Baipenzhu Reservoir Inflow Flood Forecasting Based on a Distributed Hydrological Model

Round 1

Reviewer 1 Report

General Comments:

1. The main objective of the paper is not clear. It does not bring anything new and revolutionary to the field, but rather a well-argumented case study.
2. Methodological approach is rather insufficient. More details should be added. Numerous decisions were not thoroughly argumented in text.
3. Comparison of ASTER and SRTM DEMs, provides reasonably similar results, and does not reveal any groundbreaking flood-related conclusions, at basin level. This is also stated by the authors themselves in the conclusions section: “Among these factors, the results show that there are only slight differences in elevation and slope.” / “From the perspective of the model structure, there is little difference between the two modeled river units and slope units, but the reservoir units are quite different.” / “the DEMs from different data sources have little effect on the simulation accuracy of the Liuxihe model.”
4. Furthermore, because the main objective of this study is not clearly stated, the conclusions are rather general, meaning they only describe results, and do not reveal novelty information.

Specific Comments:

1. English language could be improved. Regular language improvements should be performed. Furthermore, a more appropriate choice of vocabulary is recommended.
2. A map describing the geographical location should be inserted in the Introduction section.
3. L40: “flood control pressure downstream” – what does this mean/imply?
4. L43: “lake-type reservoir” – this is ambiguous
5. L87 – phrase unclear - “the reservoir unit is specially set up”?
6. L117 “ASTER3 is closer to the true value.” – what is it referenced next to?
7. Figure 1 and Table 1: The 2 areas of the basin, vary significantly. There are some areas next to the watershed divide that were included in one case, and not in the other. Why is this? How was the divide extracted? Manually? Automatically?
8. Have the ASTER or SRTM models been filtered/filled prior to the analysis?
9. Figure 1. Maps should be re-generated. They should contain geographical grids, measurements units, a more appropriate color scheme. Furthermore, all figures should add the missing information.
10. L141- they are not “physical properties”. They are rather classes of a given layer/parameter. Properties could refer to temperature, soil particle size etc. Also, Fig 2.b.: what does the legend mean? What are the numbers?
11. L163-166: Please provide more details. What is the difference between a “watershed unit” and a “reservoir unit”? What is a slope unit? What is the purpose of using Google Earth imagery, for identifying river nodes? Couldn’t this process also be performed in the GIS software used, by applying Horton-Strahler classifications, and generating rivers in raster format, and then converted to vector? What is the purpose of Table 4?
12. L177-178 “According to experience” – Numerical evidence must be provided, otherwise this could simply be a random value.
13. L180-181 “According to the parameterization 180 experience of the Liuxihe model, it is uniformly set at 0.7.” – references should be added
14. Why is the evaporation coefficient the same, regardless of the land use type? There are differences in evaporation values, between the given categories.
15. Figure 5: You have not described the reasoning behind using polygons (for the Thiessen/Voronoi polygons), and not layers of gradient raster format.
16. L256-258: how were the “certainty coefficients” calculated? How did you obtain the validation values? Please provide more details
17. L302-303: what does this phrase mean? “The land use types and soil types of the basin differ slightly between the DEMs.” How can the land use and soil layers differ from one DEM, to another??? What is the reasoning between this argument?

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

General comments

The authors have done a good job of building and calibrating a hydrologic model. However, the objective of the study and the methods are not clearly defined. The title of the paper needs to be updated to reflect the objectives and the findings of the study. The title of the study alludes to inflow flood forecasting. However, it only describes the implementation of a hydrologic model. Also, the conclusions and discussions should be align with the results. 

Specific comments

Introduction - Major revision

Pg 1-2

Line 29-49

The Introduction should be general and provide sufficient background, introduce methods, and propose improvements. The information about the reservoir, rainfall, and watershed should be moved to a separate section called Study Area under Method and Data. The authors should refer to the latest research about reservoir inflow forecasting.

Line 50-56

The authors should better describe the different types of hydrologic models (lumped, semi-distributed and distributed), their limitations and applicability for reservoir inflow forecasting.

Line 57-83

What is 3S technology? The following two paragraphs need improvement. The authors should list studies that describe inflow forecasting and the improvements in the proposed framework. 

Pg 2-3

Method and data

This section can be renamed to Methods and materials and should include study area, datasets used and description of the modeling and forecasting framework.

Line 86-98

The model structure, parameters, inputs and outputs should be described with equations and the associated methods in a section called modeling framework.

Line 99-119

This section can be condensed as it contains some redundant information.

Figure 1 can be improved and the legend needs to be updated with the units.

Figure 2 can be improved and the legend needs to be updated.

Pg 5

Line 143-150

This section needs to be accompanied by a figure describing the location of the stations. Also, it's unclear as to why only a single event is required to optimize parameters. 

Results

This section should be renamed to Model/Framework implementation.

Line 153-166

The significance of the model structure should be described. How would the model structure affect the simulated outputs? Please improve.

Figure 3 needs improvement.

Pg 6-7

Line 172-187

This section needs improvement. The assumptions need to be stated clearly and the parameters need to be described with the associated hydraulic equations.

Table 6. What is the NO column in the table? Does it describe the different parts of watershed? If so, please elucidate this in the model structure section.

Line 190-199

Describe Particle Swarm Optimization and provide the final parameters that were selected after optimization. Can the same set of parameters be used to predict low flow events?

Discussion

This section should be renamed to results

Line 204-217

Is this the objective of the paper? Not sure how evaluating the data source ties to forecasting inflow. 

Table 7 should be replaced by a figure.

Line 221-224

What does watershed of a reservoir mean?

Improve this paragraph.

Line 224-228

Depict the meteorological and hydrological stations on a map. 

Line 229

What is the statistical analysis?

Linne 230-241

This section is unclear. If Liuxie model is a PBDHM, why can't distributed rainfall be used. What is the rationale to divide the basin into multiple rainfall zones? 

Line 257-258

What are the certainity co-efficients? Describe these co-effcients mathematically.

Figure 6

Where is the outlet of the basin? What areas do these hydrographs correspond to?

Line 265-291

Please list the optimized parameters? Were the model parameters optimized for one event and used for multiple events? 

Conclusions

The authors should change the title to Discussion and conclusions. This section needs to be revised to reflect the objectives of the study. The conclusions should be supported by quantitative metrics. 

 

 

 

 

 

Author Response

Please refer to the attachment

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Dear authors,

The reply for your revised manuscript has been attached in the word file.

Comments for author File: Comments.docx

Author Response

Please see the attachment.

Author Response File: Author Response.docx