Wednesday, August 06, 2014

Teekalet


This is the western of the two spits that form the entrance to Port Gamble bay.  Point Julia, on the east, was described in the previous post. It's likely that this one was fairly similar, but it's tough to tell, since the mill was built in 1853 and the spit was significantly altered by the time of the 1856 T-sheet.

AERIAL VIEW

Development of the mill site involved extensive filling of the back shore and beach areas, probably with dredged material, and then protecting this with walls and whatever rubble was available. Wharves and piles extended farther out to allow deep water access to boats.  The existing shoreline edge is an accident of the historic development and its shape reflects the requirements of handling logs and lumber.

Now, with cleanup and redevelopment planned, there is an opportunity to make adjustments to this hard edge that would result in a more appealing, accessible, environmentally functional, and low maintenance shoreline. This would require thinking about the configuration of the edge - and the relationship of individual segments to wave action. Based on the beaches that already exist between rubble headlands, I suspect one could keep just a few hard segments (hopefully done in something nicer than broken concrete) and enhance pocket beaches between them. Not saying this will happen, just that it would be nice!


Sunday, July 27, 2014

Point Julia


The entrance to Port Gamble - the bay - is marked by two spits.  The one on the east is Point Julia and is actually a recurved spit or a cuspate foreland.  The one on the west, below the town of Port Gamble, may have looked similar, but is now lost beneath the old Port Gamble mill site.  I'll come back to that in my next post.

AERIAL VIEW

Point Julia lies on the lands of the Port Gamble S'Klallam Tribe. It's a complicated feature due to the presence of a couple of small stream mouths, but the primary tidal marsh drains out through a narrow channel near the tip of the point.  It looks like there's been some fill added to the old berm and marsh and it's possible this has influenced the plumbing a little, but unlike its counterpart across the channel to the west, this one still works!




Cape Shoalwater

I'm falling a little behind, but wanted to post some photos from earlier in the month before they get so old that I just abandon them entirely - which sometimes happens.

Cape Shoalwater forms the northern entrance of Willapa Bay, but defining it precisely is tricky since it has been shifting north and shrinking rapidly for many decades. I guess the simple explanation is that the ebb tide channel that drains Willapa is migrating northwards - but just why this is happening and when it might change - is much more complicated.

AERIAL VIEW

Washaway Beach continues to wash away, at something like 100' every year. Because the retreating bluff is cutting through the street grid on a diagonal, it always tends to look sort of the same.  It's always cutting across the road at an angle, there are always a couple of houses on the brink. There are always trees falling over the edge and old water pipes sticking out of the beach.  A lot of homes have gone in since I first visited in 1990 - even since my last visit in 2010.

Washaway Beach:  March 2010

Just east of Washaway, the migrating channel intersects older Pleistocene sediments. The highway is trapped against the higher, more resistant ground here - since all that's left to seaward are a few resistant knobs and a lot or riprap (and the old box culvert that I assume went under the old highway before the road was relocated).

Considerable effort and money has been spent to protect the road along here, including a large groin built just to the west about a decade ago.  But the shore continues to retreat.  During the past decade or two, the spit to the east (Graveyard or Empire) has unraveled and the Corps has recently carried a large nourishment project near Tokeland.



Friday, July 11, 2014

Crescent City




In contrast to our leisurely drive down the coast, our return to Seattle was much faster. We took two days, with the night spent in Crescent City. My beach time was limited to some evening glimpses of the Humboldt Lagoons (reported on during the trip down) and an early morning walk on the beach in front of the hotel.

What caught my eye was the abrupt lower edge of the gravel beach. This isn't that unusual, but sometimes it is more distinct than others. This is just a snapshot in time - I don't know what this beach looks like at other times - but I generally associate this morphology with beaches where the amount of sediment is limited and the combination of wave conditions and sediment size conspires to push material exclusively onshore. I'm sure there are other factors, too.

AERIAL VIEW

Crescent City is probably best known in coastal circles for its attractiveness to tsunamis, which tend to stack up and strike with more vengeance here than elsewhere on the west coast.  I guess it's mainly about the shape of the coastline and more importantly, the shape of the bottom offshore.




Ocean Beach



After so many spectacular beaches in the last few days, I almost hate to include this one, but my beach collection is an attempt to compile a wide range of specimens, not just the prettiest ones. This is the south end of San Francisco's Ocean Beach, which I also posted about a couple of years ago. But that post was taken where both the beach and the weather were doing a little bit better.

