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Marine Park in Blaine, just south of the Canadian border, is located on the northwestern edge of a large peninsula built out of fill when they dredged their port and marina. The shoreline edge is pretty ragged and was composed of rocky headlands formed from old concrete and rock debris and a few scattered, somewhat accidental beaches. I visited it six years ago when the City was contemplating improvements to the park's shoreline (Blaine 2010).
AERIAL VIEW
One segment of the shoreline has recently been fixed up. The concrete has been replaced with better constructed and more attractive riprap promontories and the pocket beach has been enhanced. The idea of taking advantage of the existing headlands is a good one and it facilitates the creation of stable pocket beaches. There's probably more that they could do along here, but this is a great start.
There were signs of some erosion of the bank just north of the large log and root wad (see pictures). This isn't anything serious, although it bears watching. I wonder if it's a result of last months high tide storm interacting with the large log that's been placed on the bank. This log, which includes a big root wad, seems too high to have just floated in, so I assume it's an installation. As we've seen on other sites, there's some risk associated with placing big wood high on a steep profile - - it may eventually get undermined. But then it roll down to a more natural place on the beach.
We were in Chicago a little less than three weeks ago, winding up our brief trip back to the midwest. My only foray to the beach was on the morning we left, when I dodged rain squalls on my way to meeting M for breakfast at Tempo.
I've got much better shots of these beaches from an earlier trip: Chicago: July 2010
The first three photos are from Oak Street; the bottom one is from Ohio Street Beach.
But rain or not, I still love these public beaches against the backdrop of Chicago's skyline. There's nothing terribly natural about them - nourished and groomed pocket beaches have replaced the spits and marshes that once marked the mouth of the Chicago River - but it shows that we can still provide ways for people to interact directly with the water, even in our most urban settings.
There are a lot more photos from this trip, mainly of skyscrapers, over on the other blog (hshipman: Chicago).
Much of the southeastern shore of Lake Michigan, from Wisconsin south through Chicago towards the Indiana Dunes at the south end of the Lake, consists of eroding bluffs. But there are a number of locations where the bluff is absent, either because a lower river valley intersects the shore or because the beaches have accreted out into the lake.
AERIAL VIEW
I don't know the explanation for Wind Point, just north of Racine, but it extends out into the lake. It's low, but doesn't appear depositional. I suspect there may be bedrock control - a more resistant layer at modern lake level - but would need to do considerably more homework for this to be anything more than speculation.
Sediment transport is pretty strongly from north to south on this shore of the lake, reflecting the strong north wave action (winds and long fetch). The presence of both sand and gravel, like on Puget Sound, is mainly a function of glacial sediment sources.
These small trees being eroded away just south of the lighthouse tell a story, but it's not a story I learned during my short visit!
A couple of days after getting back to Seattle, I was throwing out some old stuff in my cubicle and ran across a 2" thick report I had obtained in the mid-1990s that described in detail the geology and engineering of the Lake Michigan shoreline of Milwaukee County. Aerial photos show that this beach was constructed in 1988 (Photos from Southeastern Wisconsin Regional Planning Commission, 1989).
Like other Great Lakes cities, much of Milwaukee's shoreline was built out into the lake with fill, the better to create marinas, public facilities, and recreational space. As a result, beaches tend to be highly engineered pocket beaches, often shaped by groins, adjacent jetties, and offshore breakwaters. McKinley Beach is part of a segmented headland breakwater system - there's a longer beach a short distance farther north (see aerial below).
AERIAL VIEW
The gap in the riprap constrains the direction that waves can approach the beach and the breakwater prevents sand and gravel from escaping the confined pocket. Regardless of the direction with which waves approach (the big waves come mainly from the north on Lake Michigan), they pass through the narrow opening and break in regular curves on the crescent-shaped beach.
My brief search for beaches turned up this small pocket in Olin Park, on Lake Monona southwest of downtown Madison. There's a nice view back at the State Capitol and Monona Terrace (hshipman).
