Development of Transient Hydrodynamic and Hydrodispesive Models in Semi-Arid Environments

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This is an interesting manuscript focusing on the quantity and quality of groundwater in Rharb coastal basin. The authors presented impactful findings. Isuggest to improve the abstract further, it seems quite general, include some results and implications. Its very hard to understand Figure 4, it can be better presented, the legend is not right especially the abscence of blue color, the boreholes can be presented as points.  The uncertainity analysis can be improved in Figure 9, the data points are not very clear, you may also look at the paper (Numerical Groundwater Flow Modeling of Kohat Basin: An example from Himalayan Fold and Thrust Belt Pakistan, Vol 69 (2), 263-276, Mausam Publications.  https://doi.org/10.54302/mausam.v69i2.305) and cite it in the introduction part, the graphs are presented nicely there which could be as a reference for you. 

Figure 11 needs to be improved, please keep every figures with text as consistent. 

The information about tomography survey or data is not mentioned, it would be better to provide us more details and at least 2-3 profiles if data is collected for this research. 

Try to look for grammatical mistakes and make the writing more professionally sound. Good Luck 

 

 

 

 

Comments on the Quality of English Language

Can be improved but ok

Author Response

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Review Report

Manuscript Title: Development of Transient Hydrodynamic and Hydro-dispersive Models in Semi-Arid Environments

Manuscript ID: hydrology-3391973

 

General:

The manuscript has developed a numerical model for monitoring both the groundwater quantity and quality in aquifers of Rharb Basin located in the North-West of Morocco. The data regarding recharge, aquifer exploitation, and basin characteristics have been used in modelling. The field data associated with electro-facies resistivity and high-resolution seismic refraction tomography have been collected and analyzed. Decline in water levels of the aquifer have been simulated by using the transient hydrodynamic model (MODFLOW). Salt concentrations are predicted by the hydro-dispersive model (MT3DMS) built in MODFLOW. SEAWAT has been applied to study seawater intrusion. The manuscript needs improvements before its publication. The following suggestions may please be incorporated to improve the manuscript.

Suggestions for Improvement of the model.

Main Suggestions for Improvement:

i)                    Kindly provide some critical literature review for hydrodynamic and hydro-dispersive modeling in “Introduction”. Kindly provide literature reviews both for international and local readers

ii)                   In “Introduction”, kindly highlight the novelty of the research work presented in this paper.

iii)                 Kindly add “Calibration and Validation” of model as heading and explain how the model was calibrated. Also kindly explain how validation of the models was achieved.

iv)                 Kindly explain which parameters of the model were calibrated. What values of different parameters were used as initial input and what values of these parameters were achieved after calibration. Kindly provide an equation for the index (error) used to check the efficiency of the calibrated and validated models.

v)                   Kindly explain how the model was calibrated and validated for “salt-water intrusion”

vi)                 Kindly provide also the results of “Validation of models” in “Results and Discussion” section.

vii)               Kindly add “Sensitivity Analysis of Model Parameters” as heading and discuss the sensitivity of the model predictions for various parameters.

viii)              Kindly add some predictions which might be useful for future water resources management in the study area.

ix)                 Kindly provide justifications for using old data. Why the recent data have not been used for modelling in this research.

 

Minor Improvement:

x)                   Kindly provide the source of Figure 2 and Figure 3. If it is drawn by the authors themselves, then kindly provide details of data collection.

xi)                 Kindly check equation 1. I think something is missing in this equation. “d”alone does not mean any thing--------It might be “ )”-------Kindly forgive me if I am wrong.

xii)                While discussing “Simulation period, spatio-temporal discretization, and boundary conditions”  kindly check “ The discretization [12] of the study air respects the following two conditions:” ---What is meant by “study air”

xiii)              Again under “Simulation period, spatio-temporal discretization, and boundary conditions”----Kindly check “This results in 46748 cells to represent the entire system, with 14252 for the upper aquifer, 12259 for the aquitard, and 20237 for the lower aquifer”------I think we should add cells after 20237 as: “This results in 46748 cells to represent the entire system, with 14252 for the upper aquifer, 12259 for the aquitard, and 20237 cells for the lower aquifer”

xiv)              Kindly use either “Modflow” or “MODFLOW” throughout the manuscript. My suggestion is better to use “MODFLOW”.

