Response to Reviewer RC1:

We sincerely thank the Reviewer for their evaluation and valuable comments on our manuscript. We improved our manuscript incorporating your suggestions, fixed any inconsistency and double checked the citation formatting. Below we provide a response to each point raised in the Specific Comments.

1.Definitions of Key Terms: The definitions of terms in Section 2 of the manuscript include few examples of mitigation, prevention and adaptation measures. In our view, extending the list of examples at this stage would detract from the clarity of the definitions. Instead, the link between mitigation/prevention definitions and countermeasures adopted in the investigated 49 cases is provided in Section 5.1 “Applicability of subsidence reduction measures”, Figure 6. Furthermore, Table B1 in Appendix B offers more specific links between the measures cited in each reviewed paper/case and the objective of the corresponding intervention.

2.Limitations of Current Data: In the revised manuscript, we emphasized that “Currently, the information available to structure the scoring is limited, as demonstrated in Table B1 in Appendix B. This affects the criteria used to assign scores, possibly leading to over- or underestimations of the effectiveness of certain subsidence countermeasures. This limitation should be taken into account when applying the indicators from Table 4, as it may influence the selection of subsidence reduction measures. The lack of comprehensive and consistent data further underlines the need to collect and share experiences in evaluating the performance of subsidence reduction measures to create a more systematic framework.”  To fill this gap, future works should report more systematically the performance of subsidence countermeasures using the indicators of effectiveness presented in this paper, which “can serve as the basis and catalyst for this improvement”.

3.Comparative Effectiveness:  In the revised manuscript we clarified the methodology used to evaluate the effectiveness of subsidence countermeasures. Specifically,  “the effectiveness of subsidence countermeasures is evaluated by assigning equal weight to all indicators of effectiveness, treating them as equally important. The qualitative values of each indicator are scored on a scale from 1 to 3 […]. The overall effectiveness of subsidence reduction measures is determined by averaging the scores across all indicators. ” Additionally, when two subsidence countermeasures have equal effectiveness, other factors (such as costs and long-term sustainability) can influence the choice of the preferred measure. For example, in Shanghai, injection wells were preferred  over aquifer recharge due to their lower costs; while in San Joaquin Valley, aquifer recharge was favored because it allows greater volume of water to be replenished compared to injection wells. These example underline the importance of  “multi-criteria assessments that weigh effectiveness alongside costs and sustainability”, as underlined in the revised Discussion.

4.Broader Impacts: Thank you for the valuable comment. In the revised manuscript, we expanded the discussion on the indirect consequences of subsidence reduction measures, focusing on their environmental, social and economic impacts, which we believe are critical for policymakers. Particularly, we added that “Environmental considerations encompass potential alterations of local ecosystems, changes to water quality, depletion of natural resources, and increased energy consumption with associated carbon emissions. For instance, creating artificial retention ponds may disrupt natural habitats, while recharging aquifers – whether through surface or deep injections – may affect water quality. Similarly, infrastructure-heavy solutions, such as injection wells, can contribute to greenhouse gas emissions, especially if they rely on non-renewable energy sources. Social impacts involve the displacement of communities due to relocation, leading to social stress and loss of community identity. Equity issues can also arise, as the increased costs or reduced availability of potable water disproportionately affect low-income populations. Other economic implications include rising property values, which can lead to gentrification and displacement of lower-income residents. Given these challenges, stakeholder and decision makers should adopt a multidimensional approach to subsidence (risk) management that integrates technical considerations with environmental stewardship, social equity, and economic feasibility. Proactively addressing the indirect consequences of subsidence reduction measures can contribute to sustainable and resilient urban development.”

Response to Reviewer RC2:

We sincerely thank the Reviewer for their evaluation and valuable comments on our manuscript. We carefully revised our manuscript addressing your suggestions and resolving any inconsistency. And we believe that our revised manuscript now aligns with your expectations. Below we provide a response to your questions and comments.

