Sustainable Water and Energy Management Through a Solar-Hydrodynamic System in a Lake Velence Settlement, Hungary

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript titled “Sustainable Water and Energy Management Through a Solar- Hydrodynamic System in a Lake Velence Settlement, Hungary” presents a thorough investigation of the use of an interconnected solar-hydrodynamic network of water reservoirs, highlighting the optimization between solar capacity and geographical features. The effectiveness of developing cost-effective solutions comprising of proper management of retained rainwater and optimizing solar panel energy output, is notable. The experimental design is robust, the preparation of materials is detailed, and the tests employed are sufficient to support their claims. Overall, the study is really interesting, and the manuscript was well written. However, there are several issues that need to be addressed.

Comment 1: The number of keywords is overwhelming and might defeat the purpose of making your research easier to search and index. Limit the number of keywords to 5 or 6. In line 45, indicate the proper subsection no. (i.e., 1.1). Use en dash when presenting numerical ranges (i.e., in line 161, 0–150%, instead of 0-150%). Check all chemical formulas in the manuscript and make sure they follow proper naming conventions (line 221, CO₂). For all cited statements, I suggest putting the citation at the end of the sentence or paragraph (line 219, [48]).

Comment 2: The study contributes to scientific knowledge due to its novelty, as reporting a specific phenomenon, either anthropological or environmental, leads to never before known facts, data, and observation. The statistical and modelling aspects in optimizing the different parameters involved are well designed based on previous data, but I feel that the discussion portion can be improved by providing more information, such as the “secondary” effects of weather on the parameters measured (i.e., when it’s rainy, it definitely affect the amount of rainwater stored but does it affect relative cloudiness and ultimately, solar energy output? Is there a way to quantitatively correlate rain to cloud formation to solar energy generation?). I suggest using predictive models (i.e., surrogate modeling, proxy estimation, or variable imputation). These models treat the unmeasured variable as a target to predict based on correlations with available data. For example, solar power output is inversely related to cloudiness (more clouds reduce irradiance and thus power generation), while rainy days strongly correlate with high cloud cover. A good starting point in discussing this is in lines 1019–1020, but I can see that it only focused on the winter of 2022/2023.

Comment 3: Be consistent with table format. Follow the journal’s prescribed table formatting and spacing to make it easier to follow tabulated information.

Comment 4: I suggest presenting table 8 as a figure and label each figure accordingly (i.e., Figure 10a-f). Please do the same for table 6. For table 9, characteristics, separate them as a figure with larger axis labels for readability.

Comment 5: I am curious if the values presented for solar power output/energy generation, as stated in line 725–726, is the total for all the solar panels in the region detected by satellite imagery? How do you compensate for fluctuations in case some of them gets broken, under maintenance, temporarily inaccessible, covered with snow (winter), etc.? It might be challenging to get specific values for this as each homeowner does not report the status of their personal solar panels, but would it be possible to include an error band (or separate line) in figure 8 using predictive models to show the margin of error for these reasons?

Comment 6: For figure 11, revise the figure to make it more reader friendly. Try  It’s a bit confusing to look at it with the overlapping numbers and ambiguous axis labels. Please put the direct values on the x-axis instead of using generic A-D labels.

Comment 7: Consider reporting the standard deviations for data presented in bar charts, if available, or at least mention the number of measurements undertaken for each period.

Author Response

Reviewer 1

The manuscript titled “Sustainable Water and Energy Management Through a Solar- Hydrodynamic System in a Lake Velence Settlement, Hungary” presents a thorough investigation of the use of an interconnected solar-hydrodynamic network of water reservoirs, highlighting the optimization between solar capacity and geographical features. The effectiveness of developing cost-effective solutions comprising of proper management of retained rainwater and optimizing solar panel energy output, is notable. The experimental design is robust, the preparation of materials is detailed, and the tests employed are sufficient to support their claims. Overall, the study is really interesting, and the manuscript was well written. However, there are several issues that need to be addressed.

 

C1: The number of keywords is overwhelming and might defeat the purpose of making your research easier to search and index. Limit the number of keywords to 5 or 6. In line 45, indicate the proper subsection no. (i.e., 1.1). Use en dash when presenting numerical ranges (i.e., in line 161, 0–150%, instead of 0-150%). Check all chemical formulas in the manuscript and make sure they follow proper naming conventions (line 221, CO2). For all cited statements, I suggest putting the citation at the end of the sentence or paragraph (line 219, [48]).
Keywords have been reconsidered and number reduced to 6.
Subsection number (1.1) has been added to line 45.
We found the dash /en dash error in Sections 1.3, 4.1, 4.4 (total 5 places) – corrected.
Proper naming and use of chemical formulas have been corrected throughout the manuscript.
Citations have been corrected where the repositioning did not modify their explanations.