xv)                In equation 1 small “h” is used as hydraulic----whereas in equation 2 capital “H” is used as hydraulic head. Is there any specific reason for that. I suggest to use the same notation throughout the manuscript.

xvi)              Equation 3 needs improvements in its write up. “i, j, k” I think should be subscript and within brackets----“m” should also be subscript.

xvii)            Kindly explain what is difference between heads at nodes (i, j, k) and (i, j-1, k)--------Why “j-1”?------Why not “i-1”

xviii)           Kindly improve presentation of all equations. Type equations in “Equation Editor”

xix)              Kindly delete “include” from “3.1.2. Inputs and outputs of the transient model include”

xx)                Kindly check “These withdrawals are internal documents consisting of daily historical data from three surveys conducted by COMBE [16], ENGEAMA (Inquiry 1992), and the Sebou Hydraulic Basin Agency [1] following the surveys of 2005 and 2008”. --------------“Withdrawals” I guess should be some numerical data values----Not internal documents.

xxi)              Kindly cite all the tables in the text. Table 1, Table 4 and Table 5 have not been cited.

xxii)            Kindly use the same notation for any parameter throughout the manuscript. At one place the authors have used “Table 1” whereas at another place they have used “Tab.3”

xxiii)           Kindly explain “8 points” given in Table 1. If possible kindly show these points by a Map.

xxiv)           Kindly check the statements given below: “To simplify the task, and since irrigation withdrawals constitute more than 90% of the total withdrawals, we only consider this data. Data on drinking water reserved for consumption and industrial water are not precise, and some information such as coordinates is missing. The return flow from irrigation is also subtracted from the inputs, this time to compensate for the portion of water supply for drinking and industrial purposes as outputs, since their volumes are analogous.” ------------kindly explain what is meant by “this data” and “this time”

xxv)         Kindly explain how 156 zones were derived from calibration of the model. You have stated that “Recharge data is inserted based on the division of the Rharb plain into 156 zones derived from the calibration of the steady-state model”.

xxvi)           Kindly explain the “Reference piezometers------540/8, 698/8, 1552/8--------” given in Table 2.-----If possible kindly show these piezometers with the help of a Map.

xxvii)         Kindly improve the quality of figures

Author Response

Comments 1: Kindly provide some critical literature review for hydrodynamic and hydro-dispersive modeling in “Introduction”. Kindly provide literature reviews both for international and local readers.

Response 1: Thank you for pointing this out. We agree with this comment. Therefore, We have revised the introduction and added new references. (Line 29-34).

Comments 2: In “Introduction”, kindly highlight the novelty of the research work presented in this paper.

Response 2: We agree with your comment because it reflects a very important point in any study for publication. We have therefore mentioned a study on multi-layer mathematical modeling (3 layers) which is being done for the first time for the Rharb basin. The other studies were on single-layer hydrodynamic modeling. (Line 72-75).

Comments 3: Kindly add “Calibration and Validation” of model as heading and explain how the model was calibrated. Also kindly explain how validation of the models was achieved.

Response 3: We have included a sub-section on calibration and validation, to help readers understand that calibration is based mainly on storage coefficients, and validation is based on comparison with field measurements. (Line 253-270, 272-274).

Comments 4: Kindly explain which parameters of the model were calibrated. What values of different parameters were used as initial input and what values of these parameters were achieved after calibration. Kindly provide an equation for the index (error) used to check the efficiency of the calibrated and validated models.

Response 4: The main parameter adjusted at the transient model level is the storage coefficient, whose initial parameters are shown in Appendix A. (Line 254, 261,273).

Comments 5 : Kindly explain how the model was calibrated and validated for “salt-water intrusion”.

Response 5 : Validation of the SEAWAT model is based on comparison with tompgraphic profiles obtained from field measurements carried out by the Agence du Bassi Hydraulique du Sebou, following field surveys in 2005 and 2008. (Line 447-448).

Comments 6 : Kindly provide also the results of “Validation of models” in “Results and Discussion” section.

Comments 7 : Kindly add “Sensitivity Analysis of Model Parameters” as heading and discuss the sensitivity of the model predictions for various parameters.

Comments 8 : Kindly add some predictions which might be useful for future water resources management in the study area.

