Tuesday, March 31, 2015
Port Browning is the name of the bay, the community, and the marina (and the pub), although apparently the beach is called Hamilton Beach* (and lies at the end of Hamilton Road). Pender Island's primary (and only) shopping district, Driftwood Center, is located half a mile inland.
I suspect this may be the longest single beach on either of the Penders, although if you look at the map, you might note that it's really only half a beach. It extends across the south side of the bay but abruptly ends at a small rocky knob, just short of the marina. There appears that there may have once been a small marsh - maybe even a lagoon - behind the berm and under the lawn, but not any more.
*Hamilton Beach is probably better known for blenders and kitchen mixers, but there is apparently no connection to Pender Island. Hamilton and Beach were two employees of the company when it was begun in Racine, Wisconsin, back in 1910. Thank you, Wikipedia!
This small pocket beach faces northwest towards the head of Bedwell Harbor (Medicine Beach).The resort - which is a bit out of synch on an otherwise low key kind of island - climbs up the hill behind the beach. The marina and Customs station (this is a convenient place for boaters to check in when they cross the boundary) extend out into the cove. The resort is closed (well, they allow tourists to wander through) so everything was pretty empty.
The beach, like many, is a combination of mineral sediment and shell debris. Pocket beaches tend to form in coves, which correspond to valleys in the landscape, and therefore are often fed by small streams. And these streams carry sediment - in this case, both glacial and Cretaceous I suppose - from their watersheds down to the beach. For the sake of geologic accuracy I should point out that the clasts within the Cretaceous Nanaimo Group are presumably much older than that.
The shell on beaches around here is mainly clam shell, washed up from lower on the beach face, and barnacle fragments, washed off rocks on adjacent promontories or the piles that support the docks.
I liked the way the shell had piled up on the upper beach - right against the bulkhead and even up and over it (I wondered if some of this had been spread over the rockery as a landscaping touch, but I think a bulk of it ended up here naturally.)
Monday, March 30, 2015
Gowlland Point, assuming I got the geographic names correct, is just northeast of Brooks Point. It's built from a massive reddish conglomerate and has a navigation marker on the tip. The view to the southeast includes the San Juans (the international border is only a mile or so offshore) and Mount Baker (in the clouds today).
To the north of Gowlland Point - and below the stairs at the end of the road -- is a pair of coalesced pocket beaches. The rocky ledge that divides them includes both a conglomerate with heavily weathered cobbles and some spheroidally weathered gravel beds, but what really stood out was an amazing boulder of heavily altered rock on the beach itself.
Brooks and Gowlland Points (on South Pender Island) are adjacent and some of the descriptions make it a bit hard to distinguish the two - not that it really matters. I believe the more northeasterly point, and the more distinctive one, is Gowlland, which I'll save for the next post. The top photo is of Gowlland, taken from Brooks (or so I think). The second is of Brooks, taken from Gowlland.
Both points, and everything else around here, are carved out of strongly folded Nanaimo Group conglomerates (Cretaceous) - which I think I first learned about during an orientation field trip at UW more than 30 years ago! Nanaimo sedimentary rocks - which are not all conglomerates - form most of the southern Gulf Islands. The aerial view shows the extent to which sedimentary structure controls the shape of the islands.
I wish I had photos of the gigantic boulders in the forest on the way here along Gowlland Point Road. From some drive-by geology - and some inferences from Google Earth - they look like rockfalls along the steep ridge between the road and Greenburn Lake. I suspect they are old - maybe they are blocks of the conglomerate that fell off the cliff or out of the edge of the glacier when the ice retreated?
Friday, March 27, 2015
Eroding sedimentary beds at the east end of the beach shed blocky cobbles that quickly gave way to more rounded gravels down the beach - although I didn't investigate whether this was due to dilution (with glacial gravels) or rounding (by breakage and abrasion).
The distant view (with Salt Spring Island in the background) is from Mount Norman on South Pender.
The beach shelters a small back-barrier marsh - protected as a natural reserve.
