The influence of Covid-19 Pandemic and Climate Change on Water Use and Supply: Experience of Istanbul, Turkiye

Reviewer comments

Author responses

1. Weather conditions and climate change are two different things. There is a big misconception in the article about these two subjects. Weather condition is the atmospheric conditions that comprise the state of the atmosphere in terms of temperature, wind, clouds, precipitation, which is very temporary and unstable. But climate is the average weather in a place over many years. Climate change is a shift in those average conditions, that is accelerated in recent years due to environmental problems.

In order to avoid such misunderstandings, paper has been revised by clearly defining these terms.

2. The introduction begins with the importance of water and water management, which is good. Climate change must be defined and explained along with its effect on the water circle. Pandemic and climate change have to be discussed more about their origins and related effects on settlements. Some research claims that pandemic is also a result of climate change. Make sense of the connection between. So, the title of the article should be "The Impacts of Covid-19 Pandemic & Climate Change on Water Environment: The Case of Istanbul and London."

The title has changed accordingly. “The influence of Covid-19 Pandemic and Climate Change on Water Use and Supply: Experiences of Istanbul and London Area”

3. Towards the end of the introduction, some unclear sentences appear. In line 117, "... unexpected situations such as the Covid-19..." What else? Every situation that is examined must be written here. In the line 118-119, specify the dates that data compiled. "previous years" is not a certain phrase. In lines 121-122, is there an implication for Covid-19 lockdown? Which lockdown? When? These paragraphs should be rewritten clearly.

Changes have been made accordingly.

4. DPSIR is abbreviated for what? Explain the methodology.

Abbreviation of DPSIR and methodology section have been added.

5. In the figures, there are some graphics shared with meaningful data compiled from related authorities (some of them are not cited). In order to make sense of the metadata, this information should be selected between the exact dates. Istanbul's water consumption is between 2000-2020, but population and water consumption are between 2000-2019. The water reservoir level is between 2000-2021, etc. (?)

All data is referenced in the methods section, which now has more consistent time frames. We have updated our data sets (now up to March 2022).

6. Since this is a comparison article, the same data should be shared and interpreted for London, too. And before this, it should be explained why these two cities were chosen as case studies. What are the common and comparable features?

Study area section has been added in methodology.

Reviewer comments

Author responses

The article is highly original in that it is the first time a DPSIR framework has been used to study the effects of Covid-19 and climate change on water consumption.

1. Some parts of the article are written too long. A shorter and simpler narrative style will be correct in terms of attracting the reader's attention.

Some paragraphs (especially in discussion) have been shortened. Table 1 including “the main findings of how countries have been affected by different phases of the pandemic with sources and main comments related to the final DPSIR framework” has been added.

2. Due to one of the sample areas of the article is Istanbul, it would be more accurate to replace the municipality of Bolu street disinfection photo in Figure 5 with a photo from Istanbul.

Disinfection photo from Istanbul has been added.

Reviewer comments

Author responses

The authors present a paper, in which they examined how unexpected situations such as the Covid-19 pandemic might affect water usage and availability. Although the paper is well-written and well-structured, I do have some concerns about the paper, which merit further attention.

1. My first comment relates to the usage of the DPSIR framework. I agree with authors that the application of the DPSIR framework for signaling differences in water consumption patterns during the pandemic. Since climate change and covid-19 are two different drivers (van der Voorn et al, 2020) which manifest themselves at different time scales, including their impacts, there lies a major challenge in obtaining some separate evidence that the pandemic restrictions affected human activity in Istanbul for which they examined air quality parameters, and these suggest air pollution in Istanbul was lower in 2020 than in 2019 indicating decreased human activity consistent with Covid-19 restrictions. However, in order to distinguish between the impacts of these two drivers, I believe the current set of indicators is not sufficient and therefore, I have two suggestions for improvement:

As we try to define how covid and weather-related changes have an impact on water environment, looking at the details of climate and covid relationship will be another research topic. However, we have looked at the below comments and revised paper accordingly.

2. In order to provide more evidence on “waste”, the authors could consider Wastewater-Based Epidemiology, which could be especially informative given that asymptomatic and oligosymptomatic infections are unlikely to be detected during clinical surveillance  see e.g., Bivins et al (2020) and Bhattacharya et al (2021)

Thank you for the comment although we have touched on wastewater discharges, we cannot address any epidemiology aspects of this as we are not gathering information of this kind during the study. This issue may be explored further in later paper dealing with emergent strategic issues.

3. Since people were in lockdown, they may have ordered products and services online. This would increase (slightly) traffic patterns and at least demand for transportation, which in turn increase CO2 emissions.

Figure 17 (Monthly total number of vehicles) and its explanation “decreased number of vehicles measured on one of the main roads in Istanbul after many governmental restrictions (e.g., fully lockdowns) were applied from early April 2020” has been added.

