Sunday, August 21, 2016

Jackson Rock


Fulford Harbor, like pretty much everything else on Saltspring Island, is oriented NW-SE, reflecting the underlying geologic structure of the islands sedimentary rocks. Last week, during our annual trip to the island, I paddled from the head of the harbor out to Wen,Na,Nec (August 2013) and Jackson Rock, then back on the other side.

AERIAL VIEW

The northeast side of the harbor (the Fulford/Reginald Hill side) is steep and rocky and there are few beaches. The southwest side (from Drummond Park out toward Isabella Point) is a little more gradual and includes both more erodible glacial? sediments and a stream mouth or two, so the beaches are a little better developed.

Here on Jackson Rock, the only material available to build the tiny beaches is broken shell. And the orientation of the beaches and bars is a messy function of the islets' irregular configuration and bathymetry.



Sunset Beach


Sunset Beach is actually several beaches, held in place against three large rock groins just west of the Burrard Bridge on the north side of the entrance of False Creek. The inner shorelines of English Bay are oblique to the dominant wave action, which arrives from the west (roughly), so beaches don't stay put unless there's a natural promontory or an artificial structure of some sort for them to pile up against.

AERIAL VIEW

Looking at English Bay from the air is useful, since it shows the westward orientation of the beaches not just on Sunset Beach, but also the larger beach farther west on English Bay (December 2014) and the beaches in Kitsilano (May 2016) on the south side of the bay.

This last photo shows the seawall and path just west of Sunset Beach - I guess it illustrates the challenge of creating and maintaining beaches where the orientation is wrong (especially where there is also no sediment).

Friday, August 19, 2016

Clam Bay



There are enough constructed beaches on Puget Sound, and Puget sound is large enough, so that it's easy to lose track of some of them. Including some of the nicest ones. Particularly when they're located a little off the track. This one, which I last visited in October 2010, is located in Manchester, pretty much in front of the Manchester Environmental Lab (EPA and Ecology). It is a secured area, so professional interest is tolerated, but a lunch stop with the kids would be frowned on.

AERIAL VIEW


The "Shore Protection System" (some might call it a gravel beach) was built in 1999-2000? as part of cleaning up and capping the old Navy dump site (nothing like a little lagoon behind a spit in which to dump stuff, then burn it for fire training exercises). The Corps is responsible for occasionally checking on how it's doing, but I don't know if there has been any tweaking of the original beach work. Frankly, it looks like it's doing just fine.


This is a really neat beach. It has a slightly engineered look, particularly the coarse gravel storm berm, but what a great alternative to the rock revetment that might have been built otherwise. Remind me someday to figure out how to draw more attention to these projects!

Manchester State Park




This is the second of three posts from Manchester in south Kitsap County. Each from a very different kind of beach! Here on Puget Sound, we don't go for that notion of miles and miles of unchanging beach - we'd rather keep people guessing.




AERIAL VIEW

The State Park is located just inside the mouth of Rich Passage. It's located near the trace(s) of the east-west Seattle Fault and the upland consists of the terrace raised by movement on the fault. The shore here is basically a small pocket beach, fed by erosion of the low terrace on both sides. The erosion on the west side had begun to threaten the roadway (now a path) and within the last few years an effort was made to protect the low scarp by using anchored logs backfilled by gravel.

It looks to me like there have been some problems - waves have scoured behind the root wads and the path is still vulnerable (just the edge, nothing's going away very fast). This is a tricky site - the wave energy isn't terribly high, but there's little protective beach on this obliquely-oriented, sediment-starved reach, so eroded sediment is rapidly swept farther into the cove.



Manchester



Pomeroy Park, in downtown Manchester (not to be confused with the grittier versions in England and New Hampshire), is a nice centerpiece to the small community's waterfront. Which contrasts nicely with the distant Seattle skyline.

AERIAL VIEW

I noted this site and the elevated boat ramp several years ago: Manchester: October 2010

Kitsap County recently completed an innovative stormwater project in town and the new outfall was integrated into the base of the pier. This is an interesting design and personally, I like the idea of allowing stormwater (relatively clean stormwater, at least) to run out across the beach much like a natural stream.

This does pose some coastal design issues, though, since the stream can erode sand and gravel on the upper beach and transport it to the lower beach. During heavy flows at low tide, this may result in a channel of sorts and this in turn can lead to localized erosion on adjacent banks. This has been addressed in part with a series of tiered logs backfilled with gravel. Fortunately, this type of erosion can be fairly ephemeral, and as long as there is adequate sediment on the beach, can recover quickly.


Traditionally, one approach to reducing erosion below an outfall would have been to construct an apron of angular rock across the beach. The irony is that this would have protected the beach from erosion by burying it under rock. I'm glad they didn't do that here - or at least if they did, it's below beach grade.


Tuesday, July 19, 2016

Kukutali


I'm just trying to catch up. And this post will do it, although it's already a month old. These photos are from a visit on Father's Day with M - the first time I'd been here in a long time and the first time since the new entrance had been improved.

AERIAL VIEW

The Kukutali Preserve (Kiket Island) is co-managed by the Swinomish Tribe and Washington State Parks. And it's a wonderful place for a short hike on a beautiful day. Two tombolos, each side of which is a pocket beach, along with a bunch of smaller beaches scattered along the rocky shore. The tide was low enough so we could walk out to the tip of Flagstaff Island (the upland portion is off limits - this kind of meadow is both fragile and scarce).

