Study on River Protection and Improvement Based on a Comprehensive Statistical Model in a Coastal Plain River Network

Round 1

Reviewer 1 Report

After developing a complex mathematical model encompassing the characteristics of a coastal plain river, the authors divided a case study coastal plain river network (Pinghu City) into several zones then the related  the model to what has occurred in Pinhu City in the period 2018-2022. While the concept being approached by the authors is ambitious, the paper suffers from ambiguity in that some important descriptors are not adequately defined. In particular, the title of the paper refers to a “coastal plain river network”, but it is unclear what this means. Does this refer to the natural systems of distribution making up the coastal plain river system, does it include man-made irrigation channels as well as the river system, and does it include the water reticulation systems provided to towns and villages on the coastal plane. Are the wastewater collection systems also included? The paper is quite difficult to interpret as many factors are only defined mathematically, and some assistance from a native English speaker would assist understanding. It is unclear whether the paper is primarily oriented towards water conservation and efficiency of water use, or flood mitigation. Changes that have occurred in the river network over 2018-2022 should be better described to explain why such action was taken.

The following comments are made:-

Line 25 – Define what is meant by the “coastal plain river network”.

Line 26 and 30 –Seven references are introduced. Most hypothesise outcomes from the impact of climate change, which is not a significant consideration of the submitted paper. Reference 3 deals with the likely impact of building additional hydropower dams on the agriculture of the Zambezi Basin (much larger than most Chinese coastal plains). Reference 7 discusses the potential impact of climate change reducing hydropower generating capacity in Central and Southern Africa. The submitted paper does not discuss any issues of hydropower, nor would it seem likely that a hydropower dam would be built on a coastal plain as there would be no suitable site for a dam to achieve sufficient head to serve as a power source. The authors may wish to review their choice of references.

Line 36, 37 encompasses Figure 1. This figure has no key, so it is not clear what it shows. If one assumes the blue lines represent rivers and canals, it may have relevance to a much later piece of text, the case study beginning at line 175. But this figure is not mentioned anywhere in the text. All tables and figures must be referred to in the text if they are to be included. A perusal of Pinghu in  Zhejiang on Google Earth shows a well developed dense city, and a population of 700,000, surrounded by smaller towns. A better description should be given as part of the case study as the paper suggests its model is useful for addressing social and economic issues as well as environmental issues arising from the “river network”, though ultimately, no social or economic issues were discussed.

Line 39 – “As a natural resource composed of river water area, water quantity, water quality and river function,…” . The authors should explain the importance of these factors. For example, irrigators will be concerned about water quantity and quality, while geographers and town planners will be concerned about river area in terms of development opportunities. (There is scope for ambiguity in the term “river water area”, as it may be identified as meaning the irrigable area of land in agronomic terms.)

Line 56 – “The river network resources have multiple ownership”: - This needs to be explained – is ownership of the river vested in the Chinese central government, the province or how? Does river ownership relate to land ownership? How is the resource governed?

Line 62 – “Nowadays, the river network enhances its functions….”. This statement is teleological. The river does not enhance anything. The river is not a sentient being.  How the river is managed by whoever is responsible for its governance may enhance the various functions listed.

Lines 66 and 67 – Figure 2 is not referred to anywhere in the text. Unless referred to, it should be deleted.

Limes 68, 69 -and elsewhere – Various references to “River network” would be better expressed as “the river network”.

Line 72 -  “the purification of pollution is always an important role of the river network” would be much better considered in terms of pollution control at source rather than dealing with it after pollution has occurred. (This appears to be recognised at line 276.)

Line 83 – What is meant by the expression “water surface rate”? Needs descriptive definition at first mention. Reader should not be expected to await a mathematical description at equation 8, line 149

Line 91 – What is meant by “to calculate the compensation of river water surface occupation’?

It is suggested that lines 24-93 should probably be encompassed as the “Introduction”. At this point of the text, the introduction has covered very general principles, and the reader does not anticipate the case study of Pinghu that is introduced later in the text. The end of the introduction should include a summary of the purpose of the research to be described. It is noted that there is no reference to the relationship between river water and ground water, and whether any parts of the river network involve gaining or losing water from groundwater. This referee has also noted that ground subsidence has been recorded in the literature in Pinghu county – is this attributed to over-pumping of groundwater, even though groundwater does not appear to be considered in this paper.

