Tuesday, April 25, 2017

Cama Beach

Last week I got a chance to visit Cama Beach to talk to this spring's Sound Water Stewards class. The weather cooperated for the beach walk - which it seems like it usually does, but this year I wasn't so sure!  I managed to grab a few photos, but not many. When I'm with a group, I'm too busy answering questions or looking for topical material to remember to take pictures.

AERIAL VIEW

The beach at the south end is very low, although not necessarily lower than in 2012 (Cama Beach: May 2009). However, a little farther north, near the old gate in the seawall, it was as low as I've ever seen it. The old wooden piles were completely exposed and there were large patches where the beach veneer was completely absent, with the underlying silt and clay showing through.

At the north end, we checked out the two big slide scars from previous years (see linked posts below). Despite this winter's record rainfall, it doesn't look there's been that much activity.

There was eelgrass hanging from the branches of the trees - a reminder of the interaction between the terrestrial and marine ecosystems. And there was a wonderfully delicate micro-berm of ground up clam shell marking last night's high tide.

Previous posts that mention Cama Beach.



Saturday, April 08, 2017

Hug Point



Hug Point is a small rocky headland that extends out across the beach a few miles south of Cannon Beach. The rocks include both Tertiary sediments and an intrusion of Columbia River basalt. 100 years ago, travel along the coast generally used the beach, but at Hug Point, a road was carved into the promontory (the old roadbed doesn't show in these photos).

AERIAL VIEW

Fall Creek arrives at the beach over an 8' waterfall. As streams often do on these kinds of beaches, it exposed the coarse cobble that underlies the upper part of the more ephemeral sandy beach. 


Cannon Beach



Cannon Beach extends south from Tillamook Head and Ecoloa State Park. It's best known, visually and geologically, for Haystack Rock, a very large sea stack located just offshore, yet still accessible during low tides. Haystack Rock is Columbia River basalt, extruded into the surrounding sediments as the flows reached the former coast and then subsequently exposed by erosion.

AERIAL VIEW

Cannon Beach seems to be several communities stretched out along the shore. The northern end is very low - a barrier beach associated with the mouth of Ecola Creek. But much of the rest of the town to the south lies on somewhat higher ground behind a modest bluff, although I'm not sure if this is a marine terrace or just old dunes.



Wednesday, April 05, 2017

Indian Beach

Indian Beach, in Ecola State Park, is a two kilometer long pocket beach tucked into the southern side of Tillamook Head. The upper beach is a very steep coarse gravel and cobble berm - the lower beach is flat and sandy.


AERIAL VIEW

A small stream empties out onto the northwest end of the beach. And a landslide (or several landslides) empty out onto the other end of the beach. The cliffs that rise behind the beach is Columbia River Basalt that flowed out to the coast 15 million years ago, before the modern coast range was established.



Tuesday, April 04, 2017

Seaside Point and Cove


South of Seaside, the wide sandy beach runs into the rocky headland of Tillamook Head, which projects westward into the Pacific. But even this northern edge of the headland has a beach, it's just a very different one. The lower beach is rounded boulders and the upper beach is a coarse gravel and cobble berm. I assume this coarse material is all basalt, eroded from the promontory and spread eastward along it's northern shore.

AERIAL VIEW

The westerly swell sweeps along this shoreline, breaking at a very sharp angle and creating (at least under the right conditions) a strong left break just offshore. Seaside Point is a beach with a guarded, but apparently well-deserved, local reputation. During our visit, the waves seemed a little choppy and chaotic (surfers probably have a better vocabulary), but there were still a lot of surfers in the water. A strong rip develops right along the beach, making it easier for them to paddle out, but also creating a bit of a hazard.

I think the little divot in the corner (where the headland meets the main beach) is what is referred to as "the cove." The cobble beach takes an inland excursion (see aerial), leaving a sandy pocket - makes an easier entry for the surf crowd then stepping through the boulders farther out. Interestingly the cobble then continues a little farther north until it is overwhelmed by the sand (see previous post). I was curious about the origin of the cove (it's more complicated than simply being an inside corner between the north-south sandy beach and the east-west cobble beach), but so far my ideas are pretty speculative (even more speculative than usual).

Sunday, April 02, 2017

Seaside



The main beach in Seaside is broad and sandy, with a wide band of low grassy dunes between the promenade and the beach - enough to keep storm waves out of town, but not enough to shelter the town from a significant tsunami. The plate boundary is not far offshore - twenty minutes would be barely enough time to get to high ground under the best of conditions.

AERIAL VIEW

Seaside lies just north of Tillamook Head, at the south end of the Clatsop Dunes. This segment of beach, from Seaside north to the Columbia River is a sub-cell of the larger Columbia River cell and most of the sand on these beaches came out of the Columbia River. The other three sub-cells all lie north of the river mouth, in Washington.

The flat sandy beach in these photos is a big contrast with the cobble beaches at the very south end which I'll describe in the next post. But as you walk south - to the vicinity of "U" Avenue - a cobble berm begins to assert itself.


Wednesday, March 22, 2017

Lincoln Park


Lincoln Park is one of the better documented beaches on Puget Sound, although much of what was written is now 25 years old. And apparently, this is the first time I've included it in the blog. A good reminder that there are just too many beaches.

