Three referees posted their comments and evaluated the manuscript. The referees had different opinions about the quality of the manuscript. Some of the main concerns were related to the methodology itself. In the manuscript, the methods and standard procedures for isotope analysis in the soil samples were described only briefly, and therefore it was difficult to evaluate the quality of the data.
The authors answered in detail on how soil samples were taken/stored and how the soil water isotope were analysed. It is important to include this in the revised version of the manuscript like all other concerns raised by the reviewers.

At the same time, the authors need to make sure that the manuscript gets shorter by deleting unnecessary information or being more precise with wording as outlined in the reviewer comments. According to some of the answers given, I recommend to go back to the text again and carefully check whether more improvments can be made, and I recommend putting some information into Supplementary Information.

Based on all the comments and the detailed answer about the used analytical method, the manuscript can be potentially reconsidered for publication in HESS after major revisions.

Two referees reviewed the revised version of the manuscript. One reviewer pointed out a substantial improvement and only minor changes are required (mainly imprecise language, see reviewer comment). The still missing precise language was also pointed out by the other reviewer (not in the public report though). This person also pointed out some other critical points, which at least should be discussed (volatile organic compounds) or where authors should be more precise (which information can be gained from hydro(geo)logical values like water balance and groundwater levels and for which information are the isotopes required) or less enthusiastic (first study using the direct vapor method in wetlands --> it has been used in unsaturated sediments, soils and in saturated sediments (aquifer, aquitard) before and a wetland isn’t anything different). For details, please see report. Additionally, (i) carefully check the entire reference list; e.g. Sodenberg et al., 2011, should be Soderberg et al., 2012; (ii) check tenses and spelling; (iii) define all abbreviations; (iv) check y-axis in Figure 8: is it really 8000 cm? not 800 cm?; (v) the term “evaporation line” should not be used because it was later discussed that this is a result of differently evaporated water with different initial values.
If these changes requiring minor revisions are included into the manuscript, it can be accepted for publication in HESS.