Monday, February 23, 2009
I had a few minutes while waiting for the ferry early this morning and a few more after it got back in at the end of the day to walk down to the beach at Ship Harbor. I always say I'll spend more time exploring this great wetland - historic cannery - development controversy - ferry terminal, but whenever I'm here, I'm either in line for the boat or anxious to get home. Unfortunately, the pictures are more of the sky than of the beach. Maybe next time!
Friday, February 20, 2009
I'm not sure what this creek is really called, but given that it ends in Seahurst Park and has no other obvious name that I am aware of, this one makes sense. Interesting contrast to this past weekend's Carkeek Park post). Both are small streams on the eastern shore of the main basin of Puget Sound. Piper's Creek reaches sea level landward of the coastline and, at least before the Great Northern was built, may have had a small drowned valley estuary at it's mouth. Seahurst Creek reaches the Sound in a fairly steep valley (remember, click on title of the post to get map/aerial view) and spills out across the beach in a small delta and the only "estuary" is the series of small pools that form behind the small spit at it's mouth.
Not many streams along this shoreline preserve the dynamic nature that probably once characterized all of them. The next creek north emerges from a pipe that runs beneath the monster house built on the original stream mouth. Some emerge in riprap channels. But few have the freedom that this one has to build, erase, and rebuild spits every couple of years. Funny that this is the only one that really fills up with kids in nice weather (all trying to re-engineer it - some sort of natural human propensity to build bridges and dams and levees).
Seahurst Park Web Site
In the last few years, the south beach at Seahurst has become the poster child of "restored" beaches on Puget Sound. And maybe for good reason. It's hard to believe that in the early 1960s, there was a road on the back of this beach, and that until early 2005, the upper beach was completely buried under fill and riprap and stacks and stacks of hemorrhaging gabions.
There are no shortage of nourished beaches in the United States, but not many of them look like this. Mixed sandy gravel beach and lots of drift logs. Sure doesn't look like Indian Rocks. There's interest now in restoring more of the beach on the north half of the park (Seahurst Park, from a year ago), where things get much more complicated and expensive.
I walked here along the beach from Seahurst Park early this morning, figuring it was simply wrong to spend all day in a meeting near the beach without actually spending time on the beach. The shoreline between Seahurst and this small city park is one of the rare stretches of relatively unaltered shoreline still left on mainland King County. High, forested bluffs, small landslides, and lots of large wood on and above the beach.
Eagle Landing was acquired a few years ago by the City of Burien to preserve a short stretch of this beach and to provide some public access to a largely private shoreline. It lived up to its name this morning, as there were two bald eagles perched on a branch above the beach just north of the park.
The stairway zig zags down the bluff (maybe the park should be called Many Landings) ending at the beach with a small set of steps that have been banged up by drift logs. There is actually an ancient timber bulkhead at the toe of the bluff, but it is has been largely buried by the soil and trees have continued to creep over it.
Eagle Landing Park (lots more info and pictures)
Monday, February 16, 2009
Piper's Creek is one of Seattle's better know urban streams, draining three square miles of the city's northwest neighborhoods. It has several hundred spawning salmon (fishus iconicus) and provides foraging for tens of thousands of school kids every year.
Piper's Creek has a small delta heavily influenced by wave action. The stream mouth is usually diverted south by a spit, although occasionally the stream breaks out and heads straight down the beach. This beach is sheltered from the more common southerly storms by Meadow Point to the south, but has a substantial fetch from the north and this afternoon a strong, cold wind showed why the stream hooks to the south.
Piper's Creek may once have had an estuary, too, but the railroad has largely separated the wetland on the landward side of the tracks from the stream mouth on the Puget Sound side (the stream emerges through four culverts - two big, two small).
I wonder what this place looked like before the railroad was built? Maybe a more substantial spit and a small estuary in the lower part of the valley. And of course, sand and gravel beaches extending north and south in both directions instead of disappearing under 100 years of transcontinental double-track.
Wednesday, February 11, 2009
Beach Watchers' annual Sound Waters event (another 500+ people this year) has become a recurring excuse to come up to Whidbey and spend a February Saturday afternoon walking on the beach. After the morning sessions and lunch and touching bases with a bunch of the regulars, I headed for West Beach (the broadly accepted term for the entire northwestern shore of the island). These are the pictures that didn't fit neatly within the previous posts.
Sunday, February 08, 2009
Clamber over the bedrock ledges at Rocky Point and you round the corner to find a broad expanse of brand new beach. This wasn't here in the early 1990s, just sand bars and a rapidly eroding bluff. But in the last decade, the bars have emerged as a series of prograding spits and a complex network of lagoons. I don't know of another place on Puget Sound where so much land has been created so recently.
