Wave Runup on Cobble Berms

On the US West Coast, many sandy beaches are backed by natural cobble berms. These berms naturally adjust and steepen in response to large winter waves, protecting the backshore and allowing the beach to remain stable over a wide range of wave conditions. Beaches that lack cobble berms are often less stable than their berm-backed counterparts. This has led coastal engineers to wonder, can nourishing beaches with cobble provide a nature-based alternative to hard structures like seawalls and rip-rap? Engineers have successfully used such “dynamic revetments” in practice, but they are asking nearshore scientists for better constraints on their basic properties and dynamics.

Many beaches in Oregon, like this one in the community of Arch Cape, are backed by a cobble berm that provides a natural and dynamic form of coastal protection against large winter waves.

Funded by Oregon Sea Grant and the US Army Corps of Engineers, our group is using observations of Oregon cobble-berm beaches (both natural and engineered) to better understand different aspects of how waves interact with the berms, and how they evolve over time.

Beginning Winter 2023, the project team is collecting video observations of wave run-up over cobble berms, in collaboration with Oregon coastal beachfront home owners. Below is a recent video from one of the beach cams.

Video (10x speed) of wave run-up at Arch Cape during a high tide on December 25, 2022

Researchers: Doruk Ardag, Hailey Bond, Brandon Weid, Meagan Wengrove, Greg Wilson