Multi-Geophysical Characterization of Karst Landfills in Croatia: Mapping the Waste–Bedrock Interface and Assessing Waste Volume

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

As is well known, karst is a significant global landform unit. Due to its unique dual above-ground and underground structure, karst regions are highly susceptible to complex environmental pollution. This paper presents a detailed exposition of environmental risk assessment and remediation planning for landfills in karst areas, offering novel insights and strong practical guidance for pollution control in these regions. However, certain details require refinement, specifically:

1. The current abstract needs systematic improvement by incorporating key result data and, more importantly, emphasizing the innovative aspects of this research.
2. While the literature citations are comprehensive, they currently resemble a simple listing of references rather than a critical analysis of the research development trajectory. It is recommended to include appropriate commentary.
3. The authors should explicitly state the scientific hypotheses or unresolved issues addressed by this study at the end of the literature review.
4. The instrumentation and parameters used in the experiments are missing. The authors did not specify the ERT equipment or SRT source type (e.g., explosives, drop weights), which is critical for method reproducibility.
5. Data processing requires further clarification. For example: What software was used for inverse modeling? What were the convergence criteria?
6. The authors describe the results extensively but provide insufficient analysis. Further elaboration on the underlying data is recommended.
7. The authors should consolidate the method descriptions. Move generic parameters for ERT and SRT data acquisition (such as array types) from Sections 4.1 and 5.1 to Section 3. Case studies should retain only site-specific information, such as site geology.
8. The Discussion section needs improvement. The authors have not effectively compared the results of this study with previous research, nor have they provided in-depth explanations for the observed phenomena. Additionally, the limitations of the methodology are not sufficiently discussed.
9. The Conclusion section requires further refinement. The authors provide only a brief summary of the preceding content without strengthening the paper's central argument. Importantly, it lacks any outlook for future work or specific recommendations for engineering practice.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

I read the manuscript "Multi-Geophysical Assessment of the Landfills in Karst: Croatian Experiences" with interest. The Authors used a multi-geophysical assessment incorporating the electrical resistivity tomography (ERT) and seismic refraction tomography (SRT) to evaluate the volume of the waste and to delineate the contact between the waste material and the karst terrain (landfills Sodol and Sorinj). The research goal was achieved. The Authors demonstrated the effectiveness of geophysical methods in estimating waste volume, determining the depth to bedrock, and assessing its condition. They found that resistivity values ​​up to 120 Ω·m correspond to waste material, while higher values ​​reflect changes in the bedrock. P-wave velocity data allowed for the separation of waste from bedrock: compact bedrock was identified by velocities of approximately 3000 m/s at Sodol and 2000 m/s at Sorinj. The article contains interesting results from a practical point of view, the findings of this study are valuable. I am convinced that presented aspect is interesting to journal's audience of "Sustainability".

The research and interpretation methods are adequately described and the results are clearly presented, however I suggest to include the following aspects:

1. The title is incomplete "...Assessment of the Landfills..." - it is worth justifying what will be assessed at this landfill.
2. The introduction chapter contains a description of the study area, which should be included in the next chapter. I suggest rewriting this chapter to include examples of similar solutions from other regions.
3. Figure 2 should include more elements that facilitate location (e.g., cities, rivers, etc.). The map should include a scale and color explanations.
4. Please add a scale to the appropriate figures (eg. Fig. 3, Fig. 6 and others).
5. I suggest enlarging figures 4, 5, 7, 8 and 9 to improve readability.
6. Line 201 - It is written „The Sodol landfill is located in Ogulin, Karlovac County (Figure 3a)”, but Fig. 3a does not show the names „Karlovac County”.
7. Line 277-278 – It is written „The Sorinj landfill is located on the island of Rab, within …., Figure 6a.", but Fig. 6a does not show these names.”

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript entitled “Multi - Geophysical Assessment of the Landfills in Karst: Croatian Experiences” is interesting and relevant. The revision remarks are below mentioned which must be addressed prior to considering the manuscript for publication.

1. Improve the abstract by including the cardinal findings/ conclusions.
2. Reframe the headings and sub-headings by including methodology and results and discussion. Section-2 should be merged with Section-1. Authors may choose to keep different subsections under the main headings (Introduction, Methodology, …).
3. Introduction is poorly developed and needs improvement. It should ideally begin with broader context and then converge to the research gaps and necessity of current study. The novelty of your work should be clear and additionally highlighted in the last paragraph of Introduction.
4. Authors should discuss the studies on alternatives to landfills (such as AD, etc.) while developing broader context in Introduction. It should include important studies about AI deployment in AD should be discussed. For e.g. https://link.springer.com/article/10.1007/s10668-023-04326-2
5. Elaborate why SRT is not a best approach to evaluate the landfill composition/ structure and the water content.
6. A schematic (or a line diagram) is recommended in the methodology section (currently there is no methodology).
7. Despite the availability of several approaches, why the authors have employed Wenner-Schlumberger array, with electrodes spaced five meters apart? Explain.
8. Authors should outline the reasoning for using the Delta-t-V method for processing collected seismic data.
9. Explain the significance of figures 8 and 9.
10. The Conclusions section is weak. The Conclusions section should indicate research gaps and research directions identified as the results of research presented. Clearly mention the limitations of the work.
11. The language requires more attention to ensure the clarity and correctness required for a scientific publication.
    
    

Comments on the Quality of English Language

English needs improvement.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

Accept