Round 1

Reviewer 1 Report

A general assessment of the paper.

The article under review contains three parts. The first part is a very brief description of the geology and hydrogeology of the study area

The second part is rather detailed, for the non-specialist in this field introduction to the fuzzy logic methodology and its implementation in the

 FAHP method used in this work

The third part is the results of applying this method to the ranking of selected MAR sites

There is a general methodological point to the article. I do not understand from its content, but is the used method practically the only possible for ranging in these conditions? Indeed, in the discussion of the results the authors write that the resulting ranking of sites may be explained by the composition of geological formations which transit from fine up to silty clay.... Ie could not be an experienced hydrogeologist based on the analysis of traditional hydrogeological data to perform the same ranking without the use of FAHP?

Also, I don't understand where the location of these seven proposed MAR sites came from? Was this some kind of deliberate choice or did the authors just pick 7 points on the map to develop their approach?

Specific comments.

Lines 108-127. It would have been more correct to formulate them as a goal from the research objectives, leaving the readers to decide how strong the innovation in the proposed research is

Line 145 coefficient of transmissivity, T, replace with transmissivity, T

Lines 138 -143 are in conflict with lines 147-151. From 138-143 I understood that there is one aquifer overlapped at the top and bottom by weakly permeable layers. But in lines 147-151 it talks about "the shallow aquifer system" and "the deep aquifer system". To avoid such misunderstanding, it would be good to give the principle hydrogeological section from north to south, showing its line in Fig.

Lines 145 and 204. Use the same units of dimensionality for

Line 205. Is the accuracy of the transmissivity determination really in tenths? Replace the interval 25.9─2937.6 with 25-2950

Line 225-228. Write more clearly. I still couldn't figure out how criterion C9 differs from C8.

List of references. The authors should have revised the list of references downwards. There are more than 80 titles. Really all of the mentioned works are important for understanding this article?

Author Response

Dear Editors,

Please find enclosed the revised manuscript entitled “Hybrid fuzzy multi-criteria analysis in selecting of discrete preferable recharge sites for water storage and recovery” to be considered for possible publication in your journal. The article has been accepted to be published after major revisions.

 

Αll comments have been taken into account while revising the manuscript, meanwhile other minor changes have been also done using the “Track Changes”. Along with the revised manuscript, you shall find included revision notes listing all the changes we have done and a detailed response to all the comments received by the two Reviewers.

We gratefully acknowledge the helpful comments which contributed to the improvement of our paper.

Thank you very much for your consideration.

Yours sincerely,

PhD Candidate Papadopoulos Ch.

Ass. Prof. Dr Mike Spiliotis

Dr. Gkiougkis I.

Prof. Dr Pliakas F.

Dr. Nerantzis K.

Prof. Dr Papadopoulos B.

 

 

Response to Reviewer #1

1. A general assessment of the paper. The article under review contains three parts. The first part is a very brief description of the geology and hydrogeology of the study area. The second part is rather detailed, for the non-specialist in this field introduction to the fuzzy logic methodology and its implementation in the FAHP method used in this work. The third part is the results of applying this method to the ranking of selected MAR sites.

Response: We thank the Reviewer for his comment. The first part was extended by adding new text in the revised manuscript using the Track change. Regarding the second part, in subsection 3.1, a brief description of the nine criteria is presented. Regarding the subsection 3.2, the authors deemed appropriate to present some basic information regarding fuzzy logic and sets in order for a non-specialist in this field to be familiar with this mathematical approach. However, only the basic concepts of fuzzy logic, in which the fuzzy methods presented in subsections 3.3 and 3.4 are based on, were presented. Nevertheless, the subsection 3.2 was transferred to Appendix A and thus, only the subsections that describe the fuzzy hybrid methodology remain in the revised manuscript (subsections 3.3 and 3.4 are renamed to 3.2 and 3.3 correspondingly in the revised manuscript).

 

2. I do not understand from its content, but is the used method practically the only possible for ranging in these conditions?

Response: Based on the literature, the FAHP-LFFP method and the FIS are applied in the examined problem (ranking of discrete alternatives regarding their suitability for applying MAR) for the first time. There are other (hybrid) multi−criteria methods that could be used in the composition of criteria, (e.g. fuzzy ELECTRE, fuzzy pattern recognition), however, the use of such methods would have increased the complexity of the problem solution on one hand and more information would have been required on the other. The proposed methodology has been developed in order to analyze both large and small datasets constituting a practical method producing reliable results for ranking discrete alternatives. Indeed, it would be of great interest to compare the results of the proposed method with those of other methods that might be applied in these conditions. Based on the above, the following text was added in Discussions of the revised manuscript:

“...the FAHP-LFFP based nonlinear method (e.g. fuzzy TOPSIS, fuzzy ELECTRE, fuzzy pattern recognition). However, the use of such methods would have increased the complexity of the solution process on one hand and more information would have been required on the other.

