|The authors have worked extensively on the comments given during the first round of review. While I acknowledge these efforts, I have the following concerns, which are the reasons why I suggest to reject the paper for publication in HESS:|
Response to comments 29: you mention that the hydroclimatological model requires spatially varied parameters, but you only used one set "to verify the model with less calibration effort" in Athabasca. I wonder what the results would be if you calibrated the hydroloclimatological model as it should have been done. Would the results be similar to the North Fork Tolt River?
Response to comments 32: I do not agree with your explanation. You write that "lower water depth...means stream temperature changes quicker". In SWAT, river width can be orders of magnitude off the real value because the simplified GIS algorithm does not account for local stream characteristics. You can easily check this by overlaying your stream network on Satellite Images. In most cases this is not a significant problem (though it can be for routing and transmission losses). But in your case, if your width is overestimated by a factor of let's say 5, your depth would be underestimated by a similar value. Keeping in mind that you are proposing a new method of stream temperature calculations in SWAT, I think you should know
(a) if your river width is somewhere near reality and if not, correct it in the .rte (which is not complicated: you can cluster your subbasins according to river order and get representative widths for each order and change the .rte accordingly) and
(b) how sensitivity water depth is in your equation
Response to Comment 38: Sorry, your answer and p.9 l.16-19 is still confusing for me. "blue dots are the observed period daily average (not continuous) ... measured periodically (monthly or weekly)" So how long is an "observed period daily average" continuously measured? I don't think someone is waiting at each gauge for 24hours and takes a sample every hour, but I suspect what you got is 'only' an instantaneous observation at the particular time of the day when the observation took place at max once a month, or? In that case, I think your explanation is misleading. Please rewrite so that the reader knows the true quality of your data. Considering this, I do not agree with your abstract p.1 l.21-22: What you used is not "high frequency observed stream temperature data"
p.14 l.24 - p.15 l.9: Your model performs worse in the second catchment. This raises the question "Why is this the case"? You don't discuss possible reasons anywhere.
And equally important: why did you choose this particular catchment out of the seven other catchments? Do you expect your model to perform better in the other catchments?
Besides that, in the abstract and conclusion you only mention the RE and hide the NSE, but in the Athabasca where the NSE is higher, you mention the NSE. I think this is not good practice.
p.17 Figure 6: It looks like the original SWAT is exactly below the newly developed model, right? Is this a labelling error? Considering that you built the model on top of the Hydroclimatological model (which is significantly different from the two), this is very confusing. Based on this result, I do not understand your interpretation on p.18, l.8-9 "the equilibrium temp provides a potential tool for more-accurate water quality concentration simulation" Based on these results, I think it is impossible to know which model version is "more-accurate".
Also, the selection of lines and markers in unfortunate. I suggest to remove the markers and use different thicknesses for the two lines that closely ovelap.
p.8 l.8: The the
p.8 l.10: drainage area of 105 km²
Response to Comment 40: In the "...version4.pdf" I received, I couldn't find the information.