The rover diaries
The team
Iain Stewart's diary about the challenge for the Rover programme, from the BBC/OU series Rough Science 4
Day One
Challenge: Iain and Ellen to find water in one of the driest places on Earth. Kathy and Mike to purify the water; Jonathan to build a Mars Rover.
Owens Lake is one of hundreds of dry lakes, or playas, that the American West is home to. It is a legacy of a glacial past when enormous lakes, filled to brimming at the height of the last ice age, began to shrink as the climate sharply dried 10,000 years ago. More extreme drying over the last few thousand years continued the shrinkage, but the lake began to dry up in earnest in 1913 when local mountain streams and the Owens River that used to flow into it were siphoned off to water Los Angeles. This is where our search for water begins.
Surrounding our salt lake are stranded beaches, former lake shorelines that - like rings on a bathtub - are tell-tale geological evidence for the gradual disappearance of a large body of water. Our first stop of the day is at one of these high ‘fossil’ shorelines. Its well rounded beach pebbles showed clearly the signs of water action, as did the smoothed walls of a nearby outcrop of limestone. But the water was gone, and the ravines and gullies that had fed the lake were equally dry. Most of these dry stream channels were also carved out during the lake’s wetter glacial past, today carrying water only during the occasional rainstorms.
So instead our plan is to track up one of these dry stream beds to look for water higher up in the hills.
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Content last updated: 18/07/2006
