Thursday, November 16, 2006
A blustery day in Port Townsend. Strong winds out of the south and a high tide. A plume of sediment traveled north along the beach toward the point, though it looked like it was taking a detour around the pier/jetty and the Marine Science Center. Nearshore waters always get muddy (silty?) after heavy rains and when waves are churning up the beach, but these were probably exacerbated by the very recent landslides between the Fort and Chetzamoka Park - since the tide was probably eating directly into the fresh dirt.
Out at the lighthouse, the waves were wrapping sharply around the point, breaking westward along the north beach. The south beach at Point Wilson is swash-aligned and you could see it today - waves at the pier were breaking to the northeast and waves at the point were breaking southwest - with a null point somewhere in the middle. This may be why the south side of Point Wilson appears to be building - it is collecting sediment both from the bluffs to the south and from the persistent erosion of the north side of the point. It's hard to conjure a storm that would erode the south beach significantly. (I guess this may need a cartoon to really understand).
Postscript: JAPANESE TSUNAMI? I was looking at the tide record for Port Townsend during the storm,which shows the 8.3' midday high tide coming in at almost 10', and noticed some interesting one-hour wobbles in the water level curve that lasted all afternoon. They are only a few inches in amplitude, but it just happens that Wednesday afternoon is when the Kurile Island tsunami reached Crescent City and the rest of the west coast of North America! The pictures above were taken about 1:20PM local time - though conditions weren't exactly conducive to observing a 3" tsunami! Probably requires some more analysis to confirm, but tantalizing.
Wednesday, October 04, 2006
The beach heads north from Possession at the south end of the island, eventually growing wider and forming Columbia Beach. Then it squeezes under the ferry dock, and surprise, it pops out on the north side in a new park. They tore down the old buildings and have created a great, and much needed, little diversion for folks waiting to catch the boat.
Freeland. I've been swinging by this beach now and then to watch how it responds to the new stormwater outfall in the middle of the park (not terribly well, as the flows seem sufficient to carve a significant channel across the beach and transfer much of the sand offshore, which also results in erosion of bank adjacent to the outlet). This time, however, the beach was doing okay - other than it was blanketed with 6" of dead eelgrass. This is a typical autumn phenomenon, albeit one that varies significantly from year to year and that is probably more characteristic of some beaches than others.
Building ON the beach. Literally (or littorally?). This style of development is, fortunately, pretty rare on the Sound once you get away from the urban waterfronts. Somehow seems more like Orange County than Skagit County.
I'm digging back in photos after a long absence - to early September. Back to Fort Ebey State Park, scouting for a field trip and wondering if a tour bus can make the bend at the end of the road (three weeks later, it did, but just barely).
Angle of Repose. Not just a novel by Stegner, but a measure of the angle at which slopes form in loose materials. In gravel and coarse sand, typically around 34 degrees. Check it against the horizon line - it really works!
Saturday, August 05, 2006
It's always fun to visit a beach I've never seen before. Maple Beach is on the east side of Point Roberts, facing out over Boundary Bay with views of Mount Baker and the eastern portions of Vancouver. It extends north to the border, which is marked by a tower, a road and the backyard fences of suburban Vancouver.
Lighthouse Park is at the southwest tip of Point Roberts, that little orphaned piece of the USA that hangs down below Vancouver. The high ground of Point Roberts and neighboring Tsawwassen was once an island, until subsumed by the growing Fraser Delta.
The west side of Point Roberts is one of the few places in the Salish Sea where humans may have managed to alter the direction of net longshore drift (there may be another smaller example northeast of the Hood Canal bridge). We can block it or reduce it, but it took the Canadians to actually reverse it. Prior to the causeways to the Tsawwassen Ferry Terminal and the Roberts Bank Delta Port, net shore drift was probably to the south, driven by the extended fetch from the north, but the causeways may provide some shelter, increasing the relative importance of southerly winds and waves. This is all pretty speculative, but makes an interesting story.
Lighthouse Park has a difficult erosion history, probably complicated by changes to wave and sediment patterns and the unfortunate location of the old lighthouse building. Seems like everything would be easier if the structure could be removed (the navigation beacon could remain) and the beach allowed to do its own thing (but then I always say that).
This visit was pleasant, but didn't match my first visit, when a kid's concert was going on at one of the shelters and a pod of Orcas headed past just offshore.
The beaches on English Bay benefit from their orientation (using groins) and added sand. They are just one element of Vancouver's magnificent, public shoreline, and are located between Stanley Park and the dense urban neighborhood sprouting along False Bay. The 13 mile seawall path allows bikers to go from downtown around Stanley Park and False Bay all the way to Kitsilano.
Four evenings every summer, the beach hosts a few hundred thousand people for fireworks. Each following morning, Vancouver Parks cleans up the mess and makes the beaches look like new again, with the help of big beach toys.
