About the Talk

Ian Miller of Washington Sea Grant (University of Washington) will discuss Coastal Response to Dam Removals on the Elwah River: Present and Future at 4 pm on Saturday, January 12 in Port Townsend as part of the Jefferson Land Trusts Geology Group Lecture Series.

For nearly a century, two dams on the Elwha River disrupted the flow of sediment from the Olympic Mountains to the Strait of San Juan de Fuca, contributing to the erosion of the Elwha River delta just west of Port Angeles and altering coastal habitat both to the east and west.

Removal of the dams was completed last fall, and now the river is free to flow in its natural course. Already, salmon have returned to the river and are starting to spawn. Researchers from a variety of state and government agencies are tracking how the river’s ecosystem responds with millions of tons of sediment make their way north to the coast.

Ian’s talk will provide a “status report” on how the coastal zone is responding to the removal of the dams and rapid erosion of the sediment impounded behind them.

About the Speaker

Based at Peninsula College, Dr. Miller focuses on research, education, and outreach on natural coastal hazards on the Olympic Peninsula, including hazards due to climate change, tsunamis, and chronic erosion. He has a bachelor’s degree in marine ecology from Western Washington University and earned his doctorate in oceanography from the University of California—Santa Cruz in 2011.

About the Talk

The great Missoula floods and other megafloods of the Columbia River:  Agents of catastrophic landscape change in Washington

Dr. Richard Waitt of the U.S. Geological Survey (Vancouver, WA) will present a fascinating review of the Great Missoula Floods, which has been a topic of interest of his for several decades.

As a result of more than 40 years of research, the great Missoula flood is now known to have consisted of perhaps 100 repeated floods that occurred intermittently across several millennia. A single monstrous ‘Spokane Flood’ was first proposed in J Harlan Bretz in 1923, as an agent of catastrophic landscape change in Washington. The hypothesis of scores of gigantic Missoula floods was proposed and developed by Richard Waitt and Brian Atwater in the late 1970s to late 1980s.

Between about 18,500 and 15,000 years ago, immense floods from glacial Lake Missoula in Idaho and Montana drowned the Wenatchee reach of the Columbia Valley by different routes. The earliest debacles raged 1,000 feet deep down the Columbia and built the high Pangborn bar at East Wenatchee.

After advancing ice blocked the Columbia valley north of Spokane, several great floods descended Moses Coulee (channel) and up the Columbia past Wenatchee. When ice covered intakes to Moses Coulee, the Grand Coulee and Quincy basin became the westernmost floodway. Receding ice-dammed glacial Lake Columbia until it burst. Smaller great flood(s) swept down the Columbia probably from glacial Lake Kootenay in British Columbia. Huge fluted points produced by early man (Clovis) atop Pangborn bar were buried by loess starting about 13,000 years ago. Although Clovis people came to the Northwest two millennia after the last Missoula flood they may have seen outburst flood(s) from glacial Lake Kootenay.

 

About the Talk

The Hazel/Oso Landslide of March 22, 2014: Geologic Background, Other Landslides, and Landslide Policy Implications for Washington

On March 22, 2014, at 10:37 a.m, a massive landslide struck a rural area of the Stillaguamish River Valley, killing 43 persons and displacing many more. News of this catastrophe spread through the surrounding communities, some of which were cut off from outside help. However surprising this may seem, the geology history of the area shows that is has a long history of hazardous behavior.

About 20,000 years ago, the advance of the Puget ice lobe into the Puget Sound area blocked the outlets of several rivers flowing out of the Cascade Range. Glacial-related sediments deposited within the Stillaguamish River Valley were later incised, initially by the combined flow of the Stillaguamish and Sauk Rivers and then by continued erosion of the North Fork Stillaguamish River. The erosion has left steep, high terraces of unconsolidated sediments along the valley walls, which have led to multiple deep-seated large landslides that have covered the North Fork Stillaguamish River Valley floor on multiple occasions. The catastrophic Hazel/Oso Landside is simply the latest valley-covering landslide in this long post-glacial history.

There are some unique geologic aspects of the Oso Landslide that will likely offer some valuable lessons regarding landslide risks and help inform policy regarding landslides. This talk will attempt to put the Hazel/Oso landslide in perspective with other landslide hazards in Washington State. While the Hazel/Oso Landslide may hold some technical and policy lessons, information on other landslide sites in Washington State will be presented, including some landslides in Jefferson County. Part of the presentation will discuss how landslide risks and public policy meet and various approaches to landslide hazard risk reduction.

About the Speaker

Dan McShane has a B.Sc. and M.Sc. in Geology from WWU in Bellingham. He has worked as a geologist and engineering geologist in Washington State since 1989. He is currently employed by the Stratum Group as an Engineering Geologist in Bellingham, WA. Dan writes a geology blog (http://washingtonlandscape.blogspot.com) that provided some early information about the Oso Landslide to the general public as well as geologists not familiar with the specific area.