The FAHP−LFFP method and the FIS are applied in the examined problem for the first time. According to Table 4, the solution (ranking order of the alternatives) is not changed regardless of which M-value or fuzzy inference engine are used, except for the case of min implication, in which the less preferable alternatives exchange order. Thus, based on the knowledge of previous studies [53−57,59] regarding the hydrogeological conditions of the case study, and by taking into account the stability of the solution, the results of the proposed methodology are considered reliable. It would be of great interest these results to be compared with those of other (hybrid) multi−criteria methods that could be applied in the composition of criteria (e.g. fuzzy ELECTRE, fuzzy pattern recognition).”.

 

3. Indeed, in the discussion of the results the authors write that the resulting ranking of sites may be explained by the composition of geological formations which transit from fine up to silty clay.... Ie could not be an experienced hydrogeologist based on the analysis of traditional hydrogeological data to perform the same ranking without the use of FAHP?

Response: First of all, we would like to note that the analysis in the proposed methodology is based on traditional reliable hydrological data derived from previous studies and on the experts’ experience regarding the case study.

An experienced hydrogeologist could certainly recognize preferable recharge sites, however, as the number of criteria and alternatives increases the selection of the most preferable recharge site becomes a complex issue, and therefore, multi−criteria analysis is an appropriate approach.

For example, an experienced hydrogeologist could analyze traditional hydrogeological data and select the most preferable recharge site by rejecting or not each criterion separately. However, the weight of each criterion would not be taken into account in that case. Moreover, a criterion may be partially satisfied by an alternative. For example, a recharge site may be located between an underlying drainage axis and an underlying recharge axis. Thus, these reasons could lead to incorrect results and the most preferable recharge site might not be selected, something that should be avoided given the cost of a MAR application (Amineh et al., 2017).

In addition, in the case of a large number of criteria and alternatives, an experienced hydrogeologist would need much more time (or/and available specific scientific instruments) to select the best alternative using a different way of analysis without compensation between the criteria. From the above, it is obvious that the examined problem is an interdisciplinary issue that could be addressed by utilizing knowledge of primary research and by using multi−criteria analysis.

To highlight the above, the following text was added in section of Discussion in revised manuscript:

“However, this is not an absolute condition due to the significant variability of alluvial composition in the study area [57] on the one hand and the contribution of the other criteria in the analysis on the other. For instance, the alternatives Al₁ and Al₆ are less preferable than Al₂. Certainly, in the case of evaluating just few alternatives, the best alternative might be identified on the basis of traditional hydrogeological analysis even though the criteria weights would not be taken into account. However, the more alternatives and criteria the more complexity for the selection of the most preferable recharge site by an expert. Moreover, the MAR application is desirable to be as effective as possible given its no negligible cost [93], and thus the solution of the selection problem should really be the best. As pointed out, the proposed methodology can be applied on both a large and small number of alternatives/criteria and this is a merit of the proposed methodology.

and the following text was added in section of Conclusions as follows:

“The proposed methodology can be used for distinguishing discrete preferable points (alternatives) for MAR application without limitation in number of the examined alternatives. In addition, the selected criteria can be added or subtracted depending on specific local conditions. In case of application another type of MAR the selected criteria should be adjusted as well. Certainly, in the case of a short number (<10) of alternatives to study, a classical hydrogeological analysis may lead to the selection of the most preferable alternative. However, in that case, the criteria weights would not be taken into account and thus, there is the possibility not to obtain the best solution. On the other hand, in the case of a large number of examined alternatives and criteria, where the complexity increases, the proposed methodology might be also a useful tool for ranking discrete alternatives. Other than that, it can be used as an alternative way to identify suitable recharge sites in case of low data availability.”.

and the following reference was added in the References of the revised manuscript:

93. Amineh, Z.B.A., Hashemian, S.J.A-D., Magholi, A. Integrating Spatial Multi Criteria Decision Making (SMCDM) with Geographic Information Systems (GIS) for delineation of the most suitable areas for aquifer storage and recovery (ASR). Journal of Hydrology 2017, 551, 577−595, doi: 10.1016/j.jhydrol.2017.05.031.

 

4. Also, I don't understand where the location of these seven proposed MAR sites came from? Was this some kind of deliberate choice or did the authors just pick 7 points on the map to develop their approach?

