thumbnail

Seasonal variability in hydrologic-system response to intense rain events, Matanuska Glacier, Alaska, U.S.A.

Annals of Glaciology

By:
, , , , , ,
DOI: 10.3189/172756499781821715

Links

Abstract

Two rain events at Matanuska Glacier illustrate how subglacial drainage system development and snowpack conditions affect hydrologic response at the terminus. On 21 and 22 September 1995, over 56 mm of rain fell in the basin during a period usually characterized by much drier conditions. This event caused an 8-fold increase in discharge and a 47-fold increase in suspended-sediment concentration. Peak suspended-sediment concentration exceeded 20 kg m-3, suggesting rapid evacuation of stored sediment. While water discharge returned to its pre-storm level nine days after the rain ceased, suspended-sediment concentrations took about 20 days to return to pre-storm levels. These observations suggest that the storm influx late in the melt season probably forced subglacial water into a more distributed system. In addition, subglacially transported sediments were supplemented to an unknown degree by the influx of storm-eroded sediments off hillslopes and from tributary drainage basins. A storm on 6 and 7 June 1997, dropped 28 mm of rain on the basin demonstrating the effects of meltwater retention in the snowpack and englacial and subglacial storage early in the melt season. Streamflow before the storm event was increasing gradually owing to warming temperatures; however, discharge during the storm and the following week increased only slightly. Suspended-sediment concentrations increased only a small amount, suggesting the drainage system was not yet well developed, and much of the runoff occurred across the relatively clean surface of the glacier or through englacial channels.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Seasonal variability in hydrologic-system response to intense rain events, Matanuska Glacier, Alaska, U.S.A.
Series title:
Annals of Glaciology
DOI:
10.3189/172756499781821715
Volume
28
Issue:
1
Year Published:
1999
Language:
English
Publisher:
Ingenta Connect
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Annals of Glaciology
First page:
267
Last page:
271
Number of Pages:
5