Thursday, July 04, 2019

Omak Lake

Another lake, this one in north central Washington, visited during my winding drive back from Montana a couple of weeks ago.

Omak Lake has no outlet. It's a low spot in an ancient channel of the Columbia River that has been subsequently occupied by the advancing ice sheets. While the shoreline shows evidence of fluctuating water levels, I guess there isn't enough precipitation to keep up with evaporation (or subsurface drainage?). Much of the shoreline is bedrock, but there are beaches in a few spots where abundant sand and large enough waves cooperate.

Besides shaping the landscape, the glaciers left erratics picked up elsewhere. The top photo show one along the edge of the lake itself. But the main objective of this little side trip was Balance Rock, perched on a small eroded pedestal high on the slope south of the lake.


The small city of Sandpoint, Idaho, lies at the northwestern end of Lake Pend Oreille, near its outlet to the Pend Oreille River, which in turn flows into the Columbia just north of the Canadian border (although it has to first flow through the powerhouse at Seattle City Light's Boundary Dam in order to generate some of the watts that run my computers and my air conditioner).

The Clark Fork River is the largest inflow to the lake and drains a large portion of western Montana. During the waning stages of the last glaciation, about 15,000 years ago, ice advanced south from Canada into the area that is now the north end of Lake Pend Oreille, blocking the Clark Fork and creating Lake Missoula (Lake Missoula and Camas Prairie). Or actually, many Lake Missoulas, as the ice dam kept breaching, emptying the lake, and multiple large floods swept across this landscape and southwest into Washington (Frenchman Coulee and Potholes Coulee).

None of which has much to do with this post, which simply highlights City Beach in Sandpoint. Historical photos on the web show a lot of saw mills and train tracks, but don't provide much evidence of what this spit-like landform at the mouth of Sand Creek looked like prior to development.


What was lumber-based industry is now lake-oriented recreation - beaches and boats and hotels. The sand appears to have been imported and piled along the shoreline, where waves have redistributed it to form a series of small beaches that wrap around the point. This movement of sand, and ultimately the shape of the beaches, is influenced by several groin-like structures. (If it turns out that these beaches are completely natural, and I'm completely off base, my apologies, but it's really hard for me to explain them without human intervention).

Saturday, June 29, 2019

Kootenai Falls

This isn't really a beach. It's actually not a beach at all. But there's moving water and geology, and if you're paying attention, ripples left in the sand by shallow water waves a mere 1500 million years ago.

Kootenai Falls is one the few big, unaltered drops left on any of the large western rivers. Most have been lost to dams and reservoirs, for hydropower and irrigation. Even those that haven't been completely submerged have often been drastically changed by structures and upstream diversions. 


The falls drop over resistant beds within the incredibly thick Proterozoic Belt Supergroup. The photos capture some of the extensive ripple marks, but unfortunately, none of the stromatolites (fossilized mounds formed by layered growth of cyanobacteria - a very, very long time ago) that are also exposed well near here.

Here's an early post on Gravel Beach that featured similar rippled Belt Series rocks, albeit ones found now on Puget Sound: Picnic Point 2007

And here are links to some other waterfall posts, all over at hshipman (waterfalls tend to find themselves on those pages more often than here on Gravel Beach):

Kootenai Falls: September 2012 (a previous visit)
Shoshone Falls: June 2012, September 2017
Great Falls: September 2017
Thompson Falls: September 2014


City Beach is located at the south end of Whitefish Lake, about a mile northwest of town. The sand and gravel beach may be natural, although I suspect it's been improved upon - if only because there simply aren't similar looking beaches elsewhere along the lakeshore. There are beaches, at least where the shore is oriented into the waves, but they are not as wide as this one.


A cluster of large boulders in shallow water creates a distinct inflection in the shape of the beach and may help segregate the more gravelly beach in front of the wall to the east from the sandier beach toward the boat launch.

Saturday, June 22, 2019

Lake McDonald

I suspect this is the same beach I posted pictures from several years ago (Gravel Beach: Sept 2012), although there are several fairly similar beaches along this stretch of Going to the Sun Road. The lake seemed a little higher this year and was encroaching into the trees in a few places along the shore. I don't think the level of the lake is controlled - the outlet, McDonald Creek, appears to be free-flowing - but it makes sense flows and water levels would be higher in June than in September.

There was a neat little recurved spit - looked a response to winds blowing west down the lake.

Most of the bedrock in Glacier belongs to the Belt Supergroup (a very thick stack of very old Proterozoic sedimentary rocks). The red and green argillites are widespread and when eroded by time and glaciers, yield red and green gravel, which waves shape into these nice little beaches.