Response: We would like to apologize for not clarifying some critical points of methodology. The method has been developed in order to analysis both large and small datasets with various hydrogeological parameters. Hence, we include some parameters such as aquifer type (e.g. confined) in order to help to this analysis. Certainly, when we have a short number (<10) of points to study, a classical hydrogeological analysis may lead to the selection of the most preferable point even though the criteria weights would not be taken into account. Nevertheless, application of MAR requires to consider many criteria in order to select the most suitable site often from a series of alternative. Many authors highlight that the cost of MAR is a critical parameter (Amineh et al., 2017) and hence multi−criteria analysis can help to avoid critical mistakes. On balance, the methodology was implemented in the following steps:

• Literature review and building of a detailed data base including hydrogeological, morphological, etc., data.
• The points with lithological profiles and hydraulic data of the aquifer and vadose zone were chosen for the application and development of the methodology. The other sites were eliminated.
• 10 points was then chosen, from which 3 points refer to confined aquifer and for this reason were excluded from the analysis.
• The method was applied in the final chosen points (7 in total) and the most suitable for MAR application was determined.

To clarify, the last paragraph of subsection 3.1 in the revised manuscript was changed to:

“In that point it should be noted that the proposed methodology has been developed in order to analyze both large and small datasets with various hydrogeological parameters. Hence, some parameters such as aquifer type (e.g. confined) have been included in order to help to this analysis. Initially, all available information (lithological profiles, hydraulic parameters etc,) was selected, and after the first screening, the alternatives with no available profiles were eliminated and thus, ten alternatives remain. Based on the lithological profiles, three of ten alternatives overlie confined aquifers, and hence, these alternatives are excluded from the analysis (Figures 3 and 4). On balance, the following preparatory steps were carried out (Figure 5):

• Literature review and building of a detailed data base including hydrogeological, morphological, etc., data.
• The points with lithological profiles and hydraulic data of the aquifer and vadose zone were chosen for the application and development of the methodology. The other sites were eliminated.
• 10 points were then chosen, from which 3 points refer to confined aquifer and for this reason were excluded from the analysis.
• The method was applied in the final chosen points (7 in total) and the most suitable for MAR application was determined. ”.

Figure 5. Preparatory steps for screening of the final alternatives.

 

5. Lines 108-127. It would have been more correct to formulate them as a goal from the research objectives, leaving the readers to decide how strong the innovation in the proposed research is.

Response: It was done as suggested. In the revised manuscript, the text was changed to:

“The main proposal of this study is the ranking of seven alternatives representing suitable sites for applying MAR systems using floodwaters via a hybrid fuzzy multi−criteria methodology, in the context of increasing the local groundwater resources for later water use in cases of drought. As described in the following section, the local conditions of the case study favor the application of floodwater spreading using infiltration basins. The evaluation of the alternatives is based on nine criteria that are selected based on the local condition and the type of MAR. The weights of criteria are obtained through a fuzzy analytic hierarchy process (FAHP) based methodology, however, they are crisp numbers. Fuzzy inference systems (FIS) are used in the rating of each alternative with respect to each criterion. The use of FIS is preferred since the objective function regarding the criteria is unknown. The composition of criteria is achieved through a simple aggregated model where a final ranking of the alternatives is obtained. The case study refers to the aquifer system of the agricultural plain, at the southeast of the city of Xanthi in Northern Greece.

.”.

 

6. Lines 138 -143 are in conflict with lines 147-151. From 138-143 I understood that there is one aquifer overlapped at the top and bottom by weakly permeable layers. But in lines 147-151 it talks about "the shallow aquifer system" and "the deep aquifer system". To avoid such misunderstanding, it would be good to give the principle hydrogeological section from north to south, showing its line in Fig.

Response: The description of geological structure and hydrogeological conditions of study area has been clarified in previous research (Pliakas et al., 2005), and thus, a detail description was not preferred to present. To avoid the abovementioned misunderstanding the useless information that another deeper aquifer system exists (apart of the examined shallow aquifer hosted in the intermediate geological formation) was removed. In addition, the thicknesses of geological formations were corrected in order to be identical to the corresponding ones of the research of Pliakas et al. (2005), while the reference Pliakas et al. (2003) (which was the reference [56]) was replaced with the reference Pliakas et al., (1999). Therefore, the following changes were done in the revised manuscript:

• “three main geological formations are present: (i) the upper formation (8−80 m in thickness), of low permeability, consisting of clayey sand which interchanges at certain locations with gravel sand of small thickness, (ii) the intermediate aquifer formation (10−70 in thickness), , consisting of permeable gravel sand, considered as a shallow confined aquifer, in some locations changing to semi-confined aquifer, (iii) the lower impermeable formation consisting of clayey silt in depth of 30−90 m,
• transmissivity, T, ranges from 90−915 (m²/day), while storage coefficient, S, ranges from 2.4 × 10^-4 to 8.75 × 10^-2,
• the shallow aquifer system is naturally recharged mainly from direct infiltration of precipitation and partially from percolation of River Kosynthos (upstream zone of coarse-grained deposits), “.