 

C2: The study contributes to scientific knowledge due to its novelty, as reporting a specific phenomenon, either anthropological or environmental, leads to never before known facts, data, and observation. The statistical and modelling aspects in optimizing the different parameters involved are well designed based on previous data, but I feel that the discussion portion can be improved by providing more information, such as the “secondary” effects of weather on the parameters measured (i.e., when it’s rainy, it definitely affect the amount of rainwater stored but does it affect relative cloudiness and ultimately, solar energy output? Is there a way to quantitatively correlate rain to cloud formation to solar energy generation?). I suggest using predictive models (i.e., surrogate modeling, proxy estimation, or variable imputation). These models treat the unmeasured variable as a target to predict based on correlations with available data. For example, solar power output is inversely related to cloudiness (more clouds reduce irradiance and thus power generation), while rainy days strongly correlate with high cloud cover. A good starting point in discussing this is in lines 1019–1020, but I can see that it only focused on the winter of 2022/2023.

We examined the relationship between solar radiation measurements from meteorological stations and PV output and found it to be linear with R-squared about 0.96, so we felt the actual performance data we gathered would be a better estimate.

 

C3: Be consistent with table format. Follow the journal’s prescribed table formatting and spacing to make it easier to follow tabulated information.
All tables have been corrected based on journal’s template file.

 

C4: I suggest presenting table 8 as a figure and label each figure accordingly (i.e., Figure 10a-f). Please do the same for table 6. For table 9, characteristics, separate them as a figure with larger axis labels for readability.
Tables/Figures updated.

 

C5: I am curious if the values presented for solar power output/energy generation, as stated in line 725–726, is the total for all the solar panels in the region detected by satellite imagery? How do you compensate for fluctuations in case some of them gets broken, under maintenance, temporarily inaccessible, covered with snow (winter), etc.? It might be challenging to get specific values for this as each homeowner does not report the status of their personal solar panels, but would it be possible to include an error band (or separate line) in figure 8 using predictive models to show the margin of error for these reasons?

we just got the available production capacity from satellite images and used a 0.95% inverter factor (IF), around line 530 to include downtime. The whole project is a somewhat rough estimate so this 0.95 multiplicator should be enough for initial estimates.

C6: For figure 11, revise the figure to make it more reader friendly. Try  It’s a bit confusing to look at it with the overlapping numbers and ambiguous axis labels. Please put the direct values on the x-axis instead of using generic A-D labels.
Figure has been modified, axis-changed.

 

C7: Consider reporting the standard deviations for data presented in bar charts, if available, or at least mention the number of measurements undertaken for each period.
Table 8. has been added to show further details of solar production. For 20-year rain events, the detailed table is even more complex and larger so it would break the continuity and readability of the manuscript if inserted into the text.

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

The paper presents an integrated approach combining stormwater management, renewable energy storage (via small-scale pumped hydro energy storage), and multi-purpose reservoirs in a Hungarian settlement. The topic is relevant, multidisciplinary, and timely, given climate adaptation, water security, and renewable energy challenges. However, several issues weaken the manuscript’s clarity, novelty positioning, and methodological rigor.

1. Language and Readability

Several typo mistakes, grammatical issues, reducing clarity.

• Example (Lines 17–20): “These issues, particularly acute in water management, are exacerbated by prolonged droughts, growing population pressures, and shifting land use patterns.” 
• Typos: “informatioin” (Line 492), “evalution” instead of “evaluation” (Line 474).        The entire manuscript needs professional English editing.

2. Novelty Not Well Differentiated

Lines 154–195: The paper cites many similar micro-PHES and solar integration studies (e.g., Guignard et al., Boroomandnia et al., Danso et al.) but does not clarify what is truly new. Is it the star-shaped reservoir topology, the Hungarian case study, or the multi-purpose use (wildlife, vineyards, recreation)? Without clearer positioning, it risks overlapping with existing literature. For example, the statement “This research offers a scalable, cost-effective solution” (Abstract) is too generic and could apply to several prior studies.

3. Hydrological Modeling Oversimplified

Equation (1), Lines 411–417, uses only four land categories with fixed runoff coefficients (0.9, 0.2, 0.2, 0.2). Runoff is estimated using only four surface categories (roads, forests, farmland, gardens) with fixed coefficients. This coarse classification ignores urban impervious variability, soil infiltration rates, and land-use heterogeneity. For example, “for in-town detached housing surfaces, it was 0.2 (Cintown)” (p.11) seems very low for built-up areas, underestimating runoff. The simplification may make results less reliable for design purposes. Also, No sensitivity analysis is shown.

4. Unclear MATLAB Optimization Method

Lines 355–367: The paper mentions a “MATLAB-based solver for nonlinear hydraulics” and “multi-objective optimization” but provides no detail about:

• What solver (e.g., fmincon, genetic algorithm)?
• What decision variables (pipe diameter, pump timing, reservoir size)?
• What objective functions (efficiency, cost, reliability)?
• What constraints were applied?