Comment nr. 1: We agree that the cost of subsidence countermeasures is a relevant factor in practice when selecting suitable options. We acknowledge that costs should be considered as sub-category in the Q&R system. However, to facilitate a comparison among worldwide case studies, “this paper does not include any sub-category” such as costs, as it “would hinder the comparability of diverse applications”, as explained in Section 4.1. In the revised manuscript, we also expanded the Discussion to highlight the importance of economic considerations in decision-making. We also recognize that the integration of cost considerations into the framework is an important step for future refinements, and we propose exploring this in future work. This would allow for a more comprehensive decision-making process that accounts for both technical effectiveness and financial feasibility.

Comment nr. 2: We appreciate you comment and appreciate the opportunity to clarify the application of Q&R system to the three examples. The Q&R system is indeed designed as a decision tree, though it was not formally illustrated as such in the manuscript. By progressively answering the questions outlined in Section 4, a user can identify a set of applicable subsidence countermeasures for a given case study, taking into account the geology, primary cause of subsidence, desired intervention, targeted action, scale of application, and type of urban setting. This same process was applied to the three case studies (Shanghai, Jakarta, and San Joaquin Valley), which demonstrate how the Q&R system can be used in practice. The selection of subsidence countermeasures in each case derives from the comprehensive responses to all the questions in the system. We hope this explanation clarifies the intended use of the Q&R system as a decision tree approach in the case studies.

Comment nr. 3: We acknowledge the Reviewer’s concern regarding the scale of application in the selected case studies. To address this, in the revised manuscript we reclassified the scale of application of subsidence countermeasures using a logarithmic scale. This allows a better diversification of scales.

Comment nr. 4: We understand your concerns regarding the validity of the methodology based on the three examples. As clarified in Section 5.3, the cases of Shanghai, Jakarta and San Joaquin Valley were selected from the total of 49 reviewed case studies because they are the most extensively documented, either through available literature or the insights provided by academic scholars and experts on subsidence mitigation and prevention. While these cases rely on existing literature, the Q&R system’s framework is designed to generalize across various scenarios by systematically evaluating factors such as geology, causes of subsidence, and urban settings. Unfortunately, no other cases had such detailed information on the history of subsidence management to be included as additional examples. To further acknowledge this, we remarked in the revised Discussion that additional testing on independent data sets is necessary to fully validate the methodology.

Comment nr. 9: We appreciate the opportunity to clarify this point. The reduction potential (RP) indicator focuses specifically on the physical reduction of subsidence (i.e., diminished settlement) and damage (e.g., reduced width or number of cracks). The RP is assessed by comparing the amount of subsidence or damage observed before and after the implementation of a subsidence countermeasure.  We clarified this in the revised manuscript to ensure that the definition of RP is clear.

Comment nr. 10: In the revised manuscript, we clarified that operational reliability refers to the functionality of subsidence countermeasures during their service life.

Comment nr. 13: Thank you for this valuable suggestion. We carefully revised the manuscript and updated the classification of service life (SL) to better reflect typical service life of engineering structures (50 – 100 years). The revised thresholds are defined as follows: short (SL< 20 years), medium (SF: 20-50 years) and long (SF> 50 years).

Comment nr. 20: Thank you for raising this important point. The frequency of subsidence countermeasures in the 49 case studies did not influence the expert responses, as the academic scholars and experts were unaware of this information during the expert sessions and surveys. However, it is important to note that the effectiveness of each countermeasure is assessed based on the mode, meaning that the frequency of a countermeasure does influence the performance  assessment. We discuss this limitation in the revised Discussion. Specifically, the frequency of countermeasures  may lead to over- or underestimations of their effectiveness.  “This limitation should be taken into account when applying the indicators from Table 4, as it may influence the selection of subsidence reduction measures.”

Comment nr. 21: We agree with the Reviewer regarding the use of the mode as a more appropriate metric. Indeed, in the revised manuscript we clarified that “The mode is used as metric to assign a single value to each indicator of effectiveness for the subsidence countermeasures. In cases of equally frequent results, expert judgment is preferred if available; otherwise, the highest value is assigned. It is important to note that for some subsidence reduction measures some indicators are missing due to insufficient information in the consulted sources (see Table B1 in Appendix B). When no data is available, no value is assigned to the corresponding indicator of effectiveness.”

