribution to green roofs' future performance assessment and a fundamental decision support tool.
• Materials & methods: Based on the existing research, the authors defined three main goals. They used an experimental extensive GR system according to FLL guidelines and its one year of monitoring the climate of the Porto region for obtaining of runoff coefficient and to determine it by using different time sequences to conclude which one is more long-term performance.
It is clear how all of the data were obtained. This section gives readers enough information so that they can use the study for other areas.
• Results & discussion: The data are well-controlled and robust. Results are well-presented with relevant and current tables, figures, and references.
Results section were obtained and the methods used to analyze the data are suitable and scientifically sound. With some adaptation, this described methodology could be used more generally not only for the selected area of the world.
The authors know about the limitation of their work:
- mainly in connection with the size of an experimental stand (0,4 m2),
- their approach does not explicitly take into account the bigger areas of green roofs (200 m2 will be fine).
In GR runoff studies it is important to perform a broader analysis that takes into account the performance of the green roof structure for at least one complete year or better at least three years.
I hope they will continue with such interesting and inspirative research such way.
I have a few comments for improving the manuscript before publishing.
In the paper are some small grammar mistakes (manjority/48; intriltration/ 52, ...
- Numbering of the equation is enough (1) not Eq. 1;
missing some spaces before letters/ 205,
the Title of the figure should be directly under this picture/ 233
- Why is chosen year of the study 2017?
- Important figure 9 is very small for reading
Author Response
Authors are grateful to Reviewer #1 for the time spent analysing our study and the important suggestions presented. Please find specific responses to each comment in the attached file.
Kind regards, Cristina Monteiro
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Irrigation, When you start these; What are the key values to irrigate?
-Evaporation:
You only counted Rain, - No information about dayly ET in dedendence to the water balance?
My question is: Runoff- coefficient can be different:
One hand: full year values: what runs off in compare to the full year precipitation?
Important are run-offs in relation to event. It is also important how saturated the soil is at the beginning.
In the sence of the German FLL the run-off is a technical terms from some defined experiments.
As an example: Your table 2 show for Jan 26 to Feb. 08 200mm Precipitation and a run-off of 10 mm. It will be interesting to see the graph, how the rain was distributed – or in other words the intensity is an important factor. How you manage this intensity in your survey?
You developed a calculation model? Table 3 to clarify this?
I prefer to get this described more in detail.
Abstract: line 29: What you explain is the Reduction in Percentage, a coefficient in my understanding is a number between 0 and 1. Please check it with the understanding in the FLL Green-roof guideline (2018)
Author Response
Authors are grateful to Reviewer #2 for the time spent analysing our study and the important suggestions presented. Please find specific responses to each comment in the attached file.
Kind regards, Cristina Monteiro
Author Response File: Author Response.pdf
Reviewer 3 Report
Water (ISSN 2073-4441)
Title: EXTENSIVE GREEN ROOFS: DIFFERENT TIME APPROACHES TO RUNOFF COEFFICIENT DETERMINATION
Authors: Cristina M. Monteiro, Cristina Santos , Paula M. L. Castro
1. Abstract: The abstract is also concise. The keywords appropriately reflect the content of the manuscript.
2. Introduction: Previous studies cited, and a critical comparison of different methodological approaches well described. The manuscript objectives have been significant and concisely stated.
3. Materials and Methods: The study region, data sets and processing have been clearly described.
4. Results: These are satisfactorily presented
5. Conclusions: Discussion is concise. Conclusions are in line with the discussion.
In conclusion, I did find much of this manuscript well organized and convincing, I did learn about “EXTENSIVE GREEN ROOFS: DIFFERENT TIME APPROACHES TO RUNOFF COEFFICIENT DETERMINATION”. I do recommend it.
Author Response
Authors are grateful to Reviewer #3 for the time spent analysing our study and the positive provided feedback.
Kind regards, Cristina Monteiro
