Future Development and Water Quality for the Pensacola and Perdido Bay Estuary Program: Applications for Urban Development Planning

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Review Report

Title: Future Development and Water Quality for the Pensacola and Perdido Bay Estuary Program: Applications for Urban Development Planning

 

Manuscript ID: land-3674618

 

General:

This manuscript has used future development and Event Mean Concentration (EMC) models for Escambia and Santa Rosa counties in Florida (USA) to assess impacts from development patterns on water quality and runoff, and water resource protection priorities. Future development densities, developed land, stormwater volume, total nitrogen, and total phosphorus have been analyzed. Urban infill, redevelopment, land-use scenarios and stormwater management have been considered very important parameters for broader growth management strategies, for reducing sprawl and addressing urban stormwater impacts. However, the manuscript needs improvement before it is published. The following suggestions may help in improving the quality of the paper.

 

Comments

• Kindly add a few words about the data collection and analysis
• Kindly improve slightly the literature review. Some critical reviews are important. Presently this part is missing. For example Line 48 to 51: “One of the models used in Florida (USA) is the Sea Level 2040/2070 model, which incorporates assumptions about future population growth, sea level rise, and development likelihood or “suitability” to identify a set of future land-use scenarios [18–22]”------5 references have been coated without any in depth discussion on the published papers. The same concept of citing references has been used at many places. Citing references without any discussion does not highlight the research gap and originality of the research.
• Kindly provide governing equations for various models where applicable and explain how output is obtained from the equations.
• Kindly provide calibration and validation of models where applicable.
• The models may kindly be discussed in the section of “Materials and Methods” whereas in “Introduction” section, the literature review with some critic discussions be presented. It will avoid any duplications.
• The novelty of the research paper may be highlighted in “Introduction” section.
• Kindly improve the conclusion section. Provide some solid conclusions based on the results and discussions.

 

Author Response

Kindly add a few words about the data collection and analysis

• The data used is the best publicly available data for the study area. This is noted at the beginning of the Materials and Methods section, which also notes that the data used in each analysis are discussed in more detail in the relevant methodology section.

 

Kindly improve slightly the literature review. Some critical reviews are important. Presently this part is missing. For example Line 48 to 51: “One of the models used in Florida (USA) is the Sea Level 2040/2070 model, which incorporates assumptions about future population growth, sea level rise, and development likelihood or “suitability” to identify a set of future land-use scenarios [18– 22]”------5 references have been coated without any in depth discussion on the published papers. The same concept of citing references has been used at many places. Citing references without any discussion does not highlight the research gap and originality of the research.

• We have reviewed the paper and addressed this in several locations, including the specific text mentioned. Specifically, discussion of the five references has been broken out in lines 53-65 (one reference was deleted).

 

Kindly provide governing equations for various models where applicable and explain how output is obtained from the equations.

• The standard equation used for EMC calculations has been added for reference (line 307). Other analysis were not equation based, but were spatial models and have been described in the text.

 

Kindly provide calibration and validation of models where applicable.

• Future Development Models are estimates of what land development patterns ‘may’ occur. As such none of these models are intended to be predictions of future population of development patterns. These are merely representations of what ‘may’ occur, and therefore no calibration or validation models exist, nor was it within the scope, budget, or timeline of the project to develop such models. This is also not applicable for the water quality/water storage models discussed as they are prioritization models, and project scope and budget did not allow validation (such as on-site soils or hydrologic testing) to confirm the results of these models, which were run at a regional scale.

 

The models may kindly be discussed in the section of “Materials and Methods” whereas in “Introduction” section, the literature review with some critic discussions be presented. It will avoid any duplications.

• Model parameters, inputs, and execution have been discussed in each relevant model subsection within the Materials and Methods section.

 

The novelty of the research paper may be highlighted in “Introduction” section.

• We have added text to the introduction that identifies how this study is unique.

 

Kindly improve the conclusion section. Provide some solid conclusions based on the results and discussions.

• We have improved the conclusion section to more specifically refer to conclusions and suggestions provided in the discussion.

