Meltwater characteristics as indicators of the hydrology of Alpine glaciers

Collins, David Nigel (1979) Meltwater characteristics as indicators of the hydrology of Alpine glaciers. PhD thesis, University of Nottingham.

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Abstract

Hydrological, hydrochemical and sedimentological observations were undertaken in the catchments of Feevispa (Feegletscher), Findelenbach(Findelengletscher) and Gornera (Gornergletscher), Swiss Alps, in an attempt to use meltwater characteristics as indicators of the nature and functioning of glacial hydrological systems.

Annual and seasonal hydrographs of the Feevispa allowed calculation of catchment water balance. Considerable annual variation resulted from excess icemelt over snow accumulation giving greater outputs than inputs. Diurnal hydrograph analysis showed that large quantities of water are stored in Feegletscher and Gornergletscher.

Rapid erratic fluctuations of subglacial sediment supply caused involutions in daily clockwise suspended sediment concentration-discharge hysteresis loops in the Gornera. During draining of the Gornera, exceptionally high discharges evacuated large quantities of sediment from beneath Gornergletscher, but bequeathed no lasting impact on conduit capacity. Close interval sampling and continuous monitoring of sediment concentration permit interpretation of the nature of ice-meltwater-sediment interactions on Alpine glacier beds.

Chemical composition of meltwaters emerging from the glacier portals was monitored during several ablation seasons. Electrical conductivity, a surrogate measure of ionic content, was continuously recorded and Na+, K+, Ca2+ and Mg2+ determined by atomic absorption spectrophotometry. Meltwaters from glacier surfaces have low solute contents, of atmospheric origins, whereas after passage through internal conduits; meltwaters become chemically enriched from lithospheric contact. Marked diurnal variations (clockwise hysteresis) of solute concentration in portal meltstreams reflect the mixing in varying proportions through time of waters of different compositions, delimiting trapezoidal solute concentration discharge relationships.

Two components of discharge through Findelengletscher and Gornergletscher were separated on the basis of chemical composition using a simple mass-balance mixing model. A large proportion of total flow passes rapidly through major moulin-arterial canal networks. For basal flow, two contrasting regimes were discriminated, both independent of (Findelengletscher) and interlinked with (Gornergletscher) cavity storage at the ice-bedrock interface.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Grove, J.M.
Subjects: G Geography. Anthropology. Recreation > GB Physical geography
Faculties/Schools: UK Campuses > Faculty of Social Sciences, Law and Education > School of Geography
Item ID: 13034
Depositing User: EP, Services
Date Deposited: 17 Jan 2013 09:14
Last Modified: 16 Sep 2016 06:01
URI: http://eprints.nottingham.ac.uk/id/eprint/13034

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