Impacts of Groundwater Management Policies in the Caplina Aquifer, Atacama Desert

Round 1

Reviewer 1 Report (Previous Reviewer 2)

General comment

The paper objectives are clearer. The review of policy and scientific analysis on the Caplina are sufficiently described and interesting to be cross-analysed to identify the key failures in the management of that aquifer over the 55 years. This is an important input to find way out (assessing possible options) of this degrading situation.

 After having described “What impacts do groundwater management policies have on the Caplina aquifer?” it would be very interesting to have hypotheses on the why? We have potential explicative elements across the paper, but sometime too generally tackled (for instance,L 373 “Governance and governability problems are the main factors in the process of deterioration of water quality due to marine intrusion”, what does it mean in term of water management ?? water licences are not allocated appropriately?, decisions are not applied for whatever reasons, money is missing to  implement the policy…?) or furtively mentioned (example L 359:” unauthorized users extract water and generate an imbalance leading to a chaotic situation, extractions far exceed  recharge “ do we know which users? Is this for domestic uses or for commercial/agricultural purpose? What is the magnitude of that extraction ?)

The issues mentioned have led to this failure of policies in limiting the degradation of the water balance of the Capelina aquifer but an order of importance of those reasons is useful to then prioritise the measures to be taken.

Detailed comments

Include in table 1 the scale of application

Layer with administrative sub-divisions of TACNA Region could be available maybe in Fig 1, if not readable, subdivisions of that regions should be described somewhere in section “study area”.

Basically, the amount extracted, increased by 150 % in almost 25 years from 1965- to 1989 and by almost 190 % during the next 20 years until 2019. So a degradation of water balance even faster in the last 20 years. This bring many questions that need to be addressed (maybe in section 3 or in section 4), before going beyond the list of measures that could help in solving the problem in term of policy tool, governance, reduction of extraction etc….):

Why the ban on additional extraction of groundwater (from a reference amount I assumed) that has been set from the 1984 and renewed until 2004 in la YARADA does not help in maintaining the balance in that specific area? The extension of preservation and conservation to the whole Capelina aquifer in 2006 seems to have been not effective as well, hypothesis on the why? What measures precisely were implemented to fit that regulation? What are the potential/combination hypotheses that are possible in explaining the degrading situation despite the preservation/protection policies put in place.

The section 4.3 suggests a participative governance where results of science could be shared on which a strategy could be defined to find a way out as you mentioned:

“The measures must incorporate the reduction of extraction volumes, water culture and the incorporation of external sources to replace the water used or artificial recharge of aquifers [36,37].”

Question: no feasible options that could help to restore the Recharge-Extraction balance are suggested in the literature?

In the conclusion:  the way forward this review should be defined- doing a review is good but having objectives on how to use this output interesting.

Figure 1 reference in L153 is broken.

L179  the sentence has an error, please correct and reformulate

L344-349, the sentences is long and probably there is

Author Response

Reviewer 1

After having described “What impacts do groundwater management policies have on the Caplina aquifer?” it would be very interesting to have hypotheses on the why? We have potential explicative elements across the paper, but sometime too generally tackled (for instance,L 373 “Governance and governability problems are the main factors in the process of deterioration of water quality due to marine intrusion”,

what does it mean in term of water management ??

Answer. We added the main reasons in Lines 383 to 293.

water licences are not allocated appropriately?,

Answer. No. the problem is the lack of interest and political decision of the authorities at the regional and national level to carry out correct monitoring of the application of the policies and regulations provided.

decisions are not applied for whatever reasons, money is missing to  implement the policy…?)

Answer. We added the main reasons in Lines 383 to 293.

or furtively mentioned (example L 359:” unauthorized users extract water and generate an imbalance leading to a chaotic situation, extractions far exceed  recharge “ do we know which users?

Answer. In Lines 383 to 293, in a) we specify that the unregistered irrigation users are the problem.

Is this for domestic uses or for commercial/agricultural purpose? What is the magnitude of that extraction ?)

Answer. Mainly agricultural purposes. The magnitude of the groundwater extraction is currently around 197 million cubic meters. We specify it in Table 3.

The issues mentioned have led to this failure of policies in limiting the degradation of the water balance of the Caplina aquifer but an order of importance of those reasons is useful to then prioritise the measures to be taken.