Response 8 : We couldn't agree with you more, because a model is a tool for predicting the outcome of a phenomenon under study. We therefore plan to update the study once we have the contractual possibility of obtaining new data, and thus update the study, to take into account climate and operating scenarios in order to provide evolution scenarios. (Line 474-480).

Comments 9 : Kindly provide justifications for using old data. Why the recent data have not been used for modelling in this research.

Response 9 : We used data from 1992 to 2007, because beyond 2007, the series of irrigation pumping records we collected were not well prepared (missing coordinates, and sometimes even the flow rates used). (Line 209-211).

Minor Improvement:

x) Kindly provide the source of Figure 2 and Figure 3. If it is drawn by the authors themselves, then kindly provide details of data collection.

- Illustrations are created by the authors in ‘’Canvas 15’’.

xi) Kindly check equation 1. I think something is missing in this equation. “d”alone does not mean any thing. It might be “ ”. Kindly forgive me if I am wrong.

- Thank you for your comment, we have checked and corrected the eqouation as a result.

xii) While discussing “Simulation period, spatio-temporal discretization, and boundary conditions”. Kindly check “ The discretization [12] of the study air respects the following two conditions:”. What is meant by “study air”.

- We rectified air by area.

xiii) Again under “Simulation period, spatio-temporal discretization, and boundary conditions”. Kindly check “This results in 46748 cells to represent the entire system, with 14252 for the upper aquifer, 12259 for the aquitard, and 20237 for the lower aquifer”. I think we should add cells after 20237 as: “This results in 46748 cells to represent the entire system, with 14252 for the upper aquifer, 12259 for the aquitard, and 20237 cells for the lower aquifer”.

- The calculation has been redone at text level (Line 214-216). xiv) Kindly use either “Modflow” or “MODFLOW” throughout the manuscript. My suggestion is better to use “MODFLOW”. - We have homogenized the name throughout the text, adopting MODFLOW.

xv) In equation 1 small “h” is used as hydraulic----whereas in equation 2 capital “H” is used as hydraulic head. Is there any specific reason for that. I suggest to use the same notation throughout the manuscript.

- We have adopted the capital H for equations.

xvi) Equation 3 needs improvements in its write up. “i, j, k” I think should be subscript and within brackets “m” should also be subscript.

- We have corrected the character levels this time.

xvii) Kindly explain what is difference between heads at nodes (i, j, k) and (i, j-1, k) Why “j-1”? Why not “i-1” xviii) Kindly improve presentation of all equations. Type equations in “Equation Editor”.

- We have improved the equation format by using the “Equation Editor”.

xix) Kindly delete “include” from “3.1.2. Inputs and outputs of the transient model include”

- Thank you, it was a typographical error.

xx) Kindly check “These withdrawals are internal documents consisting of daily historical data from three surveys conducted by COMBE [16], ENGEAMA (Inquiry 1992), and the Sebou Hydraulic Basin Agency [1] following the surveys of 2005 and 2008”. “Withdrawals” I guess should be some numerical data values. Not internal documents.

- Indeed, these are numerical values.

xxi) Kindly cite all the tables in the text. Table 1, Table 4 and Table 5 have not been cited.

- We have checked and cited all the tables in the text.

xxii) Kindly use the same notation for any parameter throughout the manuscript. At one place the authors have used “Table 1” whereas at another place they have used “Tab.3”.

- thank you, we have opted for Table.

xxiii) Kindly explain “8 points” given in Table 1. If possible kindly show these points by a Map.

- After verification, there are 7 points shown in figure 10 (Legend: Punctual storage coefficients).

xxiv) Kindly check the statements given below: “To simplify the task, and since irrigation withdrawals constitute more than 90% of the total withdrawals, we only consider this data. Data on drinking water reserved for consumption and industrial water are not precise, and some information such as coordinates is missing. The return flow from irrigation is also subtracted from the inputs, this time to compensate for the portion of water supply for drinking and industrial purposes as outputs, since their volumes are analogous.” kindly explain what is meant by “this data” and “this time”.

- We have rectified the text to correct these errors (Line 238-248).

xxv) Kindly explain how 156 zones were derived from calibration of the model. You have stated that “Recharge data is inserted based on the division of the Rharb plain into 156 zones derived from the calibration of the steady-state model”.