Comment nr. 22: As shown in Table B1 in Appendix B, the minimum number of responses required to populate each cell in Table 4 is 1. We believe that a stricter criterion on the response frequency would have limited the number of conclusions that could be drawn. However, we recognize this as a limitation, which is discussed further in the manuscript. Moreover, we advise additional testing on independent data sets and “a detailed evaluation of effectiveness via measurable parameters – such as water table levels, water infiltration rates, volume of extracted or recharged water, soil compaction, surface rebound, settlement rates, crack widths”.

Comments nr. 23-25: Thank you for your valuable comments. In the revised manuscript we provided additional details on the Shanghai case study by specifying the extent of the area affected by subsidence (i.e., more than 90,000 km² ), where countermeasures are needed. This further clarify why the “regional scale” is used. Moreover, we acknowledge that the size of the impacted region is an important factor, but we would like to emphasize that the choice of subsidence countermeasures is based on the comprehensive responses to all questions in the Q&R system, not just this one category. Regarding the selection of subsidence countermeasures based on their performance, we clarified in the revised manuscript that “The effectiveness of subsidence countermeasures is evaluated by assigning equal weight to all indicators of effectiveness, treating them as equally important. The qualitative values of each indicator are scored on a scale from 1 to 3 [...]. The overall effectiveness of subsidence reduction measures is determined by averaging the scores across all indicators. This approach ensures a balanced evaluation of all criteria and facilitates the prioritization of subsidence countermeasures.”  Typically, the top two subsidence reduction measures are considered the most applicable and effective. Additionally, while we acknowledge that the viability of subsidence countermeasures, particularly on a regional scale, often depends on cost considerations, we intentionally excluded cost from the Q&R system to facilitate a broader comparison across different regions. Including cost as a sub-category could have hindered the comparability of diverse applications, as discussed in Section 4.1. However, we highlight the importance of considering cost and other factors like sustainability in the Discussion.

Comments nr. 26-31: Thank you for your valuable comments. In the revised manuscript, we provide additional details on the Jakarta case study, which helped clarifying the scale of application for the subsidence countermeasures. As part of the revisions, we now use a logarithmic scale for categorizing the scale of application, which reclassifies the area of Jakarta – which is 660 km² – as large scale, rather than regional as previously described. This reclassification not only differentiates Jakarta from Shanghai, but also led to a reassessment of the applicability of countermeasures. Some countermeasures, such as building jacking, were not selected in our analysis because they were considered less effective that other options. Furthermore, as clarified in the revised manuscript, measures as building jacking and retention ponds were implemented in Jakarta largely in response to freshwater scarcity and flood risk, rather than subsidence reduction.

Comments nr. 32-34: Thank you for the valuable comments. In the revised manuscript we provided additional details on the San Joaquin Valley case study, such as the extent of the area affected by subsidence (i.e., 10.000 km²) and the sinking rate of 31 cm between 1925 and 1970. We also clarified throughout the text how the measures were selected based on their applicability and effectiveness. In San Joaquin Valley, the two options resulting from our procedure were either implemented (aquifer recharge) or considered as an alternative (injection wells). The final choice of subsidence countermeasure was influenced by additional considerations, such as the volume of recharged water and the sustainability of the measures. However, these considerations are not part of our methodology in its current form, though they should be considered for future improvements, as highlighted in the Discussion.

Comment nr. 35: We appreciate the opportunity to clarify this point. While the subsidence countermeasures presented in the manuscript and their applicability are derived from existing literature, the cases of Shanghai, Jakarta and San Joaquin Valley were chosen to demonstrate how the proposed procedure can be used in practice. These examples were selected from the total of 49 reviewed case studies because they are the most extensively documented. We have updated the manuscript to emphasize this perspective, which better reflects the preliminary nature of this work.