Groundwater Buffers Decreasing Glacier Melt in an Andean Watershed—But Not Forever

Somers, Lauren; McKenzie, Jeffrey M.; Mark, Bryan G.; Lagos, Pablo; Ng, G. H. C.; Wickert, Andrew D.; Yarlequé, Christian; Baraër, Michel; Silva, Yamina

doi:10.1029/2019gl084730

Cited by 74 publications

(61 citation statements)

References 77 publications

(105 reference statements)

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“…Saberi et al (2019) use field data and numerical modeling of a proglacial headwater catchment on Volcán Chimborazo in Ecuador to estimate that 18% of groundwater discharge is sourced from glaciers which cover 34% of the watershed area. Somers et al (2019) examine a proglacial watershed in the tropical Andes of Peru and estimate that glaciers contribute approximately 2% of groundwater discharge to the Shullcas River which has approximately 2% basin glacier coverage. Using contrasting methods, Liljedahl et al (2017) examined two glacierized watersheds in the Alaska Range.…”

Section: Recharge From Glaciersmentioning

confidence: 99%

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A review of groundwater in high mountain environments

2020

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Mountain water resources are of particular importance for downstream populations but are threatened by decreasing water storage in snowpack and glaciers. Groundwater contribution to mountain streamflow, once assumed to be relatively small, is now understood to represent an important water source to streams. This review presents an overview of research on groundwater in high mountain environments (As classified by Meybeck et al. (2001) as very high, high, and mid-altitude mountains). Coarse geomorphic units, like talus, alluvium, and moraines, are important stores and conduits for high mountain groundwater. Bedrock aquifers contribute to catchment streamflow through shallow, weathered bedrock but also to higher order streams and central valley aquifers through deep fracture flow and mountain-block recharge. Tracer and water balance studies have shown that groundwater contributes substantially to streamflow in many high mountain catchments, particularly during lowflow periods. The percentage of streamflow attributable to groundwater varies greatly through time and between watersheds depending on the geology, topography, climate, and spatial scale. Recharge to high mountain aquifers is spatially variable and comes from a combination of infiltration from rain, snowmelt, and glacier melt, as well as concentrated recharge beneath losing streams, or through fractures and swallow holes. Recent advances suggest that high mountain groundwater may provide some resilience-at least temporarily-to climate-driven glacier and snowpack recession. A paucity of field data and the heterogeneity of alpine landscapes remain important challenges, but new data sources, tracers, and modeling methods continue to expand our understanding of high mountain groundwater flow.

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Section: Recharge From Glaciersmentioning

confidence: 99%

“…High mountain communities are already experiencing climate change impacts and are particularly vulnerable (Gurgiser et al, 2016;Heikkinen, 2017). Though groundwater provides some resilience to high mountain water resources, it is also vulnerable to long-term climate change (Somers et al, 2019).…”

Section: Representing Heterogeneitymentioning

confidence: 99%

A review of groundwater in high mountain environments

2020

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“…The recent study of Christensen, Hayashi, and Bentley (2020) identified that in a talus‐moraine feature in the Canadian Rockies, groundwater from the moraine supplies most of the water to the basin outlet springs and that moraine, located downstream the talus, could serve as a “gate keeper” of the basin. While knowledge alpine hydrogeology is advancing with more and more studies, current knowledge remains limited and difficult to extrapolate to other alpine areas (Christensen et al, 2020; Somers et al, 2019). As a result, most studies about alpine areas oversimplify groundwater processes in hydrological models.…”

Section: Introductionmentioning

confidence: 99%

Characterizing seasonal groundwater storage in alpine catchments using time‐lapse gravimetry, water stable isotopes and water balance methods

