Impact of permafrost dynamics on Arctic groundwater ow systems with application to the evolution of spring and lake taliks

Scheidegger, JM (2013) Impact of permafrost dynamics on Arctic groundwater ow systems with application to the evolution of spring and lake taliks. Doctoral thesis, University of East Anglia.

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ow in permafrost is restricted to unfrozen zones, known as
taliks. There is an interaction between groundwater
ow and heat
ow, because
the permafrost distribution determines the occurrence of groundwater,
but groundwater also contributes to advective heat transport in
uencing the
distribution of permafrost. However, the advective heat
ow 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
uxes can be more signi�cant. This
thesis aims to improve understanding of the impacts of permafrost dynamics
on Arctic groundwater
ow systems for past and predicted climate change.
Numerical modelling of coupled heat and
ow including phase change
of water/ice is used to study di�erent environments; lakes in a periglacial
environment, and lakes and springs in a proglacial terrain. Results show
that the transient e�ects of heat storage can in
uence 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
ow can in
uence the
permafrost distribution by permafrost erosion and aggregation. The magnitude
of heat advection is driven by topographically driven groundwater
and the release of groundwater from elastic storage. The latter is signi�cant
in previously glaciated areas that have undergone a large change in hydraulic
head over time. In partially frozen ground, the choice of the permafrostpermeability-
reduction function is crucial to quantify groundwater
ow and
advective heat
ow. The occurrence of through taliks is in
uenced by the
regional scale groundwater
ow, but taliks also in
uence the regional scale
hydrogeologic system by reversal of the general groundwater
ow direction.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Environmental Sciences
Depositing User: Users 2259 not found.
Date Deposited: 11 Jun 2014 13:50
Last Modified: 11 Jun 2014 13:50

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