 

55. Pliakas, F., Diamantis, I., Petalas, C. Results from a Groundwater Artificial Recharge Application in Polysitos Aquifer at Xanthi Plain Region (Greece) by Reactivating Old Stream Beds. Proceedings of the 5^th Greek National Hydrogeological Conference, Nicosia, Cyprus, 12−14/11/1999, pp. 97−113 (in Greek).

 

7. Lines 145 and 204. Use the same units of dimensionality for.

Response: It was done as suggested. In the revised manuscript, line 145 was changed to:

“transmissivity, T, ranges from 90−915 (m²/day),”

 

8. Line 205. Is the accuracy of the transmissivity determination really in tenths? Replace the interval 25.9─6 with 25-2950.

Response: It was done as suggested. In the revised manuscript, the text was changed to:

” T ranges between 25─2950(m²/day).“.

 

9. Line 225-228. Write more clearly. I still couldn't figure out how criterion C9 differs from C8.

Response: Regarding criterion C8, type of aquifer, there are two classes, the confined aquifers, and the unconfined aquifers. The methodology obviously cannot be applied in the case of confined aquifers, therefore where there is an underlying confined aquifer (this is shown by the available lithological profiles) the alternative (recharge site) is excluded from the analysis. Regarding criterion C9, piezometry, there are also two classes, the drainage axis, and the recharge axis. Even if there is an unconfined aquifer an underlying recharge axis is not desirable.

The methodology has been developed in order to analyze both large and small datasets with various hydrogeological parameters. Hence, some parameters such as aquifer type (e.g. confined) have been included in order to help to this analysis. The following text was added in the end of subsection 3.1 of the revised manuscript:

“In that point it should be noted that the proposed methodology has been developed in order to analyze both large and small datasets with various hydrogeological parameters. Hence, some parameters such as aquifer type (e.g. confined) have been included in order to help to this analysis. Initially, all available information (lithological profiles, hydraulic parameters etc,) was selected, and after the first screening, the alternatives with no available profiles were eliminated and thus, ten alternatives remain. Based on the lithological profiles, three of ten alternatives overlie confined aquifers, and hence, these alternatives are excluded from the analysis (Figures 3 and 4).”.

 

10. List of references. The authors should have revised the list of references downwards. There are more than 80 titles. Really all of the mentioned works are important for understanding this article?

Response: This study investigates the most preferable site for applying MAR, and for this reason the methods of FAHP and FIS are applied. Thus, several references refer to these issues. Furthermore, a noticeable number of references refer to the importance of the problem considered in this research and to a literature review. Therefore, it would be nice to let us not remove any reference as we believe that all references cited are necessary for a better understanding of all aspects of this paper.

 

Author Response File: Author Response.docx

Reviewer 2 Report

This study proposes a hybrid fuzzy multi-criteria methodology for the selection of the most preferable site for applying Managed Aquifer Recharge systems by utilizing flood waters. But some information is not clear. It does require major revision

• Case study: this part should be reorganized. Some information is deficient. The geological sectional map is suggested. The distributions of irrigation wells and pumping volume should be introduced. Furthermore, the precipitation condition is also important.
• Figure 1: the position of Kosynthos River should be labeled in the figure
• There are red points labelled as “settlement” in figure 1. I am not sure what is function of red points in this study?
• Page 5 Line 200: the hydraulic conductivity mentioned in this part is horizontal hydraulic conductivity or not? Whether the effect of the anisotropy of the aquifer is considered? please give explanation.
• Page 5 Line 230: How were the seven alternatives selected? Please give more information. And the author mentioned “Three alternatives represented confined aquifers…” on line 231. What are the three alternatives?
• Conclusion: the conclusions are suggested to list item by item by the number 1, 2, 3 ….
• It should be stated in the Discussion and Conclusion which alternative is the optimal site for water storage and recovery.

Author Response

Dear Editors,

Please find enclosed the revised manuscript entitled “Hybrid fuzzy multi-criteria analysis in selecting of discrete preferable recharge sites for water storage and recovery” to be considered for possible publication in your journal. The article has been accepted to be published after major revisions.