Arnoux

Halloran

Berdat

et al. 2020

Hydrological Processes

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Alpine areas play a major role in water supply in downstream valleys by releasing water during warm and dry periods. However, the hydrogeology of alpine catchments, which are particularly exposed to the effects of climate change, is currently not well understood. Increasing our knowledge of alpine hydrogeological processes is thus of considerable importance for any forward-looking hydrological investigations in alpine areas. The objectives of this study are to quantify seasonal groundwater storage variations in a small Swiss alpine catchment and to evaluate the capabilities of time-lapse gravimetry in the identification of zones of high groundwater storage fluctuations. Time-lapse gravimetric measurements enable rapid localisation of zones of dynamic groundwater storage changes and help to highlight aquifers with a higher storage decrease. Temperature sensors enable measurement of the temporal trend in stream and spring drying in the post-snowmelt period. Stable isotope measurements allow us to identify the origin of surface water exiting the catchment. The results improve our comprehension of a conceptual schema highlighting two different hydrogeological systems: (a) a shallow, rapidly depleted one fed directly by snowmelt and (b) a deeper one, with a slower recession, fed by main recharge during peak snowmelt and emerging at the lower part of the catchment below the talus and moraine of the catchment where bedrock is exposed. These dynamics confirm the high variability of storage in the talus and moraine aquifers and highlight the dominant role of Quaternary deposits and their connectivity to store water over seasonal and multi-year timescales. The mechanisms explaining the importance of Quaternary deposits are the combination of moraine and talus with different permeabilities allowing the storage of sufficient quantities of water permitting continuous release during drier periods of the year.

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“…Recent studies indicate that climate change could cause long‐term decline of proglacial aquifer storage due to reductions in diffuse recharge, from rainfall and snow melt (Somers, Mckenzie, Mark, & Lagos, 2019), and in focused recharge from glacier‐fed river channels (Liljedahl, Gädeke, O'Neel, Gatesman, & Douglas, 2017). The dynamic behaviour of proglacial aquifer storage dynamics (e.g., intra‐annual variability) will also change in response to regional precipitation variability and meltwater runoff dynamics (Allen, Whitfield, & Werner, 2010).…”

Section: Introductionmentioning

confidence: 99%

Proglacial groundwater storage dynamics under climate change and glacier retreat

Mackay

Barrand

Hannah

et al. 2020

Hydrological Processes

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Proglacial aquifers are an important water store in glacierised mountain catchments that supplement meltwater-fed river flows and support freshwater ecosystems. Climate change and glacier retreat will perturb water storage in these aquifers, yet the climate-glacier-groundwater response cascade has rarely been studied and remains poorly understood. This study implements an integrated modelling approach that combines distributed glacio-hydrological and groundwater models with climate change projections to evaluate the evolution of groundwater storage dynamics and surfacegroundwater exchanges in a temperate, glacierised catchment in Iceland. Focused infiltration along the meltwater-fed Virkisá River channel is found to be an important source of groundwater recharge and is projected to provide 14%-20% of total groundwater recharge by the 2080s. The simulations highlight a mechanism by which glacier retreat could inhibit river recharge in the future due to the loss of diurnal melt cycling in the runoff hydrograph. However, the evolution of proglacial groundwater level dynamics show considerable resilience to changes in river recharge and, instead, are driven by changes in the magnitude and seasonal timing of diffuse recharge from yearround rainfall. The majority of scenarios simulate an overall reduction in groundwater levels with a maximum 30-day average groundwater level reduction of 1 m. The simulations replicate observational studies of baseflow to the river, where up to 15% of the 30-day average river flow comes from groundwater outside of the melt season. This is forecast to reduce to 3%-8% by the 2080s due to increased contributions from rainfall and meltwater runoff. During the melt season, groundwater will continue to contribute 1%-3% of river flow despite significant reductions in meltwater runoff inputs. Therefore it is concluded that, in the proglacial region, groundwater will continue to provide only limited buffering of river flows as the glacier retreats.

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Groundwater Buffers Decreasing Glacier Melt in an Andean Watershed—But Not Forever

Cited by 74 publications

References 77 publications

A review of groundwater in high mountain environments

A review of groundwater in high mountain environments

Characterizing seasonal groundwater storage in alpine catchments using time‐lapse gravimetry, water stable isotopes and water balance methods

Proglacial groundwater storage dynamics under climate change and glacier retreat

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