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Portage is one of those names that crops up in many different places - but the three that come to mind on Puget Sound (I'm not counting Portage Bay below UW) are all tombolos, or at least were tombolos at one time). All three were places where simply lugging your canoe over the beach berm saved you several miles of paddling in rough water.
One of these is at the tip of the Lummi Peninsula at the north end of Bellingham Bay, where a spit (really just a bar, but that's another story - one I don't know) connects to Portage Island. Another is the passage between Indian and Marrowstone Island, which was closed by a barrier beach until the Corps of Engineers excavated the channel and built jetties early in the 20th century.
The third is this low isthmus that connects (or separates, depending on your perspective) Vashon and Maury Islands. As with all of these, there is always some debate about whether historically there was an open channel, but in general, maintaining a channel in these situations would be difficult, as the beach would tend to close up the gap pretty quickly. There has to be a pretty strong tidal differential to maintain enough flow to keep something like this open (or a complete lack of sediment). That doesn't mean that sometimes storm waves and high tides would not have periodically washed over the top, but that's not the same as a navigable connection unless you're in a kayak and willing to do battle with the logs.
AERIAL VIEW
The north side of this tombolo would have been the primary berm since the exposure is greater and there is much more robust beach. The south side lies within Quartermaster Harbor and is fairly sheltered. Typically, in a situation such as this, the wetland that formed in association with the tombolo would have drained to the southern, more protected side. Trails across these features become roads and a desire to maintain access during storm conditions leads them to be elevated and armored. Here, it's still only a short hop from the beach on the north side of the road to the remaining wetland on the south side. And the south side, like any south-facing beach at the north end of an embayment on Puget Sound, is a magnet for anything that floats and blows across the surface of the water. Logs, old styrofoam floats, plastic water bottles, sneakers, tennis balls.
Two weeks ago (I hope readers don't think this blog is live - or even almost live), I was on Vashon to give a talk and had a chance to swing by Dockton, where another small restoration project has just happened. For the "before," check out my post from a few years ago:
Dockton: May 2008
Note that the restoration project is just west of the boat ramp and county park - there is another, larger restoration project just waiting to happen under that parking lot!
The county has recently pulled out the old riprap and excvated an s-shaped channel to capture the upland runoff. The hydrology may be defined as much by culverts under the road (which lies just uphill) as by the original stream network. The result is a small stream mouth estuary - or what will become one. Besides the channel, the beach berm has been reshaped to form a small spit. Waves (what few there are here) and tides will spend a year or two reshaping the berm, but the bulk of the changes from here on out will be in the vegetation and in what ever fauna choose to colonize or pass through. It will be fun to watch.
AERIAL VIEW
Maury Island cuts eastward across the north-south grain of the Puget Sound landscape, begging questions about both why it's here and its effect on glacial processes 16,000 years ago. Point Robinson lies at its eastern tip, collecting sediment that is transported up the southern shoreline of the island (where it merges with a much smaller contribution from the northern shore of the island).
AERIAL VIEW
Point Robinson is a small cuspate foreland and like many other similar features, its location and its morphology lend themselves to a lighthouse.
Point Robinson: January 2010
Tramp Harbor lies on the eastern shore of Vashon Island, just south of Ellisport and Point Heyer (KVI Beach), and just north of the Portage, the narrow isthmus (historically, a tombolo) that connects Vashon and Maury Island.
AERIAL VIEW
Like many other early roads on Puget Sound, Dockton Road (George Edwards Road on some maps) was built on the beach. It was fairly simple to construct above normal high tides - often on piles, later on fill - and it was certainly easier than the alternative, which was building roads through steep, unstable, and heavily forested terrain.
These shots capture a simple point about bulkheads and beach fill. While most walls bury the uppermost beach and tend to isolate the marine and terrestrial environments, some transform the beach much more than others.
These walls all differ in their waterward extent, which is as much about the amount of fill behind them as about the character of the wall itself. The first picture shows the base of the old wharf/pier, a rectangular mole extending to mid-tide (not counting all that rock dumped in front). Not much beach!
This next one shows the roadway itself, protected by an old wood bulkhead. The upper beach is missing - along with the drift logs and the natural bluff toe. Old riprap and quarry spalls cover what's left of the beach.
The following photo shows a section of wall that was replaced a number of years ago. Still no upper beach, but the design reduces the impact on the beach somewhat, and some of the rock debris on the lower beach has been cleaned up.
The last picture is a residential rock seawall at the north end of the bay. It is fairly typical of modern era bulkheads on Puget Sound. It was built closer to the toe of the bank, so its immediate impact on the beach is certainly less than the ones described above. But it still eliminates the upper beach, so no drift logs and none of the natural riparian zone that would have once been observed. They lock up sediment on the beach and prevent new sediment from being delivered by erosion. And unlike roads on the beach, these residential structures are much more widespread and are still being built. Regardless of their individual impacts, their aggregate influence on Puget Sound beaches can be significant.
It is called Point Heyer on the maps but is known locally as KVI Beach, after the radio transmitting tower on the point.
Point Heyer is a recurved spit, shaped primarily by winds and waves out of the north, and is the terminus of a littoral cell that collects sand and gravel from two miles of eroding bluffs and small streams. As usual, most of the wind comes out of the south, but Maury Island limits the fetch, so northern waves have much more influence. The southerly winds are still more than enough to pile the drift logs up into the northern corner of the marsh (within the lagoon itself, wind moves the logs, not the waves).
The spit is hooked around to the west, into Tramp Harbor, and the tidal inlet is pushed to the farthest end. The eastern limb is narrow, consistent with a barrier beach migrating westward in step with the retreating bluff to the north. The western limb is broad, since it is the ultimate resting place for much of this sediment moving down the shore. We often call these landforms accretion beaches or depositional landforms - because they have built over long periods of time seaward of the original coastline. But that doesn't mean they are actively accreting. In this case, the eastern limb is erosional - or at least maintaining a state of dynamic equilibrium (if your house was built on it you would call it erosion), but the western limb is truly accretional.
It's hard to find a tidal marsh in this part of the Sound. There used to be more, but these small estuaries and lagoons were easy targets for early settlers and small industry and most were filled by the early part of the last century.
Another shoreline with a complex 19th and 20th century history, mainly involving boats and boatyards, the remains of which can be found on this beach and on to the northwest. This appears to have originally been a small stream mouth, marsh, and low-energy beach. Wave energy is low, but sufficient to maintain a beach of medium gravel among the riprap, historic artifacts, and remnant marsh exposed on the shore (the presence of marsh on the beach face is due to the low wave energy, the presence of eroded marsh soil at beach grade, and probably the abundance of freshwater seepage). This may have begun as a small barrier beach with a back-barrier marsh, or more likely, a low, freshwater wetland, with a narrow beach across it's eroding front. Or a combination of both.
The park itself consists of a parking lot and boat ramp, along with a concrete seawall behind the minimal remaining beach. In the 1970s, we pumped state money into building parking lots on the beach - the better to sit in your car and watch the birds with your engine running. The stream itself emerges from a pipe near low tide. To the west, there's a chance to remove fill and riprap, rebuild a wetland and barrier beach, capture the upland drainage and create a stream mouth, and add some historic interpretation and recreational benefits as well.
