Reflections in a Wildland Lake
Launch: Big Eddy Marina. From Lewiston, ID go east on 12, cross the Clearwater River at Orofino, then westerly beside the river through Ahsahka, and turn right at the sign to Big Eddy Marina.
---------"Lake What?" El asked. We were in the visitor center of McNary Dam, getting information about locks along the Snake and Columbia Rivers.
---------"LakeDworshak," I answered. "Ever hear of it?"
---------"Thought he was a composer," El said with a happy grin. "Never knew they had a lake named after him."
---------I was holding a Corps of Engineers brochure entitled, "Dworshak Dam and Reservoir...A Treasure Worth Discovering." The cover photo pictured a narrow sinuous lake twisting back through forested Idaho mountains. The temperature outside the visitor center was in the high nineties and that photo looked inviting. "Listen to this ... picturesque 184 miles of shoreline ... seculded coves ... watch a blue heron fishing in the shallows ... convenient floating restrooms located throughout the reservoir ... wildlife watchers find great rewards ...retreat from the hot summer sun ... "
---------"Whoa," El interrupted, "retreat from the hot summer sun? Where is this place?"
---------A quick glance showed it to be just outside Lewiston, the start of our second phase of cruising the Columbia from headwaters to sea.
---------"Let's leave Halcyon, and go up in the truck and see what's there," I suggested. "Tomorrow's another scorcher, and some elevation and trees sound great." So off we went. We drove to Dworshak State Park, and after navigating the steep winding descent we congratulated ourselves on doing the check-out of the reservoir without Halcyon pushing us down the hill. The park was so nice, we camped there for three nights. A Pacific front arrived, with cold showers, and the world cooled off delightfully. We checked out the ramp at the park, but decided there must be an easier way into the water without twisting down that steep grade. The ranger suggested Big Eddy ramp as the easiest access, so off we went to check it out. We stopped at the Corps visitor center near the dam to see the displays and get more information.
--Dworshak is the tallest straight axis concrete gravity dam in North America - 717 feet high
---------The next day we trailered up to Big Eddy and plunked Halcyon into the pond. Well, it was a little more complicated than that, since this reservoir is a storage reservoir on the Columbia System (the North Fork of the Clearwater drains into the Clearwater that joins the Snake that joins the Columbia - whew). Anyway, the lake was down 65 feet (it can go down 180) and the ramp was a long way down.
The dock is somewhere down there near the vanishing point of the ramp - ears popped twice on the descent.
---------"Kinda ugly, isn't it?" the fisherman at the dock asked.
---------"Well, it would be more picture perfect if it was full," we opined. "But I'm a geologist, and look how beautifully the geology is exposed with the lower water level," Bill pitched in. "And," El added with that infectious smile, "there's a singular beauty about the microterraces., don't you think?"
---------"Well ... " He stared at the stepped mud slopes next to the ramp. "Yep," he drawled his answer. "Guess there are some folks who can see beauty in anything ..." He looked around again at the stair-stepped banks of the lake ... "and you know, it is kinda purty, ain't it?" he said, adding his grin to El's.
Yep ... Kinda Purty
GEOLOGY IN THE BASEMENT
---------The geology is beautifully exposed at Lake Dworshak, and different from any we had previously cruised through. We were cruising through the batholith. A what, you ask? A batholith - bathos (deep) lith (rock) - "deep rock." These rocks were once deeply buried in the earth's crust, now exposed by uplift in the Rockies and eroded deeply to open a view into the deep stuff that underlies virtually all the continent. It's under you right now. But, we don't often get to see these rocks since they are covered by a thick blanket of rock.
