Friday, 4 December 2009

the rephotographic survey

I was considering the link between the images of the fog bow (28th November post) and the earlier post of Timothy H O'Sullivan's image, "Fissure Vent at Steamboat Springs" and started to think of his image above, Rock Formations, Pyramid Lake, Nevada 1867, in connection with the images of the cloud inversion on Ben More last weekend. The rock formations rising from the surface of the lake reminded me of the way the hills burst through from the layer of low lying cloud. I've since then been informed that the location had been part of Mark Klett's rephotographic survey in 1979. In that image (below), the lake has dramatically dried out, and this seems to be a shocking and surprising change over such a relatively short time.


...that is until you see the 2000 revisitation by Klett (below). In this image, the water has partially returned, so there's more rising and falling in the water levels than one would perhaps have imagined. It's easy to look at the first two and assume there's a catastrophic connection with desertification, global warming, etc, but it may well be that this is more normal for Pyramid Lake than at first appears. Derby Dam was constructed in 1903, so it's likely there has been some man made influence in the change in the water level. Another likely cause is the diversion of the Truckee River for irrigation in the early 20th century, and which has reduced inflow such that nowadays, it is rarely sufficient for the spawning of the Tui Chub and the Lahontan Cutthroat Trout, both now endangered species. Nevertheless, the final image does show that the situation is more ambiguous than we may perhaps think.

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