The Darfur conflict sparked his idea to study the geology of northern Sudan, which lies only tens of miles south of East Uweinat.
Topographic data acquired from satellite images that can penetrate the Sahara's fine-grained sand cover revealed buried features of the lake.
Further studies showed that the lake reached a size of 11,872 square miles (30,750 square kilometers). Its shoreline rose about 1,880 feet (573 meters) above sea level, with up to a dozen rivers running into the lake.
"There would have been some water there 5,000 to 10,000 years ago, but before that it was dry," El-Baz said.
The region alternated between wet and dry conditions going back tens of millions of years, he said.
When the lake was filled, much of its water would have seeped through the sandstone to accumulate as groundwater.
"The rock types, geographic, and topographic settings are almost identical to those in Egypt," El-Baz said.
"There is no reason why there would be plenty of water across the border in Egypt and no water [in Darfur]."
A major part of the Darfur conflict is related to water, experts say, with nomads and farmers fighting for access to a limited number of hand-dug wells.
But a shortage of available water has not actually been the biggest problem for the region. Rather, resources to extract existing water are lacking, said Alex de Waal, program director for the Social Science Research Council in New York City.
"In the long term, however, that whole part of Africa, which has been put under pressure for so long, really has a question mark over how it is environmentally sustainable," said de Waal, who has worked in Sudan for more than two decades.
"How do you sustain a population that is six million people in a semi-arid environment with very unpredictable rain?
"The possibilities of using a massive subterranean aquifer to provide water for an increasingly urbanized population and also for agricultural purposes in this semi-arid environment is a major long-term consideration," he said.
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