The Simulation of Sediment Transport and the Determination of the Total Volume of Alluvium Using MIKE 21 Software—Case Study: The Șolea Stream (Vâlsan Basin), Romania
, Daniela Sârbu 3, Maria Chevereșan 4 and Laura Comănescu 1
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsStudy Summary
This study uses the MIKE 21 hydrodynamic and morphodynamic model to estimate sediment transport and alluvium volume for the Șolea Stream (Vâlsan Basin) in Romania. Model calibration was performed using hydrological data and morphological measurements, followed by simulation of sediment transport under different flow conditions. At the end of the study, the total alluvium volume transported under specific flood conditions was calculated, and recommendations for flood management and sediment control in the region were presented.
Method and Study Area Evaluation
The MIKE21 software is a widely used method in hydrological and morphodynamic studies for a long time. It is being applied only for the first time in the study area. What makes this study unique is the application of a known method to a new region. It offers a regional contribution but adds limited methodological innovation to the literature.
Evaluation of Results
Determining sediment transport for the application area provides important insights into basin management and the operation and construction of water structures.
Modeling two-dimensional flow and sediment transport with MIKE21 makes the results more valuable.
Evaluations and Criticisms
1. Lack of methodological innovation: The MIKE 21 software is quite common in the literature, thus limiting scientific contribution.
2. Data reliability: The long-term reliability of the hydrological and sediment data used and their reliability are not clearly discussed.
3. Lack of validation: The model results were not validated more extensively with measured data. This reduces the reliability of the model.
4. The study focused on only a single stream section, thus limiting generalizability.
5. Weak discussion of results: Comparison of the findings with similar studies in the literature is limited.
6. Language and visual quality: While the English language is generally understandable, the flow is weak in some sentences, and the resolution of the figures is low.
7. The results section is not directly linked to the results, but rather limited to presenting the model outputs.
8. No uncertainty analysis was conducted. The assessment of the sensitivity of model parameters and input data is insufficient.
9. The conclusion is not sufficiently strong. The significance of the findings in engineering and scientific contexts should be discussed in more detail.
General Assessment
The study offers a useful application at the regional scale but does not offer any significant methodological innovation. The use of MIKE 21 software is standard; the article's contribution is primarily at the regional level. Although it contributes limited methodological innovation to the literature, it is valuable from a local perspective as it is the first application for the Șolea Stream.
Major Revision:
1. The data and validation process should be detailed,
2. Literature comparisons should be expanded,
3. The resolution and language flow of the figures should be improved,
4. The results should be discussed more comprehensively,
5. An uncertainty and sensitivity analysis should be added.
Referee Suggestion Decision: Major Revision
Author Response
Evaluations and Criticisms
Lack of methodological innovation: The MIKE 21 software is quite common in the literature, thus limiting scientific contribution.
Indeed, the Mike 21 software is quite often found in specialised literature, but compared to its usage level for large watersheds, this software is not very frequently used. Specifically, we, the authors, considered that the Mike 21 software makes scientific contributions to the analysis of small watersheds, where torrential flow is quite high compared to the low river discharges within them. The scientific contribution considered very important is represented by its level of use for small areas compared to large river basins where researchers' attention is much more applied.
Data reliability: The long-term reliability of the hydrological and sediment data used and their reliability are not clearly discussed.
As we mentioned in the article, a special hydrological study was commissioned from National Institute of Hydrology and Water Management at a cost to obtain the necessary parameters specific to the study area presented in the article and the stream under investigation for the mathematical modelling. These parameters could not be found in other scientific papers or at National Administration “Romanian Waters”, because this stream is not cadastered, and studies in the area have not been conducted at this detailed level. Historically, between 1970 and 2015, there were torrential floods with significant consequences for financial losses to the environment and for land and infrastructure that were severely affected by these floods. We, the authors, believe that the data used in the mathematical simulation for a multi-year flow can represent predictability in terms of awareness of much more harmful effects compared to flows with probabilities of 1% or 5%, and the proposed land improvement works should cover the triggering of other negative effects on the environment and human life.
Lack of validation: The model results were not validated more extensively with measured data. This reduces the reliability of the model.
The study focused on only a single stream section, thus limiting generalizability.
Following the research in the area of ​​small hydrographic basins from the Valsan hydrographic basin component, the Solea stream has the most landslides produced triggered by floods compared to the other small hydrographic basins. In this sense, we chose the section of this stream due to the presence of steep slopes, torrentiality and the effects produced by floods. We considered that this section of this stream is the most representative of all the others at regional, zonal level and can be applied to the other sections in the area even with smaller ameliorative measures due to much lower flows.
Weak discussion of results: Comparison of the findings with similar studies in the literature is limited.
As we have previously stated, we have no way to compare with other similar results precisely because such sediment transport simulations have not been carried out with the Mike 21 software. Moreover, even at a national level, such a scientific approach has not been carried out and that is why we consider it to be among the first research of this type in Romania.
Language and visual quality: While the English language is generally understandable, the flow is weak in some sentences, and the resolution of the figures is low.
The results section is not directly linked to the results, but rather limited to presenting the model outputs.
We can consider that the result of the mathematical simulation regarding the amount of sediment resulting from the use of the multiannual flow is representative for knowing what sediment input a stream of the Solea level can have, and for a future analysis, we can estimate the amount of sediment that can be discharged into the Valsan River, the main river into which the other streams of the Valsan hydrographic basin flow. We consider that the result provided by the MIKE 21 model is representative for the total assessment of the amount of sediment that could be discharged by all the other streams if they are not equipped with upstream sediment retention works (as is happening today when land reclamation works are no longer functional).
