Dear Authors,

In you study entitled 'Stable water isotope monitoring network of different water bodies in Shiyang River Basin, a typical arid river in China' is an interesting work which tries to share key data (primarily water stable isotopes) from various water bodies. After carefully reading the MS and exploring the dataset attached, I came to the conclusion, that the way this dataset is presented is insufficient for ESSD in its present form.

Main overall concerns:

• The MS does not fit well into the scope of ESSD in its present form. It lacks to interconnect the data it shares and to show how it is valuable in relation to the Earth's system.
• The title says 'Stable water isotope…’ yet It seems to me that sections 6.2 and 6.3 are the ones that truly reflect the title of the MS. Sadly, the other valuable information that was presented in the earlier sections is not tied into the main logical thread of the MS, nor it is demonstrated how vital those may be to be used with water stable isotopes.
• The presentation of the dataset is poor. I am missing at least one table/figre that really gives an overview on the whole dataset that is presented in the MS from the variables side. After all that is in the focus according to the title. The information provided in Sect. 4 is relevant, yet insufficient. I am missing an overview figure or table in which every variable, with measurement units, temporal sampling frequency, number of samples for the investigated interval etc. are provided. The reader must get an overview on the dataset that is presented, before any detail on the measurements is discussed.
• The study lacks to show how the data it shares is relevant in hydrological research as one would expect based on the introduction.

Specific comments:

Abstract

• “The purpose of this study is to clarify the hydrological and ecological processes of arid inland river basins in Eurasia and provide a scientific basis for their sustainable development.” However, this aim is not achieved at all. The MS lacks to show how the data presented are interconnected, let alone illustrate such aims.
• The paper is supposed to be about a water stable isotope monitoring network. Yet it only comes up in the second half of the abstract.
• The penultimate sentence tries to describe how the dataset could be utilized. This should be much more elaborated on and should be one of the main messages of the abstract.

The Introduction seems as if it was written to another paper. Considering sections 4 and onward, those are not tied to the questions described in the introduction, which is a major problem. The introduction correctly addresses issues that the dataset at hand could be used to solve. However, when the dataset is presented its values and possible applications are not presented in light of the Introduction.

Study area description is sufficient, but it lacks a discussion on how this particular area is important from an international perspective. Indeed, in line 47-49 it is mentioned that the area is important and unique, but there is no reference to back this up, nor it is compared with other similar areas from around the world. Thus the readers of ESSD would not know how important it is globally.

Observation network design

This is the section in which a much more detailed and primarily integrated picture has to be presented about the dataset. This is where a flowchart or table has to be included with the sites, variables, sampling frequencies etc. so the reader could see on one page what the whole dataset is.

In the Data and methods, the analytical procedures could be placed in appendix. Focus on the data. The Data set section could be placed in the Data and methods section.

Section 6 is way too thin. The dataset is not described sufficiently. It must be embedded into international literature, while meeting the requirement of ESSD “Any interpretation of data is outside the scope of regular articles.” Thus he dataset should be described to such an extent which enables the readers to clearly know the value of the dataset and its applicability.

Minor comments related to the presentation of the study

In numerous cases you start the sentence starting with a reference to a figure or table. Please do not start the sentence referring to the content of the figure. State the new finding and refer to the figure in parenthesis. It is not the figure that is important, but the underlying information.  Do present the information first and then cite the figure in parenthesis. Please correct this in every relevant place.

L53-56: This aim/hypothesis must be introduced in detail in the Introduction. In addition the Introduction fails to describe sufficiently why is the dataset of the Shiyang River have the potential to reflect on the whole of the Earth’s system.

L63: Use the format m³ s^-1 everywhere necessary.

L64: Please use the Köppen-Geiger climate classification system and refer to its codes. doi: 10.1127/0941-2948/2006/0130

L73: Did you set it up before 2015, or in 2015, or at various point in time between 2015 and 2020? Please explain and if necessary, provide a figure illustrating the evolution of the system.

Figure 2. The meaning of the different shapes should be explained.

Figure 5. Please extend the figures' captions following:  https://www.internationalscienceediting.com/how-to-write-a-figure-caption/ and the link above. Moreover, the panels are not named.

Dataset: The data is clear, but two temporary .xls files were also compressed with the actual datasets.

Please also find a commented pdf with additional minor comments, instructions, suggestions.

