Saturday, August 23, 2014

Centennial Beach



Technically, this post is slightly out of order, since I meant to post it after Beach Grove and they sort of go together. Centennial Beach is just updrift (south) of Beach Grove and is essentially the Canadian extension of Maple Beach on the U.S. side.

AERIAL VIEW


Centennial Beach is just the most recent of a series of spits and wetlands that have formed on this northeastern shore of Point Roberts, much of which is encompassed within Boundary Bay Regional Park. The aerial view provides a nice glimpse of the complex geomorphology of this area.



Causeway Beach


Causeway Beach is basically the southern edge of the causeway that serves the Tsawwassen Ferry Terminal. I don't know how much intention went into building this beach, or whether it is just an artifact of the gravel-size material eroding out of the armored fill. Regardless, this beach would not have been here before the terminal was constructed - this was just the wide flats of Roberts Bank.
AERIAL VIEW

The beach has an impressive fetch to the south. Its orientation makes it unlikely that it has any significant source of coarse sediment, other than from itself. And it's not a uniform width - it undulates along the south side of the highway - in some places there is a wide backshore (little more than a rough gravel parking lot) and in others it narrows to nothing and the roadway is protected by newer riprap.


Beach Grove



Every year, I end up in Richmond or Tsawwassen early on a Saturday morning in August, prior to catching the ferry over to Salt Spring Island.  And every year, I have a choice of beaches to visit. This year, I went back to Beach Grove (2009) and Centennial Beach (2009).

AERIAL VIEW
Beach Grove is built on low land - old spits, marshes, that kind of stuff - on the eastern side of the Tssawwassen-Point Roberts hill (once an island, before claimed by the growing Fraser River delta). It receives beach sediment from Lily Point and Maple Beach to the south, although most of this material probably wound up in the series of spits that form Centennial Beach. Most of Beach Grove's shoreline consists of a narrow foreshore in front of a continuous lone of concrete seawalls. Offshore are the broad tidal flats of Boundary Bay.

Beaches can be narrow for a lot of reasons. In this case, I suppose they include 1) a dearth of coarse sediment from the south, 2) the fact that the community was pretty much built on top of the berm and backshore, and 3) the broad fine-grained flats essentially bury the intertidal beach (the flats intersect the beach face at a very high tidal elevation).


Boulevard Park




This past year, a new beach took shape in Bellingham at Boulevard Park. The park inherited a large area of historic fill on which a log mill once operated. Unattended, fill tends to erode away, and to prevent this the foreshore was covered in riprap and old concrete debris. The lawn was a nice place to listen to a concert or throw a frisbee, but getting to the water was a treacherous walk through a dump.


For many years folks have talked about making this shoreline more friendly, and finally, last year, the city went forward with plans to excavate some of the old fill, reconfigure the edge to complement the incoming waves, and construct a gravel beach. This was the first chance I'd had to visit since it was completed.

AERIAL VIEW


Orientation is a key factor on these sites and sometimes the shoreline you're given isn't consistent with a stable pocket beach. In this case, the local designers employed a rock groin at the northeast end and even added a small rock hook at low tide to keep gravel from getting away. I understand there is still considerable offshore aerial transport of the pebble, but it would take a lot of kids throwing a lot of rocks to put a big dent in the local sediment budget.  And the waves will tend to move some of them back - with time.

Now if the city could figure out how to clean up the rest of the debris along this shoreline, this could become the crown jewel of what will ultimately become a wonderful string of pearls along the Bellingham waterfront!



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.