Flood Risk Management with Transboundary Conflict and Cooperation Dynamics in the Kabul River Basin

Round 1

Reviewer 1 Report

Solving flood risk management with Transboundary conflict is very emerging issue. After reading the article, I realized authors put in lots of hard work but didn’t articulate in writing and presenting. The following points could improve the manuscript.  

1. Climate change impact assessment using SWAT and HEC-RAS not a novel study idea, however using the result and solving Transboundary conflict makes this study interesting. But not enough discussion here. My earnest request please read some climate change policy papers before another revision. There are hundreds of them published each year.
2. I am not sure it’s a policy paper or a technical paper. Since it submitted in the Water Resources Management, Policy and Governance section I will consider it as policy one. So I will see more discussion on policy in the main page than technical discussion.

P.S.: I didn’t have the appendix/supplementary material on May 8, 2021, 7:48 PM. I didn’t find one.

3. There are no LULC maps. No climate station locations, no GCMs info. Please revised. Read any typical climate change impact assessment paper, you will know what I am referring to here.
4. Very difficult to compare Figure 2 & 4, it’s rotated or cropped. Please present it properly. Also Fig 4 subplots no are unusual style, covered the legend (some crossing the image boundary). It showcases of the inattentiveness of the authors.
5. If Table 3 & 4 merger together, it will be better to compare reservoirs impact on flooding.
6. Line: 612- Supplementary Materials: The following are available online at mdpi.com/xxx/s1. Not sure where it’s pointing me.

After carefully reading the article, I will suggest a major revision. The manuscript has the potentiality if properly phrased each technical point.  

Author Response

Reviewer #1 Comments:

Solving flood risk management with Transboundary conflict is very emerging issue. After reading the article, I realized authors put in lots of hard work but didn’t articulate in writing and presenting. The following points could improve the manuscript.  

1. Climate change impact assessment using SWAT and HEC-RAS not a novel study idea, however using the result and solving Transboundary conflict makes this study interesting. But not enough discussion here. My earnest request please read some climate change policy papers before another revision. There are hundreds of them published each year.

[Thank you for your comment; and yes, we agree that using the result and solving Transboundary conflict makes this study interesting. We have reviewed several recent “climate change policy” papers and improved the discussions accordingly – please see lines 193-245; lines 264-268; lines 276-279 in the revised manuscript as well as Appendix B-Supplementary Materials.]

1. I am not sure it’s a policy paper or a technical paper. Since it submitted in the Water Resources Management, Policy and Governance section I will consider it as policy one. So I will see more discussion on policy in the main page than technical discussion.

[Thank you for your comment; and yes, we agree that this is a science-based and science-informed policy and governance paper.]

1. There are no LULC maps. No climate station locations, no GCMs info. Please revised. Read any typical climate change impact assessment paper, you will know what I am referring to here.

[Thank you for your comment; we have cited the LULC map included in the supplementary materials – please see Figure 2 in the revised manuscript.]

1. Very difficult to compare Figure 2 & 4, it’s rotated or cropped. Please present it properly. Also Fig 4 subplots no are unusual style, covered the legend (some crossing the image boundary). It showcases of the inattentiveness of the authors.

[Thank you for your comment; we have revised Figure 2 to clarify the KRB as a whole and the focused Kabul River at Nowshera study area (at the Motorway-1 Bridge outlet) in Figure 4. Please see revised Figure 2.]

1. If Table 3 & 4 merger together, it will be better to compare reservoirs impact on flooding.

[Thank you for your comment; we have merged Tables 3&4, and removed Table 4 and added text to improve the clarity of the discussions of the table – please see lines 330-331 in the revised manuscript.]

1. Line: 612- Supplementary Materials: The following are available online at mdpi.com/xxx/s1. Not sure where it’s pointing me.

[Thank you for your comment; we have made sure that the Supplementary material is properly uploaded along with the revised manuscript.]

After carefully reading the article, I will suggest a major revision. The manuscript has the potentiality if properly phrased each technical point.  

Reviewer 2 Report

While comparing the Figure 1, 2, 3 as below mentioned, the resulted maps (Figure 4) does not match with the study area (Figure 1, 2). The author needs to fix these maps.

Author Response

Reviewer #2 Comments:

While comparing the Figure 1, 2, 3 as below mentioned, the resulted maps (Figure 4) does not match with the study area (Figure 1, 2). The author needs to fix these maps.

[Thank you for your comment; The Study area is the Kabul River Basin in Afghanistan and Pakistan with the outlet located near the Motorway-1 Bridge west of Nowshera city. The flow results under various climate and dam scenarios were used to determine the flood inundation in the city of Nowshera that is located at the downstream of the outlet. We have revised Figure 2 to clarify the KRB as a whole and the focused Kabul River at Nowshera study area in Figure 4. Please see revised Figure 2.]

