The authors have done a commendable job of explaining seasonal and lithologic controls on groundwater flow in an alpine karst basin in the Canadian Rocky Mountains. This study stands out through its integration of multiple, complementary data sets, including continuous monitoring of stage and electrical conductivity over multiple years; development of a stage-discharge rating curve for the spring; repeated sampling for hydrochemical and isotopic analyses; tracer testing; time series analyses; and information from other sources (geologic mapping, meteorological data, and satellite imagery). The approach and findings contribute to the literature on the hydrology of alpine karst, which has been understudied outside Europe and which constitutes an important resource for human use and ecological functioning in various parts of the world.

In general, I would answer yes to all the questions posed to reviewers. I reviewed the manuscript before reading the comments already posted online. In particular, I affirm Dr. Worthington's comments on clarifying the discussion of groundwater velocity and expanding the discussion of the range of residence times in the system. My suggestions primarily address providing additional information, plus some minor editorial corrections. Note that I did not check citations against the references and vice versa.

Main comments:

line 36: Re: “the unique alpine settings offer potential advantages that are not available in lowlands”— What are these advantages? Rephrase following lines 549–551.

lines 75–76: Note that the age of the Palliser Fm. is Devonian.

Fig. 1 and lines 90–91: Which direction does the syncline plunge? Are conduit development and flow paths to the spring structurally controlled?

lines 195–198: The assumption that diurnal timing of maximum snowmelt coincided with maximum air temperature seems reasonable, but I recommend citing one or more references to support this assumption.

lines 264–265: Re: "a is an empirical coefficient taking a value of 0.082 m^-1/2 s^-1/2 for an intermediate value of S_F (= 1.4) within the expected range” — Fig. 5b shows a = 0.077. Which value is correct?

line 325: SO₄ should be > 99% of total anions analyzed by ion chromatography (emphasis added). HCO₃, which was analyzed by alkalinity titration, is the dominant anion in groundwater here.

lines 336–337: Re: “the component associated with snowmelt recharge having a higher Ca/Mg ratio and carbonate fraction but lower ion concentrations” — the lower Ca/Mg ratio between snowmelt periods could reflect proportionally more solute contributions from dolomite, which dissolves more slowly than calcite (for example, see Barna et al., Environ. Eng. Geosci. 26(3), 2020, p. 281, and references therein).

lines 342–344: Were saturation indices for dolomite, calcite, and anhydrite calculated?

lines 345–347 and Fig. A2: How were rain and snow samples collected? Were snow samples fresh? Were steps taken to limit evaporation or sublimation, which can alter the isotopic composition? How does the LWML compare to other LWMLs from the region?

lines 416–417: The observation “The component with low carbonate fraction represents groundwater released from over-winter storage, which is presumably in contact with evaporite deposits within the Palliser Fm.” is consistent with Barna et al. (2020, p. 281) and references therein.

Fig. 14: Do dashed lines on the surface represent local drainage basin divides? Note on legend.

Minor edits:

lines 8, 19, 546, 565: By definition, inaccessible terrains can’t be accessed. Use “remote” or “relatively inaccessible” instead.

lines 36–37: “accumulation and melt has” should be “accumulation and melt have”

line 74: “Front Range…is” should be “Front Ranges…are”

line 128: “with a 0.45-μm membrane filters” should be “with 0.45-μm membrane filters”

lines 134–135: “by a cavity ring-down spectroscopy” should be “by cavity ring-down spectroscopy”

line 135: “to the Vienna Standard Mean Ocean Water” should be “to Vienna Standard Mean Ocean Water”

line 142: “and the V-SMOW” should be “and V-SMOW”

Fig. 3 caption: “Augst” should be “August”

line 206: “the k^th the element” should be “the k^th element”

line 273: “unlikely serve” should be “unlikely to serve”

line 305: “hereafter referred to” should be “hereafter is referred to”

line 336: “ion concentration” should be “ion concentrations”

line 355: “appear” should be “appeared”

line 423: “majority discharge” should be “majority of discharge”

lines 450–451: “the Darcy’s law” should be “Darcy’s law”

lines 455–456: “discharge…and velocity…is estimated” should be “discharge…and velocity…are estimated”

line 465: “Jennin” should be “Jeannin”

line 470: “than ~3.7 m” should be “than the value of ~3.7 m”

line 733: “mapping procedure  map” should be “mapping procedure and map”

line 746: “Wavel” should be “Waveland”

line 765: “Alberta  British Columbia” should be “Alberta and British Columbia”

line 775: “Tracer test” should be “Tracer tests”

line 855: “Savanna” should be “Savannah”

The authors investigated a remote, high-alpine catchment in the Canadian Rocky Mountains using multiple approaches, despite having very limited information at the beginning of the study. They combined hydrological, geological, hydrochemical and isotopic information to characterize the karst system, which is strongly influenced by snow and glaciers. The main outcome is a hydrogeological conceptual model that reflects the system's main hydrological and hydrogeological processes. Additionally, the authors highlight that the methods applied to this study could be transferred to other high alpine systems with similar characteristics. The manuscript is clearly structured and well written. The results seem solid. Overall, it is great work, demonstrating considerable effort in terms of fieldwork in such a remote area, as well as the combination of many different investigative methods and guidance to reach reasonable and logical interpretations, which is surely a strength of this study. However, critical discussions are missing in some places, which could be improved. I recommend considering this work as a minor revision.

