A Critical Evaluation of the Water Supply and Stormwater Management Performance of Retrofittable Domestic Rainwater Harvesting Systems

Round 1

Reviewer 1 Report

Very well written and organised manuscript with interesting case studies and approach. Although the research is specific for 3 domestic rainwater harvesting systems in Broadhempston, UK, the work and its conclusions are relevant for other cases/locations.

Below a few minor comments and suggestions that are meant to improve/clarify the manuscript in some aspects:

• Title a bit too long. Proposed: “A critical evaluation of the water supply and stormwater management performance of retrofittable domestic rainwater harvesting systems”
• Page 5, line 177 – Can you specify here the climate input variables?
• Page 7, Figure 2 – Repeat the explanation of the dotted lines (Tank full/Tank empty) in graphs b) and c)
• Page 8, Figure 3 – Repeat the explanation of the three lines in graphs b) and c)
• Page 11, Figure 4 – (Similar comments as for Figure 2 and 3) Repeat the explanation of “x” in graphs b), c) and d); repeat the legend of lines (as in graph e) in graph f);
• Page 13, lines 393-394: It would be interesting to further understand and discuss how (or by whom) the systems are managed and the degree of investment (both initial and maintenance costs) and technical knowledge needed to apply active control systems in rainwater and stormwater management. In this particular case, it is not entirely clear if the management of the RWH systems is made by the Broadhempston Community Land Trust or by the householders from Broadhempston.
• Active release systems, as explained in page 5. Line 177 are “remotely controlled in real-time, and they manage the release of water according to the rainfall forecast and available retention volume in the tank”. Such systems have a risk of failure. This topic could be addressed in the discussion, since good solutions that are easy to implement by researchers, may reveal to be not feasible in practice.
• Page 12, lines 381-383: The statement that “the value of engaging with the community and maximising their demand from the system can yield greater benefits than engineering solutions alone” is very interesting and valuable. It is therefore recommended that it is aggregated to the Conclusions.

Author Response

Thank you very much for your helpful comments. Please find my responses below your comments in bold

Title a bit too long. Proposed: “A critical evaluation of the water supply and stormwater management performance of retrofittable domestic rainwater harvesting systems”

Changed to proposed title. (Line 5-7)

Page 5, line 177 – Can you specify here the climate input variables?

Changed from ‘climate’ to ‘rainfall’. (Line 185)

Page 7, Figure 2 – Repeat the explanation of the dotted lines (Tank full/Tank empty) in graphs b) and c)

The explanation of the lines has been repeated for each of the graphs (Line 254)

Page 8, Figure 3 – Repeat the explanation of the three lines in graphs b) and c)

The explanation of the lines has been repeated for each of the graphs (Line 262)

Page 11, Figure 4 – (Similar comments as for Figure 2 and 3) Repeat the explanation of “x” in graphs b), c) and d); repeat the legend of lines (as in graph e) in graph f);

The explanation of the lines has been repeated for each of the graphs as requested (Line 327)

Page 13, lines 393-394: It would be interesting to further understand and discuss how (or by whom) the systems are managed and the degree of investment (both initial and maintenance costs) and technical knowledge needed to apply active control systems in rainwater and stormwater management. In this particular case, it is not entirely clear if the management of the RWH systems is made by the Broadhempston Community Land Trust or by the householders from Broadhempston.

Have added ‘The systems were installed by technicians from a telemetry provider and were checked periodically throughout the monitoring period. Besides this, the systems were not manged and were emptied solely by the householder for their non-potable water demand.  Remote access to the systems was limited as it was reliant upon consistent availability of householder Wi-Fi’ to the data collection section (Section 2.1) (Line 117-120)

Active release systems, as explained in page 5. Line 177 are “remotely controlled in real-time, and they manage the release of water according to the rainfall forecast and available retention volume in the tank”. Such systems have a risk of failure. This topic could be addressed in the discussion, since good solutions that are easy to implement by researchers, may reveal to be not feasible in practice.

Added ‘As shown by the periods of downtime in the monitoring data (Figure 1), obtaining a complete dataset of results proved difficult. This was due to intermittent communications which relied upon householder Wi-Fi connections. Without a steady stream of communication from the telemetry, sensor failures could not be identified, or rectified, in a timely manner. These communication challenges will need to be overcome for the successful implementation of active systems and further work is warranted to explore the benefits of a range of communication protocols that could support active technologies to be reliably adopted.’ To the discussion (Line 356-362)

Page 12, lines 381-383: The statement that “the value of engaging with the community and maximising their demand from the system can yield greater benefits than engineering solutions alone” is very interesting and valuable. It is therefore recommended that it is aggregated to the Conclusions

Added ‘This illustrates the value of engaging the community and that through maximizing their demand for the available non-potable, greater benefits can be achieved than through engineering solutions alone.’ To conclusion number 4. (Line 429 – 432).

Reviewer 2 Report

It is a high-quality manuscript presenting a well-designed, executed and analyzed study. Reviewing this manucript was a pleasure for me.
I have only two minor comments that Authors could use:
1. change the style of sentence in line 88 to show that it is a aim, not a report.
2. add units where possible

Author Response

Thank you very much for your helpful comments. Please find our responses below your comments in bold.

1. change the style of sentence in line 88 to show that it is a aim, not a report.

Changed to ‘examine the impact of different demand patterns on model accuracy.’  (Line 90-91)

2. 
   add units where possible

The sentence ‘These all have units of m³ and a 5-min time step.’ Has been added after equation 1. (Line 140 -141) And (m/5min) has been added after R_t rainfall rate (line 143)