Category Archives: Water

Efficiency

The first people who lived on Puget Sound lived lightly on the edge of the land, mostly on the coast. They didn’t travel far from the shore where mountains were piled like shards of flint and old growth forests layered the ground with the bones of trees once 200 feet tall, where narrow valleys carved by the sharp edge of ice through winters that lasted a thousand years were a succession of bogs and swamps and wet grass meadows, where streams were a clutter of sloughs and islands and beaver ponds and driftwood snags and rivers were blocked with driftwood dams so massively built they persisted for hundreds of years.

The first people lived lightly and within their means. Those who followed, the ones who ‘settled’ the land as if it were unruly and needed restraint, didn’t see the land as it was but as it might be. They saw the opportunity of shaping the land in their own image, optimizing it for their own use. It was their manifest destiny, their biblical imperative.

First were the loggers who felled the old growth forests moving inland from the water’s edge. They cleared the beaver ponds from streams and built splash dams to raise the water level, floating downed trees to the saw mills. Then came the men who sweated and sawed and dynamited the logjams to allow steamboats and rafts to navigate the rivers. South on the Willamette above Corvallis, Oregon more than 5,500 driftwood logs were pulled from a 50-mile length of river. The driftwood measured 5 to 9 feet in diameter, 90 to 120 feet in length, and maybe 500 to 700 pounds per foot dry weight.

The streams and rivers of Puget Sound were eventually straightened, diked, and disciplined.

On the Skagit River in Washington driftwood was piled like windfall 3/4 mile long and 1/4 mile wide. The Stillaguamish River was blocked by six logjams from the head of tidewater for 17 miles upriver. Dead trees were so large, so numerous, and so deeply embedded in the river bottom that a steam snag boat hammered and hauled and labored for 6 months to open a channel only 100 feet wide.

The streams and rivers of Puget Sound were eventually straightened, diked, and disciplined. The wetlands were drained by the farmers that followed. Less than 10% of the historic wetlands and floodplains of Puget Sound remain. By most contemporary opinions it was a good thing. Fallow land was made productive. Forests were harvested like crops. Isolated communities were connected by river traffic. But all the wood removed from the water that seemed such a nuisance at the time had served a purpose that wasn’t recognized for another hundred years.

When water approaches an obstruction in the current like a driftwood dam it begins to well from hydraulic back pressure. The raised water tops the river banks and onto the floodplain, creating side channels and backwaters, habitat for fish. It spills over the obstruction forming a plunge pool. The deeper pool allows fish to remain cool in the heat of summer and protects them from predators. Numerous species of salmon and trout live in the same pool, each occupying different layers defined by water temperature and granularity of sediment, accommodating different species of fish or even the same species in different sages of its life-cycle. Where the current rushes around the edge of the driftwood a stream of vortexes form at the boundary of still water like pinwheels on parade, providing nutrients for the inhabitants of the pool. The driftwood dam raises the water level in the river, especially during times of low water when fish are stressed and struggle to survive.

…the salmon were once so common that, after spawning, their bodies were pitched into carts and plowed into fields as fertilizer.

None of this was known a hundred years ago. Even the wildlife managers responsible for the health of salmon and trout populations cleared deadwood from rivers and streams, genuinely convinced they were helping with upstream migrations and breeding, unaware that they were tampering with the deposition of sediment and the spawning grounds of the very species they were trying to promote.

On the Ozette River west of the Olympic Mountains the salmon were once so common that, after spawning, their bodies were pitched into carts and plowed into fields as fertilizer. After 26 large log jams were removed from the river the salmon populations crashed. Some will likely never recover.

Simplicity isn’t always a solution. Mirroring Einstein, a thing should be as complex as necessary, and no more.

Life is messy. Trying to clean it up, remove the clutter, straighten what’s crooked, smooth what’s rugged and irregular isn’t likely to make it better, even for ourselves. Optimizing the land for our own use above all others has reduced the land’s resilience and replaced it with a system that’s robust but fragile. We squeeze from the land every bit of efficiency possible, much like we do our companies and ourselves. The danger of such extreme efficiency is its proximity to disaster. It only takes a slight push from a highly optimized system to push it over the edge into chaos.