For example, Section 3.1 says “The MATLAB solver minimizes head loss and energy use” but does not explain the optimization process or provide convergence metrics. This weakens reproducibility.

 

5. Imbalance Between Hydraulics and Socio-Economics

Lines 576–603: Pipe hydraulics and equations (Darcy–Weisbach, Colebrook–White) are treated in great detail, while socio-economic, ecological, and stakeholder trade-offs are only described narratively. This creates an imbalance: the “multi-purpose” claim is not supported with quantitative data (e.g., willingness-to-pay, ecosystem service valuation).

6. Evaporation Not Quantified

Lines 243–246: The Introduction highlights evaporation as a major issue for Lake Velence (>40% losses), yet evaporation from the proposed reservoirs is not quantified in the results. Without this, feasibility is uncertain, especially since evaporation could cancel out stored water benefits in summer.

7. Energy Balance Not Compared to Demand Curves

Equations (6–8), Lines 498–530: While PV output and PHES potential are estimated, results are not compared against actual settlement load curves (hourly or seasonal demand). For example, winter heating loads are mentioned, but no demand profile is shown. This makes it unclear whether the PHES can truly cover peak shortages.

8. Fragmented Results

Section 4.1 (Lines 648–686) presents runoff; Section 3.2 (Lines 434–475) irrigation demand; Section 3.3 (Lines 481–519) PV output. Results on runoff, irrigation, wildlife demand, and energy storage are presented in isolation. There is little integration to show how the system balances all demands simultaneously. For example, irrigation and wildlife needs are quantified, but it is not shown whether reservoir capacity and PV surplus can meet them in a drought year.

9. Missing Cost-Benefit Analysis

The abstract and discussion claim “short payback period” and “cost-effective,” but no actual financial analysis is shown. CAPEX (reservoir construction, piping, pumps) and OPEX are not presented, nor compared to benefits (energy savings, irrigation value, tourism). This undermines the sustainability claims.

10. Discussion Skews Positive

Lines 302–310: The discussion emphasizes co-benefits (recreation, tourism, microclimate, biodiversity) but avoids limitations. Potential trade-offs such as land acquisition, ecological disruption, water rights, or stakeholder resistance are not discussed. For example, vineyards may compete with wildlife watering in drought years, yet no conflict analysis is shown.

Comments on the Quality of English Language

Several typo mistakes, grammatical issues, reducing clarity.

• Example (Lines 17–20): “These issues, particularly acute in water management, are exacerbated by prolonged droughts, growing population pressures, and shifting land use patterns.” 
• Typos: “informatioin” (Line 492), “evalution” instead of “evaluation” (Line 474).        The entire manuscript needs professional English editing.

Author Response

Reviewer 2

The paper presents an integrated approach combining stormwater management, renewable energy storage (via small-scale pumped hydro energy storage), and multi-purpose reservoirs in a Hungarian settlement. The topic is relevant, multidisciplinary, and timely, given climate adaptation, water security, and renewable energy challenges. However, several issues weaken the manuscript’s clarity, novelty positioning, and methodological rigor.

 

Language and Readability

C1. Several typo mistakes, grammatical issues, reducing clarity.
Mistakes, typos have been corrected throughout the text.

 

Example (Lines 17–20): “These issues, particularly acute in water management, are exacerbated by prolonged droughts, growing population pressures, and shifting land use patterns.”

Typos: “informatioin” (Line 492), “evalution” instead of “evaluation” (Line 474).        The entire manuscript needs professional English editing.
Corrected.

 

C2 Novelty Not Well Differentiated
Corrected, introduction has been improved, novelty added.

C3.   Lines 154–195: The paper cites many similar micro-PHES and solar integration studies (e.g., Guignard et al., Boroomandnia et al., Danso et al.) but does not clarify what is truly new. Is it the star-shaped reservoir topology, the Hungarian case study, or the multi-purpose use (wildlife, vineyards, recreation)? Without clearer positioning, it risks overlapping with existing literature. For example, the statement “This research offers a scalable, cost-effective solution” (Abstract) is too generic and could apply to several prior studies.

all 3, the star-shape, the hungarian case and the multi-purpose use. actually, especially the multi-purpose use is in focus which is supported by the star-shaped arrangement and this is incorporated into the combined socio-economic assessment

 

C4. Hydrological Modeling Oversimplified   Can we increase the complexity a bit? It will probably not have a very big impact on the final result, but would look more scientific.
Modeling has been broadened with 2 additional land uses and made it more complex.

