SewerSedFoam: A Model for Free Surface Flow, Sediment Transport, and Deposited Bed Morphology in Sewers

Round 1

Reviewer 1 Report

I have read this paper with great interest, and find the use of CFD in OPENFoam quite novel and interesting. The paper builds and refers to the traditional deterministic modelling of sediments in sewers, and brings the science here one step forward. 

In a few places in the paper references are not linked correctly:

Error! Reference source not found

Author Response

Thank you for your review and comments!

The faulty figure references mentioned in the review have been corrected in the updated draft.

Reviewer 2 Report

The authors developed a sewer sediment model called “SewerSedFoam”, by linking suspended sediment transport, bedload transport, and deposited bed morphology in sewers. I think the topic is interesting and most part of this work was well written (except for lines 29~30, 54, 95~101, 141, 486, and 496, which need to be deleted or corrected; Table 2 was missing; double Fig. 1&2), so I recommend acceptance upon minor revision.

1) Please explain explicitly how you coupled suspended sediment, bedload, and deposited bed. The paper mentioned an interactive model for sediments and used Fig. 2 to show that SS (suspended) and BL (bedload) go to Bed Morphology first in each time step, and then move to the next time step by re-calculating flow velocity and then re-running sediment dynamics. Please clarify this in the main text.

2) Please discuss briefly in one or two sentences (such as your future work?) about the new models for sediment transport by citing for example the following references which showed clearly that the classical model, such as the Advection-Diffusion equation (1) or (2), does not work for sediment transport at the local scale:

- For modeling suspended sediment transport at the local scale: Chen et al., Fractional dispersion equation for sediment suspension, Journal of Hydrology, 491, 13-22, 2013.

- For modeling bedload transport at all scales: Zhang et al., Linking fluvial bed sediment transport across scales, Geophysical Research Letters, 39, L20404, 2012.

3) Please discuss briefly how users can apply your model. For example, you validated “SewerSedFoam” using two cases. Case 1 had only observed bed information, and Case 2 had no observed data. Considering the various unknown parameters and multiple steps in the model systems, what we need to observe in the field and what are the main parameters that we should pay attention to, in order to use your model?

Author Response

Thank you for your review and constructive feedback.

I have corrected the incorrect figure and table references in lines 54, 141, 486, and 496. I have also deleted lines 29-30 and 95-101.

Please find my corrections in response to your other comments detailed below:

1) I haved moved the last paragraph of the 'Bed Morphology' section to the 'Model Implementation' section. This paragraph details the interpolation that occurs in the mesh once the change in bed heights are calculated. I have added additional detail to this paragraph on the coupling between flow, sediment transport, and bed morphology. The new paragraph is in lines 281-290 of the updated manuscript.  

2) I have added some sentences on improving suspended sediment and bedload modelling as a part of future work on the model and referenced the recommended papers. These changes are in lines 560-564 in the Conclusion.

3) I have added some detail on the data requirements of using SewerSedFoam in the Conclusion between lines 568-577.

Reviewer 3 Report

General comment:

The present paper constitutes a very detailed, spatially and temporally, study of sediment transport in sewers. All the significant physical processes, that take place during sediment transport in sewers, are taken into account:

inflow of bed and suspended loads, bed deposition, bed erosion, morphological bed variations, bed stabilization, concept of critical shear stress and interaction of the above physical processes.

The written presentation of the paper should be improved from the typical point of view, according to the annotated manuscript.

Specific comments:

The numbering of figures and tables should be corrected, according to the annotated manuscript. Figure 9: The term "bed consolidation multiplier" should be explained in more detail. The following reference could be added in the "Introduction": Hrissanthou V. and Hartmann S., 1998: "Measurements of critical shear stress in sewers", Water Research, Vol. 32, No. 7, pp. 2035-2040. See annotated manuscript!  

Comments for author File: Comments.pdf

Author Response

Thank you for your comments and constructive feedback, particularly your detailed pdf annotations! The manuscript has been corrected according to your annotated pdf. My changes based on your other comments are below:

I have fixed the figure and table numbers and the references to them I have added some detail to clarify the 'Bed Consolidation Multiplier' term in Figure 9, these changes are in lines 540-541. I have included the recommended reference in the Introduction in line 84.