Gravity

You might reasonably expect a satellite to orbit the earth in a trajectory smooth as a ball bearing in its race. Reasonable but wrong. It’s more like an Old Ford on a country road, bouncing and rattling over gravitational potholes.

The gravitational topography of the planet is less like a cue ball, more like a golf ball with all its bumps and dimples. You’ll remember your high school physics lessons on gravitation. Large objects exert gravitational force at a distance. The more dense the object, the greater the force. Massive mountain chains like the Rockies, Himalaya, and Andes create positive gravitational anomalies—areas of increased gravitational force. Negative anomalies are associated with declivities like the Mariana Trench, a rift in the sea floor of the Pacific Ocean 6.8 miles deep.

As a satellite approaches the Andes it’s pulled subtly closer to the earth. When it approaches the Mariana Islands and the adjacent sea floor trench, it bobs slightly higher. The effect is local and canceled when the satellite reenters the normal gravitational field. It’s rather like bouncing down the washboard surface of a dirt road.

The gravitational force exerted by the Andes isn’t limited to circling satellites. The roots of the Andes Mountains are washed by the Pacific Ocean. The Pacific itself is pulled toward the mountains like a massive standing wave.

It’s not only massive piles of rock that creates gravitational anomalies. The Greenland ice sheet is almost 1,500 miles long and 680 miles wide. It covers roughly 80% of the surface of Greenland—660,235 square miles. It’s typically over a mile thick and almost 2 miles at its deepest—683,751 cubic miles of ice.  And it’s the second largest body of ice on the planet.

That much ice warps the surrounding ocean, pulling it like taffy. The impact of melting Greenland ice on sea level has been recognized for some time but the effect of its reduced gravitational field has only recently been acknowledged. It further complicates a complex picture.

If all the Greenland ice sheet were to melt it’s estimated the global sea level might rise as much 23 feet but it would have little impact on sea level in the Arctic ocean. That’s counter-intuitive. The reason? Rise in sea level expected from melting ice would be countered by the fall in seal level resulting from reduced gravity. Northern Europe might be spared. New York would not.

The gravitational influence of the Greenland ice is limited to the Arctic Ocean. Melting of the northern ice would contribute to the volume of the oceans globally, increasing sea level worldwide, but that rise in the Arctic would be offset by the declining sea level resulting from reduced gravity. Areas beyond the northern ice’s gravitational influence such as the Eastern Seaboard of the US would suffer the unmitigated rise in sea level.

Western Europe isn’t without risk. If the Antarctic ice sheet melts, the sea level will likely fall in the Southern Ocean but rise dramatically in the North Atlantic.

And, of course, the change in the gravitational field would affect the Earth’s rotational momentum…

A Mythical Bridge

image  Hood Canal Bridge. Photo attribution: timtim 011 on Flickr.com.

The Hood Canal is a narrow body of water extending about 50 miles from its entrance at Foulweather Bluff, past a hard turn to the northeast at The Great Bend, and another 15 miles to the shallow tideland at Lynch Cove. It has an average width of 1.5 miles, a mean depth of 177 feet, 212 miles of shoreline, a surface area of 148 square miles, and it’s spanned by a mythical bridge.

Certainly the Hood Canal Bridge has a concrete reality, not to mention construction. It’s supported by cement pontoons that float, mostly, above a depth of water between 80 and 340 feet, water subject to a tidal range as much as 18 feet. It spans the 7,869 feet between the Kitsap and Olympic Peninsulas. Together the two spans weigh almost 5,000 tons. You can find all that on Wikipedia. But the bridge floats upon a fjord, has foundered and been refloated, and even its current reconstruction has resurrected the dead.

A Historical Misnomer

image 
Hood Canal Bridge from a distance. Photo attribution: keistersmom on flicker.com.