AERIAL VIEW
I don't know enough about these midwestern lakes to understand much about the formation of beaches and their distribution. Things that are always important are water levels (I think this lake is controlled pretty tightly), along with wind and wave conditions, particularly during larger storms. But there are also local factors like ice cover in the winter, the geology of the shoreline, and the original riparian forest. The history of a site is also critical - sometimes fill has been placed to extend the shoreline farther out into the lake. Small beaches are often created from scratch or are nourished. This one has formed in a small cove bracketed by riprapped shorelines on both sides.
Although probably not relevant to the beach itself, this area was originally the site of many hundreds of native american mounds in various sizes and shapes. It's so easy to overlook the prehistory of these places - particularly where so much of it has been obliterated. And in the midwest, we often forget that the aboriginal cultures first encountered by Europeans were in themselves hugely transformed from the extensive Mississippian Culture that existed hundreds of years earlier.
After a weekend in Madison, I thought some sort of post was in order, although the gray weather, the limited time to explore the shoreline, and the paucity of actual beaches didn't exactly lend itself to exciting content.
Downtown Madison is located on an isthmus between Lake Mendota on the north (this post) and Lake Monona on the south (next post).
AERIAL VIEW
These first few photos are from the University of Wisconsin, showing the UW Limnology Lab and the Memorial Union Terrace (being remodeled).
These last two photos are from Burrows Park, in Maple Bluff, on the east end of the lake. I suppose once upon a time the lake's shorelines were heavily forested, but as the trees came down and the shoreline developed, erosion became a problem, and much of the lake is probably hardened.
I guess this year's mild winter led to the lake only being frozen for a couple of months - and it was fully thawed by our late March visit.
A major windstorm coincided with high tide early on the morning of March 10th. The Seattle tide gauge pushed 14.3', a little less than 2' above the predicted 12.4'. In some places, the impacts were reported greater than the storm on February 4th, 2006 (ten years ago). In others, the effects were less. The differences may have been due to the relative role of high water versus waves, to local variability in wind intensity and orientation, and to small changes in beach conditions that can lead to big differences in how waves impact the landward area.
A week later, I was finally able to get to the beach - a quick series of stops on the way to an event in Langley. But it was enough to get some sense of the effects of the storm at a few places that I'm getting to know pretty well.
So here we are back at Ala Spit. The overtopped and eroded berm was rebuilt this fall (Ala Spit: November 2015) and this storm gave it a serious test. Pictures forwarded by others showed this portion of the spit pretty much submerged during the peak of the storm, but apparently not enough for the waves to wash the drift wood over the back into the lagoon - or at least not much of it.
AERIAL VIEW
But farther out the spit, beyond the area of the recent projects, the effects of the previous week's storm were much more evident. The spit had been overwashed, the logs largely floated off, much of the vegetation stripped or buried, and the previous berm spread out in a relatively uniform sheet of gravel back from the leading edge of the spit.
The gravelly overwash deposits contrast nicely with the sandier material farther inboard of the beach and also suggests some differences between the processes that shaped each. I suspect the gravel sheet is classic bedload transport by breaking waves, thus the abrupt landward edge and the fact that smaller overwash lobes were generally oriented northwesterly, perpendicular to the beachface. The ripples in the coarse sand suggest flowing water -- with currents flowing in a much more northerly direction (more parallel to the overall trend of the spit).
Overwash is typically accompanied by erosion of the upper beach face - it's where much of that gravel comes from. Here you can see how it stripped the the area of the previous berm right down to the underlying substrate (some organic, some anthropogenic, confirming a complex natural and human history).
The fact that the most significant overwash occurred here rather than at the rebuilt neck of the spit is interesting, but not necessarily surprising. The new berm had been built very high, probably higher than the natural berm in this area, and therefore was less prone to inundation (this in marked contrast to the circumstances five years ago during a lesser storm when an earlier attempt at a restored berm washed over into the lagoon (Ala Spit: December 2011). It's also possible that the orientation of the storm was a little different. But there's another possible twist, one that only really good morphological monitoring could confirm. This segment of beach may have been starved of sediment by the 2011-2012 washover events just updrift. In which case, this is exactly where you might expect the spit to be most vulnerable!
This fall the rock revetment between the boat ramp and the pier was removed and that section of beach restored. I've included a picture of that beach at the bottom of this post, but this entry is really about a portion of the same beach another 100-200 meters to the south.
