Shallow groundwater level time series and a groundwater chemistry survey from a boreal headwater catchment
Abstract. Groundwater can respond quickly to precipitation and is the main contribution to streamflow in most catchments in humid, temperate climates. To better understand shallow groundwater dynamics in a boreal headwater catchment, we installed a network of groundwater wells in two areas in the Krycklan catchment in Northern Sweden: a small headwater catchment (3.5 ha, 54 wells) and a hillslope (1 ha, 21 wells). The average wells depth was 274 cm (range: 70–581 cm) and recorded the groundwater level variation at a 10–30 min interval between 18. July 2018–1. November 2020. Manual water level measurements (0–26 per well) during the summer seasons in 2018 and 2019 were used to confirm and re-calibrate the water level logger results. The groundwater level data for each well was carefully processed and quality controlled, using six data labels. The absolute and relative positions of the wells were measured with a high-precision GPS and terrestrial laser scanner (TLS) to determine differences in groundwater levels and thus groundwater gradients. During the summer of 2019, all wells with sufficient water were sampled and analyzed for electrical conductivity, pH, absorbance, anion and cation concentrations, as well as δ18O and δ2H. This combined hydrometric and hydrochemical dataset can be useful to test models that simulate groundwater dynamics and to evaluate subsurface hydrological connectivity. We therefore made the data available on https://www.safedeposit.se/projects/82 (Erdbrügger et al., 2022).
Jana Erdbrügger et al.
Jana Erdbrügger et al.
Groundwater levels (2018-2020) and sampling (2019) https://doi.org/10.5880/fidgeo.2022.020
Jana Erdbrügger et al.
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Erdbrügger et al. present a database of groundwater level recorded at 75 wells in a Swedish experimental catchment for two years, from July 2018 to November 2020. They also present the hydrochemistry acquired in the wells during one sampling campaign in summer 2019. A full description from the setup of the well network to the data quality are presented. Additionally, some results illustrate the interest of having such hydrological/hydrogeological data published.
As it is more and more important having access to such information, the publication of these data is for me very relevant. However, I also think that the manuscript, as submitted, needs a substantial improvement before being published in ESSD. Please see below my general comments.
Please find below some more detailed suggestions/comments:
The name of the catchment and the country should appear in the title
Lines 28-29: I don’t see the choice of N and Hg relevant when speaking about GW solutes. You should find a better choice.
Line 43: “…understanding of hydrological…”
Line 97: “Shallow” GW?
Line 107: catchment area?
Line 108: “long-term data”: give the initial and final dates that cover the time series
Line 125-126: not clear at all
Line 127: 6m depth, is this soil developed on deposited material (colluvium, alluvium…)?
Line 137: The ICOS station should be presented on the map in figure 1
Lines 176-177: better to give the range than the average
Lines 341-243: why not using the same procedure for all wells?
Lines 266-270: precision of the measure by the automatic sensors?
Line 302: The first step for the manual selection should be shown in figure 5 to clarify all the used procedure.
Lines 306-309: this is not clear to me. Please explain why this can happen. Is it because this measurement is not always as sensitive even if correctly done?
Line 342: “recovery time”, should be interesting to know the necessary time to recover at each well to show the spatial heterogeneity of some hydraulic properties. This could be one of the example results, for instance.
Line 393: how often, the wells were dried and in what hydrological state?
Lines 397-399: the purging description (lines 390-395) should appear in this paragraph because it is a part of the sampling protocol.
Line 407: which should correspond to the shallower part oof the GW, shouldn’t it?
Line 412: what pumping speed? Was it low enough to completely avoid this effect? How did you evaluated this for all wells and how variable was it for all wells?
Line 432: is it not mainly transpiration that would affect GW level? Can evaporation from the surface of the soil impact the GW level?
Lines 433-434: how many wells and why these ones?
Line 444: The deep GW was not defined previously
Line 445: what statistical test did you used to estimate the significance?
Line 446: is it not 12.5 because in the figure the range is closer to 10. If not 1.25 is in the same order of magnitude that the mean analytical error we have with standard isotope analyzer, then not really large.
Tables 1 and 2 are not necessary
Tables 4 and 5 should be removed and their information added to the related online files
Table 6 is not necessary as fully described in the text at 4.4. The caption is not detailed enough. Is it for manual or logger data?
Table 8 not needed
Figure 1 and 2 should be merged and well labelling added on Figure 2
Figure 4 is not clear. All the information provided in the figure caption should be indicated on the figure too.
Figure 6 and 7 should be merged to show the 6 different classes together.
The legend should be added on figure 8
Appendix A should be put in the online repository with the other files.
Kryckland_gw_levels.csv: avoid the acronyms and put together the column for mnl
Kryckland_gw_sampling.csv and Kryckland_gw_chemistry.csv should be merged in one file
Field_protocol.csv is not clear because some column (like Y and Z) do not have title and what means g/d in column N?
Lab_analysis_description.pdf: harmonized the language to english