 

Αll comments have been taken into account while revising the manuscript, meanwhile other minor changes have been also done using the “Track Changes”. Along with the revised manuscript, you shall find included revision notes listing all the changes we have done and a detailed response to all the comments received by the two Reviewers.

We gratefully acknowledge the helpful comments which contributed to the improvement of our paper.

Thank you very much for your consideration.

Yours sincerely,

PhD Candidate Papadopoulos Ch.

Ass. Prof. Dr Mike Spiliotis

Dr. Gkiougkis I.

Prof. Dr Pliakas F.

Dr. Nerantzis K.

Prof. Dr Papadopoulos B.

 

 

Response to Reviewer #2

1. This study proposes a hybrid fuzzy multi-criteria methodology for the selection of the most preferable site for applying Managed Aquifer Recharge systems by utilizing flood waters. But some information is not clear. It does require major revision.

Response: We thank the Reviewer for his helpful comments.

 

2. Case study: this part should be reorganized. Some information is deficient.

Response: It was done as suggested. Case study reorganized and more information was given:

2. Case study

The study area is the aquifer system of the agricultural plain, at the southeast of the city of Xanthi in the Prefecture of Xanthi, NE Greece (Figure 1). The wider region of study area is located within the boundaries of the Tertiary Vistonida basin [53], while the aquifer system is hosted in the alluvial plain consists of loam, clays, sands, gravels, etc. Gravels and sands of Pleiocene−Pleistocene occur at north of study area, while Pleiocene brackish sediments, mainly consist of sand and clay, with no wide surface spread, occur near to Vistonida lagoon. Clastic sediments of Eocene and Oligocene, consist of conglomerate-breccia, limestones and mollasic formations, occur in both the south and north of study area, while the background consists of igneous rocks that underlay andesitic rocks of the same geological period.

Geological formations of the alluvial plain become from fine up to silty clay in the SE-E direction towards Vistonida Lagoon [54,53]. Regarding the geological structure and hydrogeological conditions, relevant assessments have shown that [55,56]:

• three main geological formations are present: (i) the upper formation (8−80 m in thickness), , of low permeability, consisting of clayey sand which interchanges at certain locations with gravel sand of small thickness, (ii) the intermediate aquifer formation (10−70 in thickness), , consisting of permeable gravel sand, considered as a shallow confined aquifer, in some locations changing to semi-confined aquifer, (iii) the lower impermeable formation consisting of clayey silt in depth of 30−90 m,
• transmissivity, T, ranges from 90−915 (m²/day), while storage coefficient, S, ranges from 2.4 × 10^-4 to 8.75 × 10^-2,
• the shallow aquifer system is naturally recharged mainly from direct infiltration of precipitation and partially from percolation of River Kosynthos (upstream zone of coarse-grained deposits), ,
• the groundwater flow has a SE direction, being almost identical to the old riverbeds’ direction of the area,
• groundwater main recharge axes appear in S-SE direction towards Vistonida lagoon,
• the high quality of the water of River Kosynthos gives rise for its use for artificial recharge purposes.

The climatic conditions of wider area differ in the lowlands than in the mountains [57]. Based on precipitation and temperature records from the meteorological station of Genisea (41⁰ 04’ 07’’ N − 24⁰ 59’ 44’’ E) located in the study area, the mean annual cumulative precipitation is 605.6 mm regarding the period of 1966−2018. The available temperature data concern the period of 1988−2018, in which the mean annual temperature is 14.4 C⁰, while mean temperature of the summer months is 23.9 C⁰. In the wider region, both wet periods (that caused flood events as the flood of Kosynthos River in 1996) and drought periods have occurred. In fact, a drought period might effect on groundwater level of the examined aquifer. Particularly, the groundwater level of January of the shallow aquifer is significantly related to drought of the previous hydrological year and the drought of the first trimester of the current hydrological year [58].

The exploitation of the aquifer system mainly takes place in the south of the riverbed of Kosynthos River where there is a significant number of irrigation wells. The most of these wells there are not deeper than 50 m, while there are few shallow wells (up to 10 m) that are not in use any more [59,57]. According to Diamantis et al. [59], the annual pumping volume is estimated 48x10⁶ m³ approximately. The spatial distribution of the irrigation wells and other detailed information regarding the study area can be found in the studies of Diamantis et al. [59] and Pisinaras [57].

and the reference Diamantis et al, 1997 [59] was added in the revised manuscript. Therefore, appropriate changes were made in References of the revised manuscript:

