Adar said that there could be "a leak from the canal for several days, and we could contaminate all—or at least a significant portion of—the aquifers."
Every Israeli and Jordanian community in the valley depends upon these underground layers of water-bearing rock and sand, he said.
"There is no such thing as 100 percent sealing efficiency," Adar said. "Even if the canal leaks from across the Jordanian border, it's the same basin. It's the same bathtub."
The canal would also cause a massive flow of water from the Red Sea to the Dead Sea via the Gulf of Aqaba.
"The gulf will no longer be a dead end, and a substantial current would be created. This needs to be examined, and it hasn't been thus far," Adar said.
Adar also raises concerns that an influx of seawater would change the chemical makeup of the Dead Sea.
The sea is naturally fed by fresh water from the Jordan River and its tributaries and by seasonal flash floods running out of desert canyons on the Israeli and Jordanian banks.
But channeling in seawater would likely dump surpluses of calcium, sulfur, and gypsum into the sea.
"The fact is that this water will raise the Dead Sea to its original level. This is positive," Adar said.
"But we also need to examine the hydrochemical evolution that will be caused."
Adar said building the canal is not the only way to save the rapidly shrinking Dead Sea.
Rather than siphoning water from the Dead Sea's sources, local authoritie could "desalinate more seawater from the Mediterranean," he said, referring to the process that creates fresh water by removing salt from ocean water.
"And if Syria, Jordan, and Israel reach an agreement to let natural runoff enter the Dead Sea via the Yarmuk and Jordan Rivers, it will recover. It may take another hundred years to recover. But it will."
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