Sand Beach

Acadia National Park and Mount Desert Island, and this portion of the Down East coast in general, are better known for its rocky headlands than for its beaches, but there are beaches, and each is very different than the next.

Sand Beach, is just that. The sand is mainly shell fragments. It is a pocket beach - actually a barrier - with what appears to be an occasional outlet at its easternmost end. The beach is backed by dunes and a lagoon, then by forest and rocky hills. The back of the beach, at least at each end, lay against a coarse cobble berm. I suppose this may be much better exposed in February after a stormy winter than in August.

Rockland

Rockland Harbor is sheltered by a beautiful stone breakwater that extends across the north side of the bay from an armored headland (the golf course for the Samoset Resort). There was a nice little pocket beach tucked in on the inside of the base of the breakwater. It consisted of sand, gravel, and periwinkle shells. The beach wrack consisted of washed up fucus and apples.

Pemaquid Point

I'm back in Maine for a long weekend on the Down East coast.

There are beaches of one sort or another (all small) scattered around Pemaquid, but the point itself is a classic rocky headland. Like much of mid-coast Maine, the glaciers pretty much followed the metamorphic fabric so the strike of these tightly folded Paleozoic rocks parallels the point as it plunges southward into the Atlantic.

The waves today were modest, at best, and remain so throughout this trip. As I write this, one week later, Hurricane Earl is probably stirring up things a bit.

Southey Point

The northeastern tip of Salt Spring Island, along Trincomali Channel, consists mainly of sandstone ledges and boulders derived from them, but there are also beaches where the bedrock allows and where sediment is available. The aerial image shows how the rocky points trap pocket beaches and barriers across the mouths of the small valleys.

On Tuesday, I paddled around from Southey Point. On Thursday, I came back by foot to explore a couple of these small beaches. They are composed of sandstone gravel and pebbles and a high proportion of broken shell. Some of the shell is washed up from the lower beach, but some of it is eroded out of the bank, which either due to waves or previous inhabitants, is thickly layered with clam shells. The sandstone makes beautiful skipping stones, the best of which are always concentrated high on the berm. It has something to do with their shape and preferential transport by the swash.

The largest beach shelters a high salt marsh and tiny estuary, with the small stream trickling out where the spit pushes it against the bank on the western edge. Occasional high tides have pushed a wedge of gravel into the estuary, forming a small flood-tide delta. The stream drains out across a broad intertidal delta-fan, with lots of evidence that the stream and the wave-built gravel bars shift around. This is a big pile of sediment in a place without an obvious source of new sediment, except for the clam shell. I suspect the stream and the waves have been pushing the stuff back and forth on the beach for millenia - the stream carries it down during low tides (alluvial fan), the waves carry it back up during storms (swash bars).

False Creek

The shoreline of False Creek has been redeveloping in chunks over the past couple of decades - often with big short-term events driving the pattern. Expo 87 on the north side and more recently, the 2010 Olympic Village on the southeast shore. The latter is where I spent a very gray hour on Saturday morning exploring an estuarine edge trying to balance between public use and environmental improvements ... both far better than an inaccessible private or industrial waterfront, but a tough combination to mesh sometimes.

Based on some historical maps and photos I've seen, and a fuzzy geomorphic sense of what this type of setting should look like, I suspect this low energy rocky coast is probably not the muddier, marshier fringe that once existed, but by intentionally complicating the texture and shape of the shoreline it can't help but be a dramatic improvement over what was here just a few years ago.

The habitat island is connected to the mainland by a pseudotombolo - not a very likely geomorphic feature for a sheltered bay like this one - but a landform that gives rise to a diversity of environments, particularly when combined with the new stream (is this False Creek?) that channels urban runoff through the park. The shoreline is largely shaped by riprap and armor rock, but lots of finer material has been added to enhance the quality and variety of habitats.

Ohio Street Beach

Ohio Street Beach is a small wedge of sand trapped between Chicago's big water treatment plant and the city itself.

North Avenue Beach

North Avenue Beach is a broad crescent of sand held in place by a long curving concrete jetty (groin?). The beach was quiet in the morning, but by afternoon it was packed with volleyball players and sunbathers.

There's a great map of Chicago's lakefront parks at: Lakefront Map

Oak Street Beach

Once upon a time, sand worked its way southward down the west side of Lake Michigan, building out into the lake in a series of spits at the mouth of the Chicago River. But one thing led to another and the beaches were gradually (or not so gradually) left behind as the city moved into the lake.

Then David Burnham came along and saw the potential for a hugely public, albeit hugely artificial, shoreline. Like many other Great Lakes cities, lake fill was an obvious solution, but in Chicago they seemed to have done it better and bigger than others. The result is miles of public park along the lake front, trimmed with stepped concrete walls, artificial beaches, marinas, and park space. The wind and wave regime hasn't changed appreciably since the city arrived, so sand placed along the shore would move southward rapidly were it not configured with jetties and landfill into a series of north facing pocket beaches. Some are isolated, some segmented by groins.

Oak Street Beach, at the north end of Michigan Avenue, fits into a corner in the lake fill - kept in place by Lake Shore Drive as it curves east around the northern part of downtown. The straight seawall north of Oak Street precludes a beach, so it sort of pretends to be one. Despite what could easily have been viewed as ugly, I thought it was actually pretty neat and it certainly got its share of use, at least later in the day (these shots are mainly early in the morning). I suppose it was underwater in the mid-1980s when lake levels were high.

St. Joseph

Silver Beach in St. Joseph was crowded at lunchtime on Saturday when we passed through (more pictures at hshipman).

St. Joseph is on the southeastern shore of Lake Michigan, at the mouth of the St. Joseph River. As at nearby South Haven and New Buffalo (and Michigan City, in Indiana), waves and longshore transport are from north to south, building up sand on the north side of the river mouth jetties. This also used to happen on other side of the lake, at the mouth of the Chicago River.

Geologically, this sand is destined for the south end of the lake, where it will be blown inland to bury 19th century steel mills and freeways under hundred-foot tall dunes.

Point Pelee

The northern shore of lake Erie (Google Maps) is punctuated by three elegant landforms. The location of each may be determined by glacial features like moraines, but the shape of each is all about wind and waves and moving sediment. There are good bathymetric maps and geologic explanations of Lake Erie at NOAA's NGDC.

Long Point is a spit, neither a simple nor a small one.

Point aux Pins (Rondeau Provincial Park) is an arcuate promontory that might be categorized as a recurved or cuspate spit. Its southeastern shore is composed of a beautiful series of accreted beach ridges, while its western shore is somewhat more tenuous. There is a big offset in the shoreline at the jetties at Erieau and the map on the wall at the Eau Buoy Cafe showed that in 1868 the natural opening was much larger and located pretty much where the town is today.

Point Pelee, where all of the these photos are from, is a large cuspate foreland, tapering to a slender point. It has lost ground, or at least changed shape, over time, making the riprap on the west side of the tip seem both unfortunate and sort of futile. The sinuous tip vanished southward under the waves, tempting me to wade out farther, but the biting flies argued against it.

Point Pelee is the southernmost point in mainland Canada. The country's true southernmost point is a very similar looking spit at the southern tip of Pelee Island, maybe 25 km south of here.