53. Pliakas, F.; Kallioras, A.; Damianidis, P.; Kostakakis, P. Evaluation of precipitation effects on groundwater levels in a Mediterranean alluvial plain based on hydrogeological conceptualization. Environmental Earth Sciences 2015, 74, 3573–3588, doi: 10.1007/s12665-015-4417-4.
54. Sakkas, I.; Diamantis, I.; Pliakas, F. Groundwater artificial recharge study of Xanthi-Rhodope aquifers (in Thrace, Greece). Greek Ministry of Agriculture Research Project, Final Report. Sections of Geotechnical Engineering and Hydraulics of the Civil Engineering Department of Democritus University of Thrace, Xanthi, Greece, 1998 (in Greek).
55. Pliakas, F., Diamantis, I., Petalas, C. Results from a Groundwater Artificial Recharge Application in Polysitos Aquifer at Xanthi Plain Region (Greece) by Reactivating Old Stream Beds. Proceedings of the 5^th Greek National Hydrogeological Conference, Nicosia, Cyprus, 12−14/11/1999, pp. 97−113 (in Greek).
56. Pliakas, F.; Petalas, C.; Diamantis, I.; Kallioras, A. Modeling of groundwater artificial recharge by reactivating an on old streambed. Water Resources Management 2005, 19(3), 279–294.
57. Pisinaras, V. Ανάπτυξη ενός πλαισίου ολοκληρωμένης διαχείρισης πολύπλοκων συστημάτων υπόγειων υδατικών πόρων (Development of a Methodology Framework for Integrated Management of Complex Groundwater Systems). PhD Thesis, D.U.Th., Kimmeria Campus, Xanthi, Greece, 2008 (in Greek).
58. Papadopoulos, C.; Spiliotis, M.; Gkiougkis, I.; Pliakas, F., Papadopoulos, B. Fuzzy linear regression analysis for groundwater response to meteorological drought in the aquifer system of Xanthi plain, NE Greece. Journal of Hydroinformatics 2021, 23(5), 1112, doi: 10.2166/hydro.2021.025.
59. Diamantis, I., Pliakas, F., Petalas, C.. The contribution of artificial recharge as a remedy procedure regarding the impacts of various interventions on the natural environment of plain regions. The case study in Thrace, Greece. Proceedings of the International Symposium on Engineering Geology and the Environment, organized by the Greek National Group of the International Association for Engineering Geology and the Environment (IAEG), Athens, Greece, 23−27/6/1997, pp. 2663−2667.

 

3. The geological sectional map is suggested.

Response: It was done as suggested. A modified geological map of the case study, based on the geological map of the entire area derived by Hellenic Survey of Geology and Mineral Exploration (HSGME), is added in the revised manuscript (Figure 2).

 

Figure 2. Geological formations of the area under consideration (modified map based on geological map of Hellenic Survey of Geology and Mineral Exploration−HSGME).

 

4. The distributions of irrigation wells and pumping volume should be introduced.

Response: It was done as suggested. An estimation of the annual pumping volume was introduced (Diamantis et al., 1999). Regarding the spatial distributions of irrigation wells, the research of Pisinaras is referred where there is available map, and thus, we proffered not to reproduce it. Therefore, the following text was added in Case study of the revised manuscript:

“According to Diamantis et al. [59], the annual pumping volume is estimated 48x10⁶ m³ approximately. The spatial distribution of the irrigation wells and other detailed information regarding the study area can be found in the studies of Diamantis et al. [59] and Pisinaras [57].”.

 

5. Furthermore, the precipitation condition is also important.

Response: Information regarding the mean annual cumulative precipitation was introduced. Thus, the following text in the first paragraph of section 2 of the revised manuscript was added:

“The climatic conditions differ in the lowlands than in the mountains [57]. Based on precipitation and temperature records from the meteorological station of Genisea (41⁰ 04’ 07’’ N − 24⁰ 59’ 44’’ E), the mean annual cumulative precipitation is 605.6 mm regarding the period of 1966−2018. The available temperature data concern the period of 1988−2018, in which the mean annual temperature is 14.4 C⁰, while mean temperature of the summer months is 23.9 C⁰.”.

 

6. Figure 1: the position of Kosynthos River should be labeled in the figure.

Response: It was done as suggested. A label of Kosynthos River is added in Figure 1 of the revised manuscript as follows:

 

Figure 1. Geomorphology of the wider area and the alternatives.

 

7. There are red points labelled as “settlement” in figure 1. I am not sure what is function of red points in this study?

Response: The red points labelled as “settlement” are small villages and the only thing that they serve is that the area is more recognizable. For this reason the “settlement” was replaced by “village (<2000 pop.)” in Figure 1:

 

Figure 1. Geomorphology of the wider area and the alternatives.