In the early 1900s, Luna Park was an amusement park on a pier - must have been a neat place on summer evenings. A couple years ago, the city fixed up the little park, removing the decaying seawall and allowing the sea to flow underneath.
Harbor Avenue was once on piles over the beach, below the high bluffs of Duwamish Head. Eventually, they filled it all in, burying the original beach under the road and beach houses. Now the beach houses are five story condos, the better to stop landslides from knocking roller bladers into the Sound.
Three pocket beaches tucked into the western shore of Elliott Bay, separated by riprapped headlands of 19th century fill. The pockets probably correspond to location of wharves, where fill wasn't dumped. The coarse, well-sorted gravel leads to steep beach faces. The beaches were constructed in the late 1980s.
Sunday, July 09, 2006
In January, 1997, a family of four was killed by a landslide at this site on Bainbridge Island (see Brenda Bell's article, The Liquid Earth, in the January, 1999, Atlantic Monthly). Other nearby houses were lost to separate slides during the previous winter and in March 1997, although without the fatalities. Today, a double-tiered retaining wall is being built on the slope so the waterfront lots can be redeveloped.
Some seawalls are special. I'm sure there is a great story to go with this one, but it's not one I've learned yet. The concrete pipe segments that remain upright are acting as planters for dune grass.
More pictures of the evolving beach at Chimacum. The spit seems to be becoming more distinct. The hydrology of the back-barrier lagoon is still a bit confused - with two outlets and a drainage governed by the incidental topographic subtleties of February's excavation work. Some organic material is accumulating in the nascent lagooon. The hydroseeded vegetation on the upland is beginning to take hold, along with a healthy assortment of nettles, blackberry, and morning glory.
Back to May for this one. Some beaches attract more attention than others. After the Clallam River reaches the coast, it hangs a sharp left and heads a mile or two west before finding its way to the sea. But it doesn't always find its way to the sea in the same place. And sometimes, it doesn't even have the oomph to reach the sea at all, disappearing into the gravel behind the berm for months at a time. This presents a bit of a challenge if you are anadramous. A bridge usually provides pedestrians a way across the river to the beach. Except last year, when the river migrated right under the seaward end of the bridge, taking the steps away and leaving a bridge to nowhere. The best answer is often to roll with the punches rather than fight (or even try to predict) nature's whims. Simpler to build a new ramp and prepare for occasional closures.
Wednesday, June 28, 2006
I liked Pass-a-Grille, maybe because I enjoy these older beach communities where condos and t-shirt shots don't dominate the landscape. I also like beach towns where there there is continuous public access to the beach; not isolated parks and narrow corridors between hotel towers.
I suppose the presence of intact, early 20th century buildings, is an indication that this area has been spared a direct hit for close to a century. I can't help but wonder if someday I'll be looking at news footage of this barrier wiped clean of structures. I wonder how you rebuild to FEMA standards while maintaining the requirements for historic landmarks?
It's been thirty years since I've been in Florida, and now two trips in less than six weeks! Our time at the beach has been limited by our family's general abhorrence of hot, muggy weather, but we've managed some short excursions (for the rest of the story, go to hshipman blog).
The flight from DFW to Tampa bypassed a large storm over New Orleans, so I didn't get good views of the coast until we got to Mobile - I was hoping for a good overview of post-Katrina Pass Christian and Biloxi. We flew a few miles north of the coastline from Mobile to Appalachicola area before cutting across the Gulf toward Tampa Bay. The photo may be Destin, though these resort beaches tend to all look the same from 35,000' (or maybe even from sea level?).
The hurricane deflectors (very small in this picture) remind me of lightning rods on the ridges of Pennsylvania barns or the wire spikes that keep seagulls off of waterfront restaurants and pigeons off of public monuments. They have been constructed up and down the southeast coast. Since hurricanes aren't very frequent, authorities let people live in them when they aren't actually being used to protect the nation from tropical storms.
Saturday, May 20, 2006
This was a new one for me. It's a log crib, bolted together with stainless cable and hardware, extending out in front of the base of the bluff. It was built within the last year or so, presumably as a softer approach to erosion control than a conventional bulkhead. I'm still struggling with what to make of it. If nothing else, I wish it didn't extend so far onto the beach and that it had incorporated soil and plantings. Functionally, it appears equivalent to a failing timber seawall -- maybe that's a good thing. I wonder what the hardware will look like in 20 years?
The north side of Samish Island is a great place to talk about human impacts to beaches and we've been bringing the CTP class, and other groups, here for years. Bulkheads, bluff modifications, and groins. Sediment supplies have been heavily impacted (some material still comes from farther northwest) and what sediment that's left is heavily compartmentalized by two large projecting fills that act as groins. The spit (Samish Beach) at the distal end has undergone a variety of changes over the decades and was most recently the site of a large (by Puget Sound standards) private gravel nourishment project.