Wednesday, May 31, 2017

Dry Creek



The beach begins at the Elwha and ends at the tip of Ediz Hook -- at least in a simple, first-order conveyor belt of gravel, kind of way -- which is probably a little too simple. The central portion, between the eastern edge of the historic delta and the base of Ediz Hook, consists of 5 km of steep bluff. Dry Creek is in the middle.

AERIAL VIEW

From the Elwha to the ravine at aptly named Dry Creek, the bluffs are unarmored and the beach is wild. From Dry Creek to Port Angeles, things are a mess. The waterline was buried in the beach below the bluffs, but has subsequently been exposed by erosion and is now a 3km reach of riprap and sheet pile, below bluffs that continue to erode, albeit slower than they once did. Maybe it's fortunate that this beach is hard to access and most folks in town don't realize how bad it looks. Unfortunately, I don't have any pictures of this stretch to share in this post. I'll come back sometime.

The real highlight of this stretch, however, is the landfill immediately east of Dry Creek. The big wall goes back to 2006 or so and we can argue whether it's better or worse than the old refrigerators eroding out of the bank. But after the wall was built, folks discovered that maybe the eastern part of the landfill was at risk, too. The closest cell was a deep pit immediately behind the high eroding bluff. The good news is that they could have rocked the whole thing, but instead made the decision to move the vulnerable garbage out and move it landward. But in the process, they've left a remarkably bizarre landscape! And over time, this stretch will only get weirder.


There are a lot of photos of Dry Creek, the Elwha, and Ediz Hook in the blog. Searching within the blog on any of these terms should bring up earlier posts (although they sometimes bring up unexpected posts as well). Unfortunately, there are no pictures of the water line or of the landfill when the garbage was still slumping onto the beach.




East of the Elwha


As noted in the previous post, the rapid growth of the Elwha Delta following dam removal appears to have slowed. But during the past year or two, this eastern beach has grown rapidly as a result of a huge influx of sandy material. In places the beach has grown outward many tens of meters - with a steep cobble beach being replaced by a much broader sandier one.

AERIAL VIEW

Beach Lake refers to the lagoon, probably associated with an old channel of the river, that had been trapped behind the historic berm but that had been narrowed and breached by the rapidly retreating beach. Decades ago, a significant portion of this reach had been armored and this riprap was left in a broad arc on the beach face as the shoreline continued to erode.There was also at least one groin-like structure. All of these were recently removed by the Coastal Watersheds Institute and this, combined with the fresh sediment from the delta, has resulted in a much renewed beach.

The upland structures are slated to be removed. The plan is that this will become a public access - to a wonderful stretch of beach and to a highly regarded local surf break.

There is still one last stretch of rock and decayed timber bulkhead at the very eastern edge of the delta. As the beach has retreated, this rock has projected farther and farther onto the beach and looks like it may be exacerbating erosion at its eastern end. If it could be removed, the beach would be completely unarmored and unimpeded from the river mouth all the way to the Dry Creek (next post).



Elwha Delta


This is the first of two posts from the mouth of the Elwha. This one is built around photos taken near the tip - on both sides of the river mouth. The next post will be from a little farther east.

The river is currently flowing out into Freshwater Bay on the western side of the delta, although the linked imagery from Google Earth currently doesn't reflect this.

AERIAL VIEW

The broad crescent-shaped beach on the west side of the delta seems much simpler than the messy beach on the eastern side of the delta (next post). It has continued to accrete into Freshwater Bay and appears to be doing so in a fairly uniform fashion along its length. I guess this is how I might expect a swash-aligned beach to respond to additional sediment. But the beach on the east side is progressing much less cleanly - perhaps because of its drift alignment and the uneven transfer of sediment along its length. I say perhaps - I often say perhaps - to clarify that this is some speculation based on fairly limited observations. There are others watching this much more carefully and hopefully they will be able to put together a more rigorous story (and maybe a different story) in time.

The Elwha Dam was gone by mid-2012, the Glines Canyon Dam, farther upriver, was out in 2014. Fresh sediment reached the shore very quickly after the lower dam was removed and the new delta built out rapidly for at least four years. That process seems to have now slowed as the initial plugs of sediment flushed through and the reservoir bottoms have begun to stabilize.

