The Response Mechanisms of Topographic Changes in Small Loess Watershed under Rainstorm
Round 1
Reviewer 1 Report
The main question is: how was the transition from the prototype landscape to the model made?
What scaling factors were used?
How did the assumed scale distortions affect flow depth and velocities, the erosion rates on slopes and in linear forms?
How have delivery ratios changed? This important characteristic is highly dependent on the size of the catchment.
In its present form, the article describes in details the processes of erosion and sediment deposition in erosion rills about 30 m long, not on the hills and in the gullies.
The comments:
It is necessary to give a drawing of a digital model of the initial relief of the created physical model
Why is there no figure with the spatial distribution information of erosion and deposition on the model at the maximum intensity of sprinkling (120 mm/h)?
Please, check all figures for drawing and figure captions quality. For example, the note “The scale of the lower and left borders represents the horizontal and vertical coordinate” is not clear, what is the vertical coordinate?
Author Response
Please see the attachment. The response to Reviewer 1 is on page one and page two.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Good efforts by the authors to work on such a model. It might not serve the real watershed.
1. This watershed does not account for wind, storms, sun, and another natural factor that play an important role. Thus authors must have a section of LIMITATIONS of the study.
2. Did the authors compare their results of Sediment and runoff yield rate with any such event where Rain rate was 30, 60, 120 mm/h over the natural watershed from where the mud and grass were acquired? What is the authenticity of the results?
3. Reader did not find any extraordinary results on "soil erosion in a gully", runoff volume, rate of runoff yield..etc! The authors should highlight any exciting results from such a model.
4. What does terrain three-dimensional laser scanning technology do in this manuscript? Please explain the critical role of this technology. If you don't use this one then!
Author Response
Please see the attachment. The response to Reviewer 2 is on page three and four.
Author Response File: Author Response.docx
Reviewer 3 Report
The manuscript deals with a very interesting topic and shows the results of the experiment.
However, the text is written very poorly in terms of style, grammar with a lot of typographical errors (spaces between words, commas, brackets, units of measurement and the like).
Also, the content of the text is dry to read and I would definitely suggest the authors to give the manuscript to a more experienced colleague who would stylistically reformulate the content of the manuscript and present the results of the experiment more clearly and concisely. There is no number of lines in the manuscript, so it is more difficult to give comments. That is why I will attach a document with errors.
In addition to this, here are some specific comments:
Figure 2: Poor quality.
Chapters 2.3 and 2.3.1: Too many subchapters, one of which is blank. Definitely reduce. The same is true for other chapters (3. Results, 3.1 and 3.1.1; 3-2 and 3.2.1)
5th and 6th line in chapter 3.2.2: Half of the sentence is interrupted.
Comments for author File: 
Comments.pdf
Author Response
Please see the attachment. The response to Reviewer 3 is on page five.
Author Response File: Author Response.docx
Reviewer 4 Report
(1)the study on the response mechanisms is meaningful ,valuable.
(2)it's better to give a manuscript in the state of final version,not with a lot of modification traces in the manuscript to reviewer.
(3)in the line 32," resulted in frequency and intensity of rainstorms", it's not clear for description,it's better to be modified as "resulted in high frequency and intensity of rainstorms"
(4)some mistakes such as line rian-storm(correct writing rain-storm),,lines 287,289, 266 et al , dims (correct writing dams)
(5)not clear for words in lines 365,449,603,732
Author Response
Point 1:
the study on the response mechanisms is meaningful, valuable.
Reply 1:
`Thanks for your review and appreciation about our manuscript.
Point 2:
it's better to give a manuscript in the state of final version, not with a lot of modification traces in the manuscript to reviewer.
not clear for words in lines 365,449,603,732.
Reply 2:
We are terribly sorry for this manuscript with a lot of modification traces is difficult to read, which made troubles for reviewers. In the latest version of this manuscript, the modification and other unnecessary elements have been revised so that the manuscript is complete and neat. Besides, the sentences in lines 365,449,603,732 have been clear without covering words.
Point 3:
in the line 32," resulted in frequency and intensity of rainstorms", it's not clear for description, it's better to be modified as "resulted in high frequency and intensity of rainstorms".
Reply 3:
Thanks for your helpful advice and we have modified it in Line .
Point 4:
some mistakes such as line rian-storm(correct writing rain-storm),,lines 287,289, 266 et al , dims (correct writing dams).
