A Three-Parameter Hydrological Model for Monthly Runoff Simulation—A Case Study of Upper Hanjiang River Basin

Round 1

Reviewer 1 Report

Recommendations to authors

- Line 2: The title “A three-parameter monthly model based on the proportionality hypothesis and its application in Upper Hanjiang River Basin” seems to be somehow incomplete; please replace the “monthly model” by “monthly hydrological model”. I am not sure if the expression “based on the proportionality hypothesis” adds critical information to the title or raises questions. My suggestion for the title would be: “A three-parameter hydrological monthly model to simulate and forecast the monthly runoff in a river basin - A case study from Upper Hanjiang River Basin”.

- The abstract must be re-written to improve English used. Please re-consider the whole text.

- Line 14: replace (donated as the TMPH) by just (TMPH)

- Line 15: since only two are the “major modules are involved in the TMPH” and you mention these two modules, it is not correct to use “i.e”, and you must remove it.

- Line 22: replace (donated as the UHRB) by just (UHRB)

- Line 24: "the TMPH model performs well and better than the widely used two-parameter monthly 24 water balance (TWBM) model". Please provide a quantitative (maybe Nash-Sutcliffe Efficiency (NSE) values, and Kling-Gupta Efficiency (KGE) values) and not qualitative assessment of the performance of the proposed model.

- Line 27: Keywords should not be included in the title (there is no meaning since all searches are usually performed using the topic as field tag that includes both title and keywords). Therefore “Upper Hanjiang River Basin” must be removed, and the rest of the keywords should be refined or replaced.

- Line 288: The graphs are fine (Fig. 4 & 5), but the interpretation must be improved to support the effectiveness of the proposed model over the model with the two parameters. I would suggest that you should comment on the outliers (points away from the y=x line). It seems that the new model performs better at higher runoff values (>5000 m3/s), while at lower values the performance of the two models is almost the same. This becomes more apparent in Fig. 6, where the peaks for maximum monthly runoff for both TMPH and observed runoff are very close to each other, while TMBM peak leads to an overestimation. 

- Line 311: Please consider adding a limitation section to the discussion to describe potential issues regarding the data required for the 3-paramters used in the proposed model.

- Line 326: “The proposed TMPH model have significant better performance than the TWBM 326 model, with the value of NSE increasing from 0.72 to 0.79”. The question is simple: a difference of 0.07 can be considered as “significant better performance”? I think the word “significant” must be removed. Also, you must mention that even if the new model achieves a better performance, it is still a simulation model with estimated accuracy.

- Line 322-329: I think that you should stress not (only) on the better performance of the proposed model regarding NSE, KGE values but on the fact that it provides better results in the case of higher runoff values.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

This manuscript presented a three-parameter monthly model based on the proportionality hypothesis and applied to this model to Upper Hanjiang River Basin. In general, this manuscript is accessible to readers but it requires to supplement more works. The results of this manuscript is too simple. To verify the performance of a newly developed model, only one case study is not persuasive. I strongly suggest that the proposed model needs to be applied to the basins with different climatic conditions and catchment areas. And it also needs to be compared with more monthly water balance models, such as the well-known “abcd” model.

1)      The proposed model appears to ignore the process of ground water and might fail capture the runoff in dry seasons.

2)      Please give the specific units of the variables and parameters in the model.

3)      The authors employed two efficiencies to evaluate the performance of the model, but just used Nash-Sutcliffe Efficiency as the objective function for calibrating model parameters. Maybe Kling-Gupta Efficiency is more comprehensive than NSE in evaluating the model.

4)      Figure 2: The hydrological stations presented in this figure should be meteorological stations.

5)      The conclusion of the manuscript may be valid only for the Upper Hanjiang River.

6)      It is better to supplement more deep investigation for the proposed model, such as the applicability or sensitivity of the model. The content of the manuscript is too thin.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Recommendations to authors

-          Line 12, 32, 225, 229, 311: Please avoid the use of the statistical word “significance”. Therefore, instead of “significant tools”, you can use “useful tools” (line 12) and “significant role” can be replaced by “important role” (line 225).

-          Line 106: All equations must be mentioned in the text. Therefore, please add “Eq.1”. It should be like this “as follows (Eq. 1):”

-          Line 112: Add “Eq. 2” after “as follows:”

-          Line 128: Add “Eq. 3” after “water balance equation:”

-          Line 138: Add “Eq. 4” in the text.

-          Line 147: Add “Eq. 5” after “we obtain:”

-          Line 162: Add “Eq. 6” after “as follows:”

-          Line 170: Add “Eq. 7” after “calculated by:”

-          Line 171: Add “Eq. 8” after “as follows:”

-          Line 172: Add “Eq. 9” after “we have:”

-          Line 174: Add “Eq. 10” after “as follows:”

-          Line 175: Add “Eq. 11” after “given as:”

-          Line 183: Add “model” before “parameters”.

-          Line 200: Add “Eq. 12” in the text.

-          Line 211: Add “Eq. 13” in the text.

-          Line 129: Please remove the frame from Figure 1.

-          Line 232: The caption of Figure 2 can be improved. Instead of “The sketch map of the UHRB”, you can consider using “The region of Upper Hanjiang River Basin (UHRB) in South China”.

Reviewer 2 Report

In general, the authours have made modifications to the manuscript or given proper explanations. It can be accepted in the current form.

Author Response

Thank you for your comments