 

Equation (1), Lines 411–417, uses only four land categories with fixed runoff coefficients (0.9, 0.2, 0.2, 0.2). Runoff is estimated using only four surface categories (roads, forests, farmland, gardens) with fixed coefficients. This coarse classification ignores urban impervious variability, soil infiltration rates, and land-use heterogeneity. For example, “for in-town detached housing surfaces, it was 0.2 (Cintown)” (p.11) seems very low for built-up areas, underestimating runoff. The simplification may make results less reliable for design purposes. Also, No sensitivity analysis is shown.
Modeling includes 2 additional land uses (4 -> 6 surface types) and became more complex. A sensitivity analysis (table 5) has been inserted into the text to show effects of possible future developments and land use changes.

 

C5. Unclear MATLAB Optimization Method

Lines 355–367: The paper mentions a “MATLAB-based solver for nonlinear hydraulics” and “multi-objective optimization” but provides no detail about:

What solver (e.g., fmincon, genetic algorithm)?

What decision variables (pipe diameter, pump timing, reservoir size)?

What objective functions (efficiency, cost, reliability)?

What constraints were applied?

For example, Section 3.1 says “The MATLAB solver minimizes head loss and energy use” but does not explain the optimization process or provide convergence metrics. This weakens reproducibility.
Sections 3.1 and 3.4 have been improved and clarified.

 

Imbalance Between Hydraulics and Socio-Economics

Lines 576–603: Pipe hydraulics and equations (Darcy–Weisbach, Colebrook–White) are treated in great detail, while socio-economic, ecological, and stakeholder trade-offs are only described narratively. This creates an imbalance: the “multi-purpose” claim is not supported with quantitative data (e.g., willingness-to-pay, ecosystem service valuation).
Detailed economics is added (intro, method, result and discussion).

 

C7. Evaporation Not Quantified

Lines 243–246: The Introduction highlights evaporation as a major issue for Lake Velence (>40% losses), yet evaporation from the proposed reservoirs is not quantified in the results. Without this, feasibility is uncertain, especially since evaporation could cancel out stored water benefits in summer.
Evaporation issue has been added to the manuscript. Here is a short description: about 60% of the evaporation loss is recovered from direct rain over the lake and about 35% is recovered by inflow from the catchment over the year. The remaining amount partially comes from groundwater or missing from the water budget. Luckily, the reservoirs have positive sub-catchment inflows that compensates the evaporation losses. We applied the ratios of Lake Velence for the reservoirs, the annual evaporation loss is the total surface of the reservoirs (55,500 m2) multiplied by 0.913 m as average evaporation loss of the lake. This is 50,671.5 m3 evaporation loss. If we take the volume of rain over the reservoirs, that is 55,500 m2 multiplied by 0.532 m, resulting 29,526 m3. The difference is 21,145.5 m³. The inflow from the catchment is about 2.5-fold larger than the missing evaporation loss, therefore the reservoirs have water balance. Water demands and evaporation loss together make 44,045.5 m³ which is usually far lower than inflow from catchment, the water balance is only challenged in extreme drought years or if the landscape and land use changes very unfavorable, into an unsustainable direction.

 

C8. Energy Balance Not Compared to Demand Curves

Equations (6–8), Lines 498–530: While PV output and PHES potential are estimated, results are not compared against actual settlement load curves (hourly or seasonal demand). For example, winter heating loads are mentioned, but no demand profile is shown. This makes it unclear whether the PHES can truly cover peak shortages.
Demand curves are described before Equation 8 and the following has been added to make it more clear: the number of households in the settlement is 285 out of which 247 has gas connection; therefore 38 houses has potential electrical heating. The average household energy demand for heating was estimated of 4,700 kWh in 2022/23 and 3,500 kWh in 2023/24 heating season from October till April. The energy balance (PV output and demand curve) is compared in Figure 9. in 30-day moving averages.

 

C9.

Fragmented Results

Section 4.1 (Lines 648–686) presents runoff; Section 3.2 (Lines 434–475) irrigation demand; Section 3.3 (Lines 481–519) PV output. Results on runoff, irrigation, wildlife demand, and energy storage are presented in isolation. There is little integration to show how the system balances all demands simultaneously. For example, irrigation and wildlife needs are quantified, but it is not shown whether reservoir capacity and PV surplus can meet them in a drought year.

results are described in this sense in discussion and a sensitivity socio-economic analysis is given there

 

C10 Missing Cost-Benefit Analysis

The abstract and discussion claim “short payback period” and “cost-effective,” but no actual financial analysis is shown. CAPEX (reservoir construction, piping, pumps) and OPEX are not presented, nor compared to benefits (energy savings, irrigation value, tourism). This undermines the sustainability claims.
Detailed financial evaluation and economic analysis have been added to Sections 3.5 and 4.5, and to Discussion, using LCA, LCCA, CBA and DEA methods.

 

C11 Discussion Skews Positive

Lines 302–310: The discussion emphasizes co-benefits (recreation, tourism, microclimate, biodiversity) but avoids limitations. Potential trade-offs such as land acquisition, ecological disruption, water rights, or stakeholder resistance are not discussed. For example, vineyards may compete with wildlife watering in drought years, yet no conflict analysis is shown.
Added to discussion in socio-economic assessment.