- We have replaced the word ''zone'' with ''parcel'' to indicate that it refers to a set of cells with equal infiltration value (Line 243/248).

xxvi) Kindly explain the “Reference piezometers------540/8, 698/8, 1552/8--------” given in Table 2.If possible kindly show these piezometers with the help of a Map.

- Pilot piezometers appear on Figure 9. (b) Degree of correlation between observed and calculated piezometries.

xxvii) Kindly improve the quality of figures.

- We've redone most of the figures 4.

 

Response to Comments on the Quality of English Language

Response 1: We have reviewed the entire article for grammatical errors and corrected them.

Reviewer 3 Report

Comments and Suggestions for Authors

·       Variables must be in italics, check the entire manuscript!

·     The reviewer recommends expanding the background by comparing hydrogeological models developed in similar contexts of other semi-arid basins and adding references to recent studies (in the last 5-10 years in hydrogeology and water management journals).

·       Figure 1 – Improve the legend in Figure 1 (a), including all references to the different colors.

·       Unnecessary indentation, after the eq. 2., eq. 3, eq. 4. and  eq. 6.

·       In equation 2, what is a2 referred to?

·       Indicate i,j,k as subscripts.

·       In Table 1: change the font of (interval). Time series, with a capital T.

·       Figure 8 – indicate units of measurement for time on the x-axis. What is zone 1?

·       In the text before Table 2, eliminate the dot after Table 2. After Table 2, in the text, eliminate the dots after the numbers e.g. (Fig.9 (a)).

·       Figure 9. Improving the graph. The reviewer suggests imposing the same scale on the axes to be square and increasing the size of the points on the graph.

·       Figure 13 – Adding units of measurement in the graph.

·       Figure 14 – Adding the unit of measurement on the x-axis and y-axis.

·       Figure 15 – Adding the progressive distance on the x-axis.

·       The quality of Figure 16 is not acceptable with this poor quality.

·       Make Figures 15 and 17 consistent by making the direction of the diagram uniform (for example, the sea on the left).

·       In the text, after Figure 17, define equation 6 and then recall it.

·       Standardize the format of references according to the "Hydrology" guidelines.

·       Include more details on MODFLOW, MT3DMS, and SEAWAT models and the limitations of those models.

·       Discuss possible management scenarios to mitigate impacts, such as using physical barriers or reducing collections.

·       Consider including a forecast scenario that extends the simulation period beyond 2007, to assess the effects of climate change and population growth.

·       It would be interesting to highlight specific operational recommendations for sustainable water management in the Rharb basin.