---------Most of the deep stuff has been baked by intense heat and pressure -- both from the weight of overlying material and from the violence of continental impacts crumpling and intrusion of molten magma. Geologists often refer to these rocks as basement rock -- the stuff that underlies the continent -- in fact, it is actually the core of the continent and all the more familiar rocks near the surface are Johnny-Come-Lately rocks. Basement rock is old -- very old. In Australia and Greenland, it is the oldest rock known (around 4 billion years old) and some might even be remnants of the original crust that skimmed the molten earth. Every continent has an ancient core, called Shields. Our continent has the Canadian Shield - a vast landscape of hard, old, often-mineral rich rock. The shield divides Canada, geologically, geographically, and socially. Most everything from the eastern border of Manitoba to the St. Lawrence River is hard, tough, soil-free rock. The glaciers scraped the soil off the top of the shield, leaving bare ancient rock over much of that area. Building a railroad across that region to unite the country was a major task, as highway construction still is. Look at a highway map of Canada - you can trace the border of the shield by noting where the roads stop to the north in every province. Notice all the white area surrounding Hudson Bay - the Bay itself is a salt-water-filled lowland almost in the center of the Canadian Shield, depressed by the weight of thousands of feet of only recently-departed glacial ice. The Bay is, by the way, slowly rebounding now that the ice is gone, and it is shrinking every year.
Roads Mostly Stop at the Shield
---------Anyway, after that brief digression onto the Shield, there are a few places in the United States where we can observe basement rock while cruising. Lake Dworshak is one. The rock there is not shield - just that it has gone through (more recently than ancient shield rocks) much the same process of formation. A huge molten mass, probably tear-drop shaped, bulged upward into the surrounding country rock. It baked the surrounding rock, metamorphosing (meta=change morph=form) it into dense slate, schist, gneiss, and quartzite. The molten material slowly cooled, deep underground, into pink granite. When molten stuff cools slowly, it allows large crystals to form - the slower the cooling, the larger the crystals - and granite may have some beautiful quartz and feldspar crystals.
A Real Nice Gneiss, and Gneiss Shot Through with Intrusive Quartz Dikes.
Slate, Intruded by a Granite Dike----------Pink Granite, with some Terraced Mud on Top
---------There are a few places, way up near the end of the lake, where the floods of hot lava that buried the Columbia Basin lap up onto the batholith. The basalt is easily recognized by its characteristic columnar shapes, the resut of cooling shrinkage in the lava - just as mud drying cracks into rough polygons (usually hexagons), so does lava when it cools.
Bees, Mudcracks, and Basalt Love Polygons - Best Shape to Have the Most Enclosed Volume, and Still Nest Perfectly
---------Studying the chart of the lake we noticed a square symbol labelled destination dock. Well, we had never heard of a destination dock so we made one our first 'destination' on our cruise. What a pleasant surprise -- a large rectangular floating dock, with the interior open as a 200' deep swimming pool. We used these docks for swimming, kicking back, lunch spots, and overnight homes - delightful. This lake is a deep one, with rocks and stumps, a tough one for anchoring - but these destination docks allowed us to avoid anchoring.
Great Place to Tie, or for a Sundowner
---------The entire shoreline is either Corps, State Park, or National Forest controlled so there are no developments except those ancillary to recreation. Most of the shore and for a distance of a quarter mile inland is natural. So, wildlife viewing is excellent. We spotted many deer, a heard of elk, and many birds (we turned about 1 megamillion dark stumps into black bears, but none ever moved).
Osprey, Aquatic Deer, and Elk
---------Logging was, and still is, big business in this country. A large Potlatch mill is one of Lewiston's biggest industries. For boaters, the result is some evidence of clear cutting, some bits of history left on the banks of the rivers, and fascinating tales from the 'old days.' Before the dam was closed on Lake Dworshak, the Corps hired loggers to cut all the timber below the water line so the water would be clear of obstacles. Now, the stumps can be a hazard, for those who prefer anchoring, since they are anchor traps. On the plus side, they make interesting 'art.'
Log Drive in the 'Old Days'--------------------'Anchor Catchers'-----------------
-Tippy-Toes, Octopus and Slither
-Tough Life Cruising - Your Authors
(08 - 04)
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