Posted on December 6, 2023
PORTLAND, Ore. (KATU) — Beach erosion is a natural process that continues to affect the Oregon coastline; however, some erosion can be attributed to climate change, experts say.
Data shows erosion of Oregon beaches caused by climate-related events including changes and variations of offshore wave conditions, frequency, and magnitude of storms from season to season.
With another year of El Nino conditions on tap, it is important to highlight how this event has a direct link to how our beaches are changing.
According to Jonathan Allan with the Department of Oregon Geology and Mineral Industries, places like Rockaway and Cannon Beach are a function of the last two and a half decades of climate effectively, largely dominated by El Nino type conditions.
Allan explains when we experience El Nino conditions, we observe above-average wave conditions with a shift in predominant storm tracks moving southward, which contributes to how waves impact our beaches and move sand northward.
The northern end of Cannon Beach is experiencing more sand, says Charlie Plybon with the Surfrider Foundation. There’s sand accreting there which becomes a problem for homeowners where those dunes are building up too large for some of their views, inundating their homes and compromising their infrastructure.
Researchers found that the coastline that’s just north of the Tillamook North Jetty is an area that has been eroding several feet per year for a couple of decades. South of Lincoln City and north of Newport has seen a loss of a significant portion of walkable beach during a high tide event.
As for the future, in the short term, there’s a chance to return back to a period where we see more storms which could lead to greater erosion potential.
Allan says in the longer term there are real concerns about the progressive rise in sea levels along the coastline and that could have significant and lasting impacts in terms of stability on our beaches and dunes.
This would potentially lead to larger rates of erosion on coasts buffs. Continuous El Nino events can also result in damaging impacts over a period.
Experts say we must think about the best ways to manage and nourish the beaches.
Plybon says that in Oregon, a lot of homeowners are on the front lines of erosion, seeing these beaches shrinking in front of them. They have responded with seawalls and riprap and in Oregon that’s now allowed if your house was developed prior to 1977.
If you’ve visited the Central Oregon Coast you may notice you can’t walk on some beaches at high tide. That’s a result of “shoreline armoring”. Armoring is the practice of using physical structures to protect the coastline.
“When we are armoring the coastline, we are gonna have a situation where we start to lose recreation beaches depending upon how fast sea level rise occurs. and so right now there’s a whole bunch of uncertainty,” says Allan.
While things like seawalls and riprap, which are human-placed rocks, do work in the short term, these are not solutions in the long run, officials say.
Plybon believes there needs to be more engineering and guidance on nature-based solutions. One such solution is already working along the Washington coast.
Peter Ruggiero, with Oregon State, says dynamic cobble redeposits are working along the coast in Washington and have features that are mimicking cobble beaches that are very dynamic. The stone is small enough that these features might evolve with waves.
Other solutions could be dune restoration, such as constructing sand fences or planting vegetation. Unfortunately, there isn’t one right answer, officials say. Some areas might need different management plans compared to others. Ruggiero says they are still in the early days of learning the long-term impacts of the dynamic nature-based solutions. That is an area of very active study at Oregon State University.