Author Response

Response to Reviewer Comments 1. Summary Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files. 3. Point-by-point response to Comments and Suggestions for Authors Comments 1: Variables must be in italics, check the entire manuscript! Response 1: We completely agree with you, so we have corrected the error along the text. Comments 2: The reviewer recommends expanding the background by comparing hydrogeological models developed in similar contexts of other semi-arid basins and adding references to recent studies (in the last 5-10 years in hydrogeology and water management journals). Response 2: We have added recent bibliographical references. Comments 3: Figure 1 – Improve the legend in Figure 1 (a), including all references to the different colors. Response 3: Comments 4: Response 4: Comments 5: Unnecessary indentation, after the eq. 2., eq. 3, eq. 4. and eq. 6. Response 5: We have removed a few unnecessary identifiers. Comments 6: In equation 2, what is a2 referred to? Response 6: It is a2 (a: surface area of the cell (L2)). Comments 7: Indicate i,j,k as subscripts. Response 7: we have indicated i,j,k as indices, to correct the equations. Comments 8: In Table 1: change the font of (interval). Time series, with a capital T. Response 8: In Table 1: we have changed the font for (interval). Time series, with a capital T. Comments 9: Figure 8 – indicate units of measurement for time on the x-axis. What is zone 1? Response 9 : it is one of several recharge zones resulting from the steady-state calibration, based on lithology/pedology, and therefore infiltration coefficients. Comments 10: In the text before Table 2, eliminate the dot after Table 2. After Table 2, in the text, eliminate the dots after the numbers e.g. (Fig.9 (a)). Response 10 : We have rectified all the manuscript. Comments 11 : Figure 9. Improving the graph. The reviewer suggests imposing the same scale on the axes to be square and increasing the size of the points on the graph. Response 11 : We have resized the figure. Comments 12 : Figure 13 – Adding units of measurement in the graph. Response 12 : We have indicated the units (g/l). Comments 13 : Figure 14 – Adding the unit of measurement on the x-axis and y-axis. Response 13 : We have indicated unit of measurement on the x-axis (Time/years) and y-axis (Cencentrations/g.l-1). Comments 14 : Figure 15 – Adding the progressive distance on the x-axis. Response 14 : We have added progressive distance on the x-axis by modifying the illustration. Comments 15 : The quality of Figure 16 is not acceptable with this poor quality. Response 15 : We have taken figure 16 for a better pixelization, as it is an image exported from a document of the Sebou Hydraulic Basin Agency. Comments 16 : Make Figures 15 and 17 consistent by making the direction of the diagram uniform (for example, the sea on the left). Response 16 : We have revised Figure 17 to align with the meaning of Figure 15 Comments 17 : In the text, after Figure 17, define equation 6 and then recall it. Response 17 : We have replaced Figure 17 with a new one that better describes the equation. Comments 18 : Standardize the format of references according to the "Hydrology" guidelines. Response 18 : We have revised the bibliography list to make it more coherent with hydrology standards. Comments19 : Include more details on MODFLOW, MT3DMS, and SEAWAT models and the limitations of those models. Response 19 : Comments 20 : Discuss possible management scenarios to mitigate impacts, such as using physical barriers or reducing collections. Response 20 : Comments 21 : Consider including a forecast scenario that extends the simulation period beyond 2007, to assess the effects of climate change and population growth. Response 21 : We couldn't agree with you more, because a model is a tool for predicting the outcome of a phenomenon under study. We therefore plan to update the study once we have the contractual possibility of obtaining new data, and thus update the study, to take into account climate and operating scenarios in order to provide evolution scenarios. (Line 474-480). Comments 22 : It would be interesting to highlight specific operational recommendations for sustainable water management in the Rharb basin. Response 22 : We have proposed several scenarios to reduce the impacts (Line 519-530). 4. Response to Comments on the Quality of English Language Response 1: We have reviewed the entire article for grammatical errors and corrected them.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have incorporated all my comments except the following: I think the manuscript can be published without incorporating comments 6 and 7, but comment 8 according to me is important and may kindly be incorporated. It does not need any data, the authors can suggest some future scenarios and run the model for future predictions. 

Comments 6 : Kindly provide also the results of “Validation of models” in “Results and Discussion” section.

Comments 7 : Kindly add “Sensitivity Analysis of Model Parameters” as heading and discuss the sensitivity of the model predictions for various parameters.

Comments 8 : Kindly add some predictions which might be useful for future water resources management in the study area.

Author Response

- Comments 8 : Kindly add some predictions which might be useful for future water resources management in the study area. - Response 8: Thank you for your suggestion. We have incorporated predictions that might be useful for future water resources management in the study area, which can now be found in the manuscript (lines 481-498). ''5. Forecasts for Future Water Resources Management in the Rharb Basin In order to improve water quality and preserve the environment in the Rharb plain, it is crucial to rationalize and control the use of fertilizers, which are the primary source of pollution of the groundwater. Concurrently, accelerating the implementation of actions outlined in the national wastewater treatment program, particularly the installation of wastewater treatment plants in rural centers, is essential. This would significantly contribute to the management and reduction of pollution. The Rharb plain also continues to play a key role in Moroccan agriculture, with, in 2020, a beetroot area of 17.300 ha, the second largest in the country, and a citrus area of 129.288 ha, also the second largest nationally [25]. It is regarded as the breadbasket of Morocco, with 298.000 ha (representing 73,6 % of the cultivated area of the plain), accounts for a significant share of national cereal production [26]. However, this intensive agricultural activity places considerable pressure on local groundwater. Therefore, it is imperative to mobilize new water resources, particularly by developing new dams capable of reducing withdrawals from groundwater and facilitating the replenishment of aquifers through water releases. This approach is even more necessary given the rising demand for water for agriculture, exacerbated by decreasing rainfall, a phenomenon intensified by climate change.'' Thank you.

Author Response File: Author Response.pdf