Monday, December 31, 2018

Wood's Cove

I often refer to this blog as my beach collection. Right now, you're in the Orange County Gallery. But you're almost at the end (but not quite). The next room, The Salton Sea Gallery, is small, but will be very different than this one and will leave you with some contrasting views of both geology and coastal development.

AERIAL VIEW

Wood's Cove is another of these wonderful little pocket-like beaches that seem to define Laguna Beach. At the bottom of Diamond Street, there is a short path and a tall flight of stairs to the rocks at the bottom. Small beaches extend in both directions, flanked by large homes perched on the edge of the bluff. And some perched beyond the edge of the bluff.



Brooks Street


We're still working our way south through Orange County (quick time check - these are all from December 13th). Brooks Street is just one of many street-end beach accesses along this stretch of southern Laguna Beach. I wish I could have stopped at them all, but then I would have had a lot more trouble telling them apart afterwards.


AERIAL VIEW
This beach is just south of Main Beach. The base of the bluffs is anchored by a fairly continuous band of bedrock that encroaches well below the high tide line in some places. I guess this means that the homes may have a somewhat better prognosis than those built on rapidly retreating bluffs and big landslides, but I can't imagine it won't get increasingly exciting in coming decades when big storms arrive on higher tides and El Nino water levels.

For the most part, waves were pretty tame during this trip down the coast, but here they were a little larger and the surfers had definitely figured that out. Maybe they're always bigger here. Or maybe it was a fluke related to the swell direction and the offshore bathymetry.






Laguna Beach

All of these posts are from Laguna Beach, but this one is from Laguna's Main Beach, right in front of downtown. Unlike the smaller coves tucked into the convoluted coast to the north, this one is much more substantial and extends quite a ways to the south (the next post, from Brooks Street, is sort of part of the same beach.)

AERIAL VIEW
Downtown Laguna Beach, including Main Beach, are built at the mouth of Laguna Canyon, one of the larger drainages in the hills along this coast. That's why the town itself is down near sea level, instead of up on the terraces, and it's why there's room for a big, low-lying park and a wide beach, since there are no bluffs to bump up against. The coastline rises again to the south (towards the next post), although it's a little hard to distinguish the bluffs from the homes and condos built against them.



Recreation Point

I'm not sure what the best name for this post is, but the pictures are taken from Heisler Park on Recreation Point in Laguna Beach. The beach to the northwest is Diver's Cove (below). The beach in the other direction may be Picnic Cove (above), though I'm not sure that's what it goes by locally.

AERIAL VIEW

The points along this coastline are defined by more resistant geologic units (here, I think they're volcanics), with the coves backed by bluffs of more erodible sediments. But both erode, even if it's at different rates. I wonder what this coastline will look like in 80 years?


Crescent Bay

The next several posts step southwards along Laguna Beach's coastline. There are an awful lot of fairly distinct beaches along this stretch, some more accessible than others, but I had only so much time and so much navigational talent. For each that I got to, there were several that I didn't: Victoria Beach, Treasure Island, Shaw's Cove, 1000 Steps. (More on Laguna Beach's Beaches)

AERIAL VIEW

Crescent Bay is a small pocket-like beach. I say pocket-like, because while it is bounded by rocky promontories, I suspect the nearshore sediment system is more continuous than the headlands might indicate. The big waves reach deep and the sand probably extends well offshore. The continuity of the littoral system may be determined as much by offshore bathymetry as it is by the outline of the terrestrial landscape.

As in much of southern California, the Pacific Coast Highway and a bulk of the development lie on a marine terrace (or terraces) - the legacy of a tectonically-active, uplifting coastline. But the development in Laguna Beach, much in the form of expensive homes, tends to extend right to the edge of the terrace and often drapes down over it, sometimes right to the water's edge.






Sunday, December 30, 2018

Crystal Cove

Crystal Cove State Park is a long stretch of largely undeveloped bluffs and beach in the southern part of Newport Beach. The only buildings are down at Crystal Cove proper, where Los Trancos Creek empties out onto the beach.

AERIAL VIEW

The little beach enclave appears to have a long history - with some strong advocates. I haven't sorted out the whole story, but it looks like the Crystal Cove Conservancy is working with California State Parks to restore the old beach cottages on the bluff. The historical preservation part of me finds this wonderful, but the coastal geologist part of me wonders how much effort we should take to preserve structures in unsustainable locations.


But in the meantime, what a neat spot. Besides the places down at the beach, it can also be enjoyed from Ruby's Shake Shack up on the bluff along the road!


Corona Del Mar

The San Diego River (not in San Diego) drains through the completely transformed Newport Bay estuary and out to the ocean in a channel defined on the western (Balboa) side by a long jetty and on the eastern (Corona Del Mar) side by a rocky promontory (and another jetty).

