Geologic Publications for Mount Rainier

Analysis of channel width chagne on the Nisqually and White River Watersheds within Mount Rainier National Park

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Author(s): Paige Shinall, Gwen Lindberg, Robert P. Jost, Taylor R. Kenyon, Kena Fox-Dobbs, David Birlenbach

Category: PRESENTATION
Document Type: Poster 265-8
Publisher: Geological Society of America Abstracts with Programs
Published Year: 2024
Volume: 56
Number: 5
Pages:
DOI Identifier: 10.1130/abs/2024AM-405194
ISBN Identifier:
Keywords:

Abstract:
The dynamic and turbulent nature of steep mountainous rivers necessitate the development of new methods to better understand historic and ongoing geomorphic changes in these watersheds. The migration of these types of rivers has direct implications for visitor access and land management in Mount Rainier National Park (MORA), especially when located near major visitor areas such as the Nisqually River, occupying the southwest region of the park, and the White River, in the northeast region of the park. It is more important than ever to understand the historical effects of hydrologic events, such as floods and debris flows, in order to better prepare responses to the likely increasing frequency and/or intensity of these events in the face of climate change.

This study used open-source GIS software to quantify the change in active channel width using historical satellite imagery available through USGS EarthExplorer for the Nisqually and White River. The study area encompassed a 10 km stretch of the Nisqually and 15 km along the White River, each with a time series including five images spanning from 1955-2019. This included imaging from 2006 and 2009 to encompass a special interest in a historic flooding event that took place on November 6th and 7th of 2006 throughout MORA. This flood damaged park infrastructure and created limits to visitor access with repercussions that are still being addressed in the park to this day.

A GIS model was created to automate the process of extracting channel width measurements from active channel margins. The resulting widths were assessed to evaluate channel width over time and identify areas of significant change as a result of flooding or other environmental processes. Following the 2006 flood, we noted a 27% increase in the average channel width of the Nisqually and a 21% increase in the average channel width of the White River. Combining our results with field surveys and hydrologic records allowed us to confirm flooding events as drivers of the mapped channel width change in these areas. Using these river monitoring efforts in MORA can aid park management in making scientifically-backed decisions. This procedure can be applied in other river systems to analyze channel margin change and, when coupled with site specific data and context, can assist in understanding past and future hazards.

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View Report [External Link]

Suggested Citations:
In Text Citation:
Shinall and others (2024) or (Shinall et al., 2024)

References Citation:
Shinall, P., G. Lindberg, R.P. Jost, T.R. Kenyon, K. Fox-Dobbs, and D. Birlenbach, 2024, Analysis of channel width chagne on the Nisqually and White River Watersheds within Mount Rainier National Park: Poster 265-8, Geological Society of America Abstracts with Programs, Vol. 56, No. 5, doi: 10.1130/abs/2024AM-405194.