4. In addition, looking at the different time scales to be considered, the DPSIR framework depicted in Figure 1 seems to be a static representation of its DPSIR components. So, in light of the research objective, a more dynamic representation would be required to capture the dynamics across different time scales.

As we mentioned in the paper, Figure 4 only shows the overview of the factors likely to be involved in changing water consumption before going into deeper analyses. Figure 16 is the enhanced version and set out at the next level of detail the factors that may be affected by both climate change and the pandemic, and it shows the factors we believe may need to be considered in developing future resilient water systems and management approaches.

5. My second concern relates to the comparability of the Turkish case with other cases. In my opinion, there are indeed limited comparisons possible, if not impossible between Istanbul and other countries at present due to lack of data availability, as the authors stated. However, it is not just because of a lack of data but also different national characteristics in terms of socio-ecological, socio-economic, socio-technical, and governance aspects. Hence, it requires a solid framework for comparison, which accounts for these differences and similarities, to make any statements on comparability. These aspects could be interpreted as coping capacities. Van der Voorn and de Jong et al (2021) developed a framework for such a comparative analysis.

Some other factors have been added to comprehend why there is limited comparisons in the context of data availability and national characteristics.

6. My final concern relates to the need for new management plans. This would require adaptive management methodologies like for example the Backcasting Adaptive Management methodology (van der Voorn et al, 2012, 2017) or a comprehensive multi-target backcasting approach (van der Voorn et al 2020), which combines the strengths of multicriteria analysis, nexus approaches and backcasting, for supporting a transition to zero GHG emissions The former methodology can help decision makers to develop robust adaptive management plans, whereas the latter allows them to conduct a qualitative environmental assessment of scenarios to identify conflicts and synergies in regard to a broad range of environmental targets (e.g., reduction of biodiversity loss, viable habitats for flora and fauna). I would like to encourage the authors to elaborate on how these methodologies could expand the DPSIR framework in light of the research objective of the paper.

In this study, we looked for evidence of the influence of such factors on water resources and water consumption to provide more detailed framework for thinking through what kind of influences on water supply and consumption patterns needed to be incorporated into future adaptive water management planning for this, and other, major urban centres: therefore, the need for management plans (back casting or comprehensive approaches) would be another research topic in the development of new plans.

Editor comments

Author responses

The topic of  water usage during Covid-19 and impacts of climate change is important and current, thus the article is timely. However, as it stands at version 1 it is rather descriptive; there is no clear indication of exactly how some methods were undertaken (e.g. the last paragraph of p6 in the pdf). Also, some more /different analysis would help support or clarify some of the arguments. For example:

Fig. 8 links higher temperatures to low reservoir levels, despite having established a link for reservoir levels with rainfall, so are temperature and rainfall correlated? This is important when examining scenarios and also when deciphering what is driving reservoir levels – most likely an interaction of climate and socio-economics and demography

Rainfall anomaly has been added. Interaction with temperature, rainfall and reservoir levels, and other factors (socio-economic) have been discussed.

The different patterns of domestic and business water usage is important. It would be helpful, if possible to separate these out in total consumption figures.

During the data collection from the responsible organizations, it was not possible to get sector-based water consumption data due to municipality’s privacy.

Careful reasoning is also need in emergent issues, as p22 suggest more periods of dry weather and yet p14 it is only RCP8.6 in the latter part of the century that is projected to be drier.

More periods of rainfall and temperature projections have been added with different scenarios and uploaded to UCL Data Respiratory. We have retained sections on emergent and strategic issues that arise directly from our studies but recognize that these need to be dealt with in more detail in due course.

Discussion (especially the first part) would benefit from synthesis round key arguments and findings.

Discussion section has been improved accordingly, and strategic and emerging issues have been added to the discussion in more detail.

All in all I think this paper needs a more analytical approach, framed round certain arguments and hypotheses.

Paper has been revised according to all comments, and methodology and other sub-headings has been added in order to provide a more analytical approach that has used mixed methods incorporating both quantitative as well as qualitative data. We hope the additional material on the DPSIR Framework is beginning to identify where arguments and hypotheses could be developed for specific aspects of adaptive management plan.

Editor comments

Author responses

L93-95 Surely it is climate change that is having an ongoing impact on water resources and to which the impacts of the pandemic have been added / superimposed? This affects your argument. It is also related to Osman Zeybek’s and Tom van Voorn’s first comment. The relationship between climate  change and the pandemic needs setting out more clearly, especially in terms of drivers in the DPSIR framework.

