Overall, I considered this manuscript as a well written paper that is based on substantial hard work by the authors. The paper investigates the nature of subsurface groundwater flow and its interaction with hypersaline Dead Sea water. The authors conducted a multidisciplinary scientific study combining field observations, remote sensing data analysis, multiple geophysical surveying methods (shear wave reflection seismic, electrical resistivity tomography, self-potential and ground penetrating radar) and Hydrogeological modelling. The research design is so appropriate and the methodological approach adopted is adequately described and suitable for karst environment studies. The results obtained are very interested and very well presented. This manuscript contains significant scientific information and is very interesting for the readers and for the scientific community in general. The manuscript constitutes a suitable study that I recommend to be accepted for publication in Hydrology and Earth System journal after minor revisions. Below are some comments and suggestions: Could you please present the results of regional and local geological summary that you used for geophysical data interpretation? This would help readers get a sense of how you calibrated geophysical data. Page 5: The Figure 1 (b).It is difficult to identify Ground penetrating Radar and S-Wave reflection seismic profiles Page 6: Figure 2. Could you please indicate on the field photos the limits of alluvial fans, halite cover, silt-clayey marl deposits, and alluvial deposits? Page 8: Table 1. Could you please provide the Spring Id with logical numeration? Or provide the missing information for (4,5,6) Spring Id. Page 10: line 28: Pansharpening pre-processing: What were the results? Did you obtain the same spatial resolution for all the satellite images you used? These could help readers understand the smallest fluvial and karst features you were able to identify and extract on remote sensing data. Page 10: lines 32-34: What were the band combinations you chose for aerial and satellite images on which you manually digitalize the fluvial and karst features? Which bands did you choose? What was the base on which you chose these bands? Did you notice any band combination which highlights better the fluvial and karst features? Please provide more details. Page 11: Lines 17-19: Please provide spatial distance between each SP point measurements. Page 16: Figure 6: Please indicate the limits of CS (with a box). Pages 20-21: Figure 7-8: Could you please provide the name of satellite and the band combination for aerial and satellite imagery presented on the left column of these Figures?

This is a highly valuable and interesting paper linking hydrology and sinkhole development and evolution in the evaporite environment of the Dead Sea, probably the most well known area in the world for this type of processes. Therefore, the article is worth to be published, and is an interesting piece of work, quite well written and full of data. I have listed in the accompanying file a number of small edits, and requests of clarification on some issues that are not clear to me. Overall, I therefore require minor revisions and invite the Authors to carefully read the comments, suggestions, and requests of clarification provided in the attached file. Here, I just summarize the main points where the Authors should make an effort to further improve the quality of the paper, in my opinion.

The main point is the length of the manuscript, which seems to be excessive, and even with many repetitions of terms in the same paragraphs. These repetitions should be avoided, by using other terms and making efforts to vary the text.

I suggest reducing the text especially as regards the explanation of the different geophysical techniques, which are well known in the scientific literature, and do not need lengthy descriptions. At the same time, many details about the methods used for the study could be moved in the supplementary materials, in order to not make the reading too heavy.

Hydrogeological modelling: this part is very interesting, but my feeling is that more details should be provided as concerns some of the constraints of the model. In particular, it is stated that “Vertical hydraulic conductivities are assumed to be 10 times less the horizontal ones, to represent anisotropy imparted from sedimentological layering”. This assumption makes bedding as the main feature favouring conductivity, limiting very much the likely role of tectonics, which I believe is significant as well, as also documented in many articles. It would be therefore necessary to present some evidence to support this assumption, which should be presented in the section about hydrogeological modelling, and also in the conclusions.

When quoting more than one reference, the list should be organized following the chronological order. In many places throughout the article this has not been followed. Please format the text strictly following the journal guidelines.

Some figures show some problems, mostly as concerns inner writings. These are often too small to be easily read, and should therefore be increased to facilitate the comprehension of the figures.

As regards references, I suggest here some additional references about karst evaporites and sinkhole development, which could be useful especially in the introductory part of the article, also to put it in a broader international context of evaporite karst:

Bruthans J., Asadi N., Filippi M., Vilhelm Z. & Zare M., 2008.Erosion rates of salt diapirs surfaces: An important factor for development of morphology of salt diapirs and environmental consequences (Zagros Mts., SE Iran). Environmental Geology, 53 (5): 1091-1098.

Bruthans J., Filippi M., Zare M., Churáčková Z., Asadi N., Fuchs M. & Adamovič J., 2010. Evolution of salt diapir and karst morphology during the last glacial cycle: effects of sea-level oscillation, diapir and regional uplift, and erosion (Persian Gulf, Iran). Geomorphology, 121: 291-304.

De Waele J., Piccini L., Columbu A., Madonia G., Vattano M., Calligaris C., D’Angeli I.M., Parise M., Chiesi M., Sivelli M., Vigna B., Zini L., Chiarini V., Sauro F., Drysdale R. and Forti P., 2017. Evaporite karst in Italy: a review. International Journal of Speleology, vol. 46 (2), p. 137-168.

Dreybrodt, W., 2004. Dissolution: evaporite and carbonate rocks. In: Gunn, J. (Ed.), Encyclopedia of Caves and Karst Science. Fitzroy Dearborn, New York, pp. 295–300.

Filippi M., Bruthans J., Palatinus L., Zare M. and Asadi N. 2011. Secondary halite deposits in the Iranian salt karst: general description and origin. International Journal of Speleology, 40 (2), 141-162.

Gutiérrez, F., Cooper, A.H., Johnson, K.S., 2008. Identification, prediction and mitigation of sinkhole hazards in evaporite karst areas. Environ. Geol. 53, 1007–1022.

Gutiérrez, F., Linares, R., Roqué, C., Zarroca, M., Rosell, J., Galve, J.P., Carbonell, D., 2012. Investigating gravitational grabens related to lateral spreading and evaporite dissolution subsidence by means of detailed mapping, trenching, and electrical resistivity tomography (Spanish Pyrenees). Lithosphere 4, 331–353.

Iovine G., Parise M. & Trocino A., 2010. Breakdown mechanisms in gypsum caves of southern Italy, and the related effects at the surface. Zeitschrift fur Geomorphologie, vol. 54 (suppl. 2), p. 153-178.

Shaquor, F., 1994. Hydrogeologic role in sinkhole development in the desert of Kuwait. Environ. Geol. 23, 201–208.

For all the considerations above, I recommend minor revision.