We think the wetland used to be much larger, extending to much of the area now occupied by lawn, but there's still a large marsh behind the beach at the south end of Bowman Bay. It collects runoff from a fairly large area, including Pass Lake up on the main road. It drains through a 12" culvert that exits on the lower beach. This keeps the normal water level of the wetland pretty low.
AERIAL VIEW
But this winter wasn't normal. It was wet. And the wetland was filling faster than it could drain through the pipe. A couple of weeks ago, the water level got so high it flowed over the berm creating a new outlet (or at least re-establishing the old outlet -- the history isn't well known). The trail crosses this spot on a bridge, so presumably there's been some history of a channel or of flow through this area before, although the structure normally seemed more like a boardwalk with hand rails.
As the rains diminish (really, I'm sure they will!), the water in the marsh will fall, and the new channel will dry up. Waves will push gravel into the gap and rebuild the berm across the outlet. But what's interesting is that there has been talk in the last few years of restoring a more natural connection between the wetland and the bay. The conditions of the past couple of weeks actually provide useful hints about how that might work. Maybe there is some simple replumbing that would allow the natural outlet to be the primary outlet, and relegate any pipes to more an overflow feature.
The photo below is of the main beach where the restoration work was done this fall. At the time, I posted about the site (Bowman Bay) and noted the steep scarp that had formed during a big storm that occurred right after the project was completed. This photo shows the scarp remaining, but it has been broken down by foot traffic and the beach in front has built back up, reducing the overall effect. Personally, I think this beach needs a few good high tide storms to cut that upper bank back another 10-15', dropping that big super-elevated log down a couple feet to a more natural position and creating a more natural berm for the dune grass to recolonize.
The northern half of Birch Bay's eastern shoreline is a long curving gravel barrier beach, separating the bay from extensive wetlands farther inland. Birch Bay Drive pretty much follows the original berm and there isn't much high tide beach left - what wasn't buried by the road has eroded away to a narrow strip, much of it covered in riprap or a concrete seawall. Dozens of small groins reflect an early, and not terribly successful, attempt to hold the beach together (Birch Bay - Part Two: March 2015).
AERIAL VIEW
Except for the groins and a few big storm drains, the beach is pretty much continuous and accessible, from the north end south to the mouth of Terrell Creek. South of the creek, things get sort of ugly, but that's another story (Birch Bay - Part One: March 2015). There is one other exception - a notable one.
M and I had a Sunday afternoon appointment in Blaine and stopped in here for lunch beforehand. It was quiet and our table was just a few feet above the beach - and considerably seaward of the high water line. This might be pretty exciting on a stormy day, but I guess that's why they have those shutters that can be pulled up to cover the lower portion of the windows. Keeps the gravel from breaking the glass, the salt water off the carpet, and the logs from landing on the tables.
There are major plans to rehabilitate the beach in next year or two, fulfilling portions of a vision Wolf Bauer laid out almost 40 years ago. He imagined a wonderful public beach stretching along this entire shoreline -- I guess they'll sort of have to build it around this place.
The beach along Saratoga Passage is classic Puget Sound - particularly on a gray day. A forested bluff collapsing in small pieces onto a mixed sand and gravel beach. This is a north-facing (northeast, actually) shoreline and avoids the more common southerly storm waves, although the rare sustained northerly can really stir things up given the large fetch.
AERIAL VIEW
There are scattered bulkheads along here, although they have limited value in preventing the steep slopes from sliding during wet winters. But this particular stretch is remarkably undeveloped, except for an occasional stairway. And this huge elevated rectangle of upland - built out across the beach in the 1960s. Back when such things, even if not entirely legal, were rarely noticed.
In many cases, including many on southern Whidbey Island, homes would have been built on the reclaimed land, at risk from slides and storms, increasingly expensive to maintain, and an unnecessary intrusion into what Wolf called the shore process corridor (more on Wolf in a subsequent post).
Here, there is an opportunity to make it right. The small private community improves its beach access and Saratoga Passage regains a beach. It will take a lot of work, but there is interest and willingness and leadership and perhaps even funding to make it happen. Hopefully, I can report back on this site in a year or two.
