An Approach to Delineate Potential Groundwater Zones in Kilinochchi District, Sri Lanka, Using GIS Techniques
Round 1
Reviewer 1 Report
This manuscript aims to delineate potential groundwater zones in Kilinochchi, Sri Lanka using integrated Remote Sensing, Geographic Information Systems, and Analytic Hierarchy Process techniques. The AHP technique allocated thematic layers weights for the following categories: rainfall, geology, geomorphology, soil, drainage density, linear density, slope and land use cover. All thematic layers were integrated into ArcGIS 10.4.1 platform and generated a groundwater potential map. Based on my revision, this manuscript is interesting for publication, however minor comments are suggested. The suggested comments are indicated as follows:
General comments:
- The distribution of sections inside the manuscript needs to be revised, e.g., section 3 is the results and section 4 is the results, please revise and correct incorrect titles.
- Authors integrated RS, GIS, and AHP technical methods to delineate potential groundwater zones, however, it is vague how the integration process was conducted? Otherwise, the optimization parameters through this hybrid process should be illustrated.
- In this manuscript, authors applied several input parameters representing geology, geomorphology, land use/land cover, soil types, drainage density, slope, lineament, and rainfall. However, the sensitivity analysis of these parameters should be provided.
- The validation process of the groundwater potentiality for the hybrid model is vague. Authors should present an effective strategy providing the efficiency of the proposed model.
- One key issue when you use AHP to do risk assessment is to collect the experts’ reply on questionnaire. In AHP, to determine fuzzy number, generally the is required. There are two approaches to do experts questionnaire: (1) one is the pairwise comparison, proposed by Saaty (1977), improved by Li et al (2013); (2) another method to do questionnaire is to use table comparison proposed by Lyu et al (2020).
- Thus, please discuss how you did experts questionnaire? Which type of the experienced experts you invited? How do you determine the fuzzy number? Lyu et al's (2020) new questionnaire method can not only get the appropriate experts' reply but also can determine the fuzzy number based on experts' replies.
References:
Saaty, T.L. (1977). "A scaling method for priorities in hierarchical structures." Journal of Mathematical Psychology, 15, 234-281.
Li, F., et al (2013). "Improved AHP method and its application in risk identification." Journal of Construction Engineering and Management, 139(3), 312-320. Doi: 10.1061/(ASCE)CO.1943-7862.0000605.
Lyu, H.M., et al (2020). Risk assessment using a new consulting process in fuzzy AHP. Journal of Construction Engineering and Management, ASCE, 146(3), 04019112. doi: 10.1061/(ASCE)CO.1943-7862.0001757.
Specific comments
Abstract
Line 13-33: the abstract is interesting however it is still very long. I recommend the authors to be focus on the main contributions of this work. The abstract is suggested to write in 150-175 words.
Line 19-25: The main objective from this work should be clearly indicated.
- Introduction
Line 38-53: this section is very general. It is suggested to replace this section with another more specific one related to potential groundwater zones in Kilinochchi District.
Line 63-65: I suggest the authors to provide some examples for the recent studies that applied remote sensing and GIS coupled with AHP techniques for delineating potential groundwater zones in semi-arid areas. In addition, recent methods such as fuzzy AHP incorporated into GIS are suggested to be referred (Risk assessment of geohazards along Cheng-Kun railway using fuzzy AHP incorporated into GIS. Geomatics, Natural Hazards and Risk, 2021, 12(1):1508-1531. DOI: 10.1080/19475705.2021.1933614; Inundation risk assessment of metro system using AHP and TFN-AHP in Shenzhen. Sustainable Cities and Society, 2020, 56(3):102103. DOI: 10.1016/j.scs.2020.102103).
Line 48-60: It is necessary to clearly indicate for the difference between this suggested work and current literature.
- Materials and Methods
Line 104: The topography of the area has been presented but the ground water aquifer is also necessary to be provided.
Line 120-122: Authors indicated that the required data were gathered from various government agencies, field surveys, and publicly available satellite imagery on the United States Geological Survey (USGS) Earth Explorer website. Based on the collected data, is there any noisy data? And if so, how did the authors deal with the noisy data?
Line 150: what is the formula that applied to estimate the accuracy?
Table 1 shows the List of data layers and their sources, however, the references of these sources should be provided.
Line 168: The methodology adopted for the present study is shown in Figure. 2. However, it is suggested to provide the step procedures of the presented work.
Line 187: what the authors mean by “Field experience”?
- Results
Line 279: the reference related to Geological Survey and Mines Bureau of Sri Lanka is necessary to be provided.
Line 282-283: The detailed geological map of the study area that presented in Fig. 3 is superficial. The geological conditions of the five types of geology should be provided.
Line 306-307: how can the Geomorphological components be determined?
Line 326: Geomorphology map of Kilinochchi District that presented in fig. 4 needs to be clearly discussed.
Authors integrated RS, GIS, and AHP technical methods to delineate potential groundwater zones, authors need to add a flowchart show this integration process.
Line 476-490: the validation process is difficult to follow.
Author Response
We sincerely thank Reviewer 1 for the time and effort in reviewing our paper. We did our best to address all the comments and suggestions. Please find below our point by point response.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper is well written and the topic is interesting and can be a good addition to the literature.
Author Response
We sincerely thank Reviewer 2 for the time and effort in reviewing our paper. We did our best to address all the comments and suggestions. Please find below our point by point response.
Author Response File: Author Response.pdf
Reviewer 3 Report
The subject of the manuscript is to delineate potential groundwater zones in a special district of Sri Lanka by GPS techniques. This district is analysed with respect to geology, geomorphology, land use/land cover, soil types, drainage density, slopes, lineaments, and rainfall. Their weighted overlay analysis is integrated into a Geographic Information System. All this is presented well organized and clearly written. It may be useful for similar studies of other areas.
I suggest only minor changes:
L95: Km2 should be replaced by km2. The former make no sense.
L107-110: All soil names should start with small letters; no comma behind alkali
L150: It should read: ..88 %...
Fig. 4: in the legend it should read „Plateau of Miocene limestones“ and „Upwarded Pleistocene coastal plain“.
L336-337: Check the given slopes. If they are correct in Fig. 5, then they are partially wrong in lines 336-337.
L351-354: see comments for L107-110.
Fig. 6: Please use a larger font in the legend.
L374: There should be a blank between Figure and 7.
L403: There should be a blank between 75 and %.
Fig: 9: Please correct: Rainfall (mm/yr)
L421: It should read: May 2020
Fig. 8: In legend it should read: km/km2 or km-1
Fig. 10: Caption: Map of land use/land cover of…..
Fig. 11: In legend correct: Moderate, and in caption: Map of groundwater potential zones in …
Table 5: place heading correctly and change the dimension of Km2 into km2.
L471: Replace „Red earth“ by „red earth“
Fig. 13. Not well explained.
L491: Replace “Poor” by “poor”
L493: … validated by 78 wells (Figure 12)
Comments for author File: Comments.pdf
Author Response
We sincerely thank Reviewer 3 for the time and effort in reviewing our paper. We did our best to address all the comments and suggestions. Please find below our point by point response.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The reply did not show how the expert questionnaire was conducted. Who are the experts? What is the experts' work year?Author Response
We sincerely thank Reviewer 1 for the time and effort in reviewing our paper. We did our best to address all the comments and suggestions. Please find below our point by point response.
Author Response File: Author Response.pdf
