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标题：Diurnal fluctuations in borehole water levels: configuration of the drainage system beneath Bench Glacier, Alaska, USA
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作者：T.J. Fudge ; Neil F. Humphrey ; Joel T. Harper 等
期刊名称：Journal of Glaciology
印刷版ISSN：0022-1430
电子版ISSN：1727-5652
出版年度：2008
卷号：54
期号：185
页码：297-306
DOI：10.3189/002214308784886072
出版社：Cambridge University Press
摘要：Water levels were measured in boreholes spaced along the entire length of Bench Glacier, Alaska, USA, for a period in excess of 2 years. Instrumented boreholes were arranged as nine pairs along the center line of the glacier and an orthogonal grid of 16 boreholes in a 3600 m 2 region at the center of the ablation area. Diurnal fluctuations of the water levels were found to be restricted to the late melt season. Pairs of boreholes spaced along the length of the ablation area often exhibited similar fluctuations and diurnal changes in water levels. Three distinct and independent types of diurnal fluctuations in water level were observed in clusters of boreholes within the grid of boreholes. Head gradients suggest water did not flow between clusters, and a single tunnel connecting the boreholes could not explain the observed pattern of diurnal water-level fluctuations. Inter-borehole and borehole-cluster connectivity suggests the cross-glacier width of influence of a segment of the drainage system connected to a borehole was limited to tens of meters. A drainage configuration whereby boreholes are connected to a somewhat distant tunnel by drainage pipes of differing lengths, often hundreds of meters, is shown with a numerical test to be a plausible explanation for the observed borehole behavior.