Ocean Beach: December 2012

That post also includes a little bit more of the complicated story that explains why the beach to the north is healthier than this section near the zoo.

AERIAL VIEW

Admittedly, when a beach starts to unravel, expediency and budgets often lead to ugly fixes, and sometimes there really isn't a fix at all - but it sure screws up my romantic notions of treating our coasts like we really care about them!  And this is in a city that is otherwise so incredibly beautiful.



Point Arena


Our run of great weather has run into summertime coastal fog, which isn't surprising, but certainly impacts our ability to see and photograph the coast. We had a few brief breaks of blue sky on the drive from Fort Bragg to the Golden Gate where local conditions had caused the fog to sit a little farther offshore, but for the most part, it was gray.

AERIAL VIEW

Point Arena is located at the north end of a narrow sliver of California that is on the Pacific Plate, moving towards Alaska relative to the hills just to the east, which are on the other side of the San Andreas Fault and are part of geologic North America. The point itself is a broad gently-sloping terrace (or terraces - there are often several) that cuts across the planed-off ends of a thick stack of steeply tilted sedimentary layers.


Thursday, July 10, 2014

Glass Beach



Like many coastal communities, Fort Bragg used to toss much of its garbage over the edge.  Folks don't do it anymore, but the legacy remains in the form of Glass Beach on the north end of town, where a little coagulated metal and a lot of ground up glass mark the old dump site.  Glass is actually a very successful substitute for natural beach sand - since it's basically the same thing (silica, even if not quartz).

AERIAL VIEW

There are many glass beaches -  some accidental, some more purposeful. There's another one much like this on Kauai in Hanapepe (Ele'elu 2008).  And a more subtle one at Cornwall Beach in Bellingham (2006). For that matter, my first full post in this blog, back in December 2005, was also titled Glass Beach, albeit one near Port Townsend (and no pictures of glass - maybe I should go back and revisit that one).


MacKerricher



The shoreline north of Fort Bragg up towards Ten Mile River includes a series of dune fields blown inland across a low terrace.  But at the southern end, these dunes are interrupted by some rocky headlands, including Laguna Point in MacKerricher State Park. The point is flat on top - maybe 6-8 meters in elevation - and characteristic of the terrace along here.  Just north of the point is Lake Cleone, located in low drainage behind the barrier beach.

AERIAL VIEW

100 years ago, local log mills hauled their lumber on rails to a dock out on the point and the remnants of the rail bed and the trestles still remain perched on the beach.


Wednesday, July 09, 2014

Mattole River


This was our last look at the coast before seeing it again many hours later down near Point Bragg - there aren't a lot of places to get to the coast between here and there, except for Shelter Cove.

AERIAL VIEW

But what a neat spot! Just a small river mouth and a spit on a remote coast with very few other people around.  A beach dominated by dark sands, which is common along here, and I suppose reflects a combination of the provenance (the source rocks) and the freshness of the beach material (which means a lot of the darker minerals that will eventually be ground up and lost are still abundant compared to the tougher quartz that dominates many more established lighter colored beaches).

I think when I choose beaches from my collection to put on display, this would definitely be a top pick.


Singley Flat



This sort of follows on the previous post, but focuses on something quite different. Singley Flat is a steep series of marine terraces marking rapid (and episodic) uplift of this section of coast just south of Cape Mendocino.  But weak rocks (perhaps aided by frequent shaking?) leads to unraveling of the steep hillslopes. Scars and debris-filled stream channels can be found up and down this coast in aerial photos.

AERIAL VIEW

Here, an area of rapid erosion high on the hill appears to be creating a constant (well, not quite) stream of dirt and gravel that's building an alluvial fan across the terrace, which happens to be where the road is. The public works folks have tried to create a channel for the material and an oversized bridge, so that the material can pass below the roadway on its way to the beach.

I suppose this is a significant local supply of sediment for this section of beach - though figuring out the behavior of this beach given the complexities of offshore rocks, rapid (and recent - 1992) uplift, large storms, and this episodic sediment supply, would be challenging!

A foot note:  Much of what I write here is based on general observations and a smattering of internet or book work. One of my standard go-to resources for California is Gary Griggs' (and Patsch and Savoy), 2005, Living with the Changing California Coast, and I would recommend it as a starting point for anyone exploring the state's shorelines.