 

C12. Comments on the Quality of English Language

Several typo mistakes, grammatical issues, reducing clarity.
Mistakes, typos have been corrected throughout the text.

 

Example (Lines 17–20): “These issues, particularly acute in water management, are exacerbated by prolonged droughts, growing population pressures, and shifting land use patterns.”

Typos: “informatioin” (Line 492), “evalution” instead of “evaluation” (Line 474).        The entire manuscript needs professional English editing
Corrected.

 

Reviewer 3 Report

Comments and Suggestions for Authors

1: Introduction Section 1.1 (Volatile Energy Markets, Climate Change, and Water Scarcity): The discussion on the Russian-Ukrainian conflict's impact on EU energy markets is relevant but dated (references up to 2023); update with 2024-2025 data on energy prices and drought events in Europe. In addition, Suggest condensing the list of benefits and including key quantitative outcomes from the Matlab modeling in the abstract section.

2: Site Description (Section 2): The geographical overview of Lake Velence and Nadap is detailed, with useful elevation data (e.g., 189-200 m a.s.l. for settlement center). However, Figure 1's contour lines (5m intervals) could be clearer—add a scale bar and legend for elevation colors. Discuss soil permeability and infiltration rates more quantitatively, as they influence runoff calculations mentioned in the abstract.

3: Figure 2 (Possible Locations of Water Retention Measures): This figure effectively illustrates four reservoir sites with labels for functions (e.g., energy storage, vineyard watering). Improve by overlaying contour lines or slope percentages to visualize hydrodynamic feasibility. Also, specify criteria for site selection (e.g., proximity to solar panels, elevation differences >40m as in Rogeau et al.) to aid reproducibility.

4: Fossil energy, geological environment, and the greenhouse effect all have significant impacts on the basin's ecology. The above description requires the latest article as analytical support.----Settling behavior and mechanism analysis of kaolinite as a fracture proppant of hydrocarbon reservoirs in CO2 fracturing fluid. ----Sediment instability caused by gas production from hydrate-bearing sediment in Northern South China Sea by horizontal wellbore: Sensitivity analysis.

5:  Based on the preview in Section 1.4, the multi-stage optimization using historical rainfall, solar surplus, and Matlab modeling sounds robust. However, the full methodology (in later sections) should detail input parameters (e.g., rainfall data sources, solar panel efficiency assumptions) and optimization algorithms (e.g., genetic algorithms in Matlab?). Include sensitivity analysis for variables like evaporation rates.

6: The review of previous studies (Section 1.3) on pumped storage design is comprehensive, covering global and regional examples (e.g., Ghana, Melbourne, France). Yet, it lacks critical analysis—e.g., how do the cited GIS-based site evaluations (Rogeau et al., Connolly and MacLaughlin) inform the Nadap-specific methodology? Expand to include Hungarian or Central European case studies for regional relevance.

Author Response

Reviewer 3

C1: Introduction Section 1.1 (Volatile Energy Markets, Climate Change, and Water Scarcity): The discussion on the Russian-Ukrainian conflict's impact on EU energy markets is relevant but dated (references up to 2023); update with 2024-2025 data on energy prices and drought events in Europe. In addition, Suggest condensing the list of benefits and including key quantitative outcomes from the Matlab modeling in the abstract section.
Section has been improved and updated with newer data.

 

 

C2. 2: Site Description (Section 2): The geographical overview of Lake Velence and Nadap is detailed, with useful elevation data (e.g., 189-200 m a.s.l. for settlement center). However, Figure 1's contour lines (5m intervals) could be clearer—add a scale bar and legend for elevation colors. Discuss soil permeability and infiltration rates more quantitatively, as they influence runoff calculations mentioned in the abstract.

We further defined the topography in Figure 2 showing 3m contours.

 

C3. 3: Figure 2 (Possible Locations of Water Retention Measures): This figure effectively illustrates four reservoir sites with labels for functions (e.g., energy storage, vineyard watering). Improve by overlaying contour lines or slope percentages to visualize hydrodynamic feasibility. Also, specify criteria for site selection (e.g., proximity to solar panels, elevation differences >40m as in Rogeau et al.) to aid reproducibility.

 

C4: Fossil energy, geological environment, and the greenhouse effect all have significant impacts on the basin's ecology. The above description requires the latest article as analytical support.----Settling behavior and mechanism analysis of kaolinite as a fracture proppant of hydrocarbon reservoirs in CO2 fracturing fluid. ----Sediment instability caused by gas production from hydrate-bearing sediment in Northern South China Sea by horizontal wellbore: Sensitivity analysis.
Additional literatures to support the description is incorporated into the manuscript, to end of discussion section with sensitivity analysis.