The spits are mainly sand, although there's gravel, too. They are low and it looks like particularly high tides have washed fairly uniformly over the berm. The pattern of breaking waves suggested there are more bars to the north probably destined to become new spits as this whole complex builds north. This northwestward shore of Whidbey is subject to significant swell down the Strait. This, combined with the abundant sand, leads to the frequent presence of offshore bars - something we don't tend to see much of on Puget Sound. In addition, this whole shoreline (all the way to Deception Pass) appears to be subject to some fairly long cycles of erosion and accretion. Interesting that this area has been accreting during the past decade, while the beach north of the naval air station (2-3 miles) has been experiencing some signficant erosion (Cranberry Lake).
Bedrock stays mostly out of sight under the thick Pleistocene sediments of Puget Sound, but as you walk north among the logs and small dunes toward Rocky Point, basement is rising invisibly beneath your feet, all of a sudden appearing in a series of ledges at the point itself. Then it disappears for a few more miles, finally emerging at the north end of the island for good, forming Deception Pass and all of Fidalgo Island.
These rocks are Mesozoic metamorphics, part of a complex story of crushed and slivered tectonic plates that plays out in the San Juan Islands and southern Vancouver Island.
The bluff above the rocky ledges consists of dirt and debris dumped over the edge, probably the remnants of old clearing and grading on the Naval Air Station (of which this is part). Convenient, though sort of sloppy.
Libbey Road ends with a quick drop down the bluff to a small park, perhaps built into a small glacial kettle. And then there is another short drop (a steep 15-20' bluff) down to the beach itself. Many decades ago, a notch was cut into this lower bluff so that a boat ramp could be constructed. The steep ramp was exposed to big storms coming down the Strait and the northern side was gradually undermined. By the time I first visited this site in the early 1990s, just walking down the ramp was a challenge (even when new, launching a boat would have been difficult)
The old boat ramp trapped the gravel working its way northward along this beach from Partridge Point (0.5 miles south) towards Deception Pass (almost 15 miles north). We often brought field trips here to talk about the effects of groins on shorelines (and bluff erosion rates and the origins of glacial marine drift). The higher beach to the south helped protect the bluff immediately updrift, whereas the beach to the north (down-drift) has eroded, taking the bluff with it.
In the early 2000s, the county replaced the ramp with a new beach access structure. The problem is, once a groin has influenced the topography of the beach and a significant offset has developed in the shoreline, it becomes almost impossible to restore the beach without serious complications. Maintaining the structure would have resulted in the situation continuing to deteriorate. Removing it entirely would have resulted in rapid "catch-up" erosion on the south side.
The compromise was to replace the old structure with a new structure that didn't project quite as far. Which meant that the down-drift erosion continued and the up-drift side began to erode faster. The new structure had a few design and construction shortcomings, so now they've taken another shot at it. Plus, they have extended the huge timber seawall along the south side to meet up with a private bulkhead built in the mid 90s.
One of the frustrating things about trying to fix old mistakes is that sometimes there's no good solution. Better to not make the mistake in the first place. I can think of some other things where that's true, too.
Wednesday, February 04, 2009
Early in the morning of January 15th, 1997, during a very wet winter, a huge chunk of the hillside just south of Deer Creek let go, collapsing on the railroad tracks and spreading across the beach (Woodway Landslide). The point of land created by the resulting dirt pile has been gradually eroding ever since, leaving this 2-meter high retreating scarp and an assortment of broken trees, large chunks of the bluff, and train parts. And yards and yards of green and purple fabric, something probably related to the Catholic center at the top of the slope.
Slides this big are pretty unusual on Puget Sound, which is probably a good thing, since if they happened more often the human cost would be high. Figuring out where they are going to happen next is a challenge. You can predict that a shallow landslide or debris avalanche will occur on just about any steep bluff on Puget Sound sometime in the next few decades, but we only know of a few slides this big that have occurred in the last 30-40 years. They leave their marks - hillslopes covered with single-aged stands of alder, trees and big blocks of clay sticking out of the lower beach, strange promontories on otherwise steep shorelines.
This stretch of shoreline is notorious for landslides. In the 1950s, the railroad actually relocated the grade away from the base of the bluff to reduce slide damages. The result is a series of linear wetlands between the new causeway and the bluff - on top of the original beachface. But since then slides, including some very large ones in the early 1970s, have begun to fill the trough in.