We wanted to give as complete a view as possible of how water use and resources may have been affected by the Covid-19 pandemic and then examine whether climate change would make managing any future pandemic worse especially given that the IPCC see the Mediterranean basin as being more susceptible to drought in future (See FAQ 8.3: Climate change and droughts from IPCC Sixth Assessment Report Working Group 1: The Physical Science Basis – Chapter 8)

We could not take the exact approach set out in the handling editor’s comments because, although we suspect that climate change may already be affecting water resources and perhaps use in Istanbul, in that there is an upward trend in temperatures and perhaps more variable rainfall patterns (see Figure 12 and 13 in giving the anomaly data), we do not think a complete case for this can be made at present. Thus, we focused on the use of water in the pandemic first and then went on to consider the impact of climate change in case any such impacts made handling a future pandemic more difficult due to limitations on water supply or resources.

For the two reviewers who raised points relating to the weather and the climate and, in effect, ask how these are related with respect to water use in the pandemic we hope that we have made our approach clear by inserting two hypotheses and linking these with our approach to developing a DPSIR framework.  We hope this also addresses a point the handling editor made earlier about the paper gaining some benefit from the use of hypotheses (see Introduction, paragraph around line 90).

We have tried to answer these points from reviewers as thoroughly as possible to explain how we understood water use around the time of the pandemic’s beginning and how we anticipate water demand will develop under climate change.  Thus, we have now provided, as a short-term context, data for the weather in Istanbul for the period prior to and during the pandemic (see Figures 2 and 9). We also begin the climate change part of our paper with a consideration of weather data since the late 1930s – trends in which might well indicate local climatic trends. As Figure 12 and 13 suggest increasing temperatures and increasing variability in rainfall patterns in Istanbul we feel justified in then examining, under various climate change scenarios, what temperature and rainfall might look like in Istanbul out to the end of the 21st century. We now summarise these results in Table 1. We hope that all this sets out the link between pandemic water use, weather and climate change in a manner that is satisfactory.

Much less attention is given to London and the case for comparison is somewhat weakened by L362 “Despite different weather patterns”. The methods seems to refer to Turkey, as do most of the results. London / Thames Water seem to feature much more in the discussion, which uses material from the Table 1 and/or other papers and documents, with less drawn from the earlier part fo the paper. If London is to be a comparator then some attention needs to be made to the differences and how they affect the findings. See also comments on L138. If you wanted to expand the international context you could develop your comments on Table 1. Overall I do not find the case for using London as a comparator convincing and the case for including it needs strengthening.  These relate to the  concerns raised by other reviewers especially second comment from Tom van Voorn.

We agree with these points by the handling editor. The pandemic was a fast-moving matter and the experiences of various countries came through a number of different data sources at different times. As our work progressed in relation to reviewers comments the imbalance between Istanbul and London and its surrounding area became more apparent and the case for London or the London area as a comparator became less convincing. We have removed London as a major comparator and incorporated relevant aspects from this geographical region and other parts of the UK into the international section (starting from line 438) and into the section on emergent issues (starting from line 514).

There is a need  for consistency and making clear which geographical area you are talking about, as it is confusing especially for an international audience. For example, for the UK you talk about London / Thames Water (not the same geographical area, as it includes smaller cities and towns e.g. Oxford as well as a large rural component upstream of London)  / south east England (again not the same area as the other two.

We dealt with this lack of clarity by removing London as a major comparator.

In the discussion of emergent issues it is not clear for each subsection whether it is local, regional, national or international (or more generic). For example, cleaning seems very general but it is something you specifically covered for Turkey / Istanbul, whereas economic impacts is discussed entirely in relation to Thames Water.

The nature of the pandemic emergency meant it was treated differently in different countries and that they are reporting various aspects of the pandemic at different times. We thought it best to create a generic emergent issues section regardless of country of origin and use summary statements to contribute to the second DPSIR framework we include in the paper. For instance, it was not possible to get any economic impacts of the covid-19 pandemic in Istanbul or other cities except Ankara where we have shown the disruption in municipality’s revenue as real-time usages (for three months) were not billed due to governmental statements and restrictions (to protect workers and public health) (line 606-609).  We hope the changes we have made this means the paper now appears more consistent in its approach.

Editor comments

Author responses

Reviewer 1’s second comment does not seem to have been addressed other than changing the title

See our detailed response to the first statement of general comments above. 

L96 What about London – where does this fit in. It needs to be mentioned and its inclusion justified in the introduction

London as a comparator has been removed.

L96 comment by Reviewer 1 about “previous years” has not been addressed.

We have increased the range of some of our datasets and made others as consistent as possible. Complete consistency across all datasets is not possible given the nature and sources of the data. We are using data and other information that is in the public domain and that is internally consistent. The “previous year” comment has been addressed for rainfall and temperature anomalies, water consumption, and water reservoir levels throughout the paper not only at this point.

L106 why is it Figure 4 if this is the first figure referred to in the paper?

Thank you for pointing to this awkwardness in the figure numbering. Figures are now numbered carefully, and the first mentioned figure is the Istanbul map (Figure 1) in methods.

