A DECISION FRAMEWORK FOR
MANAGING THE SPIRIT LAKE AND
TOUTLE RIVER SYSTEM AT
MOUNT ST. HELENS
Committee on Long-Term Management of the Spirit Lake/
Toutle River System in Southwest Washington
Committee on Geological and Geotechnical Engineering
Board on Earth Sciences and Resources
Water Science and Technology Board
Division on Earth and Life Studies
Board on Environmental Change and Society
Division of Behavioral and Social Sciences and Education
A Consensus Study Report of
THE NATIONAL ACADEMIES PRESS
THE NATIONAL ACADEMIES PRESS • 500 Fifth Street, NW • Washington, DC 20001
This activity is supported by the U.S. Department of Agriculture’s U.S. Forest Service under Grant No. 16-DG-11261952-008. Any opinions, findings, conclusions, or recommendations expressed in this publication do not necessarily reflect the views of any organization or agency that provided support for the project.
International Standard Book Number-13: 978-0-309-46444-4
International Standard Book Number-10: 0-309-46444-7
Digital Object Identifier: https://doi.org/10.17226/24874
Additional copies of this publication are available for sale from the National Academies Press, 500 Fifth Street, NW, Keck 360, Washington, DC 20001; (800) 624-6242 or (202) 334-3313; http://www.nap.edu.
Copyright 2018 by the National Academy of Sciences. All rights reserved.
Printed in the United States of America
Cover: Front image: Mount St. Helens, 100 miles south of Seattle, Washington, boasts the deadliest and most economically destructive volcanic explosion in U.S. history when it erupted on May 18, 1980. Its original height of 9,667 feet was reduced to 8,363 feet. Spirit Lake, seen here, was raised approximately 200 feet in the eruption. The image is courtesy of Barry Maas and his images are available at https://www.flickr.com/photos/bmaas. The rear cover is courtesy of C. Scott Cameron of GeoLogical Consulting, LLC, and a member of the Board on Earth Sciences and Resources. View is looking east to the upper Toutle River valley, Mount St. Helens, and the 1980 blast zone, Spirit Lake, and in the distance, Mount Adams. Taken October 31, 2017.
Suggested citation: National Academies of Sciences, Engineering, and Medicine. 2017. A Decision Framework for Managing the Spirit Lake and Toutle River System at Mount St. Helens. Washington, DC: The National Academies Press. doi: https://doi.org/10.17226/24874.
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COMMITTEE ON LONG-TERM MANAGEMENT OF THE SPIRIT LAKE/TOUTLE RIVER SYSTEM IN SOUTHWEST WASHINGTON
GREGORY B. BAECHER, NAE (Chair), University of Maryland, College Park
JOHN BOLAND, Johns Hopkins University, Baltimore, Maryland
THOMAS DUNNE, NAS, University of California, Santa Barbara
YOUSSEF HASHASH, University of Illinois at Urbana-Champaign
JOHN KUPFER, University of South Carolina, Columbia
NING LU, Colorado School of Mines, Golden
BASIL STUMBORG, BC Hydro, Vancouver, British Columbia, Canada
KATHLEEN TIERNEY, University of Colorado Boulder
DESIREE TULLOS, Oregon State University, Corvallis
GREG A. VALENTINE, University at Buffalo, The State University of New York
Committee Unpaid Consultant
LEONARD A. SHABMAN, Resources for the Future, Washington, District of Columbia
National Academies of Sciences, Engineering, and Medicine Staff
SAMMANTHA L. MAGSINO, Senior Program Officer
PAUL STERN, Scholar*
EDMOND DUNNE, Program Officer*
COURTNEY R. DEVANE, Administrative Coordinator
NICHOLAS D. ROGERS, Financial and Research Associate
* Until June 2017.
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The 1980 eruption of Mount St. Helens resulted in a massive debris avalanche and pyroclastic flow into the Toutle River valley. This event caused sweeping changes to the hydrology of the Toutle River and to the Cowlitz River into which the Toutle flows. The headwater of the Toutle River in Spirit Lake was blocked by volcanic debris hundreds of feet in depth, and the lake bottom itself was raised 200 feet. Catastrophic breaching of the blockage by high water in Spirit Lake could release more than 300,000 acre-feet of water and 2.4 billion cubic yards of sediment into the Toutle, Cowlitz, and Columbia Rivers, causing massive damage and loss of life.
The U.S. Forest Service (USFS) is responsible for a large part of the region around and including Mount St. Helens and Spirit Lake. Following the eruption, several alternatives were considered for draining the lake and maintaining a safe water level. The solution chosen was to bore a tunnel through Harry’s Ridge into the Coldwater Creek drainage and thus into Coldwater Lake. Now, some 36 years later, that tunnel has undergone and is again in need of expensive repairs. While the tunnel is located on land managed by the USFS, it was constructed by the U.S. Army Corps of Engineers (USACE). Using funds provided by the USFS, the USACE has inspected and repaired the tunnel since its construction. The U.S. Geological Survey (USGS) has responsibility for monitoring geologic activity in the region.
