Comparing SWMM and HEC-RAS Hydrological Modeling Performance in Semi-Urbanized Watershed
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsComparing SWMM and HEC-RAS Hydrological Modeling Performance in a Semi-Urbanized Watershed The presented study comparatively analyzes the hydrological modeling performances of SWMM (Storm Water Management Model) and HEC-RAS (Hydrologic Engineering Center – River Analysis System) models in the semi-urban Moore’s Mill Creek (MMC) watershed in Alabama. Different modeling parameters (groundwater, surface storage, flow length, sub-basin detail, etc.) were tested and the accuracies of the models were compared with the observational flow depth and velocity data. In general, the SWMM model produced more realistic flow regimes, especially when the groundwater component was included. HEC-RAS simulated the surface flow well, but underestimated the late flow amounts due to the lack of groundwater interaction. The surface storage and flow length adjustments showed limited but significant effects on SWMM. Despite the heavy computational load (24–45 h simulation time), the HEC-RAS model produced quite accurate results, especially when the infiltration was open. SWMM models were completed in a shorter time (a few minutes) and provided more efficient solutions.
1-Groundwater was modeled in SWMM but not in HEC-RAS, which limits direct comparison.
2-Groundwater parameters are highly generalized and not supported by field measurements.
3-The lack of channel cross-section geometries and hydraulic structures has limited calibration, especially for HEC-RAS.
4-Some of the images are low resolution, and detailed data visualization is lacking.
5-Descriptive statistical information for the parameters should be added.
6-Graphs (e.g. Figures 1, 2) are functional but low resolution. Clearer, high color contrast images are recommended.
7-Hydrograph comparisons (Figures 3–14) show model behavior well, but descriptive notes and axis labels should be clearer.
8-Detailed visuals such as 3D surface analyses or model flow isohypses are missing.
9-The narrowness of the graphs (low width) limits the evaluation of the results.
10- Even if a groundwater simulation similar to HEC-RAS models is not integrated, its limitations should be discussed more clearly.
11-All hydrographs and visuals should be improved in terms of resolution, labels, and color usage.
12-Sensitivity analyses, variance and uncertainty analyses should be added for the accuracy of the model.
13-The deficiencies in field data and the calibration reliability of the model should be presented more transparently.
Author Response
Thank you for your comments and suggestions, which helped to improve the manuscript's clarity and contributions. Please refer to the attached file.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe article compares SWMM and HEC-RAS hydrological modelling performance in semi-urbanized watershed on the case study of Moore's Mill Creek (MMC) in Lee County, Alabama.
The introduction with the overview of literature and previous research is done thoroughly, and some conclusion that are drawn in the article based on the carried research on the case study on MMC confirm them, but in the discussion, it is needed to address and connect more with what is analysed in the Introduction and in the overview references.
The article has a section entitled Discussion and final remarks, but and additional section (Conclusion) with the emphasis on main conclusions from the research is still needed.
All acronyms have to be explained when first time mentioned in the paper (HEC-HMS in line 63, PCSWMM in line 177, SRTC in line 255 … etc.)
Figure 1 could be mentioned already earlier in the text (in line 140). The explanation in the text is not clear from the Figure, cities of Auburn and Opelika should be presented in the Figure, and the delineation of different land use for Opelika sub-watershed should be present too, and also the location of the Orr Estates Lake (mentioned in line 165) and locations of AV sensors (line 167). Yellow dots present in the figure should be explained also in the legend (location of monitoring stations).
In Figure 2., 2 small figures of the sub-watershed should be enlarged.
Table 3, lacks of measure units.
When explaining conclusions or input data from previous research and references it is useful to add more data about that research not just to cite the reference (maybe the location or other specific data about the case study or carried research that could be relevant for that conclusion)(as example [17] line 79, or [18], [21], [22] …).
Line 303, it would be useful to write that some data are from USGS Stream Stats (not just writing „… from [39]“).
Figures 3, 5, 6, 8, 9, 10, 11, 12, 13 and 14 are too small, and it is difficult to follow the description of results.
All results are presented for Capps Way and Hamilton bridge locations, except in Figure 5 where only for Hamilton bridge are available. Why?
Although many calculations with different scenarios have been done by authors and valuable conclusions drawn from this research the article still needs some improvement.
Author Response
Thank you for your comments and suggestions, which helped to improve the manuscript's clarity and contributions. Please refer to the attached file.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsAll of my suggestions and evaluations have been answered by the authors with the necessary corrections.
Author Response
The authors would like to thank the reviewer once more for his/her suggestions for the manuscript. We believe it is now improved.
Reviewer 2 Report
Comments and Suggestions for AuthorsAll comments and suggestions given in the 1st review have been addressed by authors, and the article has been improved.
The only comment that was misunderstood was (in author’s reply it is Comment no 7) where it was suggested to "add more data about the research not just to cite the reference".
It was not necessary and expected to write the number of Figure or Table from the cited article. On the contrary this confuses the reader with Figures and Tables from this submutted article so it would be better to delete these recently added numbers of Figures and Tables.
The comment was more in the direction to add more information on: where is the location of the case study that is analysed in the cited article (if applicable), or to mention some other specific information that could be relevant for your research (e.g. for [19] add “.. data from previous study in Wilmington, North Carolina“, for [23] „Yesil (Ishim) River in Kazakhstan“, for [25] „the Karasnagala watershed …. in the Western province of Sri Lanka…“.
Author Response
Response to reviewer 2:
All comments and suggestions given in the 1st review have been addressed by the authors, and the article has been improved.
- Thanks for further clarifying your comment/suggestion. As is explained below, with these changes implemented in the present version, we hope that we have addressed the final comment from the reviewer
The only comment that was misunderstood was (in author’s reply it is Comment no 7) where it was suggested to "add more data about the research not just to cite the reference".
It was unnecessary to write the number of the Figure or Table from the cited article. On the contrary, this confuses the reader with Figures and Tables from this submitted article, so it would be better to delete the recently added Figures and Tables.
- Based on this, the references to figures and tables from other studies have been removed to avoid confusion, as per the reviewer's comment.
The comment was more in the direction to add more information on: where is the location of the case study that is analysed in the cited article (if applicable), or to mention some other specific information that could be relevant for your research (e.g. for [19] add “.. data from previous study in Wilmington, North Carolina“, for [23] „Yesil (Ishim) River in Kazakhstan“, for [25] „the Karasnagala watershed …. in the Western province of Sri Lanka…“.
- As suggested, relevant information about previous studies has been added in paragraphs 6 – 8 of the Introduction (lines 77-130). An explicit reference was added in line 155 to clarify that [35] was conducted in the same watershed as the current study.
