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.
Jökulhlaups from Glacial Lake Puyallup, Pierce County, WA
Kathy Troost will present a lecture for the Jefferson Land Trust’s Geology Group entitled Jökulhlaupsfrom Glacial Lake Puyallup, Pierce County, WA.
For decades, geologists thought that normal surface flooding caused the surface channels and cobble deposits in Pierce County. However, these deposits are the result of repeated jökulhlaups (glacial outbursts) from Glacial Lake Puyallup during the retreat of the Vashon Ice Sheet about 13,500 years ago.
(Photo from https://commons.wikimedia.
The affected landscape shows evidence of large outburst floods, such as kettle lakes from the grounding of large ice blocks, large-scale bed forms, waning-flow deposits with bogs, and thick deltas at the coast. As such the floods have shaped much of the landscape in Pierce County.
About the Speaker
Kathy Troost is a Licensed Geologist with 34 years of experience in geological research and investigations focused on the Pacific Northwest. Kathy has published many geological maps and papers about Quaternary geology and deposits. She teaches at the University of Washington in Seattle, has her own consulting company, is currently the President of the Northwest Geological Society, and will complete her doctorate at UW later this year.
Jim Aldrich, who has been working on a geologic investigation of the structure geology and tectonics of the mountains for three years, was the trip leader.
Original announcement: The trip will originate and end at the Olympic National Park visitor center on the south side of Port Angeles. The trip starts at 9:00 am Saturday, September 14. The first day we will be stopping at outcrops of the Olympic Subduction Complex (OSC) Lower unit on the Pacific Coast and the oldest strata of the Coast Range Terrane on the north flank of the mountains. We will stay at a motel in Port Angeles that night. The second day we will be examining outcrops of the OSC Upper unit in the core of the range and the upper strata of the Coast Range Terrane along Hurricane Ridge Road. The longest walks to outcrops are two that are about 1/4 mile down a moderate grade. All other stops are at outcrops across a road. The field trip will end by 5 pm September 15th. Costs: There is no trip fee. Participants will have to pay for their own motel room, or the cost to share a room if they are willing to do that, and meals.
This field trip includes stops to observe and hear about the geology of the three major rock sequences of the Olympic Mountains – from the Pacific Coast to the core rocks on Hurricane Ridge.