Reviewer 3 Report

This work examines and discusses flood risk management scenarios in the transboundary Kabul River Basin using SWAT and HEC-RAS models. Even though the scenarios under investigation might be interested in local impact, a quite limited discussion regarding modelling is provided that makes this work a study or technical report rather than a research paper. To my opinion, this work is not suitable for publication in WATER in its current form. Please find below, some specific comments:

• Which River?
• L17-19. Please rewrite this sentence to make clear what each model does.
• Please specify what is KRB.
• L95-96. Are reservoirs considered in the historical flow scenario?
• L179-205. This section should be considerable extended to make clear the applied methodology. Some of the questions (at least) that should be answered in this section are: How well were the models calibrated? Was the SWAT model calibrated? For what time period? What kind of data was under consideration to calibrate the models? What are the specifications of the models (e.g. time step, spatial distribution etc.)? How the two models were coupled to run all these scenarios?
• Are RCPs scenarios or models?
• L194-195. Could you provide a discussion, perhaps supported by maps or figures, for the calibration?

Author Response

Reviewer #3 Comments:

This work examines and discusses flood risk management scenarios in the transboundary Kabul River Basin using SWAT and HEC-RAS models. Even though the scenarios under investigation might be interested in local impact, a quite limited discussion regarding modelling is provided that makes this work a study or technical report rather than a research paper. To my opinion, this work is not suitable for publication in WATER in its current form. Please find below, some specific comments:

• Which River?

[the Kabul River – please see line 13 in the revised manuscript.]

• L17-19. Please rewrite this sentence to make clear what each model does.

[Done – please see lines 18 and 19 in the revised manuscript.]

• Please specify what is KRB.

[Done – please see line 17 in the revised manuscript.]

• L95-96. Are reservoirs considered in the historical flow scenario?

[In the historical flow scenario only four large reservoirs are considered, in future scenarios existing large and proposed reservoirs are considered – please see lines 96 & 97 in the revised manuscript.]

• L179-205. This section should be considerable extended to make clear the applied methodology. Some of the questions (at least) that should be answered in this section are: How well were the models calibrated? Was the SWAT model calibrated? For what time period? What kind of data was under consideration to calibrate the models? What are the specifications of the models (e.g. time step, spatial distribution etc.)? How the two models were coupled to run all these scenarios?

[Please see lines 193 -245 in the revised manuscript]

Lines 193 -245: The study methodology consists of three parts.

1. We used a calibrated watershed-scale hydrologic model SWAT to generate different flood flow scenarios in the KRB in which the Global Weather Data (GWD), including precipitation, temperature, solar radiation, wind speed, and relative air moisture from 1979 to 2014 were obtained from the NCEP CFSR in the SWAT model calibration.  The SWAT Calibration and Uncertainty Procedures (SWAT-CUP) developed by Abbaspour et al. (2004) were applied for parameter sensitivity analysis and model calibration of the KRB SWAT model using the sequential uncertainty fitting (SUFI2) algorithm[22]. With global sensitivity analyses of 100 SWAT-CUP runs considering the Nash-Sutcliffe Efficiency (NSE) (Nash and Sutcliffe, 1970) as the objective function. SWAT-CUP identified 29 sensitive parameters corresponding to the t-test (see Table S1 in the Supplementary Materials). Three criteria, namely model bias, the NSE, and the determination coefficient (R²), were used to evaluate the model performance at flow monitoring stations statistically. The model performance over the 2008-2014 calibration period at the at the Dakah station a model bias of 3.4%, with the NSE of 0.74, and R² of 0.80 (see Figure S1 in the Supplementary Materials).
2. In this study, Hydrologic Engineering Center (HEC) River Analysis System (RAS) was used to develop the flood inundation maps under different historic and future climate scenarios with and without the proposed dams. HEC-RAS was developed by the United States Army Corps of Engineers (Yuan & Qaiser, 2011). The urban area of Nowshera was chosen as case study to determine the flood flow impacts. The HEC-RAS model was calibrated using the 2010 flood event in Nowshera based on the observed water level and satellite-based flood inundation imagery. The main calibration parameters in the HEC-RAS model, include the Manning's Roughness Coefficient and the river channel geometry and slope (obtained from the Digital Elevation Maps). Manning’s Roughness Coefficient values used in this research for different Kabul River zones were 0.04 and 0.15 for the main channel and the flood plains (Khattak, 2016; Saad et al., 2019).
3. The flood flow predictions of various historic and future climate and dam scenarios from the calibrated SWAT model were then used as input data for the HEC-RAS model to simulate the flood inundation areas. The results of the flood inundation modelling were used as technical evidence to address some of the issues related to the policy implications of power dynamics in transboundary water resources management, transboundary impacts on flood mitigation, water and transboundary cooperation uncertainties, KRB transboundary conflict and opportunities, and benefits and risks of proposed series of new large dams in the KRB.

• Are RCPs scenarios or models?

[The RCPs are scenarios – please see lines 179 and 194 in the revised manuscript.]

• L194-195. Could you provide a discussion, perhaps supported by maps or figures, for the calibration?

[Please see lines 264 -268 and lines 276-279  in the revised manuscript and the associated  Supplementary Material].

Round 2

Reviewer 2 Report

Reviewer 3 Report

The revised manuscript has been substantially improved and in my opinion, it may be published in its current form.