Comparative Water Qualities and Blending in the Ogallala and Dockum Aquifers in Texas

Round 1

Reviewer 1 Report

In this manuscript entitled " Comparative water qualities and blending in the Ogallala and Dockum Aquifers in Texas", the authors focused on the problem of water qualities and blending in the Ogallala and Dockum Aquifers in Texas. The author carried out a review of literature, tests of water quality and analysis of water blending. Overall, the results are interesting and the analysis is proper. However, a minor revision is needed before accepting for publication. There are some comments as follows for this manuscript:

1. Line 231. current “student”? It must be “study”?
2. Figure 4. You should use font color to distinguish “Dockum” and “Ogallala”, instead of font shade.
3. Figure 4, “Well records without drilling date have been excluded”, and Figure 5, “All wells which had no drilling data were excluded”. I understand the difficulty of obtaining datasets, but you should discuss the importance of wells without records, or just tell how many wells are without records. If there are important, ignoring them may lead to misunderstanding and even mistake.
4. Line 468. The author mentioned that the reason the number of wells was far greater in the Ogallala is “having more knowledge about the Ogallala aquifer for many water users and the additional cost associated with drilling a deeper well”. It is not reasonable to infer the reason, you should give more detailed proofs.
5. Line 481-482. Please draw a conclusion according to quantitative providence.
6. Line 546-548. I think the wells you put into one group just because close geographically. I don’t think “a single property owner might have access to both aquifer water”, it sounds weird.
7. Figure 12. What is the abbreviation form of fluoride? F-? f? f-? You should use one certain form of them to avoid confusion. And so to bicarbonate.
8. Why you used italics for Mg⁺ in Line 742, while didn’t use italics for Mg⁺ in Line 732? Is there some difference between them?
9. TDS represents salinity in Line 799, then represents total dissolved solids in Line 808?
10. Line 882-Line 884. What did you want to express? These sentences could be put in any manuscript which focuses on blending water. I think you should delete these sentences, remaining them couldn’t help you describe results.
11. Figure 13. The figure which has two indexes of water quality should be put in the first row to avoid confusion.
12. My main concern about this paper is the formatting of abbr. and Figures, there are some unprofessional expressions. The author should check and revise carefully.
13. Conclusions are too long, the author should reduce the number of words and merge all paragraphs into one paragraph.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript describes a case study of  potential interest for the Journal’s readership (exploitation of two aquifers of regional extension from the south of USA), well structured in the different chapters and with important implications for the proper evaluation of the blending degree of groundwater with different geochemical characteristics. I particularly appreciated the use of the geochemical modelling (Phreeqci) approach with the use of simplified geochemical parameters, such as SAR and SPC for the evaluation of the sodicity reduced soil infiltration risk. I believe that given the climatic worsening contexts affecting several areas worldwide, this type of approach may be useful for the correct management of withdrawals from compartmentalized aquifers with increasing salinity with depth.

Only a couple of suggestions (intended as minor revisions), resolved which in my opinion the article can be accepted without my further intervention:

- the readability of the article would be improved by the inclusion of two simplified geological sections in which to show the two aquifers and the aquitard (or aquiclude? – please provide more information about that) that separates them. The geological cross sections should be  orthogonal each other (with tracks to be shown in Figure 2);

- improve Figures 1,2,3 currently hardly readable, in addition to the corresponding  legendas (which do not contain all the symbols inside the figures);

- what can be foreseen (form both qualitative and quantitative viewpoint) at the long term about the exploitation of the deepest aquifer that is not currently  recharged by recent freshwater? Given the evident quota of groundwater  resources exploited for irrigation, could we not think of an increase in less water-demanding crops coupled with MAR (Managed Acquifer Recharge) systems for conveying water toward the Ogallala aquifer?

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Thanks for your improvement. Please polish the language again before publication.