Detailed comments

1. Include in Table 1 the scale of application.

Answer: we have added: Table 1 the scale of application of the policies and regulations

2. Layer with administrative sub-divisions of TACNA Region could be available maybe in Fig 1, if not readable, subdivisions of that regions should be described somewhere in section “study area”.

Answer: a description of the administrative sub-division of Tacna region was added in the study area section, Lines 160-162.

3. Basically, the amount extracted, increased by 150 % in almost 25 years from 1965- to 1989 and by almost 190 % during the next 20 years until 2019. So a degradation of water balance even faster in the last 20 years. This bring many questions that need to be addressed (maybe in section 3 or in section 4), before going beyond the list of measures that could help in solving the problem in term of policy tool, governance, reduction of extraction etc….):

Why the ban on additional extraction of groundwater (from a reference amount I assumed) that has been set from the 1984 and renewed until 2004 in la YARADA does not help in maintaining the balance in that specific area?

Answer: We identified four main reasons why the policies and regulations had no effects in maintaining the balance in the Caplina Aquifer:

1. Despite the policies and regulations provided, irrigation users continued with groundwater extractions, even these increased significantly due to the expansion of the agricultural areas and the construction of new pumping wells by unregistered users.
2. Lack of interest and political decision of the authorities at the regional and national level to carry out correct monitoring of the application of the policies and regulations provided.
3. Lack of management of the competent authority to articulate with the different sectors involved in water management to implement the strategies and obtain sources of financing, consequently, enforcing policies and regulations.
4. Lack of interest from the competent authorities in involving the academy to solve aquifer problems based on scientific research.

 We added this statement to the paper, Lines 383 to 293.

 The extension of preservation and conservation to the whole Caplina aquifer in 2006 seems to have been not effective as well, hypothesis on the why?

Answer: It is answered in the previous question.

What measures precisely were implemented to fit that regulation? What are the potential/combination hypotheses that are possible in explaining the degrading situation despite the preservation/protection policies put in place.

Answer: Basically, the measure implemented was the closure of the aquifer, which included not extracting groundwater and not drilling new pumping wells as evidenced in the paper. However, over time, the implementation of the closure became a failed attempt without being able to control the degradation of the aquifer. This situation is due to a set of previously explained reasons.

4. The section 4.3 suggests a participative governance where results of science could be shared on which a strategy could be defined to find a way out as you mentioned:

“The measures must incorporate the reduction of extraction volumes, water culture and the incorporation of external sources to replace the water used or artificial recharge of aquifers [36,37].”

Question: no feasible options that could help to restore the Recharge-Extraction balance are suggested in the literature?

Answer: Yes, there is, as we discussed in the paper. In addition, we add the following paragraph:

Worldwide, favorable mitigation measures have been identified for the conservation of aquifer systems, among which, physical and non-physical or management actions, leading to avoiding collapse and achieving recovery and conservation are addressed [40 ]. Therefore, it is possible to implement non-structural and structural measures. The first aimed at establishing a management plan and ordering of extractions and the second to the use of reservoirs and transfer of water between basins, reuse, recycling and desalination of seawater for artificial recharge of the aquifer.

5. In the conclusion:  the way forward this review should be defined- doing a review is good but having objectives on how to use this output interesting.

Answer: To write this paper, we started, first with the revision of 12 policies and regulations chronologically that were implemented in the Caplina Aquifer from 1984 to 2015, only two of them were national in scope. Second, we review all scientific investigations carried out in the study area to show the impacts of the applied policies and regulations on the Caplina Aquifer.

6. Figure 1 reference in L153 is broken.

Answer: This was corrected in the text.

7. L179  the sentence has an error, please correct and reformulate

Answer: It was corrected in the text.