 

C5. 5:  Based on the preview in Section 1.4, the multi-stage optimization using historical rainfall, solar surplus, and Matlab modeling sounds robust. However, the full methodology (in later sections) should detail input parameters (e.g., rainfall data sources, solar panel efficiency assumptions) and optimization algorithms (e.g., genetic algorithms in Matlab?). Include sensitivity analysis for variables like evaporation rates.
Sensitivity analyses have been added to Method, Results and Discussion sections.

 

C6: The review of previous studies (Section 1.3) on pumped storage design is comprehensive, covering global and regional examples (e.g., Ghana, Melbourne, France). Yet, it lacks critical analysis—e.g., how do the cited GIS-based site evaluations (Rogeau et al., Connolly and MacLaughlin) inform the Nadap-specific methodology? Expand to include Hungarian or Central European case studies for regional relevance.

There are no other case studies of this kind, that is why we wrote this article. Others were narrowly focused on a single evaluation or alternate method with little discussion of actual results such as energy savings or applied optimizations.

Reviewer 4 Report

Comments and Suggestions for Authors

Sustainable Water and Energy Management Through a Solar-Hydrodynamic System in a Lake Velence Settlement, Hungary

The manuscript addresses an important topic related to the integration of sustainable water and energy management through a solar-hydrodynamic system. The approach of designing a multi-purpose reservoir network is relevant and of potential interest to the research community. However, the manuscript requires substantial revisions before it can be considered for publication. My detailed comments are as follows:

Abstract- The abstract is currently fragmented. It should be integrated into a single, cohesive paragraph. Numerical values and concrete results should be presented to emphasize the outcomes of the research.

Introduction. The section is generally well structured, but the subdivision into multiple subsections is unnecessary. The research aim and the novelty of the work should be clearly stated at the end of the introduction.

Case Study (Section 2). The case study description exceeds 120 lines, which is excessive and reduces readability. It should be relocated under the Materials section and substantially summarized. A concise description would better guide the reader while avoiding redundancy.

Methodology- Figure 4 is a good graphical abstract; however, a detailed flowchart of the research methodology should be added. The methodology must explicitly describe all phases of the study and include the equations used, ensuring replicability in other case studies.

Figures and Tables should be improved

Figure 6, Figures 11–12: The quality and readability need improvement.

Figure 7: Results should be discussed in the context of other published studies, not merely summarized.

Figures 8 and 9: Require axis labels, legends, and comparative discussion with external references.

Table 2: Capitalization must be corrected.

Table 6: Currently mixed with figures; requires reformatting.

Table 7: The use of the “^” superscript should be revised.

Table 8: Contains mixed text and figures; it should not be considered a table.

Table 13: Could be removed.

Overall, many tables present trivial design results and unnecessarily combine figures and tables. These should be streamlined or eliminated.

Formatting and Consistency. Numerical formatting is inconsistent (e.g., commas used as thousand separators in some cases, absent in others). Standardization is required.

Discussion. -The discussion section is weak, as it does not engage with the existing literature.

Results should be critically compared and contrasted with findings from previous research.

Conclusion.-The conclusion fails to highlight the main novelty of the study, its replicability in other contexts, and its broader contribution to the research community. These aspects should be explicitly emphasized.

Author Response

Reviewer 4

The manuscript addresses an important topic related to the integration of sustainable water and energy management through a solar-hydrodynamic system. The approach of designing a multi-purpose reservoir network is relevant and of potential interest to the research community. However, the manuscript requires substantial revisions before it can be considered for publication. My detailed comments are as follows:

 

C1. Abstract- The abstract is currently fragmented. It should be integrated into a single, cohesive paragraph. Numerical values and concrete results should be presented to emphasize the outcomes of the research.

We narrowed it down to a shorter abstract, however some of the demands in the abstract make it longer as well.

 

C2. Introduction. The section is generally well structured, but the subdivision into multiple subsections is unnecessary. The research aim and the novelty of the work should be clearly stated at the end of the introduction.
Novelty has been better described and added to the end of introduction.

 

C3. Case Study (Section 2). The case study description exceeds 120 lines, which is excessive and reduces readability. It should be relocated under the Materials section and substantially summarized. A concise description would better guide the reader while avoiding redundancy.

It is more than a case study, it is a description of the enviroment where this whole ideas was constructed and why it was constructed that way. If you could point to the redundancies we will gladly remove them

C4. Methodology- Figure 4 is a good graphical abstract; however, a detailed flowchart of the research methodology should be added. The methodology must explicitly describe all phases of the study and include the equations used, ensuring replicability in other case studies.

We added a more concise set of steps in the introduction and described them more completely along the way

C5.      Figures and Tables should be improved
All Tables have been corrected and modified to uniform format; Figures have been improved.

C6.     Figure 6, Figures 11–12: The quality and readability need improvement.
Figures have been updated, better quality, better readability.

 

C7. Figure 7: Results should be discussed in the context of other published studies, not merely summarized.