Although I suggested rejection, after major revisions, the work could be reconsidered upon resubmission, however, I would suggest considering 

https://www.journals.elsevier.com/data-in-brief

https://www.nature.com/sdata/

and parallel publishing a study that describes the data in a lower rank journal then ESSD.

Best regards,

Reviewer #1

This data description manuscripts refers to an extensive dataset, consisting of water stable isotope from different hydrological compartments and hydrological data, derived from a single river catchment in north central China. The data are deposited at Mendeley in the form of three excel spreadsheets. Authors note, that these data will be extended in the future.

The data are certainly interesting and relevant for a community of hydrologists and isotope geochemists, and principally this is a work that justifies publication in ESSD. However, there is some weakness in the way the data are organized and presented. Especially, some inconsistencies in labelling the sites makes it difficult for the reader to approach and comprehend the presented data (see specific comments below).

Further a conclusive statement describing the broader relevance of the data (picking up the aim of the study as formulated in the introduction) is missing.

The authors put specific emphasis on isotopes (starting with the title). I think the accompanying hydrological data are equally interesting and should be further highlighted.

Data interpretation (section 6) does not need to be extensive in a data description manuscript, and I think is sufficient in the present form. However, also here some adjustments in presenting the data would further highlight the value of the data; for example I´d like to see seasonal isotope values plotted for each year, instead of average values for 2015-2020 (Fig. 5).

Concluding, I recommend acceptance of this manuscript, in case authors succeed in revising their manuscript, following the major comments mentioned above and the specific comments listed below.

Specific comments

Datasets:

hydrological dataset:

are all these data in each spreadsheet for QTH? => clarify.

There is a mixture of abbreviations and full names in the “monthly flow” spreadsheet

why not combining “daily flow” and “water level” to one single spreadsheet?

isotope dataset:

there is some inconsistency in the format of reporting sampling date in the different spreadsheets

l62: define JTL and CQQ.

l77ff: these sample counts do not match the numbers as reported in the Mendeley datasets (description and data tables)

l75 and l. 88 and original datatables (and other parts of the manuscript): the authors should try to make it as easy as possible for the reader to comprehend the abbreviations and relate them to study sites. For example, the data tables only contain abbreviations, with some singular explanations (“SRB stands for the Shiyang River Basin”). I think data tables should contain one sheet with an additional table with abbreviations, full name, coordinates. In the manuscript text, authors should be consistent with reporting either full names, abbreviations, or both. For example, figure caption 1 would benefit from also have the abbreviations included alongside the full names of sites. I´d suggest not to use a – h for labelling the sample points in the topmost panel of Fig. 1, but instead the respective abbreviations, similar in the labelling of the figures sub panels.

Mendeley abstract: related to the point above, it is not clear to which points P1-P12, S1-S35, etc precisely are referring to. => please try to be consistent in labelling the data in both the original dataset and the manuscript.

Fig. 1: panel (d) is occurring twice while (f) is missing. Error in caption “0bservation system”.

l96: maybe providing a picture of the rain sampler in the supplement would be an option?

l113: please provide information, at which spot soil samples have been taken in text and table caption. Why just reporting soil characteristics from one site (there have been multiple sites samples, according to the datatable)?

l137: rather write “isotope analysis” instead of isotope experiment

l165 and 167: there is something wrong with these sentences. I suggest rephrasing, e.g. don´t start with “the error is...” or the “error in…” but rather write “for vegetation samples…” etc.

l189ff:there is some repetition to the methodology section in this paragraph

l196: “The stable isotope data set and the meteorological and hydrological data set are combined into one data set.” Actually this is not the case, i.e. they are in separate sheets.

Table 3: where are evaporation data are coming from?

Fig. 4 and 5: I think it´s not “different water bodies” but rather different hydrological compartments (plant, soil water, etc). The color codes do not come out clearly in each of the sub figures legends of Fig 5.

Fig. 4: while this is interesting, there appears to be large variability in the seasonal isotope values from the different years, especially in the soil and lake compartments. Maybe it would make more sense to present data similar as for discharge flows in Fig3 (i.e. different colours for different years, instead of average values across the sampling period).

l275: “Due to systematic error, there are some errors in isotopic measurement results. However, the observation accuracy is affected by the operation characteristics of the instrument and the sensitivity difference of moisture to specific spectralabsorption, and the observation results usually have obvious nonlinear response problems, which require a lot of experimentation.” => yes, but what´s the conclusion from this statement? Are the data reliable or not? I suggest rephrasing this paragraph.