Dungeness Spit, WA USA
On October 15th, 2018 my wife Becky and I visited the Dungeness Spit. The Dungeness Spit is a remarkable thin stretch of sand and gravel beach extending out into the Strait of Juan de Fuca over 10 Km from the main coast. A big chunk of sediment comes from the high eroding bluffs to the southwest of the spite. These bluffs are exposed to fairly large waves coming into the open water of the Strait of Juan de Fuca.
Dungeness Spit was created and continues to be changed by the action of wind and water on these glacial sediments.
1. Wind drives the waves: Prevailing winds coming in from the Pacific Ocean create heavy surf. The waves easily erode soft glacial sediments, creating steep, unstable bluffs.
- Waves carry the soil: A process called longshore drift built Dungeness Spit. Waves hit the shore at an angle, pushing sand and cobbles diagonally up the beach, and then sweep it backwards. Over time, the sand is gradually moved out from the headland, creating the spit. Today the spit continues to grow at its tip, 13 feet (4.4m) per year.
- Driftwood and beach plants hold the sand in place: This keeps the forces of erosion in check. If the large driftwood was removed, waves would soon breach the spit, turning it into an island.
- Silt from the Dungeness River created tide-flats: Dungeness Spit grew, creating a protected bay. Tidal flows swept silt from the Dungeness River into the bay. The silt settled out in the quiet water, creating extensive tidal flats.
- The spit is even more complicated by the presence of another source of sediment from the southeast and from sediment inputs from the Dungeness River, as well as periodic waves generated by south winds blowing onto the backside of the spit. Beyond the lighthouse at the end, the spit is a no-entry wild life preserve as critical habitat for many bird species.
Becky and I arrived at the Dungeness Spit just before Sunset. The image above is taken towards the east. After that, Becky and I hiked down to the shoreline and took the image below of the beautiful sunset with Becky.