Rehabilitation of Urban Beaches on the Mediterranean Coast in Valencia (Spain) Observed by Remote Sensing

Round 1

Reviewer 1 Report

The first thing that should be changed is the title of the paper since it is impossible to restore such a degraded environment. Even though the restoration of urban beaches is a topic of great interest, the area chosen to carry out the study is very unstimulating. The occupation of the territory is so overwhelming that the possibilities of the coast to regenerate naturally or with assistance are practically nil. The best proof is that the only thing that has been done so far has been to accumulate sand on the beach to see how the waves would carry it away after a storm. We miss some cross section of the coast that explains the possibilities of conserving the sand contributions to try to regenerate the beach. Possibly, despite the minimal tidal oscillation typical of the Mediterranean, the depth of the water is very great a short distance from the shore and that explains the lack of success in the regeneration of the beaches. On the other hand, the proximity of the line of buildings and other constructions on the coast makes it impossible to regenerate whatever decision is made. Practically, the beaches must be in permanent regeneration since the conditions of the sea or the relief make them an unstable form in continuous degradation.

Dunes like wind constructions must be in permanent movement due to the effect of the wind. But they also have to have a destination that does not exist here due to the dense urban occupation of the upper part of the beach.

Under these conditions, the conclusions should highlight that the possibilities of the coast, unless major changes occur in the use of the territory, are simply to maintain the sandy strip of the coast for tourist use but it is practically impossible to regenerate the ecosystems.

The conclusions are a declaration of intentions that are difficult, if not impossible, to achieve.

It is striking that no geological data has been provided, which would help to know what the rococo or sedimentary substrate of the area is and its history, at least during the Holocene. This information helps a lot to understand the possibilities of the area and to know the evolution of the coast in the recent past.

Author Response

Dear reviewer, we thank you for your dedication in reviewing our manuscript and greatly appreciate your time invested. Your efforts are highly appreciated and your comments have contributed significantly to improving the quality of our article.

The first thing that should be changed is the title of the paper since it is impossible to restore such a degraded environment. Even though the restoration of urban beaches is a topic of great interest, the area chosen to carry out the study is very unstimulating. The occupation of the territory is so overwhelming that the possibilities of the coast to regenerate naturally or with assistance are practically nil. The best proof is that the only thing that has been done so far has been to accumulate sand on the beach to see how the waves would carry it away after a storm. We miss some cross section of the coast that explains the possibilities of conserving the sand contributions to try to regenerate the beach. Possibly, despite the minimal tidal oscillation typical of the Mediterranean, the depth of the water is very great a short distance from the shore and that explains the lack of success in the regeneration of the beaches. On the other hand, the proximity of the line of buildings and other constructions on the coast makes it impossible to regenerate whatever decision is made. Practically, the beaches must be in permanent regeneration since the conditions of the sea or the relief make them an unstable form in continuous degradation.

Dunes like wind constructions must be in permanent movement due to the effect of the wind. But they also have to have a destination that does not exist here due to the dense urban occupation of the upper part of the beach.

Under these conditions, the conclusions should highlight that the possibilities of the coast, unless major changes occur in the use of the territory, are simply to maintain the sandy strip of the coast for tourist use but it is practically impossible to regenerate the ecosystems.

The conclusions are a declaration of intentions that are difficult, if not impossible, to achieve.

We have added an additional explanation in discussion about the great difficulties faced by the regeneration of these beaches due to human pressure on the territory, emphasizing that it would be more of a rehabilitation process (also updated in the title of the work). So, we have reformulated the conclusions according to that. Additionally, we have replaced “restoration” for “rehabilitation” throughout the entire document where is necessary.

It is striking that no geological data has been provided, which would help to know what the rococo or sedimentary substrate of the area is and its history, at least during the Holocene. This information helps a lot to understand the possibilities of the area and to know the evolution of the coast in the recent past.

A comprehensive review of the geomorphologic context, formation, sedimentology, and factors that shape these beaches has been added at the end of Section 2.1.

