Discharge of groundwater flow to Potter Cove on King George Island, Antarctic Peninsula

Abstract

Abstract. There are only a small number of recent publications discussing glacial runoff in Antarctica, and even fewer of them deal with the groundwater flow discharge. This paper focuses on the groundwater flow aspects and is based on a detailed study performed on a small hydrological catchment, informally called Potter basin, located on King George Island (KGI; Isla 25 de Mayo), South Shetland Islands, at the northern tip of the Antarctic Peninsula. The basin is representative for the rugged coastline of the northern Antarctic Peninsula and is discussed as a case study for the possible future evolution of similar basins further to the south. A conceptual hydrogeological model has been defined using vertical electrical soundings (VESs), geological and hydrogeological surveying methods, geomorphological interpretation based on satellite imagery, permeability tests, piezometric level measurements, meteorological, geocryological and glaciological data sets. The transmissivities of the fluvial talik aquifer and suprapermafrost aquifer range from 162.0 to 2719.9×10-5 m2 s−1 and in basaltic fissured aquifers from 3.47 to 5.79×10-5 m2 s−1. The transmissivities found in the active layer of hummocky moraines amount to 75.23×10-5 m2 s−1 and to 163.0×10-5 m2 s−1 in the sea deposits, and in the fluvioglacial deposits, they were observed between 902.8 and 2662.0×10-5 m2 d−1. Finally, the groundwater flow discharge was assessed to 0.47 m3 s−1 (during the austral summer months of January and February), and the total groundwater storage was estimated to 560×103 m3. The Antarctic Peninsula region has experienced drastic climatological changes within the past five decades. Under the Intergovernmental Panel on Climate Change scenarios, a further warming of the polar regions can be expected as polar amplification of our changing climate. Although the basin in consideration is small and results are valid only during austral summers with surface air temperatures above the freezing point, it serves as model study that can be regarded as representative for the western coastline of the Antarctic Peninsula further south under expected future warming, with surface air temperatures periodically surpassing freezing point. This data can be used to adjust glacial mass balance assessments in the region and to improve the understanding of coastal sea water processes, and their effects on the marine biota, as a consequence of the global climate change.