The technical issues precipitated by the 1980 eruption include management not only of Spirit Lake and its drainage but also of the massive volume of sediments resulting from the eruption. Those sediments continue to be transported down the North Fork Toutle River where they create hazards to the environment, flood risk, and hazards to navigation. In 1989, the USACE constructed a sediment retention structure (SRS) in the North Fork Toutle River to minimize sediment transport into the
Toutle and Cowlitz Rivers by trapping that sediment upstream of the SRS. Whereas the SRS provided a temporary solution for sediment management downstream, its existence and management affects other aspects of river management, for example, restoring passage for anadromous fish in the system and protecting cultural and recreational resources.
Today, a complex system of infrastructure exists to control water and sediment flow. This infrastructure is subject to multiple natural hazards, including volcanic, seismic, and hydrologic, and is the responsibility of separate federal, state, and local agencies. The need for millions of dollars of repairs on the tunnel prompted members of Congress to request that the USFS, the USACE, and the USGS develop a long-term plan to manage water levels. An ad hoc committee of the National Academies of Sciences, Engineering, and Medicine was ultimately convened at the request of the USFS to “recommend a framework for technical decision making related to long-term management of risks related to the Spirit Lake and Toutle River system in light of the different priorities of federal, tribal, state, relevant local authorities, and other entities.” The management of a system of this complexity requires a methodical framework suitable to the systems aspects of the problem and the uncertainties that attend it. Identifying such a framework has been the committee’s goal.
The committee is grateful for the competence and efficiency of the National Academies staff assigned to this project. Complicated logistical arrangements were handled with ease and good humor by Nicholas D. Rogers, financial and research associate, and Courtney R. DeVane, administrative assistant. Leonard A. Shabman, resident scholar at Resources for the Future, served as an unpaid consultant to the committee. Paul Stern, a National Academies scholar, contributed to the committee’s meetings and report, as did Edmond Dunne. We would also like to thank National Academies staff member David Policansky for providing comments on the draft report.
The staff director for the project has been Sammantha L. Magsino, senior program officer with the Board on Earth Sciences and Resources.
Without her, this study would not have been successful. She has an ability to convert energetic discussion into consensus, miscellaneous prose into coherent text, and rambling discourse into a rational report.
Gregory B. Baecher
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This Consensus Study Report was reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise. The purpose of this independent review is to provide candid and critical comments that will assist the National Academies of Sciences, Engineering, and Medicine in making each published report as sound as possible and to ensure that it meets the institutional standards for quality, objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process.
We thank the following individuals for their review of this report:
Shane J. Cronin, The University of Auckland and GNS Science Ltd., New Zealand
Robin Gregory, Decision Research, Halfmoon Bay, British Columbia, Canada
William Hansmire, NAE, WSP USA, Los Angeles, California
James K. Mitchell, NAE/NAS, Virginia Polytechnic Institute and State University, Blacksburg
Doug Plasencia, Moffatt & Nichol, Phoenix, Arizona
Bob Royer, Gallatin Public Affairs, Seattle, Washington
Jeff Rubin, Tualatin Valley Fire and Rescue, Tigard, Oregon
Colin Thorne, University of Nottingham, Nottingham, United Kingdom
Thomas Yancey, Texas A&M University, College Station
Although the reviewers listed above provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations of this report nor did they see the final draft before its release. The review of this report was overseen by John Christian, an
independent consultant, and Catherine Kling of Iowa State University. They were responsible for making certain that an independent examination of this report was carried out in accordance with the standards of the National Academies and that all review comments were carefully considered. Responsibility for the final content rests entirely with the authoring committee and the National Academies.
The committee met four times over a 6-month period: three times in Kelso, Washington, and a final meeting in Washington, DC. In the course of those meetings, the committee consulted with interested and affected parties, including those from the private and public sectors. The committee would like to thank, in alphabetical order: Gene Crocker, Cowlitz Game and Anglers Club; Gregory Drew, Drew’s Grocery, Toutle; Joe Gardener, Cowlitz County Board of Commissioners; Ashley Helenberg, Port of Longview; Dave Howe, Regional Habitat Program, Washington Department of Fish and Wildlife; Claudia Hunter, Toutle Valley Community Association; Steve Ogden, Pacific-Cascade Region, Washington Department of Natural Resources; Nathan Reynolds, Natural Resources Department, Cowlitz Indian Tribe; Ernie Schnabler, Cowlitz County Emergency Management; and Ray Yurkewycz, Mount St. Helens Institute. The committee also met with and heard presentations from representatives of local, state, and federal agencies. They included, alphabetically, from the USACE, Sean Askelson, Jeremy Britton, Christine Budai, Angela Duren, Tim Kuhn, Paul Sclafani, and David Scofield; from the USFS, Charlie Crisafulli, Gordon Grant, Tedd Huffman, Gina Owens, and Jim Peña; and from the USGS, Jon Major.
During its open session meetings, town hall discussions, and site visits in the region, the committee had the opportunity to interact with and learn from numerous individuals from affected communities and various interest groups. Individuals also provided written feedback to the committee. Their voluntary engagement with the committee is an indication of the importance placed on the sound and responsive management of the Spirit Lake and Toutle River system.
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