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GEOREF RECORD

Mount Baker lahars and debris flows, ancient, modern, and future

David S. Tucker, Kevin M. Scott, Eric E. Grossman and Scott Linneman
Mount Baker lahars and debris flows, ancient, modern, and future (in Trials and tribulations of life on an active subduction zone; field trips in and around Vancouver, Canada, Shahin Dashtgard (editor) and Brent Ward (editor))
Field Guide (Geological Society of America) (October 2014) 38: 33-52

Abstract

The Middle Fork Nooksack River drains the southwestern slopes of the active Mount Baker stratovolcano in northwest Washington State. The river enters Bellingham Bay at a growing delta 98 km to the west. Various types of debris flows have descended the river, generated by volcano collapse or eruption (lahars), glacial outburst floods, and moraine landslides. Initial deposition of sediment during debris flows occurs on the order of minutes to a few hours. Long-lasting, down-valley transport of sediment, all the way to the delta, occurs over a period of decades, and affects fish habitat, flood risk, gravel mining, and drinking water. Holocene lahars and large debris flows (>10 (super 6) m (super 3) ) have left recognizable deposits in the Middle Fork Nooksack valley. A debris flow in 2013 resulting from a landslide in a Little Ice Age moraine had an estimated volume of 100,000 m (super 3) , yet affected turbidity for the entire length of the river, and produced a slug of sediment that is currently being reworked and remobilized in the river system. Deposits of smaller-volume debris flows, deposited as terraces in the upper valley, may be entirely eroded within a few years. Consequently, the geologic record of small debris flows such as those that occurred in 2013 is probably very fragmentary. Small debris flows may still have significant impacts on hydrology, biology, and human uses of rivers downstream. Impacts include the addition of waves of fine sediment to stream loads, scouring or burying salmon-spawning gravels, forcing unplanned and sudden closure of municipal water intakes, damaging or destroying trail crossings, extending river deltas into estuaries, and adding to silting of harbors near river mouths.


ISSN: 2333-0937
EISSN: 2333-0945
Serial Title: Field Guide (Geological Society of America)
Serial Volume: 38
Title: Mount Baker lahars and debris flows, ancient, modern, and future
Title: Trials and tribulations of life on an active subduction zone; field trips in and around Vancouver, Canada
Author(s): Tucker, David S.Scott, Kevin M.Grossman, Eric E.Linneman, Scott
Author(s): Dashtgard, Shahineditor
Author(s): Ward, Brenteditor
Affiliation: Western Washington University, Geology Department, Bellingham, WA, United States
Affiliation: Simon Fraser University, Department of Earth Sciences, Burnaby, BC, Canada
Pages: 33-52
Published: 201410
Text Language: English
Publisher: Geological Society of America, Boulder, CO, United States
References: 30
Accession Number: 2015-001556
Categories: Engineering geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sect., 2 tables, sketch maps
N48°37'00" - N49°00'00", W123°02'60" - W120°40'00"
Secondary Affiliation: U. S. Geological Survey, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201501
Program Name: USGSOPNon-USGS publications with USGS authors
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