Reply 4:
Thanks for your kind reminder and we have corrected them one by one.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
In the corrected article, I did not find the answer to the main question - how the transition from the prototype to the model was made. If the prototype was a large and deep gully with a length of 1200 m and a depth of 100 m at the outlet, then with an equal horizontal-vertical decrease of 40 times, the model turned out to be an erosion rill 30 m long and 2.5 m deep at the outlet (according to DEM at fig. 2). The processes of erosion, transport and accumulation of sediments differ significantly in these two erosion forms and these distortions of real processes should be taken into account in the simulation. This was not done, just as there was no theoretical justification for scale distortions. I can only repeat my conclusion: In its present form, the article describes in details the processes of erosion and sediment deposition in erosion rills about 30 m long, not on the hills and in the gullies. Such description have no theoretical or practical value
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Reviewer 2 Report
Good to know your responses.
Author Response
Thanks for the expert's affirmation of our work, We sincerely wish you good health! The work is smooth! Happiness!
Author Response File: Author Response.pdf
Reviewer 3 Report
I think the manuscript has been improved and can be accepted with less stylistic and grammatical checks.
Author Response
Thanks for your suggestion. The grammer and terminology have been corrected by the help of teachers and friends with fluent English.
Author Response File: Author Response.pdf
Round 3
Reviewer 1 Report
The table (Table 1) with the scaling factors at last appeared in the corrected paper. Let as check a few numbers. Rainfall intensity was 30, 60 and 120 mm/h in modelling. With the factor 6.3 the rainfall at the prototype would be 189, 378 and 756 mm/h. At the site https://en.climate-data.org/asia/china/guangxi/yulin-2710/, the rainfall depth in Yulin City is 295 mm for the most wet month (May), not for an hour.
The discharge at the model after 60 min of rainfall with 60 mm/h was 250-300 cm3/s (figure3). With the factor 10119 the discharge at prototype would be about 2.5-3.0 m3/s. This is too much for a small catchment at semi-arid Suide County. It is obvious that these scaling factors were not really used in the model design.
Author Response
Point 1:
The table (Table 1) with the scaling factors at last appeared in the corrected paper. Let as check a few numbers. Rainfall intensity was 30, 60 and 120 mm/h in modelling. With the factor 6.3 the rainfall at the prototype would be 189, 378 and 756 mm/h. At the site https://en.climate-data.org/asia/china/guangxi/yulin-2710/, the rainfall depth in Yulin City is 295 mm for the most wet month (May), not for an hour.
Reply 1:
The indoor simulated rainfall experiment was to study the response mechanism of topographic evolution in the watershed of Losses Plateau under different rainstorms, rather than to repeat a natural rainfall that has occurred in Qiaogou. In order to highlight the occurrence and development process of erosion-deposition and improve efficiency of simulation experiment, the rain intensity of simulation is relatively high than natural rainfalls, which has no influence on the study of soil erosion-sedimentation mechanism. Therefore, the rain intensity of 30 mm/h,60 mm/h and 120 mm/h were applied. The mm/h unit of rain intensity could be calculated from the max rain intensity of 5min,10min,30min and 60min in a natural rainfall. It should be noted that rainfall depth is not the product of intensity and duration of rain and the direct comparison of rainfall intensity and monthly rainfall depth has less scientific significance.
In consequence, the rainfall intensity applied in the indoor experiment doesn't conflict with the actual monthly rainfall depth in Yulin City (295mm).
The large-scale ecological construction of loess plateau has significantly reduced the amount of runoff and sediment transport in the Yellow River, but the amount of runoff and sediment transport of some typical tributaries is still high in the rainstorm condition.
Point 2:
The discharge at the model after 60 min of rainfall with 60 mm/h was 250-300 cm3/s (figure3). With the factor 10119 the discharge at prototype would be about 2.5-3.0 m3/s. This is too much for a small catchment at semi-arid Suide County. It is obvious that these scaling factors were not really used in the model design.
Reply 2:
This paper studies the response mechanism of topographic change in small loess watersheds under rainstorm by using the system of small watershed rainstorm simulation. We took Qiaogou small watershed as the prototype. Qiaogou is located in the lower reaches of Wuding River, which is one of the small experimental treatment basins of Suide Water Conservation Station of the Yellow River Water Conservancy Commission（Suide Water Conservation Station includes Qiaogou, Xindiangou and Wangmaogou.
In the rainstorm events on July 26,2017, the discharge of Wangmaogou reached 4.95m3 / s (GAO Haidong, LI Zhanbin, LI Peng, et al. Paths and prevention of sediment during storm-runoff on the Loess Plateau:Based on the rainstorm of 2017-07-26 in Wuding River[J]. Science of Soil and Water Conservation, 2018,16(4): 66-72.). Therefore, the discharge of 2.5-3.0 m3/s after 60 min of rainfall with 60 mm/h at prototype was possible under rainstorm condition.
Author Response File: Author Response.pdf