I believe this is all technically part of Newport Beach, although I'm still struggling with the geographic labels down here (most of what I know about the names of southern California beaches comes from Beach Boys songs and Google Maps).

AERIAL VIEW

There were lots of cool beach things to check out - the jetties, the small beach tucked into the rocks on this side, the beautiful beach cusps, and the classic California style hillside homes. These photos are taken from Lookout Point (west) and Inspiration Point (east), as well as down on the beach itself.


Saturday, December 29, 2018

Redondo Pier

The western shore of Los Angeles, from Malibu south to the Palos Verdes Peninsula, consists of a long series of  beaches - including Santa Monica, Venice, Dockweiler, Manhattan, Hermosa, and Redondo. I'm sure geography purists, surfers, and many Angelinos might choose to divide these up differently, but I think this captures the basic idea.

AERIAL VIEW

The Redondo Beach Pier is located at the northern end of the southernmost of these beaches, just south of the large marina complex that separates it from Hermosa Beach to the north.

The Redondo Pier is not just your typical single pier, but a strange triangle of intersecting piers, reflecting some history of multiple structures and numerous reconstructions (these things tend to attract both storms and fires).

I have nothing to add about the beach itself, other than wanting to point out that getting to it was neither encouraged nor easy. I guess you have to head south from the pier itself to do that.


Abalone Cove

This southern shore of the Palos Verdes Peninsula has a bit of a geological reputation - and not just because of its Tertiary sediments, Pleistocene marine terraces, and late Holocene cobble beaches. I first heard about Portuguese Bend in college in the context of large deep-seated landslides (and the ramifications for continuing to develop them long after the risk was recognized, as I recall). I guess the Portuguese Bend slide is perennially on the move. The impacted stretch of Palos Verdes Drive is a roller coaster with warning signs, unexpected dips, and patched asphalt. The waterlines are on the surface, which I suppose makes them easier to inspect and repair.


AERIAL VIEW

Abalone Cove is in the western portion of this messy geology. Part of it was active in the 1980s, although I guess that involved only a small area of a much larger landslide complex that extends far into the local hills. Interestingly, Wayfarer's Chapel, just up the hill from here, must be on more stable ground, as it's been there since at the early 1950s and remains intact.


The central portion of the Abalone Cove beach is armored with old concrete rubble, the lower parts of which were rounding into conglomeratic cobbles. But there were also much more appealing natural cobble beaches in both directions. By the way, that what makes these beaches more appealing isn't just that the cobbles lack rebar, but that there is still an upper beach, whereas on the armored section (as on armored beaches pretty much everywhere), the back beach is pretty much buried under the armor itself.

The bluff that rises behind the beach shows both the topography and the twisted stratigraphy typical of big landslides.




Long Beach

There are a lot of Long Beaches. Some are longer than others. Some are attached to larger cities than others. This is one of those.

As best as I can tell (and supported by interpretive signs near the aquarium), Long Beach began as a large barrier beach stretching between the mouths of the original Los Angeles and San Gabriel Rivers. It still sort of is, although there has been a lot of replumbing and terraforming in the last century.





AERIAL VIEW


And maybe calling it a barrier beach is a bit too simple. The western portion of Ocean Boulevard lies well above sea level and the beach lies out in front of a modest bluff. But the eastern portion, Belmont Shores, is a barrier, with low-lying areas inland.


The beach is well-manicured - or at least it had been very recently. New sand, nicely graded, with ditches to guide stormwater from each upland source out through the beach to the sea. The area had been hit by a big rainstorm shortly before I visited - I'm not sure whether what I was seeing was the result of that, or the response to it.


Wednesday, November 28, 2018

Fort Worden

A week and half ago, I got to spend two days at Fort Worden, a (very) little of which actually got spent on the beach. This is a familiar site (searching the blog for Fort Worden or Point Wilson turns up some related posts) and one I often use to illustrate how structures can impede littoral drift and how shorelines respond.

AERIAL VIEW


The Port Townsend Marine Science Center now occupies the end of the pier, but the structure itself has a long military history associated the Fort. At some point, planks were placed between the pier's pilings, most likely to reduce sedimentation in the small boat basin tucked in behind it. This resulted in a wide beach accumulating on the south side (sediment arrives from Port Townsend and the Chetzamoka Bluffs from this direction), and a substantial offset in the shoreline to the northeast (towards Point Wilson itself).

Every decade or so, people start wondering whether something can be done to alleviate some of the inconvenient geomorphic ramifications of the pier (and the associated boat basin and launch ramp). Trouble is, some things are hard to undo without creating other problems.