| Titre | Glacial melt and potential impacts on water resources in the Canadian Rocky Mountains |
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| Auteur | Castellazzi, P; Burgess, D ; Rivera, A; Huang, J; Longuevergne, L; Demuth, M |
| Source | Water Resources Research vol. 55, issue 12, 2019 p. 10191-10217, https://doi.org/10.1029/2018WR024295  Accès ouvert |
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| Année | 2019 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20180276 |
| Éditeur | American Geophysical Union |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1029/2018WR024295 |
| Media | papier; en ligne; numérique |
| Formats | pdf; html |
| Province | Colombie-Britannique; Alberta |
| Région | Montagnes Rocheuses |
| Lat/Long OENS | -122.0000 -115.0000 54.0000 49.0000 |
| Sujets | ressources en eau souterraine; aquifères; réseaux géodésiques; eaux de surface; rivières; bassins versants; glaciers; glace; niveaux d'eau; milieu hydrologique; budget hydrologique; télédétection;
imagerie par satellite; gravité; géodésie par satellite; débits; Changement climatique; hydrogéologie; géologie de l'environnement; géophysique; Nature et environnement; Sciences et technologie |
| Illustrations | cartes de localisation; profiles gravimétriques; diagrammes de distribution; figures; tableaux; graphiques |
| Programme | Géoscience des eaux souterraines Évaluation nationale d'aquifères |
| Diffusé | 2019 11 06 |
| Résumé | (disponible en anglais seulement)
As a result of global climate change, glacial melt occurs worldwide. Major impacts are expected on the dynamics of aquifers and rivers in and downstream of
mountain ranges. This study aims at quantifying the melt water input fluxes into the watersheds draining the Canadian Rocky Mountains and improving our knowledge about the fate of meltwater within the hydrological cycle. To this end, we use (1)
time-variable gravity data from GRACE satellites that are decomposed into water storage compartments; (2) an ensemble of glacier information: in situ observations, geodetic measurements, and a mass balance model; and (3) in situ surface water and
groundwater level observations. The glacier mass balance model estimates a total ice mass change of ~43 Gt for the period 2002-2015, corresponding to an average of -3,056 (±2,275) MCM/yr (million cubic meters per year). 78% of the meltwater total
flows west of the continental divide (to the Pacific Ocean), while 22% flows east of the continental divide (to the Arctic Ocean and Hudson Bay). However, the GRACE-derived total water storage increases, suggesting that groundwater storage
compensates for the glacial melt with an increase of 3,976 (±2,819) MCM/yr. A plausible explanation is that meltwater is not immediately flowing down in rivers but rather stored locally in aquifers. This hypothesis is supported by in situ river base
flow observations, showing base flow increase in basins draining the ice melt, mostly west of the continental divide. Direct in situ evidences such as well water level time series are not sufficiently available to fully support this
hypothesis.
The budget-based glacier mass loss estimates the ice loss at 44 Gt for the period 2002-2015, corresponding to an average of 3.1 Gt/yr. The total error is calculated through comparison with in-situ data, geodetic ice thickness change
measurements, and independent model results. Uncertainty is estimated at +/- 2.3 Gt/yr, i.e., the model-derived ice mass loss estimation falls in the range [-0.8 -5.4] Gt/yr. In contrast, the GRACE TWS trend signal, after removal of all contributors
other than glacier ice and groundwater, falls within the range [-0.4 +2] Gt/yr. These results suggest that increased groundwater storage partially compensates for the decreased glacier mass, at a rate of [+0.4 +7.2] Gt/yr. To explore this hypothesis,
observations from other authors, groundwater storage change estimates from a global groundwater model, and river base-flow analysis are used and co-interpreted. While a groundwater storage model suggests that glaciers would be the main contribution
to a potential storage increase, in-situ river flow analysis suggests a spatially heterogeneous base-flow response depending on the watershed and its groundwater residence time. This article raises questions on discordant observations from
multi-source datasets and explores explanatory scenarios. This inter-disciplinary approach triggers further investigation regarding the fate of glacier melt water, and encourage further work using data from the GRACE-FO mission. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Étude sur l'impact direct de la fonte des glaciers de la cordillières des rocheuses canadienne sur la ressource en eau souterraine. |
| GEOSCAN ID | 313073 |
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