For a lot more photos of Kukutali - and a lot more attention to the flora and fauna - check out Dave's Fidalgo Island Crossings blog.


Edmonds


Early morning in Edmonds, waiting for a ferry (more than a month ago). This beach was once the spit that sheltered the north end of the Edmonds Marsh, but that was before sawmills, the railroad, the filling of the marsh, and construction of the marina. Now it's a series of pocket beaches, largely disconnected from one another by structures that extend offshore such as the breakwater and ferry terminal.

AERIAL VIEW

But Edmonds has managed to keep its beaches, and better yet, managed to make them the centerpieces of its public waterfront. Brackett's Landing North, north of the ferry, is a Wolf Bauer project from the 1980s, although the city did some additional work on the backshore, the bulkhead and the walkway following a big storm in the mid-1990s.

Edmonds: February 2014
Brackett's Landing North: April 2009
Edmonds: April 2009


Monday, July 18, 2016

Sunlight Beach




Most of the sand that erodes from the spectacular bluffs south of Maxwelton (March 2010) works its way north past Mackie Park (previous post), then years or decades later, it arrives at the head of Useless Bay, where it spends time on the large spit at Sunlight Beach, before ending up in bars at the mouth of Deer Lagoon.

AERIAL VIEW

Sunlight Beach is a long, complicated story. And perhaps one that regularly repeats itself. Sediment for Sunlight Beach comes from the south, but the supply of this material (mainly sand) appears to be metered by a smaller spit just to the south (often referred to locally as Henny's Spit). This southern spit gradually grows, forming a small lagoon and gradually pressing its outlet into Sunlight Beach, which causes erosion and consternation -- in part because the spit berm is the location of the dike that was built a hundred years ago to keep salt water from flooding into the old marsh behind the spit and in part because since then, a large number of people have built their waterfront homes on that same berm/dike.

When the small spit is building, it may starve Sunlight Beach of sand and the beach narrows - thus a diverse assortment of bulkheads, rock revetments, and timber groins. These were visible in the early 1970s and again in the mid-1990s. And are reappearing again.

But if the small spit breaks up, for example, if a new channel opens up farther south, the remaining portion of the spit welds itself onto Sunlight Beach, creating a decade of wide beaches for the residents. Folks who moved in five years ago may not even know that they have riprap and groins down below that wonderful beach,

But then this plug of sediment moves on through, its leading edge moving towards Deer Lagoon and its trailing edge leaving rapid erosion and re-exposed structures farther east. That's what's been happening the last few years.

This is probably a difficult story to follow - it would benefit from a more systematic narrative and a lot of historic maps and pictures. Meanwhile, check out the historic images if you have Google Earth.

I was involved in a number of shoreline issues on Sunlight Beach in the 1990s. For me, early in my beach career, this place was a great case study in the complex dynamics of beaches and spits. It was also clear that while some problems might fade for a few years, most would eventually come back!



Sunday, July 17, 2016

Maxwelton


The spit at Maxwelton continues to grow northward, but local rumors (and recent Google photos) suggest the south end is beginning to erode. 

AERIAL VIEW

The Maxwelton community is built on an earlier spit and the marshy lagoon that lay between it and the bluff. But in the early 2000s, a new spit began to emerge offshore near the south end and then gradually extended itself along the shore. The tip passed the Mackie Park boat ramp around 2007 and has kept going. It's preceded by a zone of erosion, presumably because the growth of the spit starves the downdrift beach (erosion is also related to the migration of the mouth of the inlet, which tends to be pressed close to shore, as well as to changes in wave patterns around the end of the spit).

Here are some earlier posts from Maxwelton. Although I've visited this site many times, apparently I haven't posted anything since 2010!

March 2007
April 2009
March 2010

In the last couple of years, the spit has slowly stretched northward and this past winter it raised concerns for some property owners near it's advancing tip.

Of course, the interesting question is what happens next. Will the spit continue to extend, shifting problems still farther north? The T-Sheet from the 1870s shows an extremely long, narrow spit extending another mile north, well past the old mouth of the Maxwelton estuary (now in a tide gate). Or, will the updrift (southern) end erode until waves breach the lagoon, creating a new inlet and perhaps leading to closure of the current north inlet. Which might in turn lead to major changes in the spit itself.

This winter, some very high tides filled the lagoon in front of the park with logs. They're probably not going anywhere as long as the spit itself remains.

Monday, July 11, 2016

Glendale


Glendale Creek is typical of many small streams on Puget Sound that drop quickly through a steep-sided ravine before reaching the beach. The topography suggests that there may not have ever been much of an estuary, but it's likely that the stream mouth was originally deflected north by a spit (drift here is unambiguously from south to north). Building on the beach, and the placement of the stream into a pipe, greatly reduced the stream's freedom to wander and the whatever spit there was became history.


The small community of Glendale is built at the mouth of the valley and periodically gets flushed out by a gully washer (Glendale: 2009). It's pretty much like building on an alluvial fan at the mouth of a canyon - location has consequences.

The Whidbey Camano Land Trust has recently acquired property here at the beach, just south of the stream mouth. I don't know what the plans are for the site, but it seems like a wonderful opportunity to reconnect the beach with it's backshore. That won't restore the original stream mouth or the spit, but it provides access to a wonderful spot on the south Whidbey shoreline.