Geometry and flow conditions of subglacial water at South Cascade Glacier, Washington State, U.S.A.; an analysis of tracer injections
Abstract Tracers were injected into South Cascade Glacier to determine the flow condition and geometry of the subglacial water system. Results indicate that two distinct drainage basins on the glacier feed the two main streams flowing from the glacier. In the largest basin, two parallel drainage net...
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Cambridge University Press (CUP)
1993
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Online Access: | http://dx.doi.org/10.1017/s0022143000015793 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000015793 |
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crcambridgeupr:10.1017/s0022143000015793 2024-03-03T08:46:05+00:00 Geometry and flow conditions of subglacial water at South Cascade Glacier, Washington State, U.S.A.; an analysis of tracer injections Fountain, Andrew G. 1993 http://dx.doi.org/10.1017/s0022143000015793 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000015793 en eng Cambridge University Press (CUP) Journal of Glaciology volume 39, issue 131, page 143-156 ISSN 0022-1430 1727-5652 Earth-Surface Processes journal-article 1993 crcambridgeupr https://doi.org/10.1017/s0022143000015793 2024-02-08T08:41:37Z Abstract Tracers were injected into South Cascade Glacier to determine the flow condition and geometry of the subglacial water system. Results indicate that two distinct drainage basins on the glacier feed the two main streams flowing from the glacier. In the largest basin, two parallel drainage networks exist, one englacial and the other subglacial. The englacial system is an arboresecent network of conduits, whereas the subglacial system is a distributed flow system. Both systems connect to a single subglacial conduit which appears as a stream at the glacier’s terminus. The comparison between the travel time of the tracers and stream discharge indicated that the single conduit was pressurized in July and partly filled in August and September. To estimate the flow geometry (e.g. path length, flow depth and velocity), the advection-diffusion equation was formulated to express the water velocity as a function of water depth. Longitudinal dispersion of the tracer was calculated from the shear in longitudinal water velocity. Results indicate that the flow is very wide compared to its depth and that the path is sinuous. The estimated flow speed in the conduits is an order of magnitude larger than the measured speed through the glacier, indicating that other flow processes, probably englacial, route the water much more slowly. The other, smaller, basin drains the water from the surface to the subglacial distributed flow system. Based on the travel time of the individual concentration peaks, the water could be flowing through a linked-cavity system or interconnected bands of highly permeable debris separated by zones of less permeability. Article in Journal/Newspaper Journal of Glaciology Cambridge University Press Cascade Glacier ENVELOPE(-140.504,-140.504,60.249,60.249) Journal of Glaciology 39 131 143 156 |
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Open Polar |
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Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
topic |
Earth-Surface Processes |
spellingShingle |
Earth-Surface Processes Fountain, Andrew G. Geometry and flow conditions of subglacial water at South Cascade Glacier, Washington State, U.S.A.; an analysis of tracer injections |
topic_facet |
Earth-Surface Processes |
description |
Abstract Tracers were injected into South Cascade Glacier to determine the flow condition and geometry of the subglacial water system. Results indicate that two distinct drainage basins on the glacier feed the two main streams flowing from the glacier. In the largest basin, two parallel drainage networks exist, one englacial and the other subglacial. The englacial system is an arboresecent network of conduits, whereas the subglacial system is a distributed flow system. Both systems connect to a single subglacial conduit which appears as a stream at the glacier’s terminus. The comparison between the travel time of the tracers and stream discharge indicated that the single conduit was pressurized in July and partly filled in August and September. To estimate the flow geometry (e.g. path length, flow depth and velocity), the advection-diffusion equation was formulated to express the water velocity as a function of water depth. Longitudinal dispersion of the tracer was calculated from the shear in longitudinal water velocity. Results indicate that the flow is very wide compared to its depth and that the path is sinuous. The estimated flow speed in the conduits is an order of magnitude larger than the measured speed through the glacier, indicating that other flow processes, probably englacial, route the water much more slowly. The other, smaller, basin drains the water from the surface to the subglacial distributed flow system. Based on the travel time of the individual concentration peaks, the water could be flowing through a linked-cavity system or interconnected bands of highly permeable debris separated by zones of less permeability. |
format |
Article in Journal/Newspaper |
author |
Fountain, Andrew G. |
author_facet |
Fountain, Andrew G. |
author_sort |
Fountain, Andrew G. |
title |
Geometry and flow conditions of subglacial water at South Cascade Glacier, Washington State, U.S.A.; an analysis of tracer injections |
title_short |
Geometry and flow conditions of subglacial water at South Cascade Glacier, Washington State, U.S.A.; an analysis of tracer injections |
title_full |
Geometry and flow conditions of subglacial water at South Cascade Glacier, Washington State, U.S.A.; an analysis of tracer injections |
title_fullStr |
Geometry and flow conditions of subglacial water at South Cascade Glacier, Washington State, U.S.A.; an analysis of tracer injections |
title_full_unstemmed |
Geometry and flow conditions of subglacial water at South Cascade Glacier, Washington State, U.S.A.; an analysis of tracer injections |
title_sort |
geometry and flow conditions of subglacial water at south cascade glacier, washington state, u.s.a.; an analysis of tracer injections |
publisher |
Cambridge University Press (CUP) |
publishDate |
1993 |
url |
http://dx.doi.org/10.1017/s0022143000015793 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000015793 |
long_lat |
ENVELOPE(-140.504,-140.504,60.249,60.249) |
geographic |
Cascade Glacier |
geographic_facet |
Cascade Glacier |
genre |
Journal of Glaciology |
genre_facet |
Journal of Glaciology |
op_source |
Journal of Glaciology volume 39, issue 131, page 143-156 ISSN 0022-1430 1727-5652 |
op_doi |
https://doi.org/10.1017/s0022143000015793 |
container_title |
Journal of Glaciology |
container_volume |
39 |
container_issue |
131 |
container_start_page |
143 |
op_container_end_page |
156 |
_version_ |
1792501977332056064 |