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Title: Impact of permafrost dynamics on Arctic groundwater flow systems with application to the evolution of spring and lake taliks
Author: Scheidegger, Johanna Michaela
Awarding Body: University of East Anglia
Current Institution: University of East Anglia
Date of Award: 2013
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Groundwater flow in permafrost is restricted to unfrozen zones, known as taliks. There is an interaction between groundwater flow and heat flow, because the permafrost distribution determines the occurrence of groundwater, but groundwater also contributes to advective heat transport influencing the distribution of permafrost. However, the advective heat flow component is small where the hydraulic gradient is low, or where recharge is limited. Conversely, where recharge is not driven by precipitation, as for example found under a wet based glacier, groundwater fluxes can be more significant. This thesis aims to improve understanding of the impacts of permafrost dynamics on Arctic groundwater flow systems for past and predicted climate change. Numerical modelling of coupled heat and fluid flow including phase change of water/ice is used to study different environments; lakes in a periglacial environment, and lakes and springs in a proglacial terrain. Results show that the transient effects of heat storage can influence the present day distribution of permafrost. This is especially pronounced underneath surface water bodies, where there are cases for which under a steady state scenario no through talik is expected, but there are through taliks under a transient scenario. In addition, heat advection by groundwater flow can influence the permafrost distribution by permafrost erosion and aggregation. The magnitude of heat advection is driven by topographically driven groundwater flow and the release of groundwater from elastic storage. The latter is significant in previously glaciated areas that have undergone a large change in hydraulic head over time. In partially frozen ground, the choice of the permafrost permeability-reduction function is crucial to quantify groundwater flow and advective heat flow. The occurrence of through taliks is influenced by the regional scale groundwater flow, but taliks also influence the regional scale hydrogeologic system by reversal of the general groundwater flow direction.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available