L115 Framework (lower case elsewhere) for thinking  through  what  kind  of  influences  on  water  supply  and  consumption  patterns  needed to be

Change has been made accordingly to lowercase throughout.

L120 Suggest “and which considered the  importance  of  all  aspects  of  the infrastructure system and human behaviour in water use” as the (i) and (ii) are concerned with adaptation to the impacts of, while (iii) and (iv)  are components which each need to consider.

Change has been made accordingly “The water system of a large municipality might then be more resilient because it had been designed in a manner that provided for adaptation to trends in climate change impacts, and to changes in frequency and severity of extreme events of different kinds. Adaptation would include making infrastructure more resilient and making preparations to affect human behaviour towards water resources”.

Editor comments

Author responses

L137 relates to comments above about (i) figure numbering (Figure 1) (ii) London mentioned for the first time. Also Istanbul is 15th and London 37th (List of largest cities - Wikipedia) so possibly a bold claim.

Given the editor’s comments on geographical and lifestyle differences, and over- attention on London, we have removed the case of London as a comparator and used UK findings  in  the international section expanding the relevant Table  as advised by the editor.

L138 “similarities in lifestyles  and  commuting  patterns”. This needs justifying. I don’t think that the fact that the number of people commuting into London from the surrounding area is about the same as those living in Istanbul is in anyway a justification. Indeed it suggests different commuting numbers, which is not the same as patterns

London as a comparator has been removed.

L147 Figure 2 shows the monthly temperature and precipitation for 2020, but give no idea how they relate to others years, so does not show “change” across years, just the seasonal pattern. It would be better if this figure could show how the monthly totals relate to previous years or 30 year average, then a statement like “the month of May was the driest and hottest on  record in England” would be better supported.

30-year rainfall and temperature averages are now given in the figure.

L164 should not be Figure 2

Thank you for pointing the inconsistency out. Figure numbers were updated for the revised version

L203 Figure numbers should be sequential, as they are the text – should this should be Figures 5-7.

Likewise, Figures were numbered carefully and consecutively in the revised version.

Editor comments

Author responses

Figure 5 – the text Istanbul Water Consumption should be on the y axis alongside the green-blue colour scale I think.

The text of “Istanbul Water Consumption” was replaced next to the y-axis scale in this and other figures as well.

L233-4 Material in the Annex is part of your argument and should be in the main text.

Texts and figures from Annex I have been moved into the main text as advised by the editor Thanks for this suggestion.

L286 – define Q3 - not everyone will know what this means. So move description (July, August, and September) from next sentence to after Q3 or just no use Q3 at all.

Instead of using Q3, we have updated the texts by just using the description (July, August, and September).

Table 1 Brazil – should it be residential usage not residual?

Change has been made accordingly.

L379 unclear sentence -  “we examined four climate change emission scenarios to scope  for the DPSIR Framework”

The sentence has been rewritten as “Given the evidence above in (Figure 12 and Figure 13) that Istanbul may be subject to drought-like conditions relatively frequently, we examined four climate change emission scenarios (RCP2.6, RCP4.5, RCP6.0, and RCP8.5) to understand whether such events might become more frequent or more intense in future (four different time periods).”

L380-388 should be in methods.

Thank you for pointing to this. The text about climate projections were moved into the methods section in the new version

L393-428 – details on changes under each scenario would be much better as table.

All climate projection details have been given in Table 2. Thanks for this suggestion.

Editor comments

Author responses

L458 Sentence beginning “In trying  to  gain  insights” is unclear and would benefit from being brken into several sentences.

The sentence has been rewritten as “When trying to figure out what the strategic and emerging issues are, it's important to consider a wide range of socio-ecological, socio-economic, socio-technical, and governance issues. Differences between countries and local areas in their approaches to hazards, risks, and emergencies, as well as their capacities and approaches to adaptation in different but related environmental and epidemiological situations, must be taken into account.”

L486 should be predominantly

Change has been made accordingly.

L502 should be “ranging  across social..”

Change has been made accordingly.

L504 would this be better titled water quality, as this is the issue under discussion?

The title of “disinfecting public buildings and spaces” has been retitled “Water Quality” to make this more generally applicable Thank you for the suggestion.

L523 Increased sewage system blockages – duplication of material could do with re-writing.

Change has been made accordingly.

L568 should be “Actions are in hand to..”

Change has been made accordingly.

Editor comments

Author responses

Table 2 – working remotely – in Table one and the discussion you suggested that this led to changes in the balance of domestic and commercial usage, which is important to highlight.

Change has been made accordingly. Thanks for this suggestion.

Population movement – the increase / decrease related to the movement of people away from / back to the city. Again it would be good to capture this change in regional usage here.

Change has been made accordingly. Thanks for this suggestion.