Review of a Semi-Empirical Modelling Approach for Cohesive Sediment Transport in River Systems

Round 1

Reviewer 1 Report

Review of a semi-empirical modelling approach for cohesive 2 sediment transport in river systems

 

General

The article describes  an interesting work on modelling approach  to  simulate the main processes  in cohesive sediment  transport.  The characteristics of   a  semi-empirical model for  cohesive sediment developed by the Author  together with  the model parameters  which need be experimentally determined in order to achieve reliable predictions  are presented  and discussed.  The work is detailed and well-referenced.

I only have minor comments  before I can finally recommend the article for publication.

 

Minor comments

 

• The numerous  pages are difficult to follow in places.   I think that quite a few areas could be shortened, for instance some of  the model description and formulas,  figures 1 and 4.    

 

• Some additional remark is  reported in the attached pdf file (yellow notes)

 

 

 

 

Comments for author File: Comments.pdf

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 2 Report

This is a nice review of the RIVFLOC model, the lab procedures used to determine model parameters, and a comparison of these model parameters for sediment properties from multiple river systems.  

The data presented in table 2 are also presented as figures.  Some of these figures could be combined. Others could be simplified— use bar graphs, not 2-d bar graphs.

figures 15-17 can be combined into one figure, with a,b,c panels. The shear stress values can be put in the figures and/or the figure captions.

Fig 18 is messy, the observed data should be in symbols that are not connected by lines.  The calculated trends should then be a black dashed line for each experimental run, and explained in the figure caption.

fig. 19-21 can be one figure with 3 panels, the time could be included in each panel and/or the figure caption.  


The 3 parameter diagrams could also be combined into one figure.  These diagrams should not be 2-d.  I assume that there is     Analytical error in these measurements.  What is this error and did it vary among the measurements?  Can this error be put on the diagrams?

Were all measurements made using natural River water?  How did the temperature of the water and bacterial growth vary among the experiments?  Some of these issues were discussed in the papers reviewed here.

The discussion is not really a discussion, it’s an assessment that the model predicts almost no fine sediment deposition, but there is significant fine sediment in the bed, suggesting that entrapment might be an important mechanism.  New data is then presented, so this should be a section of the results.

I would like to see a discussion section that points out some of the systematic variations among the sites and explores what might lead to these.  This includes:  

a)  the high cohesion value for the Taw River, which is similar to the average values in other parameters,

b)  the varying maximum  fall velocity and associated floc size among rivers.  What is different in the rivers that have lower maximum fall velocities?  Why does the ELL River have larger floc sizes and fall velocities compared to the other non tar sand rivers?

I would also like to see some discussion of sources of error and difficulties in making measurements on natural material.  
Also, how do the results of this model and associated parameters compare with other models?

There are minor typos in the text and references.

 

 

 

Author Response

Please see the attachment

Author Response File: Author Response.docx