Line 104 – is the word “flux” correct? Qmax is defined as cubic metres/second, a measure of flow, whereas flux is defined as volume per area per unit of time.

Line 152-153 – “the urbanization and industrialization of 152 the local city will lead to the transformation of the costal (coastal) plain river network basin…”. Transformed how and why?

Line 154 – The word “simplicity” should presumably be “simplified”. However, the statement is an assumption, and may depend on what planning decisions are made at the time. No consideration is given in the paper to the adoption of “sponge city” principles now being encouraged in Chin, such as reducing impervious surfaces.

Line 168 – What is the significance of “nodes” and “chains”?

Line 169 – Describe what is meant by “line point rate” as well as referring to equation 12

Line 185 – Define be term “flux control index”.

Line 188 – “variation of the local underlying surface in Pinghu city has changed rapidly”, It would be helpful if the authors could describe in what way it has changed to provide an understanding the data later presented.

Line 191 – Define “water surface rate control index”.

Line 199 – Table 1. What defines whether a river is described as a County level river, a town level river or a village level river?  Zone A has 11 County rivers but 330 Village level rivers. Are the latter effectively irrigation channels? Are they what are elsewhere described as “chains”? Clarify.

Line 205 – “…river network adjustments has been carried out according to the principle of water area dynamic balance since 2005”. What are these river adjustments? Describe?

Lines 211, 212 – The captions to tables 2 and 3 should state the time frame over which the changes were recorded (presumably 2018-2022)

Line 215 – Table 4 in each of the “Before”, “After” and “Differential” components, there are two columns of data entitled “river network” What do they mean and what differentiates them? Most of the node and chain differential values should be shown as negative differentials according to the “before” and “after” data given.

Line 221 – “All the rivers in the study area can be divided into three different levels, namely village level, county level and town level” should be given much earlier in the text, and define how the differentiation was achieved. (See comment on line 199.)

Line 222-224 – Sentence unsound.

Line 2278 – “The total number of village-level rivers has reduced by 218”. Why? Have they been filled in for building sites or what?

Line 271 – The changes in consumption in table 5 do not appear statistically significant – was any statistical analysis carried out?

Line 275 et seq – This paragraph contains descriptive assertions and there appears to have been no statistical analyses to justify the observations.

Line 270 – What are “the water environmental zone and the administrative interface section”?

Line 397 – Conclusions. The authors have developed a model and applied it to Pinhhu City. However, the physical changes made in the river network were implemented prior to the construction of the model. The authors have not established the model as a successful basis for future amendment of coastal city river network structures.

Some grammatical unsoundness. Paper suffers from ambiguity from lack of adequate definition of terms used.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Please see attached file.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

The manuscript entitled "Study on river protection and improvement in a typical coastal plain river network", selected Pinghu city as a typical area to study the coastal river network. The title of this manuscript is vague. It is hard to understand the novel of this study without sufficient introduction and discussion.  
>> Figure 1. This figure is not suitable for the international journal. The coast is not shown in this figure.
>> Section 1. Introduction. Why do you choose Pinghu city as a typical area?  The purpose of this study is not clear in the section.
>> The citation of references in text is not formal. The references of this manuscript are not up to date.
>> Table 1.  There is no figures showing the zones A, B, C, etc. It is hard to understand the river network of the study area.
>>Section 4.3. It is hard to understand the  "river network adjustments".
>> There is no sufficient discussion on this study.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Throughout the text, I think the term "water area rate" should be replaced by "water area ratio". I assume it is the ratio of the surface area of water to the total surface area of the village, town or province. There remain numerous l grammatical errors and rather than write a long set of comments, "sticky yellow labels" have been attached to the v2 draft where changes are suggested. Changes in tense, use of the definite article and singular/plural corrections are suggested. Please ask a native English speaker to review any future draft.

Comments for author File: Comments.pdf

See annotated copy of v2 draft

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

You have modified some of my questions. However, Figure 1 need add latitude and longitude. Figure 2 need more information (such as sources). Figure 4 need information about scale, compass, longitude and latitude. 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 3

Reviewer 1 Report

The text still has some English expressions that are not grammatically ideal, though the meaning is clear. It would have been better if the Methods had been written in the past tense, but present tense is probably acceptable - let the Editor decide.

Note the incorrect spelling of Pinghu at line 200

See above