We added some further discussion of results, but as mentioned before, there is little in the literature concerning the work that we applied here.

 

C8. Figures 8 and 9: Require axis labels, legends, and comparative discussion with external references.

We are still trying to find relevant studies with which to compare, any suggestions would be appreciated

 

C9. Table 2: Capitalization must be corrected.
Table has been corrected.

 

C10 Table 6: Currently mixed with figures; requires reformatting.

 

C11 Table 7: The use of the “^” superscript should be revised.
Table has been corrected and reformatted.

 

C12. Table 8: Contains mixed text and figures; it should not be considered a table.
Table has been corrected and reformatted to a Figure.

 

Table 13: Could be removed.

 

Overall, many tables present trivial design results and unnecessarily combine figures and tables. These should be streamlined or eliminated.
Improved. Tables/Figures have been reorganized, reformatted.

 

Formatting and Consistency. Numerical formatting is inconsistent (e.g., commas used as thousand separators in some cases, absent in others). Standardization is required.
Formatting has been corrected throughout the manuscript.

 

Discussion. -The discussion section is weak, as it does not engage with the existing literature.
Part has been extended with sensitivity analysis, including environmental and socio-economy discussion. Additional references have been added.

 

Results should be critically compared and contrasted with findings from previous research.

 

Conclusion.-The conclusion fails to highlight the main novelty of the study, its replicability in other contexts, and its broader contribution to the research community. These aspects should be explicitly emphasized.

 

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

I can see that the authors took time to revise their manuscript completely. I can also see that the overall content and quality of the manuscript are much better than the original draft, but some parts can still be improved. Please review the manuscript thoroughly for lingering typographical errors and grammatical issues to improve readability. I have no further comments. The article has been revised according to my suggestions. 

Author Response

Thank-you for your efforts in the review. 

Reviewer 2 Report

Comments and Suggestions for Authors

The current responses to reviewers’ comments are disorganized, as they do not clearly separate the reviewers’ remarks from the corresponding answers. Many responses are overly brief, lacking sufficient detail or scientific justification, with some consisting of only a few words. In addition, certain comments, such as Comment C5, have not been addressed at all. I recommend first restructuring the response document to ensure clarity, then providing a scientific and well-reasoned reply to each comment, explicitly indicating the revised lines in the manuscript.

Author Response

We apologize for not being clear in our responses to your concerns, therefore the responses are listed below with line number references and more clarification.

Language and Readability

Several typo mistakes, grammatical issues, reducing clarity.
Mistakes, typos have been corrected throughout the text.

 

Example (Lines 17–20): “These issues, particularly acute in water management, are exacerbated by prolonged droughts, growing population pressures, and shifting land use patterns.”

Typos: “informatioin” (Line 492), “evalution” instead of “evaluation” (Line 474).        The entire manuscript needs professional English editing.
Corrected.

 

Novelty Not Well Differentiated
Corrected, introduction has been improved, novelty added to Section 1.4 (lines 216-220, 225-227, 234-247).

 

     Lines 154–195: The paper cites many similar micro-PHES and solar integration studies (e.g., Guignard et al., Boroomandnia et al., Danso et al.) but does not clarify what is truly new. Is it the star-shaped reservoir topology, the Hungarian case study, or the multi-purpose use (wildlife, vineyards, recreation)? Without clearer positioning, it risks overlapping with existing literature.

all 3, the star-shape, the Hungarian case and the multi-purpose use. especially the multi-purpose use is in focus which is supported by the star-shaped arrangement, and this is incorporated into the combined socio-economic assessment

 

For example, the statement “This research offers a scalable, cost-effective solution” (Abstract) is too generic and could apply to several prior studies.
The evaluation includes a detailed socio-economic assessment in new sections, Section 3.5 (lines 679-710) and Section 4.5 (lines 1049-1095).
Furthermore, discussion has been updated with sensitivity analysis for different socio-economic scenarios in detail (lines 1244-1307)

 

     Hydrological Modeling Oversimplified
Modeling has been broadened with 2 additional land uses and made it more complex. Please see Section 3.1 (lines 442-454) and Section 4.1 (lines 759-770)

 

Equation (1), Lines 411–417, uses only four land categories with fixed runoff coefficients (0.9, 0.2, 0.2, 0.2). Runoff is estimated using only four surface categories (roads, forests, farmland, gardens) with fixed coefficients. This coarse classification ignores urban impervious variability, soil infiltration rates, and land-use heterogeneity. For example, “for in-town detached housing surfaces, it was 0.2 (Cintown)” (p.11) seems very low for built-up areas, underestimating runoff. The simplification may make results less reliable for design purposes. Also, No sensitivity analysis is shown.
Modeling includes 2 additional land uses (4 -> 6 surface types) and became more complex, Section 3.1 (lines 444-450). A sensitivity analysis (table 5) has been inserted into the text to show effects of possible future developments and land use changes in Section 4.1 (lines 771-777).