We spent last weekend exploring Pender Island, so this weekend I'll see if I can dribble out posts on a few of the beaches I collected. We spend a week every summer on Salt Spring Island, but other than occasional ferry stops at Otter Bay, had never made it to Pender.
Mortimer Spit is located at the western end of South Pender Island and marks the northeastern entrance to the Pender Canal. It's oriented northward, shaped by waves from the southeast. Refracting waves and tidal currents have wrapped the tip of the spit around to its leeward shore. I'm not sure about the source of sediment - although perhaps it's a combination of glacial material and older Nanaimo Formation gravels (which we'll see plenty of on this island), eroded from the rocky bluffs along the east side of the island. But this is a pretty rugged shoreline and I doubt there's much longshore transport along here.
Mortimer Spit is a neat little site, although I'm not a big fan of beaches that look like dirt parking lots, which this one sure does.
The end of the spit provides a nice view of the Pender Canal, which separates North and South Pender. The two islands were connected by a narrow isthmus until 1903, when it was opened to provide more convenient passage for a small steamship sailing between Hope Bay and Sidney. I'm not clear from the brief accounts I've seen as to the geologic nature of the original connection and whether its opening required dredging a low spit, digging through a ridge of glacial sediment, or blasting through bedrock (all of which might be possible).
Xelisen - meaning "Lying Between" - was the name of the rich aboriginal site bisected by the construction of the Canal. This must have been a great spot, with both rocky and gravelly substrates (different things to eat), sheltered coves, and access to both ends and to both sides of the island.
Saturday, March 14, 2015
I can't think of another stretch of shoreline that's undergone such major changes in the last decade, except perhaps the site of the Ledgewood landslide (also on the west side of Whidbey Island), but that was a very different kind of change. The change here is significantly greater than the sandy accretion we're seeing at Maxwelton and Useless Bay at the south end of the island.
Rocky Point (see earlier posts linked below) is where bedrock makes its reappearance as you head north along the west shore of Whidbey Island. A few rocky ledges appear at beach level and form a hard point that undoubtedly influences the shape of the coastline along here, acting much like a large groin, with a broad beach built up to the south and sharp indentation in the coast to the north.
|Cliffside Park. The spits hadn't arrived here as recently as 2009.|
But sometime in the late 1990s or early 2000s, the sand bars began to grow and emerged as a series of north-trending spits. As new spits formed and grew north, they formed a series of small lagoons. As the berms grew in height, vegetation became established. When I visited last, in 2009, the spits had not yet reached the campground, although there was an obvious bar just offshore.
Rocky Point: February 2009
North of Rocky Point: February 2009
We visited the site on March 6th. The beach just north of Rocky Point has eroded back dramatically, but there is a wide foreland in front of Cliffside Park, as if the whole spit complex has just continued to roll north. The historical imagery on Google Earth illustrates these changes pretty well.
Forbes and Maylor Points mark the southern end of the peninsula that separates Oak Harbor on the west from Crescent Harbor on the east. The 19th century t-sheets suggest that this was once almost an island, connected to the rest of Whidbey Island by a tombolo, but evidence of this is buried benath the large fill associated with the old seaplane base (now the base exchange) and the parking lot behind the Oak Harbor Marina.
In the late 1970s, the Corps of Engineers undertook a national initiative to look at low cost methods of erosion control. One part of this project was an ambitious series of demonstration projects. There were two on Puget Sound - one at Sunnyside Park in Steilacoom and the other here, at the base of the bluff between Forbes and Maylor Points.
|Remnants of old gabion baskets|
In the winter of 1978-1979, the barely completed experiment was severely tested, and almost destroyed, by two storms, the larger of which was the same February 1979 storm that sunk the Hood Canal Bridge. Some treatments held up better than others.
I visited the site in the early 1990s (and am trying to track down my photos). This was my first time back. I found some of the old Corps' reports and maybe there's a follow-up story we can pull together. But that will take a little more work.
At Maylor Point, at the west end of the project, there is an old concrete structure looks like it was originally constructed to carry electrical conduit (some reports say drainpipes) down the bluff to the beach. It has been left behind as a flying buttress as the bluff has gradually retreated.