But first, a bit of background. The Hood Canal was named by Captain George Vancouver, one of the first cartographers to Puget Sound and therefore entitled to name things indiscriminately. Of course, those same things had been named by the people who already lived here but, frankly, they weren’t English. Vancouver named it after Samuel Hood, Lord of the Admiralty and one of Britain’s few competent commanders during the American Revolution. Actually, he named it twice—Hood Canal and Hood Channel. Both were wrong.

Outside of Puget Sound,
bridges rarely float.

A canal is an artificial waterway used either for navigation or transporting fresh water. A channel is typically a navigable passage between larger bodies of water. The Hood Canal was shaped by glaciation utterly without the help of humans. It doesn’t connect one body of water with another. It’s an inlet or, more exactly, a fjord. And a fjord, to restate the obvious, is a valley carved by ice and drowned by the sea. The fact that it’s called Hood Canal has led to some puzzlement in other parts of the world. In Puget Sound, we’ve gotten over it.

Bridges usually soar above an obstruction. Outside of Puget Sound, they rarely float. There is a floating bridge that across Dubai Creek (who knew they had creeks in Dubai?) but it’s temporary. And until 1992, a floating bridge spanned the Golden Horn in Istanbul. But the only other part of the world to make common use of floating bridges is Norway where they have even more fjords than Puget Sound.

Foundering

image The Hood Canal Bridge in a breeze. Photo attribution: Chimacum Joy on flickr.com

The Hood Canal Bridge hasn’t always floated. Eighteen years after it had been launched, it sank in a storm. Sustained winds of 85 mph scoured the Hood Canal. Gusts of 120 mph buffeted the bridge. Pontoons lost their anchorhold and drifted free. Hatches were blown open, pontoons filled with water and sank. The western half of the bridge to the drawspan foundered. It was three years before the damage was repaired. And it’s not the only time a local bridge has sank.

The lifespan of a bridge floating in salt water is longer than that of a Portuguese water dog but less than a Galapagos tortoise. Fewer than thirty years after its resurrection, the bridge builders began building its replacement. In those intervening years the population of Puget Sound has blossomed like pond scum and the industrial waterfront succumbed to gentrification. There was no place near Seattle to build the massive pontoons. Instead, Port Angeles was chosen.

Port Angeles was much further from the Hood Canal than Seattle but had the advantage of poverty. Since the timber industry and commercial fishing had shriveled, there was plenty of waterfront property available in Port Angeles and a desperate desire to utilize it. The people of Port Angeles saw the construction as their bridge to prosperity. But when the construction equipment began clearing away the industrial remnants of the timber industry from the shore of Ediz Hook, they began unearthing bones. Human bones. A lot of them.

Village of the Dead

It was Tse-whit-zen, the ancestral village of the Klallam people occupying the Lower Elwha River. The Klallam had lived on Ediz Hook for generations prior to first contact with Spanish explorers in the 1770s. Then they began to die from smallpox, influenza and measles. They had no immunity, no protection. Entire villages of First Peoples were decimated throughout the Pacific Northwest. In some places there was no one left alive to bury the dead. There may have been 3,200 Klallam before 1770; by 1880 there were 485.

image 
The ruins of Tse-whit-zen. Photo attribution: nwpainter on flickr.com

At Tse-whit-zen, the dead were stacked like cordwood. They embraced one another, husband and wife, mother and child. Among the dead was a mother with an unborn child in her womb. There was no ceremony in their burial. They were hurried into the ground by the few who remained alive but those few may have taken revenge upon the shaman and medicine men who failed them. Skeletons were found beheaded, buried face down, their hands covering their face.

The Washington State Department of Transportation finally abandoned the site have disinterring 335 intact skeletons. The construction equipment fell silent, the workers left, and the dead reclaimed their land. The bridge was built in Tacoma.

A Mythical Bridge

The bridge spans more than the Hood fjord. It’s footed in time as well as space. It guards the western approach to a land that is itself mythical, a land form by the c
ollision of the sea and the shore where mountains rise like stone waves, forests are entangled in cloud, and people hunt whales with clam shells.