We pay a great deal of attention to water out here in the West.
It's stored, shipped, stolen and, too often, squandered. It's the lifeblood of wildlife, agriculture and development. It's our most precious commodity, which is why so many people and groups constantly fight over it in court and in the legislatures.
Consequently, it's easy to forget what happens when they dam rivers or build a bigger dam downstream to store more water.
The casualties of progress often include places of historic interest, and it takes only a drive along the Merced River these days to see some examples.
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Whenever rainfall is dramatically below normal, the water level drops to reveal otherwise hidden treasures. That is the case up at Lake McClure, about an hour southeast of Modesto.
For only the 10th time since the completion of New Exchequer Dam in 1967, the old dam is sticking out of the water. (Although the recent storm has brought rain and snow to the region and might have drowned it again.)
The old concrete dam is an engineering and architectural marvel for the time it was built, 1926. Replace a few rusted parts, grab a can of WD-40, and the steel spillway gates look as if they'd be ready for action.
Two of the high-arching concrete tunnels from the long-defunct Yosemite Valley Railway surfaced in August and still are exposed. Fishermen, boaters and maybe even a daring water skier or two, I'm told, used Tunnel 3 near McClure Point to get from one side of the lake to the other until the water level dropped more and the old railroad bed dried out. Right now, you can walk through it. It's at least 100 feet above the current lake level.
With a little imagination, you can smell that distinct creosote odor and envision the smoke belching from the engines as they chugged along the mountainside and through the tunnels.
I suspect the vast majority of modern-day visitors to Yosemite National Park have no clue that, from 1907 to 1945, trains carried people up the Merced River Canyon to
El Portal to visit Yosemite Valley. The railway also brought timber from the mountains.
I also suspect many folks who make the drive today through Mariposa to El Portal on Highway 140 don't even notice the abandoned railroad bed across the river, even though they cross over and drive on it for a few hundred yards to get around the big rock slide of a couple of winters ago.
In drier years we've seen the old Melones Dam, the old town site of Melones, and the old Highway 49 and Parrotts Ferry bridges reappear on the Stanislaus River.
Same with the old Don Pedro Dam and town sites of Don Pedro and Jacksonville on the Tuolumne.
Some of the most intact and pronounced relics are those of the Yosemite railway. The original railroad line began in Merced, went past Snelling and snaked along the Merced River to the old mining town of Exchequer.
The Merced Irrigation District built the first Exchequer Dam in 1926, using the trains to haul materials until the dam was completed and the tracks were relocated to a route higher up the hillside, said Dan Pope, who is hydroelectric project manager at New Exchequer Dam.
Four times a year, Pope descends into the guts of the old dam -- sometimes beneath nearly 500 feet of water -- to inspect it. The old dam was 300 feet high and held back 281,000 acre-feet of water.
The new dam -- which is now about the same age as the old dam was when the new one was finished -- is 200 feet higher and holds about four times as much.
The dams have been off limits to the general population for security reasons since 9-11, but are visible from the McClure Point boat ramp and other places around the lake.
You can still see the railroad's Tunnel 1 burrowing into the mountain about a mile downstream from the dam.
Tunnel 2 actually was incorporated into a saddle dike and plugged with concrete when the new dam was built.
A saddle dike is a small dam that plugs a low spot elsewhere on the hillside, matching the height of the main dam.
Tunnels 3 and 4, normally under 100 feet of water, are now 100 feet above the lake level.
Farther upstream, the concrete pillars of the railroad's old Barrett Bridge still stand, as do some of the foundations from the old town and rail stop of Bagby.
Most years, all of these pieces of history are simply fish habitat. They will be again soon, if Mother Nature cooperates.
"If we receive normal rainfall, we could come close to filling (McClure)," Pope said.
The remnants of the area's history would then rest deep below the surface until the next bad rainfall year.
In the meantime, the political fights over water will continue to rage just as the rivers once did.
Jeff Jardine's column appears Sundays, Tuesdays and Thursdays in Local News. He can be reached email@example.com or 578-2383.