Major comments:

1) Introduction / Novelties:

I suggest that the authors elaborate better on the novelties of this research work in the introduction. In my opinion, there are three main novelties in the current research work: 1) improvement of the process understanding about the impact of snow/ice behavior on recharge, storage, drainage and discharge in high alpine karst aquifers; 2) the combination and application of multiple investigation approaches (hydrological, hydrogeological, hydrochemical and isotopic) to a high alpine karst system to achieve a robust and coherent conceptual site model and 3) knowledge production for the local karst system (Watridge Karst Spring).

2) Representiveness of weather parameters (P and T):

The only available weather station is located at 2260 m a.s.l. within the study area. The study area varies between 1870 (WKS) and 3406 (Mount Sir Douglas) m a.s.l. How representative are P and T measured for the entire study area, and how will the analysis and interpretation relate to the hydrological water balance and diel fluctuations of discharge and EC be influenced by these data uncertainties? It is expected that there will be spatial and temporal variation of snow/ice accumulation and melting behavior within the study area. How does this influence the diel fluctuations of discharge and EC? I suggest the authors incorporate/consider this aspect, at least for critical discussion.

3) Artificial tracer experiments:

BP14(2) shows a mass recovery of 115%, which is impossible. The authors mentioned a technical issue regarding sensor calibration. How reliable are the measurements taken by the field device installed in the spring generally? Have factors such as UV, turbidity, and temperature, which can disturb the tracer measurements, been considered? To better understand the results of the tracer experiment, the breakthrough curves (BTC) should also be compared with the system input signals (e.g., precipitation, air temperature), as the shape of the BTCs differs significantly. The BTCs do not show significant tailing, but multiple peaks, which indicate the transport via multiple paths within the main karst drainage conduit network. If we assume that the measurements are reliable, how can the significant difference in mass recovery rate between BP14(2) and BP14(1) & BP11 be explained?

4) Recharge area delineation

The uncertainty of meteorological forcing, as well as its impact on recharge area delineation and water balance calculation, should be critically discussed. In my opinion, this is one of the main sources of uncertainty when estimating the water balance of high Alpine catchments. The authors estimated that there was about 90% recharge rate (if I understood the estimation correctly) for the studied karst aquifer system. The map (Figure 1) does not show any surface drainage features (streams), so it indicates high karstification of the studied system, and precipitation or melt can easily infiltrate. The study for estimation of recharge rates for karst systems in the European Alps can be used here to support (Malard et al. 2016: A novel approach for estimating karst groundwater recharge in mountainous regions, and its application in Switzerland). To validate the recharge delineation and also the associated water balance calculation, hydrological karst modelling should be applied for future work.

5) Conduit flow and transport

In general, regarding the terms 'open channel' and 'pipe flow', I personally think that the descriptions of open and pressurized conduit flow are more accurate. Most conduits have a closed section. Depending on the water level, the conduits can be unpressurized or pressurized. The authors discussed how the existence of large pools can cause retardation during solute transport along the conduit network. In my view, there is an inconsistency or at least an open discussion point, regarding the concept of large pools when compared with dye tracer experiments. If such large pools exist in the conduit network, they should significantly impact the shape of breakthrough curves (Hauns et al. 2001: Dispersion, retardation and scale effect in tracer breakthrough curves in karst conduits; Yang et al. 2025: Effects of karst conduit structure on breakthrough curves: Experiments and modeling). Can this effect be observed or identified in the measured breakthrough curves? Additionally, the authors tried to use the concept with large pools to explain the observed increase in transport response time concurrent with the reduction in discharge. However, I think a more general reason is the change in hydraulic gradient in the groundwater level distribution in the karst aquifer during varying flow conditions. The authors used the Darcy-Weisbach equation to estimate potential flow velocity in a pressurized conduit. To my understanding, the transport time (derived from tracer experiments) and the transport response time (derived from time series analysis) should reflect the transport process through the entire aquifer (including the unsaturated and saturated parts) along fast flow paths. This is surely more than pure transport in a saturated drainage conduit. I recommend that the authors explicitly consider and discuss the role of the unsaturated part of the studied karst aquifer (e.g., the epikarst) to transport processes (transport time and transport response time). This would provide a more complete picture.

Minor comments

1) Line 30: please remove Chen et al. 2017 and add the following references (Goldscheider 2005; Lauber & Goldscheider 2014; Lucianetti et al. 2016; Frank et al. 2019):

• Goldscheider 2005: Fold structure and underground drainage pattern in the alpine karst system Hochifen-Gottesacker, Eclogae geol. Helv.
• Lauber & Goldscheider 2014: Use of artificial and natural tracers to assess groundwater transit-time distribution and flow systems in a high-alpine karst system (Wetterstein Mountains, Germany), Hydrogeol J
• Lucianetti et al. 2016: Preliminary conceptual model of an Alpine carbonate aquifer (Pale di San Martino, Dolomites, Italy), Italian Journal of Groundwater
• Frank et al. 2019: Sulfate variations as a natural tracer for conduit-matrix interaction in a complex karst aquifer, Hydrological Processes

2) Figure 1: Where are the glaciers on the map? There is a legend for them, but I cannot find any in the study area.

3) Figure 14: The symbol for flow in open conduits is difficult to see. It would be useful to have a symbol for snow cover in both figures: extensive snow cover in (a) and no snow cover, only glaciers in (b). Please ensure that the saturated part in (b) is fully colored (some saturated conduits are not colored).