How a desert detective found water in Darfur – from half a world away
Farouk el-Baz heads to Sudan next month to site wells over what he believes is a vast reserve from an ancient lake.
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To confirm their finding, Ms. Ghoreim and Baz examined other types of radar and topographical imagery. An image using radar data from the space shuttle showed darker grooves beneath the sand that led up to what they thought was shoreline. Were they ancient dry rivers that had fed the lake?Skip to next paragraph
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"Some people said, 'Oh, those lines are just fractures,' " Ghoreim says. "But when we found that they all stopped exactly along the 'shoreline,' we knew that probably wasn't true."
Topographic images then showed the elevations in the surrounding area. The land in and around the suspected ancient lake was flat and low, typical of a lakebed, and it rose like the lip of a plate near the dark lines that indicated a shoreline.
Looking more closely, the BU team found other bits and pieces of shoreline.
They put the data into a powerful computer loaded with special geology software. The program ran for three days, processing satellite images and researchers' findings, before it spat out an image of what the lake might have looked like, given the location and size of the tributaries, the shoreline fragments, and other geographic considerations. The resulting image showed a deep lake about the size of Massachusetts.
Ancient water seeps into sandstone?
The fact that sandstone lies beneath the ancient lake means that much of the lake's water should have seeped into it to accumulate as groundwater.
Most of the satellite imagery used to find the ancient lake was from free public sources. Others were rather pricey, at $3,000 apiece. But the fact is that others looking at the images could easily have missed what Baz saw, Ghoreim says.
"He is very patient and has trained eyes to look for certain things that others wouldn't notice," she says. "It's not just about looking at an image; you need to be able to find the right interpretation."
Born in Zagazig, Egypt, in 1938, Baz earned degrees from Ain Shams University in Cairo, the University of Missouri at Rolla, and the Massachusetts Institute of Technology in Cambridge, Mass. After working as an instructor and oil geologist in Egypt, he came to the United States in 1967 to work on the Lunar Science Planning and Operations at Bell Telephone Laboratories in Washington, D.C. Among his assignments: training NASA astronauts what to observe and photograph about lunar and earth geology. He left in 1973 to become research director of the Center for Earth and Planetary Studies at the National Air and Space Museum. That's when he began his research on deserts, particularly looking at how space data can help explain the origin and evolution of deserts on Earth. After a brief stint at a high-tech firm, he joined BU in 1986.
His desire to become a desert expert was spawned, ironically, from his lack of knowledge about this environment.
"I came from Egypt, which is 95 percent desert; I had studied them in the best universities and rubbed shoulders with some of the best geologists, but I realized, like the rest of the geology profession, what I really knew about deserts was close to zero," he says.
Even though Baz says the imagery of the Darfur site looks identical to the ancient lake site he found in Egypt, he still has a few critics.
"There are doubters that say, 'All I see is salt and sand,' " he says. But he's learned from his experience in Egypt not to worry: "I'm used to these doubters."
He plans to go to Darfur next month to confirm the lake's existence and select sites for the first wells. It will be years before all 1,000 wells are dug, and a pipeline is needed to transport water from the wells to where most people live, 250 miles away.