The slowing (at least from what I can see) of delta growth provides an opportunity for coastal processes to take over. During the first few years, the beach east of the delta continued to retreat, despite the huge accretion at the river mouth. But in the last year or two, a huge amount of sand has moved east, perhaps as the front of the expanded delta has begun to erode.

Previous posts about the Elwha Delta


Wednesday, May 10, 2017

Travis Spit


It's a long, four mile walk on a coarse gravel and cobble beach from Thompson Spit to Travis Spit at the northwestern tip of the Miller Peninsula. The spit extends westward about a mile across the mouth of Sequim Bay - most of the way across, at least.  

AERIAL VIEW

While Travis itself is a fairly simple landform - a classic bay mouth spit - it's part of a complex of barrier beaches that make the story much more interesting. Together Travis and Gibson form paired spits, converging on the mouth of the bay. Gibson is also fairly large, extending south from Port Williams across Washington Harbor, and sheltering a large salt marsh. There's another smaller spit that extends north from the south shore of Washington Harbor. And Paradise Cove Spit is a north-directed spit that has formed just south of the base of Travis Spit on the eastern shore of Sequim Bay. Finally, if you look carefully, you'll see a small secondary spit on the southern side of the distal portion of Travis, with it's own narrow log-choked lagoon. You really need the aerial view and the map for this.




250 meters across the Sequim Bay channel is the site of the old Bugge Cannery (clams), which has been Battelle's Marine Science Laboratory for the last few decades. From the signs, I gather that Battelle may own much of high ground on Travis Spit. The central portion of Travis is narrow, but not so narrow as to show any obvious signs of overwash.


From the tip of Travis, it was a very long walk back to the State Park trail, a not so long walk up the trail to my bike, and then a refreshing ride back to my car. With a quick stop at the Discovery Bay store for chips, I made the 5:30 Kingston Ferry.

For those interested in visiting the Miller Peninsula or Travis Spit, a couple of thoughts. Miller Peninsula State Park is undeveloped, except for a new parking lot off of the Diamond Point Road and a network of trails largely maintained and signed by volunteers. Thompson Spit is best visited by hiking or biking in from the State Park parking lot. Travis would be best visited by parking at Panorama Vista County Park, which is reached off of the East Sequim Bay Road. 





Tuesday, May 09, 2017

Thompson Spit


The Miller Peninsula, on the north side of the Olympic Peninsula, lies between Discovery Bay on the east and Sequim Bay on the west. Diamond Point is the cuspate foreland that marks the northeast corner and the entrance to Discovery Bay. Travis Spit extends from the northwest corner across the mouth of Sequim Bay. In between is about 5 miles of gravel and cobble beach, backed by steep bluffs.

AERIAL VIEW

The one exception to this long stretch of bluffs is Thompson Spit, located near the eastern end. The spit is a looped barrier - basically a spit that extends out from the coast and then reconnects farther down the shore (in this case, west to east, which is consistent with what we expect of longshore transport here). They're rarely symmetric and this one is no exception. Their updrift ends are often tangent to the adjacent bluff - as if the beach reached a sharp bend in the coastline but couldn't turn fast enough. The downdrift ends tend to merge back to the coastline asymptotically. If there is a tidal inlet, it's usually near this downdrift end (that's not the case at here, which just suggests a more complex geologic or historic story that I don't know).

The berm on the western end is low and narrow and there was evidence of overwash. The lagoon was draining through a shallow inlet and the beach in front of the inlet was marked by several organic ledges (the upper looked more like sawdust - perhaps evidence of some human history?) - which is typical where a barrier beach has migrated landward, exposing old marsh and lagoon sediments. The central point of the spit is marked by a large mound that appears to be fill - was there an old cabin or small mill here once?

This may have been referred to as Deadman's Spit at one point - the dead man being a guy named Thompson in the 1860s. But that may be reading too much into a local history I found online (Diamond Point history).

I'd like to come back and explore more sometime - lots of unanswered questions. But only the western portion of the spit is in the State Park and I'm not sure how welcoming the owners of the eastern half are likely to be.

Looped barriers are common on Puget Sound - here are a few we've visited before:
Perego's Lagoon: December 2015
Cama Beach: April 2017 (and many previous)
Kayak Point: January 2009