Thursday, June 13, 2019

West Beach

This was pretty much the best possible place (and conditions) to end a field trip on my last day in the field as a professional! The concrete artwork was colorful in the sunshine. The beach provided a great contrast to the three other beaches we'd already visited earlier in the day (Custom Plywood, Bowman Bay, and Cornet Bay). And after a fairly minimalist geologic overview, the participants went back to throwing stones and climbing on the logs until we all had to run off to catch our ferries.

West Beach: February 2013

While the fulcrum of my work-life balance is about to shift dramatically, I plan to continue Gravel Beach. This year has been a slow one on the blog and that may not pick up right away - it has been a distracting few months and my summer and fall will likely be in the mountains and the Interior (not so many beaches). And finally, I have big issues with the platform: Blogger is not very mobile-friendly. The blog takes a lot of time (at least when I'm posting much). And Google has put virtually nothing into supporting it for years. I'll keep playing around with other sharing options - some of which are linked over on the right (desktop version) - and will certainly let folks know if I decide to make big changes.

Wednesday, May 01, 2019

Colman Dock

Seattle has been replacing its downtown seawall over the past couple of years. The new one provides better habitat - better, at least, than did the old seawall. But probably not quite the mixed sand and gravel beach, drift logs, and forested bluff that once stretched continuously from Smith Cove to the little point of land at the mouth of the Duwamish River that is now Pioneer Square.

The new seawall includes a low-tide bench, textured panels, and a cantilevered walkway with glass block to allow more light to reach the water. And here, just south of Colman Dock (the ferry dock is getting rebuilt, too), a beach is being added. But unlike the Sculpture Park farther north, where a pocket beach was carved into the old filled shoreline, here the beach is being perched between rock sills on a constructed platform that juts out into deeper water. This is a very strange beach.

One of the big benefits of beaches in urban settings is that they allow people to get to the water, but I've heard a rumor that this may not be possible here.

Wednesday, April 17, 2019


The pictures in this post are from just a little farther north than those in the previous post, since Irondale and Chimacum are just different ends of the same beach. While this is a frequent stop when I'm visiting the Port Townsend area, I just realized that I hadn't posted from here for more than ten years (the project itself only occurred in 2005-2006)!

Chimacum Beach: June 2008
Chimacum Beach: July 2006
Chimacum Beach: May 2006

Like at Irondale, the beach is almost entirely sand dredged up from the bay a very long time ago and I suspect most of the clam shell on this beach probably came along with that sand.

The back-barrier wetland, behind the spit that formed following the initial project, is pretty high so only the northern portion, near the mouth, gets much saltwater inundation. The central portion looks fresh. And the southernmost portion is more meadow than wetland.

Chimacum Creek exits from its beautiful little forested estuary at the very north end - I've been meaning for years to come back and explore with the kayak. Maybe this summer - when I'll have a little more time to play with!

Tuesday, April 16, 2019


Irondale and Chimacum are the southern and northern halves of the same beach, at least as I see it, and as they have before, they will generate two posts. Short posts - since I'm way behind and I promised myself I would write less this year.

Irondale is the site of a large 19th-century iron smelter which was finally cleaned up a few years ago after more than a century of abandonment.

Irondale (March 2013) (which in turn links further back)

The old brick beehive ovens continue to gradually erode onto the beach, some of the smelter slag still crops out as ledges on the beach, and a number of old stone foundations pieces were left behind. But the beach is doing great. This is an unusually sandy system (by Puget Sound standards) - the virtue of having been constructed a century ago with sand (and clam shell) dredged from the bottom of the bay. 

There's a gentle promontory in the central portion of the site where the berm inevitably wants to shift landward, but this is neither rapid nor a problem. A few of the logs that were placed along the berm have been undermined and as I recall there might be some sort of monitoring well(?) that may in time be exposed (if so, it will make a nice erosion reference).

The Irondale Beach continues seamlessly to the north, eventually becoming Chimacum Beach, where we'll go next.

Friday, April 12, 2019


If you're going to build a town on the water, it makes sense to find a piece of ground that's low enough to allow easy access to the town pier, yet high enough so the town doesn't flood every December. You want to pick a shoreline sheltered from the prevailing winds on a relatively protected bay.

Building over the water made sense in a 19th-century maritime community and the high bank lead to buildings that sort of spill over the bluff -- people and wagons approached on the upper floors, boats pulled up below. Stairs and hoists and gangways connected the two. Early Seattle - along the central waterfront - developed similarly. As did many towns in many other parts of the world.

In many places - Langley, Seattle - development eventually led to foundations being built to replace the piles or to the beach being filled behind a community seawall of some sort. Some of this happened here in Coupeville, too, but in some spots the beach remains, between and beneath the buildings.