A Comprehensive Approach to Develop a Hydrological Model for the Simulation of All the Important Hydrological Components: The Case of the Three-River Headwater Region, China

Round 1

Reviewer 1 Report

This work regarding the parameterisation of the Hec HMS model has been very well conceptualized and presented. 

Here are my comments:

1. Add a section on the limitations of the study and the future scope

2. Add a section of policy relevance of this study.

Author Response

We are grateful for reviewer to review the article and his comments to improve the quality of the article. The comments have been incorporated and highlighted with green color in the text.

Comment 1: Add a section on the limitations of the study and the future scope

Response 1: The comment is accepted and incorporated in the article. Limitations and scope of the study has been described in section 3.3

Comment 2: Add a section of policy relevance of this study.

Response 2: This study is not much helpful for the policy makers. This is related to modeler, hydrologist and researcher. However, in the future, when we will extend this study and simulate hydrological components under IPCC scenarios and would provide hydrological analysis for the region, then we will be able to write about policy relevance section in the study. If I could not understand what you want, please explain your comment, we can add in next revision.

Reviewer 2 Report

The aim of the study to configure the Hydrological Modeling System (HEC12 HMS) in such a way that it could simulate all-important hydrological components (e.g., streamflow, soil moisture, snowmelt water, terrestrial water storage, baseflow, surface flow, and evapotranspiration) is rather interest and useful for the user of the HEC hydrological model and generally for developers of hydrological models. I consider the topic as scientific and with a high benefit for hydrological modelers.

General comments and suggestions to improve the qualitative level of the paper:

Title: I suggest to change “development of the model”. The paper focuses on a comprehensive approach to estimate initial parameters and to calibrate the model, not on the model development.

Introduction:

You mentioned, in Line 57: “the optimization methods used in HEC-HMS are either inefficient or do not work rationally…) or in Line 73: “The focus of the approach was to provide a way to estimate some logical initial values for the process parameters…”. 

Please explain better what is the problem in automatic calibration methods of HEC-HMS model? Can't be set "logical initial parameters"? Perhaps this is not a problem with the manual or automatic calibration techniques, but only a problem with the optimization techniques built into the HEC model. Why didn't you use for a better simulation of other characteristics of the water balance some multipurpose calibration methods?

Data description (Line 102, Table 1):

It is not clear how data with a different temporal and spatial resolution and a different available period were synchronized - or was it not necessary? Please explain better how the input climate data were used - as sub-basin averages or in gridded form? For the effectiveness of the model for simulating runoff and other characteristics of the water balance, especially data on precipitation and, in a complex terrain, air temperature are crucial. Perhaps a poor spatial representation of the rainfall data could be a problem in modelling?

Calibration and validation (Line 130, Fig.2, Line 140):

The HEC-HMS development procedure in Fig. 2 was developed as a part of the study? What is new compared to the original HEC-HMS model?

Estimation of process parameters (Line 159):

The physical parameters were obtained by the watershed delineation and the TRHR was divided into 82 sub-basins. The physical parameter were estimated for each sub-basin. Explain, please, how process parameters were prepared – as averages for the sub-basins or in a gridded form?  

Storage coefficients and storage depths (line 199):

Please, explain better, how the recession analysis was provided? Each individual flood was graphically separated? How were the single storm events isolated? How were the storage parameters integrated for the sub-basins?

Sensitivity analysis (Line 269):

Please, explain better how the sensitivity analysis helped in the model calibration? Which selected parameters were calibrated? Please, improve the quality of Fig. 5. Volume (the axis Y) cannot be in mm. 

Please, improve the quality of Fig.  6. Add in axis x is months.

Baseflow separation (Line 214)

The base flow separation was described in Chapter “ Estimation of process parameters” by a graphical methods. Is this separation different?

Results (Line 634)

How did the results confirm the improvement of the simulated flow and other characteristics compared to the automatic calibration of the HEC model?

Author Response

We are grateful for reviewing this article and his valuable comments to improve the quality of the article. The comments has been incorporated accordingly. The responses to the comments of reviewer has been attached herewith. If any other thing is required to improve, we can do it in the next version.

Thanks and regards

Author Response File: Author Response.pdf