8. L344-349, the sentences is long and probably there is

Answer: It was corrected in the text. The final sentences are (Lines 360-365):

As for the first case identified between farmers and mining companies in the high Andean zone, the fight for the use of water is permanent, the farmers demand a review of the water use licenses since the water resources law only establishes priorities for use and in fact. Agriculture according to the law has a higher priority, this problem that transcends fields of the national economy becomes very complex, in this sense, we find legal loopholes that do not allow resolving this type of conflict

Author Response File: Author Response.docx

Reviewer 2 Report (New Reviewer)

1. In the abstract, added some values

2. Added a new section: Geology and Hydrogeology setting

3. Try to have an idea about other transboundary aquifer examples: NWSAS (the northwestern aquifer system: transboundary aquifer between Algeria, Tunisia, and Libya (North Africa) (Hamed et al., 2022, 2023)

- Modelling of potential groundwater artificial recharge in the transboundary Algero‐Tunisian Basin (Tebessa‐Gafsa): The application of stable isotopes and hydroinformatics tools.Y Hamed, R Hadji, K Ncibi, A Hamad, A Ben Saad, A Melki, F Khelifi, ...Irrigation and Drainage 71 (1), 137-156

- North Western Sahara aquifer system hydrothermal and petroleum reservoirs dynamics: a comprehensive overview. Y Hamed, B Houda, M Ahmed, R Hadji, K Ncibi. Arabian Journal of Geosciences 16 (4), 247

4- If possible  add the climate change impact in this kind of aquifer

5- Added some recommendations about the future scenario/international conflict...

Need a minor revision

Author Response

Reviewer 2

1. In the abstract, added some values.

Answer. Some values were added in the abstract.

2. Added a new section: Geology and Hydrogeology setting

Answer. In the study area section at the end, a description of the geology and hydrogeology of the aquifer was added.

3. Try to have an idea about other transboundary aquifer examples: NWSAS (the northwestern aquifer system: transboundary aquifer between Algeria, Tunisia, and Libya (North Africa) (Hamed et al., 2022, 2023)

- Modelling of potential groundwater artificial recharge in the transboundary Algero‐Tunisian Basin (Tebessa‐Gafsa): The application of stable isotopes and hydroinformatics tools.Y Hamed, R Hadji, K Ncibi, A Hamad, A Ben Saad, A Melki, F Khelifi, ...Irrigation and Drainage 71 (1), 137-156

- North Western Sahara aquifer system hydrothermal and petroleum reservoirs dynamics: a comprehensive overview. Y Hamed, B Houda, M Ahmed, R Hadji, K Ncibi. Arabian Journal of Geosciences 16 (4), 247.

Answer. In the introduction, from lines 56-64, a paragraph was added to point out the main problems in transboundary aquifers and some approaches to improve water resources management.

4. If possible, add the climate change impact in this kind of aquifer

Answer. In the scientific evidence results section, lines 266 to 272, a paragraph was added to evidence in a general way, the potential impacts of climate change in the study area.

5. Added some recommendations about the future scenario/international conflict...

Answer. At the end of the 4.3 section (Lines 444 to 451), we added a paragraph denoting a suggestion to avoid future international conflict.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report (New Reviewer)

All my remarks have been done

It can be accepted  in this present form

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

In this article entitled “Sustainability of groundwater in the Atacama Desert headwaters, an approach from public policies against the results of science”, the study inspects an approach for groundwater sustainability in the Atacama Desert through discussing the application of groundwater resources management policies in the Caplina Aquifer and the results of scientific research carried out to understand the behavior of this aquifer. The title is appealing, but there are major issues in the manuscript.

Plagiarism: this article has a very high rate of similarity with other sources.

English: language is hard to digest.

Science: This article would fit as a review article more than a scientific article.

see above

Reviewer 2 Report

General comment

As it is now, unfortunately, it is not easy to understand what is the objective of the paper and what work has been done or its value. A deep revision is needed to provide an added value to that work, unless this is only a literature review of the relevant water policies and research literature on Caplina aquifer.

If this is a literature review please review this paper accordingly, classifying the papers, policy docs by thematic and doing a statistical analysis of the distribution of the documents to identify gaps and areas overcovered.

Detailed comments:

Major comments:

·         Introduction:

The objective of this work remains unclear. Is this work only willing to review the literature related to Caplina aquifer use and health together with the relevant policies in force? or does this work wish to provide an analysis of that evolution? And eventually explaining cause of this high depletion and providing recommendations? If this is the latter case, the paper needs a deep review to strongly substantiate what is/are the question(s) to be answered and the approach/methodology used to obtain responses. This is expected to be clearly presented at the end of the introduction, clarifying the current sentence: l 128-130

“In this work we seek to establish the sustainability of groundwater at the head of the Atacama desert, contrasting two approaches, one from public policies and the other from the evidence of science based on the results of research projects developed in this region.”