 

8. Page 5 Line 200: the hydraulic conductivity mentioned in this part is horizontal hydraulic conductivity or not? Whether the effect of the anisotropy of the aquifer is considered? please give explanation.

Response: The hydraulic conductivity K mentioned in the description of criterion C5 (Transmissivity) refers to the horizontal hydraulic conductivity, and the T−values have been obtained based on previous studies [Pisinaras, 2008). The K of the criterion C7 (hydraulic resistance) refers to the vertical hydraulic conductivity of each unsaturated soil layer. Indeed, there are saturated layers with a relatively small horizontal hydraulic conductivity that overlie layers with a relatively high horizontal hydraulic conductivity and the ideal case would be if there was available information regarding these parameters at many points, however, this was no possible. Therefore the following minor changes were done in the description of corresponding criteria in the revised manuscript:

“...account both the (horizontal) hydraulic conductivity (K) and...”

“..., the (vertical) hydraulic conductivity (K) (m/days)...”.

 

9. Page 5 Line 230: How were the seven alternatives selected? Please give more information.

Response: We would like to apologize for not clarifying some critical points of methodology. The method has been developed in order to analysis both large and small datasets with various hydrogeological parameters. Hence, we include some parameters such as aquifer type (e.g. confined) in order to help to this analysis. Certainly, when we have a short number (<10) of points to study, a classical hydrogeological analysis may lead to the selection of the most preferable point even though the criteria weights would not be taken into account. Nevertheless, application of MAR requires to consider many criteria in order to select the most suitable site often from a series of alternative. Many authors highlight that the cost of MAR is a critical parameter (Amineh et al., 2017) and hence multi−criteria analysis can help to avoid critical mistakes. On balance, the methodology was implemented in the following steps:

• Literature review and building of a detailed data base including hydrogeological, morphological, etc., data.
• The points with lithological profiles and hydraulic data of the aquifer and vadose zone were chosen for the application and development of the methodology. The other sites were eliminated.
• 10 points was then chosen, from which 3 points refer to confined aquifer and for this reason were excluded from the analysis.
• The method was applied in the final chosen points (7 in total) and the most suitable for MAR application was determined.

To clarify, the last paragraph of subsection 3.1 in the revised manuscript was changed to:

“In that point it should be noted that the proposed methodology has been developed in order to analyze both large and small datasets with various hydrogeological parameters. Hence, some parameters such as aquifer type (e.g. confined) have been included in order to help to this analysis. Initially, all available information (lithological profiles, hydraulic parameters etc,) was selected, and after the first screening, the alternatives with no available profiles were eliminated and thus, ten alternatives remain. Based on the lithological profiles, three of ten alternatives overlie confined aquifers, and hence, these alternatives are excluded from the analysis (Figures 3 and 4). On balance, the following preparatory steps were carried out (Figure 5):

• Literature review and building of a detailed data base including hydrogeological, morphological, etc., data.
• The points with lithological profiles and hydraulic data of the aquifer and vadose zone were chosen for the application and development of the methodology. The other sites were eliminated.
• 10 points were then chosen, from which 3 points refer to confined aquifer and for this reason were excluded from the analysis.
• The method was applied in the final chosen points (7 in total) and the most suitable for MAR application was determined.”.

 

Figure 5. Preparatory steps for screening of the final alternatives.

 

10. And the author mentioned “Three alternatives represented confined aquifers…” on line 231. What are the three alternatives?

Response: This sentence has not been formulated correctly. The alternatives are potential sites for GW recharge through infiltration basins where there is a well at each alternative from which hydrogeological data have been obtained in previous studies (Sakkas et al., 1999, Pliakas et al, 1999, Pliakas et al., 2005, Pisinaras, 2008, Pliakas et al., 2015). As abovementioned, in the cases of three of the ten alternatives, the underlying aquifers are confined aquifers and for this reason these alternatives are excluded from the evaluation. Therefore, the following changes have been done in the revised manuscript:

1. In the first paragraph of section 3 the text was changed to:

“Each alternative represents a potential site for MAR application where there is a well with available hydrogeological data. The alternatives are considered through the nine criteria described below in ascending order of importance.”.

2. Regarding the criterion of type of aquifer (subsection 3.1), the text was changed to:

“Based on the available stratigraphic columns [57], there are confined underlying aquifers in the cases of three alternatives and, thus, these alternatives are excluded from the analysis.”