Reviewer 2 Report

Comments and Suggestions for Authors

Comments to the Author：

 

*The introduction of Materials and Methods (starting from Line 124) in the manuscript is too complex and lengthy, seriously weakening the logical expression of the manuscript and increasing the pressure on readers to understand the entire text. The author should simplify the expression extensively and highlight the key points. On the contrary, the description of parameter settings for future development models and pollution load models is too brief, lacking discussion of model limitations, and failing to explain the rationale behind the key assumption of a 30% increase in development density.

 

*The model adopts the "static difference method" and only compares one target point in 2040, without reflecting the dynamic changes in future processes, and ignoring the influence of nonlinear growth or feedback mechanisms.

 

*The water quality and water resource storage models were not included in the soil data.

 

*The model integration in the manuscript is not comprehensive enough, and the priority protection areas for water quality and water resource storage are excluded from the development scope. This model integration method does not fully consider practical constraints.

 

*The manuscript is a predictive study and should fully discuss the sources of uncertainty and the potential impact of cumulative errors on the final results. The population migration assumption in the manuscript is that the migration direction is affected by sea level rise, which lacks persuasiveness. The weights assigned to various factors in constructing the "suitability map" do not provide a reasonable basis, which may affect the effectiveness of the development area prediction. Additionally, the EMC method employs a simplified calculation method, which may lead to overestimation or underestimation of the pollutant load in regional-scale estimations.

Author Response

*The introduction of Materials and Methods (starting from Line 124) in the manuscript is too complex and lengthy, seriously weakening the logical expression of the manuscript and increasing the pressure on readers to understand the entire text. The author should simplify the expression extensively and highlight the key points. On the contrary, the description of parameter settings for future development models and pollution load models is too brief, lacking discussion of model limitations, and failing to explain the rationale behind the key assumption of a 30% increase in development density.

• We have reviewed the section the reviewer is referring to and simplified the Study Site section as requested.
• We have expanded the discussion of other methods for calculating Gross Development Density (GDD), referencing several other models, and summarized the justification for the 30% increased used for the Gross Development Density in the Alternative Scenario, noting that this is derived from expert opinion in previous studies.
• Identification of the sources of inputs for the EMC (pollution load model) is included in the text, lines 301-303.
• Model limitations for all models has been included in the Discussion. We note that these are relatively simple models based on regional or statewide data intended to be easy to communicate to stakeholders and the public. Opportunities for adding complexity to the models in future studies exists and this is discussed in more detail in the discussion section

 

*The model adopts the "static difference method" and only compares one target point in 2040, without reflecting the dynamic changes in future processes, and ignoring the influence of nonlinear growth or feedback mechanisms.

• We have added in the Discussion section text that further discusses the intended uses and limitations of the models, including the rationale for using one target point (2040), and noting that consideration of dynamic future changes, nonlinear growth, or feedback mechanisms could be a potential future addition to the model, but was beyond the scope and budget of this project, and also inconsistent with the goal of developing a simple, easy to communicate set of models for public communication.

 

*The water quality and water resource storage models were not included in the soil data.

• Soils data was not an input in either the Water Quality nor the Water Storage Models. Soils might be considered relevant inputs for future models could be developed with additional scope and budget to identify opportunities for wetland restoration and water storage based on hydric soils data or other soil properties. Recognizing that soils could be a valuable input for similar models, we have addressed this in the discussion in lines 759-761.

 

*The model integration in the manuscript is not comprehensive enough, and the priority protection areas for water quality and water resource storage are excluded from the development scope. This model integration method does not fully consider practical constraints.

• The manuscript describes four separate models, a Future Development Model, EMC Pollutant Runoff Model, Water Quality Conservation (WQ) Priorities Model, and Water Storage (WS) Conservation Priorities Model. Discussion of how the WQ/WS models results were integrated with the Future Development Model is discussed in in lines 408-410. Evaluation of practical constraints to future development or water resource protection was not within the scope, budget, or timeline of the project, although we did provide some discussion on the importance of a suite of strategies for water resource protection in urban and rural landscapes.

