Coastal Erosion

Large Retaining Wall for Coastal Erosion

Coastal erosion is a natural process that continually affects the entire coast. Erosion becomes a hazard when human development, life and safety are threatened. Beaches, sand spits, dunes and bluffs are constantly affected by waves, currents, tides and storms resulting in chronic erosion, landslides and flooding. Changes may be gradual over a season or many years.  Changes may also be drastic, occurring during the course of a single storm event.

Erosion may be caused by large waves, storm surges, rip cell embayments, high winds, rain, runoff, flooding, or increased water levels and ocean conditions caused by periodic El Niño’s. Coastal dunes and bluffs comprised of uplifted marine terrace deposits are especially vulnerable to chronic and catastrophic hazards.

Here in Clatsop County coastal erosion has been a significant issue at Ecola State park, where continued undercutting of the park’s cliffs have produced major landslides that cut roads and trails, and at times threatened to close the park’s main entrance.

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