Too bad we never systematically monitored the erosion of this dirt pile - or figured out how to track the resulting sediment offshore or downdrift. People did report lots of accretion and scattered debris showing up at the park up in Edmonds in the years following the slide.
There's a beautiful little sandy beach where the shoreline returns to the railroad on the north side of Point Wells. Somehow a little pocket of forest got trapped between the asphalt plant and the railroad grade. A couple of small streams pass beneath the tracks, through the woods, then trickle out across the beach. These wonderful studies in alluvial geomorphology are pretty ephemeral - they won't survive the next high tide, but in the meantime, we get braided channels, incision, undercut stream banks, channel migration, and terrace formation.
Apparently, this beach, like the Evergreen beach in Olympia and Wreck Beach in Vancouver, is clothing optional (what did we do without the internet?). Which apparently entertains the folks passing by on Amtrak. But maybe just in warmer weather - the only other people I saw today were bundled up.
The weather was nice, so I continued my little Saturday afternoon walk north past Point Wells. The south side of the point is a big construction site, since I think this is where they are building the new sewer outfall from the Brightwater Plant in Woodinville. The north side is Chevron's asphalt plant - something it's been for a very long time.
Point Wells is a fairly large cuspate foreland that I suppose may have originally sheltered a marsh or lagoon. The tip, in the vicinity of the piers, seems strangely squared off. Maybe this is the way the landform was always shaped, or maybe it's some sort of response to the piers (or to dredging adjacent to the piers). The southern beach is swash-aligned and very broad. The berm and drift logs are backed by riprap and a big fence, but the beach itself is in remarkably nice shape. I wonder if some of the beach's stability results from the presence of a coarse-gravel bar or ridge out nearer the tip of the point, which appears to act like a low-tide groin? On the north side, the riprap encroaches on the beach and I doubt you could walk all the way around the point at anything greater than a mid-tide.
Someday Chevron will pack up and leave. And once the soils are cleaned up, something else will move in. Maybe it will be condos and a marina. But maybe it could be a regional park, maybe the biggest and best shoreline park between Seattle and Everett, adjacent to one of the most densely populated stretches of the urban corridor. It would be nice to pull back the riprap and the fill at the tip and on the north side, leaving a wide high tide beach all around. There's enough room for a mix of recreational uses and maybe even a little bit of restored wetland or forest. If they need to have condos and businesses, put them back at the base of the hill next to the parking lots. Oh, and then add the trail along the base of the bluff from here to Edmonds...
There are only a few places between Seattle and Everett where development has occurred waterward of the railroad tracks. This stretch of homes in Richmond Beach is one of them. It is also right up there with Skyline (Anacortes) and a few other select Puget Sound locations where the audacity of the residential development is particularly acute - it is not really typical of shoreline practices on the Sound, but it sure makes for great pictures of seawalls.
The origin of this chunk of land is interesting. It is not a small barrier or cuspate foreland, cut off from the mainland by the railroad. Neither is it all fill - created land on which homes have been built (althugh some of it may be). Rather, it appears to be a low promontory of glacial drift, probably till, that for whatever reasons, chose to project itself farther west than most of this shoreline. Of course, you can't see much of the original geology of this bluff, as it's pretty much plastered over by the concrete retaining walls that protect the homes from the consequences of their spectacular location.
Most people simply call this shoreline park Richmond Beach, but technically, I guess it is the City of Shoreline's Saltwater Park. Not to be confused with Saltwater State Park in Des Moines. But it does call atttention to the fact that there is more to the community of Richmond Beach than just the beach.
The beach is on a broad point of land that at first glance appears to be a barrier. It is a "constructional" landform and it may be okay to call it an accretion beach (Bauer did) or a barrier (I probably have), but it's actually the leftover pile of sand and gravel that built up around the pier below the big pit when this place was in full operation early in the century. The upland part of the park, which is currently being renovated, is a big bowl that began as the gravel (sand?) mine...sort of like the big divots on the southeast shore of Maury Island or north of Chamber's Creek. The best analog might be Sunnyside Beach in Steilacoom, where a park has been built on an artificial promontory with similar origins.
The landform is highly assymetric with a broad sweeping beach on the southern shore and then an abrupt northern end (see map linked to title of this post), marked by a cobble lag (as often is the case, the cobble masks an underlying substrate that is much sandier). Besides the sand/gravel operation, this site has been shaped by the railroad, which first arrived here in the early 1890s, and cuts through the park. Like many other parks along this "Great Northern" shoreline (Picnic Point, Carkeek, Howarth, etc) you reach the beach on a pedestrian overpass over the tracks.