 

*The manuscript is a predictive study and should fully discuss the sources of uncertainty and the potential impact of cumulative errors on the final results. The population migration assumption in the manuscript is that the migration direction is affected by sea level rise, which lacks persuasiveness. The weights assigned to various factors in constructing the "suitability map" do not provide a reasonable basis, which may affect the effectiveness of the development area prediction. Additionally, the EMC method employs a simplified calculation method, which may lead to overestimation or underestimation of the pollutant load in regional scale estimations.

• We agree and we’ve added a note in lines 551-553 to address this point.

Reviewer 3 Report

Comments and Suggestions for Authors

The integration of Event Mean Concentration modeling with conservation priority and future development is commendable as it offers valuable information to land-use planners. However, several concerns have to be addressed. Firstly, the figure legends (e.g., Figure 1) are overly brief and do not provide sufficient information to be understood on their own; therefore, they ought to be lengthened to clearly explain the symbols, color codes, and meaning of each panel. Second, structural incoherencies are evident, such as the misuse of a numbered subsection ("3.1.2") as a figure caption and therefore needing revision for clarity and consistency with formatting conventions. Additionally, although the study illustrates the trade-offs between urban densification and the conservation of water resources, it would greatly benefit from a more detailed sensitivity analysis of the assumptions underlying the development scenarios (e.g., 30% increase in density).

Questions for the authors:

To what degree do the model outputs depend on the assumption of a 30% development density increase? Would an increase of 20% or 40% produce noticeably different conservation results?

Can you please describe how the weighting for suitability map was determined? Was it determined by stakeholders?

How far can your modeling system be extended to other coastal or terrestrial areas experiencing differing urbanization pressures or ecological limitations?

Did the authors think of incorporating socio-economic factors (e.g., income, land prices) in prioritizing the lands for conservation?

The study would be improved by clarity, discussion of figures, and a discussion of underlying assumptions.

Author Response

The integration of Event Mean Concentration modeling with conservation priority and future development is commendable as it offers valuable information to land-use planners. However, several concerns have to be addressed. Firstly, the figure legends (e.g., Figure 1) are overly brief and do not provide sufficient information to be understood on their own; therefore, they ought to be lengthened to clearly explain the symbols, color codes, and meaning of each panel. Second, structural incoherencies are evident, such as the misuse of a numbered subsection ("3.1.2") as a figure caption and therefore needing revision for clarity and consistency with formatting conventions. Additionally, although the study illustrates the trade-offs between urban densification and the conservation of water resources, it would greatly benefit from a more detailed sensitivity analysis of the assumptions underlying the development scenarios (e.g., 30% increase in density).

• We have corrected the mistaken subsection number previously included in Figure 1 in error.

 

Questions for the authors:

 

To what degree do the model outputs depend on the assumption of a 30% development density increase? Would an increase of 20% or 40% produce noticeably different conservation results?

• We have expanded the discussion of other methods for calculating Gross Development Density (GDD), referencing several other models, and provided justification for the 30% increased used for the Gross Development Density in the Alternative Scenario, noting that this is derived from expert opinion in previous studies.

 

Can you please describe how the weighting for suitability map was determined? Was it determined by stakeholders?

• We have expanded the discussion of the methods for developing the Suitability map. Discussion is now covered in lines 212-218.

 

How far can your modeling system be extended to other coastal or terrestrial areas experiencing differing urbanization pressures or ecological limitations?

• We have included in the discussion the intended uses and application of the models to other locations, beginning with line 707.

 

Did the authors think of incorporating socio-economic factors (e.g., income, land prices) in prioritizing the lands for conservation?

• We have expanded the discussion of limitations for all models within the discussion section, including these parameters. This is discussed in lines 761-764.

 

The study would be improved by clarity, discussion of figures, and a discussion of underlying assumptions.

• We have significantly expanded figure captions and discussion within the text.

 

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

I have no other objections.

Reviewer 3 Report

Comments and Suggestions for Authors

Accept in present form