No uncertainty analysis was conducted. The assessment of the sensitivity of model parameters and input data is insufficient.
Considering the complexity of the Mike 21 model regarding the multitude of parameters introduced necessary for the mathematical simulation, we have highlighted the main parameters necessary for running the program (hydrological, geotechnical) in tables 1,2,3 and figures 6,7. The multitude of data introduced according to the Mike 21 user guide is much greater, we are not able to detail through attached figures, all of these parameters that are sometimes automatically provided by the software or that can be chosen from the software background depending on the specific areas. I did not introduce all these details because I did not want to upload the article and not fit into the editing requirements. The study is part of the doctoral thesis that I am about to finalize, this article that I propose to you for approval being a mandatory measure in order to accept the presentation of the doctoral thesis according to the legislative requirements in Romania. I can assure you that the details of the requirements regarding the parameters used, the description of the study area will be presented in much more detail in the doctoral thesis, but together with the authors who are also teachers, I considered that this information is sufficient for the presentation of the article.
- The conclusion is not sufficiently strong. The significance of the findings in engineering and scientific contexts should be discussed in more detail.
In addition to the conclusions highlighted in the article, we add the importance of identifying erosion and sediment deposition areas for the most accurate picture possible of the set of erosion processes on the river bed (as highlighted in figure no. 5).
These identifications are very important to know as precisely as possible where the hydrotechnical works necessary to retain sediments can be located as well as the correct arrangement of the river route
General Assessment
The study offers a useful application at the regional scale but does not offer any significant methodological innovation. The use of MIKE 21 software is standard; the article's contribution is primarily at the regional level. Although it contributes limited methodological innovation to the literature, it is valuable from a local perspective as it is the first application for the Șolea Stream.
Major Revision:
1. The data and validation process should be detailed,
2. Literature comparisons should be expanded,
3. The resolution and language flow of the figures should be improved,
4. The results should be discussed more comprehensively,
5. An uncertainty and sensitivity analysis should be added.
Referee Suggestion Decision: Major Revision
Comments and Suggestions for Authors
This study presents the results of applying the MIKE 21 model to a stretch of the Șolea stream (Vâlsan Basin), Romania, to determine sediment transport and identify areas of erosion and deposition. The Authors also propose methodologies to prevent riverbed degradation. This part of the study is too general.The proposed interventions should be localized within the study area.
Introduction: I suggest the Authors move the aim of the paper (lines 37-41) to the end of the paragraph. Authors should explicitly explain the effectiveness of applying MIKE 21 in the cases indicated at lines 42-48.
We modified in the text.
Material and Methods: It is not possible that there are two paragraphs in the paper with the same name and the same number (2 Material and Methods). Authors should eliminate figures 5, 6, 7 because their contents are described in the text. The paragraph is also too long, the description of the model is too detailed.
Done and renumbering figures in the thext.
Results and Discussions: The part of the text where the Authors propose intervention strategies should become a separate paragraph from the Results and Discussions paragraph. Authors should match proposed interventions to specific areas of the watercourse being studied.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThis study presents the results of applying the MIKE 21 model to a stretch of the Șolea stream (Vâlsan Basin), Romania, to determine sediment transport and identify areas of erosion and deposition. The Authors also propose methodologies to prevent riverbed degradation. This part of the study is too general.The proposed interventions should be localized within the study area.
Introduction: I suggest the Authors move the aim of the paper (lines 37-41) to the end of the paragraph. Authors should explicitly explain the effectiveness of applying MIKE 21 in the cases indicated at lines 42-48.
Material and Methods: It is not possible that there are two paragraphs in the paper with the same name and the same number (2 Material and Methods). Authors should eliminate figures 5, 6, 7 because their contents are described in the text. The paragraph is also too long, the description of the model is too detailed.
Results and Discussions: The part of the text where the Authors propose intervention strategies should become a separate paragraph from the Results and Discussions paragraph. Authors should match proposed interventions to specific areas of the watercourse being studied.
Author Response
Comments and Suggestions for Authors
This study presents the results of applying the MIKE 21 model to a stretch of the Șolea stream (Vâlsan Basin), Romania, to determine sediment transport and identify areas of erosion and deposition. The Authors also propose methodologies to prevent riverbed degradation. This part of the study is too general.The proposed interventions should be localized within the study area.
Introduction: I suggest the Authors move the aim of the paper (lines 37-41) to the end of the paragraph. Authors should explicitly explain the effectiveness of applying MIKE 21 in the cases indicated at lines 42-48.
We modified in the text.
Material and Methods: It is not possible that there are two paragraphs in the paper with the same name and the same number (2 Material and Methods). Authors should eliminate figures 5, 6, 7 because their contents are described in the text. The paragraph is also too long, the description of the model is too detailed.
Done and renumbering figures in the thext.
Results and Discussions: The part of the text where the Authors propose intervention strategies should become a separate paragraph from the Results and Discussions paragraph. Authors should match proposed interventions to specific areas of the watercourse being studied.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsMy previous evaluations were taken into consideration by the authors and necessary explanations and adjustments were made.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe Authors have effectively responded to the reviewer's comments and revised the paper. Therefore, the paper can be accepted for publication.