Monday, March 09, 2015
I've noted before that I try to keep this blog pretty focused - on beaches. Or maybe shorelines in general. Or maybe on geology. This is mainly in that last category, although there's not actually much geology in this post.
We were in New Mexico last year when I heard someone ahead of me in line ask the clerk if they'd heard about the big landslide up in Washington. Some quick work on the internet confirmed where it was. I guess I had heard other geologists mention the "Hazel" slide after the 2006 event, but knew little more about it than that. The field trip at last week's AEG workshop on landslides was my first chance to visit the slide and it was great to be able to do it in the company of people who know a lot about geology and landslides.
The Oso landslide occurred on March 22, 2014, on a Saturday morning when pretty much everyone in Steelhead Haven was at home. The hillside collapsed - on the site of an old, recurring slide - and ran out across the entire valley floor. Subsequently, geologists have begun to uncover evidence that this section of the North Fork of the Stillaguamish River has seen this kind of event before - although like earthquakes, they do not occur often and there is probably little way to predict just when and where they'll occur. And when they're not occurring, these are very attractive places to live.
Engineers and lawyers and government agencies will be debating the details for years, but I guess my takeaway was that the more we know the better, but that we can never know everything as well as we might want. Especially in hindsight. High bluffs and barrier beaches and floodplains are created and maintained by natural disasters. That doesn't mean we can't build on them, but maybe as a society we have to do more to educate ourselves about the risks.
Two miles downstream, you wouldn't know what happened less than a year ago.
For years, the old Showboat Theater floated along Portage Bay, in the midst of the oceanography and fisheries buildings, but by the 1990s, I guess they were afraid it would sink - or maybe it actually had sunk?
The old showboat went away and it was replaced by a small park and a beach, just down the hill from the South Campus Center. It's a nice place for students to hang out on nice sunny days - so it was empty on this visit.
I took advantage of a break at the Landslide Forum (Seattle Times article) to wander down with my coffee to see how the beach was doing. It's doing okay. I suppose it's a pretty confusing place to be a beach - a little bit of wind wave action from the south and a constant stream of boat wakes - and then add to that the strange plumbing of the Lake Washington system, which maintains higher water levels in the summer and lower ones in the winter (thus the wider beach in this photo).
This mill in Tacoma's Old Town was the last of the lumber mills along Ruston Way to close. It shut down in 1977 and burned down in 1979.
In the late 1990s, Tacoma Parks developed a plan to clean up the site and turn it into a park. It required sifting through issues of remediation, wetlands, public access and recreation, ecological restoration, and historic preservation (and probably many others, too). Which wasn't easy, but was eventually successful.
The concept envisioned a beach and an estuarine marshand it was tricky to figure out how to configure this given the geometry of the old site, but the design actually ended up taking advantage of the historic footprint. The beach is a swash-aligned pocket beach, constrained by the concrete foundation of the mill. The tidal lagoon fills and empties through an inlet that runs through the old structure, which reduces the likelihood that sediment clogs the inlet (an early idea was to create an inlet in the beach itself, but there was no way to make this work without extensive maintenance).
To see what this site once looked like, check out the Tacoma Library collection:
Dickman Mill, 1948
The old field of piles still lies offshore. The base of the old cone burner is a weird lagoon at high tide. The backshore has filled up with wood debris. and the estuary seems to be doing pretty well (as often the case, it took a while for the vegetation to get established). On the other hand, the park (completed in 2000) looked like it needed some work. Some of the concrete walkaways were having to be repaired and blackberry was taking over the fringes of the marsh.
Saturday, March 07, 2015
February was just one sunny weekend after another! On Sunday, three weeks ago, M and I headed up to San Juan Island for the day. Tough day.
San Juan is mainly bedrock, so beaches are scattered and usually fairly small. But at Cattle Point a thick pile of gravel has been eroding for centuries, spreading itself along the shore to form this beautiful long beach.
The beach faces across the Strait of Juan de Fuca towards the Olympic Mountains - a little hazy on this particular day. The back beach is probably one of the larger accumulations of drift wood on the Salish Sea.
From a previous visit:
South Beach: June 2011