236 Recent Advances in Hydrogeology

Wednesday, 22 October 2025
8:00 AM - 12:00 PM
HBGCC, 211

Classifying Pan-Arctic Supra-Permafrost Aquifer Function Under Present and Projected Conditions

Paper number: 236-4
Program: Technical Sessions
Time: 8:50 AM – 9:05 AM

Authors

Abstract

The changing Arctic climate is affecting groundwater flow and storage in supra-permafrost aquifers due to groundwater recharge changes and thaw-driven alterations to aquifer properties and connectivity. Changes to shallow subsurface hydrological processes can drive extensive ecological and biogeochemical alterations in addition to potential surface hydrologic regime shifts. This study uses a pan-Arctic geospatial approach to classify supra-permafrost aquifers as topography-limited (characterized by low permeability, wet climate, and/or low slopes) or recharge-limited (high permeability, dry climate and/or steep slopes) based on the water table ratio framework. Under current conditions, the continuous and discontinuous permafrost zones were determined to be predominantly (92%) topography-limited, with a net increase of 1% by the year 2100 under RCP2.6 and RCP8.5 conditions. This apparent stability masks local-scale heterogeneity, with change in aquifer function projected at dispersed locations throughout the Arctic, and in clustered hot spots of change in Siberia, Alaska, and Nunavut. Peatlands have more heterogeneous aquifer function than the regional average (62% topography-limited). Coastal zones around the Arctic are more topography-limited (96%) compared to the overall average, leaving them especially vulnerable to ocean-driven impacts on groundwater such as subsurface seawater intrusion or groundwater flooding. Arctic coasts in Siberia and eastern Canada are also particularly susceptible to water table rise due to high relative sea-level rise which may exceed the active layer thickness and result in substantive changes to saturation. The sensitivity of the classification results to input values, particularly hydraulic conductivity, remains a source of uncertainty in the analysis. Despite the sparsity of Arctic data, however, the available open-source datasets provide valuable insight into broad spatiotemporal trends in aquifer function and highlight particularly vulnerable regions. These results provide new context for conceptualizing changes to shallow Arctic aquifers as the climate evolves in the 21st century.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-412171

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