 

Unclear MATLAB Optimization Method

Lines 355–367: The paper mentions a “MATLAB-based solver for nonlinear hydraulics” and “multi-objective optimization” but provides no detail about:

What solver (e.g., fmincon, genetic algorithm)? updated, (lines 385-391)

What decision variables (pipe diameter, pump timing, reservoir size)? shown in text (lines 625-627, 305-310, 395-397)

What objective functions (efficiency, cost, reliability)? main function: efficiency, (lines 384-401)

What constraints were applied? updated in text (lines 610-681)

For example, Section 3.1 says “The MATLAB solver minimizes head loss and energy use” but does not explain the optimization process or provide convergence metrics. This weakens reproducibility.
Sections 3.1 and 3.4 have been improved and clarified.

 

     Imbalance Between Hydraulics and Socio-Economics

Lines 576–603: Pipe hydraulics and equations (Darcy–Weisbach, Colebrook–White) are treated in great detail, while socio-economic, ecological, and stakeholder trade-offs are only described narratively. This creates an imbalance: the “multi-purpose” claim is not supported with quantitative data (e.g., willingness-to-pay, ecosystem service valuation).
Detailed economic assessment has is added to introduction (Section 1.4, lines 214-247), method (Section 3.5, lines 679-710), result (Section 4.5, lines 1049-1095) and discussion (lines 1244-1307).

 

Evaporation Not Quantified
Lines 243–246: The Introduction highlights evaporation as a major issue for Lake Velence (>40% losses), yet evaporation from the proposed reservoirs is not quantified in the results. Without this, feasibility is uncertain, especially since evaporation could cancel out stored water benefits in summer.
Evaporation and refilling evaluation with sensitivity analysis have been updated: Section 2 (lines 271-274), Section 4.1 (lines 759-777), Section 4.2 (lines 807-818).

 

Energy Balance Not Compared to Demand Curves

Equations (6–8), Lines 498–530: While PV output and PHES potential are estimated, results are not compared against actual settlement load curves (hourly or seasonal demand). For example, winter heating loads are mentioned, but no demand profile is shown. This makes it unclear whether the PHES can truly cover peak shortages.

Demand curve description has been added before Equation 8. (Section 3.3, lines 550-566)

Figure 9 shows demand curve and two PV outputs as explained in the text that cites the figure.

 

Fragmented Results

Section 4.1 (Lines 648–686) presents runoff; Section 3.2 (Lines 434–475) irrigation demand; Section 3.3 (Lines 481–519) PV output. Results on runoff, irrigation, wildlife demand, and energy storage are presented in isolation. There is little integration to show how the system balances all demands simultaneously. For example, irrigation and wildlife needs are quantified, but it is not shown whether reservoir capacity and PV surplus can meet them in a drought year.

results are described in this sense in discussion, and a sensitivity socio-economic analysis is given there

 

 

Missing Cost-Benefit Analysis

The abstract and discussion claim “short payback period” and “cost-effective,” but no actual financial analysis is shown. CAPEX (reservoir construction, piping, pumps) and OPEX are not presented, nor compared to benefits (energy savings, irrigation value, tourism). This undermines the sustainability claims.
Detailed financial evaluation and economic analysis have been added to Sections 3.5 (lines 679-710) and Section 4.5 (1049-1095), and to Discussion (lines 1244-1307), using LCA, LCCA, CBA and DEA methods.

 

Discussion Skews Positive

Lines 302–310: The discussion emphasizes co-benefits (recreation, tourism, microclimate, biodiversity) but avoids limitations. Potential trade-offs such as land acquisition, ecological disruption, water rights, or stakeholder resistance are not discussed. For example, vineyards may compete with wildlife watering in drought years, yet no conflict analysis is shown.
Socio-economic assessment has been added to Section 4.5 (1049-1095), and to Discussion (lines 1244-1307).

 

Comments on the Quality of English Language

Several typo mistakes, grammatical issues, reducing clarity.
Mistakes, typos have been corrected throughout the text.

 

Several typo mistakes, grammatical issues, reducing clarity.
Mistakes, typos have been corrected throughout the text.

Example (Lines 17–20): “These issues, particularly acute in water management, are exacerbated by prolonged droughts, growing population pressures, and shifting land use patterns.”

Typos: “informatioin” (Line 492), “evalution” instead of “evaluation” (Line 474).        The entire manuscript needs professional English editing.
Corrected.

 

 

Reviewer 3 Report

Comments and Suggestions for Authors

accepted

Author Response

Thank-you for your efforts in the review

Reviewer 4 Report

Comments and Suggestions for Authors

Authors clarified the different suggestions

Author Response

Thank-you for your efforts in the review

Round 3

Reviewer 2 Report

Comments and Suggestions for Authors

N/A