Indeed, what do you intend by “establishing the sustainability of the groundwater at the head of the Atacama desert”? The figure 2 you presented clearly demonstrated that there is no sustainable use of the Caplina aquifer since 1989. So what are these 2 approaches and their interest related to that fact? Proving their policy inefficiency? Finding scientific causes not addressed by the current policy?

·         Studied area

The description of main Caplina aquifer uses  and the trend of the evolution on that human pressure for the period 1965-2019 is missing. This will provide some important explicative context to the table 3 and conflict between user sections. It can be shortly described, no need to much details, unless necessary.

·         Materials and Methods

The first two paragraphs that is crucial to understand the amount of work done and the methodology are too vague. Please expend the explanation of “the analysis of the interrelationships between the main points of Peruvian legislation on water resources, its application in water management actions”L161. This “integrated approach” L162 to analyse the relevant water policies needs to be better explained with eventually references if this is an established methodology. The data used (for instance a table, maybe in annex if many sources, with type of policy documents, classified by thematic aspects and eventually scale and timeframe)

Please explicit the period you are analysing-> that is important to have a time reference to compare with the evolution of groundwater balance shown in figure 2.

What do you wish to see with the water policy analyses? If the water policy is appropriate to Caplina aquifer-> identifying the inappropriate legislation?, assess retrospectively the (poor) efficiency of policies applied and where they need to be changed?

3.2Management instruments

Kindly present shortly what are the water licence and how the water allocation system works in Caplina.

3.3 Science results

L213- 215 analysing recent literature review 2017 _2023 is relevant if policies are analysed for the same recent period (date that is still questionable since the change in the exploitation occurred in 1980’s). Table 1 is indeed going back to the 80’s

Please clarify and justify the period of review and analysis for water policies and research/literature

3.4. Conflicting users

Please provide reference for all the different types of conflicts that are reported in the Caplina river basin, or is this coming from specific work done by the researcher?

·         4.Results and Discussion

As such this section is very too vague too short and untargeted while being the core of the paper. And actually is not really presenting the results of this work but mainly summarizing some reasoning with literature references. This section should be the main place to showcase the work done and demonstrate its interest/implication on management of this aquifer.

For instance:

L 317 to 321 :”Regarding the first case identified between farmers and mining companies, in the  high Andean zone the struggle for the use of water is permanent, farmers are demanding a review of water use licenses since the water resources law only establishes priorities for use and In fact, agriculture according to the law has a higher priority, this problem that  transcends fields of the national economy becomes very complex, in this sense, we find legal loopholes that do not allow resolving this type of conflict.”

This conclusion needs to be argued and substantiated importantly by evidence(s) found by this study.

Same on all the conflicts mentioned, conclusions are given (e.g L325 to 328; 334-337) but with no indication on what evidence(s) found by the researcher substantiate(s) that conclusion, but citing literature at the end of the paragraph. So again are we in a literature review? If so fine but this has to be clear from the beginning.

Additionally, recommendations or options to move out these situations are too lightly presented=>”The institutional framework in terms of Water Law must be consolidated and strengthened”.

The points of discussions can be around that suggestions, options, as step further needs to be taken.  It is worst to mention that only the policy aspects in arbitrating the water conflicts are considered as leverage for change of management. What about questioning the use themselves….. can some  specific uses be reduced with a better efficiency? Easily ? can cohabit with other users more easily ( domestic use cannot be reduced much, and requires a minimum quality for human health, while mining may have lower quality requirement but still if requiring too much amount of water, for instance a ban on mining would it be the only option to put back on sustainable way , the management of the aquifer ? from the table 1 it  is understood that some conservation measures were taken but were not so efficient why? Wrong areas ? not real application?? )

·         Conclusions

To be adapted based on changes made.

Minor comments:

L 137 – reference to figure is broken

L161- there is appoint in the middle of the sentence

Sentence L 240-243- there is a point in the middle of the sentence

Legend figure 2: recharged volume instead of “rechard volume”

Please make sure that  you use the terms governance and governability appropriately.