Fall 2017 Seminar Series

Nick Cohn
Ph.D. Candidate

Geology and Geophysics
Oregon State University

Friday, Oct. 20, 2017, 3:00pm
Chase 105
Abstract

Coastal landform development represents the aggregation of a wide range of physical processes driven by waves, tides, and winds. Partially because it is one of the highest energy wave climates in the world, the U.S. Pacific Northwest (PNW) coast exhibits significant spatial and temporal variability in nearshore, beach, and dune morphology. While these high energy forcings drive net beach erosion in winter, lower wave heights in summer promote net onshore sediment transport with onshore intertidal sandbar migration providing a primary mechanism of sediment exchange between the inner surf zone and backshore. This sediment delivery is essential for both beach and dune growth—where some progradational systems have foredunes growing seaward at rates exceeding four months per year. Using detailed field data that spans time scales of seconds to decades and process-based numerical modeling, morphodynamic processes driving coastal change along high energy, dissipative PNW coasts are explored. Specifically, synchronization of sediment exchanges between the nearshore, beach, and dune, and slope controls on these processes, will be discussed.

Bio

Nick Cohn is a Ph.D. candidate in geology at Oregon State University, researching coastal geomorphology. His work is varied in nature but is generally focused on understanding morphodynamic feedbacks between waves/wind on the coastal landscape on engineering time scales (days to decades). Currently, he is involved in a number of field programs and modeling endeavors focused on exploring the physical processes which allow for beach and dune building.