Saturday, October 11, 2014

Elwha Delta




The Elwha Delta continues to build outward in step with the delivery of sediment from the reservoirs behind the Elwha and Glines Canyon Dams. Both dams are gone, the river is running freely, and an amazing amount of sand has made it to the river mouth, although there is a lot more still to come. 

Gravel is beginning to appear on the new bars and spits at the river mouth, although I suspect it will take repeated cycles of river mouth movement and wave action to recycle and sort this material before more persistent coarse-grained features can form.

For a more thorough update on what's been going on, you might start with Ian's most recent post on the Elwha and then move backwards:
Coast Nerd Gazette: September 2014


One of the most interesting questions, at least to me, is how growth of the delta will eventually contribute to transport of gravel farther down the coast towards Port Angeles. This probably isn't a slow dribbling of material to downdrift beaches, but rather it may be driven by events that release larger plugs of material - a shift in the river mouth, a big storm, the growth of a new spit on the east side - who knows?  I'm glad folks are watching.

Previous posts on Gravel Beach:
Elwha Delta (October 2010)
Elwha Delta (March 2013)
Elwha Delta (July 2013)

There's a lot of great material online about the Elwha and the changes occurring on the coast. Besides The Coast Nerd Gazette, check the National Park Service, and the Coastal Watershed Institute. Lynda Mapes has written Elwha: A River Reborn and there is a documentary film, Return of the River out as well.



Hollywood Beach




Hollywood Beach in Port Angeles is one of those neat little pocket beaches that can form when sediment is trapped against an artificial headland - and which are pretty common in heavily modified shorelines. The beach is neither natural nor intentionally created. It just sort of happened and has evolved to become a neat recreational resource.


The original shoreline was located much farther to the south, nearer the base of the original bluff, but in the early 1900s the Port Angeles shoreline was filled outward and the original beach was buried, along with the remnants of the native village that once lay at the mouth of Ennis Creek.


Karl Wegman and others provide a very nice analysis of the original shoreline and its subsequent reconfiguration, with an emphasis on the archaeological implications at:
http://onlinelibrary.wiley.com/doi/10.1002/arp.1431/abstract
Also, Peninsula Daily News (May 2010)


Some lower portions of Hollywood Beach were marked off where, earlier this summer, depressions began to appear. There was much speculation about the mysterious sinkholes and I'm not quite sure where it all got left. Because the modern beach is located on top of many feet of fill, there could be any number of things underneath the beach that might give rise to this.  It sounds like one of the most likely explanations is that this is the result of old logs and wood rotting out.


The eastern part of the beach is covered in fine dark wood particles, although I don't know if this came from this location or floated in from elsewhere. Port Angeles Harbor has been in the wood products business for its' entire history and there are no shortage of possible sources of this kind of material.





Sunday, September 28, 2014

Coeur d'Alene


We spent the second week of September on the road again. Between Seattle and Minnesota again. We're getting pretty good at it, even though we never do it the same way. As usual, there was plenty of neat scenery and some geographic highlights, but not many beaches. This one in Coeur d'Alene was the only one.

AERIAL VIEW

I know little about this one - other than it is called City Beach. It lies west of the big resort complex and east of the lake's outlet (the start of the Spokane River). It's oriented pretty much toward the greatest fetch on this part of the lake. It stretches west from Independence Point - a headland formed by a stepped concrete revetment that even includes a little waterfall and a moose.

I believe the lake level is controlled by the dam at Post Falls, several miles downstream, and is therefore likely higher than it was naturally. And in recreational settings like this, beaches have often been created, sculpted, or at least supplemented with additional sediment.  But I really don't know much more of its history. It would have been fun to explore a little more, but this was the last day of a long trip and we were anxious to get home. I grabbed coffee at Calypso's and we were on our way.

For those more interested in our road trip than in beaches, you can always check it out at:
hshipman: "roadtrip2014"





Seahurst Park




These photos were taken way back on August 27th, just a few days after Seahurst Park reopened after being closed for year. At some point, I'll come back and post a longer follow up on the recent project, but I'm still in catch-up mode and will stick to little more than a few photos.

The bottom line is that the beach has been restored, an awful lot of old seawall and riprap and fill removed, and a small stream daylighted. All the responses I overheard from the folks wandering around were positive, although I suspect some were also just trying to line up what they were seeing with what they remembered.  The seawall was a useful reference point and now most of it is gone.

AERIAL VIEW

Seahurst Park: January 2014 (during construction, with links to earlier posts)


March's Point



This was a very quick stop at the end of the day (back during the third week of August), but enough time to see how this new beach was sorting itself out. I posted from here last fall, but the weather was awfully bleak and the photos awfully gray.  At that time, I said eventually I'd post more, and I guess that't still likely, but it's not now.

Bottom line - very simple (they're never really simple) beach nourishment along the toe of the bank a couple of years ago with a lot of initial reorganization of sediment.

AERIAL VIEW

The site is along the west side of March's Point, north of the old railroad trestle (now Tommy Thompson Trail).





Seafarer's Park



I've fallen way behind - a week in August on Salt Spring and another week driving back and forth from Minnesota in September resulted in some beaches being collected, but not yet stuck in the album.  So I'll add them quickly - with abbreviated comments - so I can check this off my list.



This is a neat park on the site of the old Scott Paper mill. The site has been cleaned up. Two new breakwaters were installed to replace the dilapidated timber wall that used to protect this side of the entrance to Cap Sante Marina and to provide shelter for small boats launching from the new pier. There was always a small pocket beach in the cove on the park's north side, but the low tide beach is no longer a tangle of rotting wood and the upper beach is clean gravel, not broken bricks and debris.

AERIAL VIEW

There's a lot more that I'd like to add about this site, but that will have to wait for a future post.









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!