The glacial landscape of West Seattle juts out into Puget Sound on the north side of Fauntleroy Cove. As commonly occurs on promontories on Puget Sound, a very small depositional landform - a cuspate foreland - has formed at its tip (this is in contrast to Brace Point, to the south, which is a much larger cuspate foreland). You may have learned in Beaches 101 that headlands get eroded and bays get filled in until the whole coast is straight, which may be true if you're on a coast where large waves approach straight on. But here on Puget Sound, where waves approach at a strong angle to the coast, it seems that sometimes sediment is attracted to the points, not removed from them. Or at least that's sure what it looks like to me.


AERIAL VIEW


The photos show both the more heavily visited south beach and the somewhat less explored north beach. And the riprap that protects the point itself. Note that this landform was perfectly happy without riprap, despite its exposed position, for hundreds of years. The riprap probably reflects the need to protect the walkway, which was likely built over the original backshore. Colman Pool (saltwater) replaces whatever little lagoon probably once occupied the same place on this landscape.

The south beach is the main story here. During the 1930s, the WPA built the stone bulkhead (now largely buried) and the promenade. Over the next few decades, the beach eroded and dropped in elevation and by the 1970s the wall had been repaired many times. Old photos show the beach far below the top of the wall. When Seattle approached the Corps of Engineers for help, the Corps proposed beach nourishment. Resource agencies pushed back - the idea of burying the beach under fill was unthinkable (they preferred the idea of a riprap apron at the toe of the wall).

Fortunately, nourishment won out over riprap. The initial placement in 1988 was large - something like 80,000 cubic yards - but the few subsequent renourishments have been much smaller. And despite some wrinkles along the way, I think the overall project remains a big success story. I think it was critical in reshaping the opinions of the agencies about the potential value of nourishment. This was also because monitoring, required of the original project, led to some good early work on Puget Sound beach biota and their response to seawalls and nourishment.

Wolf Bauer, who had been advocating and building gravel beaches on Puget Sound for more than a decade before the work at Lincoln Park, was a bit skeptical of the design. He had some valid gripes (the berm was too high, for one, so it immediately developed a large scarp), but I suppose he also just sort of enjoyed poking the Corps (don't we all?).

Most folks walking the beach last Sunday (the last day of winter), probably had no idea of the beach's history. I don't recall if the park has any interpretive signs showing the 1930s construction or the engineers standing below the towering bulkhead in the 1970s.

There's more about Lincoln Park - it's relationship with the sandier Fauntleroy Cove to the south, the asymmetry of the north and south beaches, and the heavily developed shoreline to the north of the Park along Beach Drive (which is also the story of the uplifted terrace of the Seattle Fault). Maybe another time.





Tuesday, March 21, 2017

Sculpture Park



Some beaches change all the time. Or at least you can be pretty sure that if you haven't been there in while, it will be different when you come back. This beach isn't one of those. It has few degrees of freedom - admittedly, that was a key point of its design. It's the beach equivalent of putting a wide-ranging predator in a small enclosure in an old-fashioned zoo. Not very authentic, but much easier to manage.

AERIAL VIEW

The sediment is all nicely sorted gravel. Which means the beachface remains the same in both shape and texture. The coarse gravel also tends to stay high on the beach - it has less tendency to want to get lost offshore (ignoring stone-throwing children). The two rock groins assure that no material escapes and therefore the beach volume and position don't change. The groins also constrain the small opening of the beach to Elliott Bay which assures that the wave regime is limited and the beach can't shift back and forth too much in its cage.

I love this little beach and wish we could incorporate beaches into our urban shorelines more often. But I also think it is a good reminder that we shouldn't confuse domesticated beaches for wild ones. On the surface, they may look similar, but the domestic ones are more predictable and as a result, may have a little less character.


Monday, January 23, 2017

Second Beach




Vancouver has many small pocket beaches that face westward out into the bay and I've probably posted from most of them by now (a few links below). Second Beach, in Stanley Park is yet another of these. Like the others, it has been enhanced by the construction of structures that help maintain the pocket and also probably by the addition of sediment at some point.

AERIAL VIEW
Second Beach lies just east of the big pool (frozen over on this trip) which looks as if it was probably constructed out over the foreshore. This improves the configuration of the shoreline for the beach itself. There's also a rock groin at the east end which keeps Second Beach from spilling around the corner and joining the much larger, but similarly aligned, First Beach (but which is usually called English Bay Beach).

English Bay: December 2014
Third Beach: April 2007
Sunset Beach: August 2016
Kitsilano: April 2016
Jericho Beach: August 2008
Ambleside: October 2011

The Stanley Park seawall west of the Second Beach pool


Stearman Beach



Much of West Vancouver's western shoreline has a bedrock foundation, with scattered beaches where favored by shoreline configuration and stream mouths. Stearman Beach is at one of these stream mouths. It and other nearby streams (Cypress Creek, just east, is considerably larger) have built small deltas and a broad gravelly foreshore, which provides sediment and elevation for the beaches (albeit small and irregular beaches).


AERIAL VIEW

The homes that look out over Stearman Beach are relatively modest, at least compared to many of the others along West Vancouver's shoreline. The ones here all have glass railings - providing for views while discouraging the curious from clambering over their seawalls.