3. The last paragraph of subsection 3.1 was changed to:

In that point it should be noted that the proposed methodology has been developed in order to analyze both large and small datasets with various hydrogeological parameters. Hence, some parameters such as aquifer type (e.g. confined) have been included in order to help to this analysis. Initially, all available information (lithological profiles, hydraulic parameters etc,) was selected, and after the first screening, the alternatives with no available profiles were eliminated and thus, ten alternatives remain. Based on the lithological profiles, three of ten alternatives overlie confined aquifers, and hence, these alternatives are excluded from the analysis (Figures 3 and 4). On balance, the following preparatory steps were carried out (Figure 5):

• Literature review and building of a detailed data base including hydrogeological, morphological, etc., data.
• The points with lithological profiles and hydraulic data of the aquifer and vadose zone were chosen for the application and development of the methodology. The other sites were eliminated.
• 10 points were then chosen, from which 3 points refer to confined aquifer and for this reason were excluded from the analysis.
• The method was applied in the final chosen points (7 in total) and the most suitable for MAR application was determined.”.

4. In order to clarify some critical points of the development of proposed methodology a flow chart was introduced in the revised manuscript (in the end of subsection 3.1):

 

Figure 5. Preparatory steps for screening of the final alternatives.

 

11. Conclusion: the conclusions are suggested to list item by item by the number 1, 2, 3 ….

Response: It was done as suggested. Conclusions were modulated in the revised manuscript as follows:

“The results show that:

1. The more preferable sites are located in the northwestern part of the study area near to Kosynthos River, while the most preferable is the Al₅ This mainly holds due to the hydrological conditions of the northwestern part which are more favorable than the southeastern ones for groundwater recharge. However, this is not an absolute condition due to the intense diversity of geological formations. In addition, the contribution in the analysis of the other criteria also affects the final rank list.
2. The proposed methodology can be used for distinguishing discrete preferable points (alternatives) for MAR application without limitation in number of the examined alternatives. In addition, the selected criteria can be added or subtracted depending on specific local conditions. In case of application another type of MAR the selected criteria should be adjusted as well. Certainly, in the case of a short number (<10) of alternatives to study, a classical hydrogeological analysis may lead to the selection of the most preferable alternative. However, in that case, the criteria weights would not be taken into account and thus, there is the possibility not to obtain a comprehensive solution. On the other hand, in the case of a large number of examined alternatives and criteria, where the complexity increases, the proposed methodology might be also a useful tool for ranking discrete alternatives. Other than that, it can be used as an alternative way to identify suitable recharge sites in case of low data availability.
3. The applicability of the methodology requires lithological profile and hydraulic characteristics of both vadose zone and saturated zone, while it can be applied only in unconfined aquifers and where there is an underlying drainage axis. Furthermore, the application of this type of MAR requires the presence of a river whose excess waters can be utilized. Thus, after a preparatory screening, seven alternatives satisfied all the assumptions and criteria were finally evaluated.
4. In general, the use of fuzzy logic in AHP can incorporate the uncertainty from the subjectivity of the initial experts’ judgments, while thefuzzy version of AHP implemented in this paper (FAHP-LFFP based non linear method) can ensure a unique and optimal solution.
5. Fuzzy inference systems (FIS) based on Mamdami’s approach are used in order to determine the rating of each alternative since the objective function (or function values) regarding each examined criterion is unknown. In addition, with use of FIS, the classes of criteria are fuzzified, and this fact is more reasonable to describe the real conditions.”.

 

12. It should be stated in the Discussion and Conclusion which alternative is the optimal site for water storage and recovery.

Response: We thank the Reviewer for his valuable comment. In this research, the alternatives represent potential site for groundwater recharge, and the goal of the proposed methodology is to lead to the selection of the most preferable alternative. However, the alternatives (wells) might be used for storage and recovery excess water if they would be evaluated in another research. To avoid a misunderstanding regarding the goal of this paper using the words “storage” and “recovery”, these words were changed throughout the revised manuscript using the Track Changes. In addition, to highlight the most preferable recharge site, the following changes were done in the revised manuscript,

in section of Discussion:

“Particularly, Al₅ is the most preferable alternative in all cases.”.

and in section of Conclusion:

“...to Kosynthos River, while the most preferable is the Al₅ alternative.”.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

I believe that the authors were able to make a number of corrections to the hydrogeological content of this article. I am still not convinced that the use of fuzzy logic is appropriate for solving this particular content problem. However, it is possible that the use of this work as a methodological example will allow readers to understand the methodology of fuzzy logic for ranking of water resources assessment objects under conditions of uncertainty and insufficient information.  Therefore, I believe that the article can be published in the presented form.

Reviewer 2 Report

The author have revised the manuscript according the reviewer's comments. Now it can be accepted.