Let me point out some remarks concerning the Sisyphe User Manual V6.0 (english version).
1. A number of variables are not defined at the right place in the text (when they appear for the first time, or when they have not been previously defined), for instance: "z1" and "ks" in eq.(2) and in eq. (7e), "a" in eq. (34), "u" (z/h) in the equation above eq. (36) and in the equation below eq. (38), etc. This objection is formal, but not insignificant.
2. The parameter value 8 in the MPP formula is not a universal constant (it stems from the slope of the regression line 0,25, which is subject to calibration), and I am glad that this has been corrected in V6.1, the default value being set to 8.
3. Table 1 with application range of sediment transport formulas. "Yes" for high bed-load flows in case of the Einstein-Brown formula is debatable.
The original Einstein's stochastic concept is based on the discontinous grain movement (succession of periods of jumps - saltations, and periods of rest), which is characteristic for low to moderate, rather than high intensity of sand transport.
3. The "angle of the current to the upslope direction" in eq. (22) is vague.
4. Section 4.4. Perhaps a few words on how is eq. (24) implemented would be useful.
5. Formulas in section 4.5 (Secondary currents) are dimensionally incorrect (fluid density is superfluous). The whole text needs revision, for instance, the sentence "The mass balance in the y-direction gives A ZERO-DEPTH AVERAGED CROSS-SECTIONAL VELOCITY" is misleading (what is probably meant is velocity in y-direction). Also, the last sentence on page 20 ("...motion which is cannot...).
6. The term "sediment diffusivity coefficient" in explanation of eq. (26) on page 23 is in conflict with keywords on page 24 "DISPERSION ALONG THE FLOW" and "DISPERSION ACROSS THE FLOW" (in one case it is diffusion, in the other, dispersion, for the same symbol "epsilon_s").
7. Maybe it is not a good idea to use the symbol "R" for the Rouse number in eqs. (34) and (35), as this symbol has been used previously for the radius in secondary currents.
8. Eq. (39) "if" instead of "si".
These are only a few things I have noticed on the first reading. I am sure there are other remarks to be made. However, it is not my intention to critisize - on the contrary, I fully respect the effort of the author, and my only wish is to contribute to the quality of this important document.