Reviewer 2 Report

In this paper, remote sensing technology is used to detect the change of beach dune area in Valencia, Spain by using satellite images, and the results show that the beach dune area has decreased significantly. The paper reveals the importance of remote sensing for the study, restoration and management of beaches and their associated ecosystems, as it helps to provide continuous spatial and temporal data. The topic of this paper is clear and logical, and it is recommended to hire after minor revision. At the same time, there are the following problems in the article, and I hope the author can further improve them:

（1）      Figure 3 of the article suggests the author to add relevant data tables and give detailed explanations to increase the readability of the article.

（2）      What specific improvements should the authors consider regarding the methodology? What further controls should be considered? The author is only elaborating the necessity of remote sensing observation recovery, and hopes that the author will further elaborate the new method.

（3）      Are the conclusions consistent with the evidence and arguments presented and do they address the main question posed?

（4）      What is the main question addressed by the research? It is hoped that the author will highlight the superiority of his own method in the part of theoretical methods.

（5）      Do you consider the topic original or relevant in the field? Does it address a specific gap in the field?

Excellent English proficiency

Author Response

Dear reviewer, we sincerely appreciate your generosity in reviewing our manuscript. Your time and effort are greatly appreciated, and your comments have been essential in enhancing the quality of our paper.

In this paper, remote sensing technology is used to detect the change of beach dune area in Valencia, Spain by using satellite images, and the results show that the beach dune area has decreased significantly. The paper reveals the importance of remote sensing for the study, restoration and management of beaches and their associated ecosystems, as it helps to provide continuous spatial and temporal data. The topic of this paper is clear and logical, and it is recommended to hire after minor revision. At the same time, there are the following problems in the article, and I hope the author can further improve them:

（1）      Figure 3 of the article suggests the author to add relevant data tables and give detailed explanations to increase the readability of the article.

We have added to the text that both Figure 2 and Figure 3 are constructed using data from Table 2.

（2）      What specific improvements should the authors consider regarding the methodology? What further controls should be considered? The author is only elaborating the necessity of remote sensing observation recovery, and hopes that the author will further elaborate the new method.

We have added a paragraph in the discussion regarding the future improvements associated with this methodology. Also, we have explained that future monitoring is needed to evaluate the results of this restoration.

（3）      Are the conclusions consistent with the evidence and arguments presented and do they address the main question posed?

We have added an additional explanation in discussion about the great difficulties faced by the regeneration of these beaches due to human pressure on the territory, emphasizing that it would be more of a rehabilitation process (also updated in the title of the work). So, we have reformulated the conclusions according to that.

（4）      What is the main question addressed by the research? It is hoped that the author will highlight the superiority of his own method in the part of theoretical methods.

We have reformulated the aim of study. Additionally, we have written an explanation in the discussion about the capabilities of this methodology in beaches dynamics and regeneration studies.

 （5）      Do you consider the topic original or relevant in the field? Does it address a specific gap in the field?

We have added a paragraph to the discussion highlighting the contributions of the method to the coastal monitoring and its possible applications in other studies.

Round 2

Reviewer 1 Report

The authors of the work have modified some of the dark points existing in the previous version. However, inaccuracies remain regarding the geological history of the sediments during the end of the Pleistocene until the present. However, the work has focused on an immediate aspect: the regeneration of a beach environment subject to the current anthropic impact. The work can, however, be considered a good methodological contribution for environmental impact studies for future researchers. However, a good synthesis of previous geological data should always be included as it helps to understand the evolution of the coast. This is, without a doubt, the weakest point of the job.

Reviewer 2 Report

In this paper, remote sensing technology is used to detect the rehabilitation of the beach in Valencia region of Spain using satellite images, and the results show that the beach sand dune area has decreased significantly. The paper reveals the importance of remote sensing for the study, rehabilitation and management of beaches and their associated ecosystems, as it helps to provide continuous spatial and temporal data. The topic of this paper is clear, the research content has far-reaching significance, and the author has also made a positive reply to the previous review comments and made corresponding modifications.

In view of the review opinions given last time, corresponding pictures are added to the paper to show the different horizontal forms of beach cross sections. In addition, the author adds paragraphs to explain the improvement of the proposed method and its contribution to coastal detection. Moreover, the author adds the difficulty of human factors in beach reconstruction to make the paper more complete. So I agreed to publish it.