As water vanishes, sinkholes - some two stories deep - are devouring land

* Roads, caravans, power lines swallowed up by sinkholes

* Sinkholes caused by poor water management

* Underground salt layers cave in without protection of sea

* Authorities struggle to cope with phenomenon

By Ari Rabinovitch

EIN GEDI, Israel, July 29 (Reuters) - A neglected grove of date palms, their leaves long fallen, trunks drooping in the searing heat at the lowest point on earth, is the latest casualty of a dramatic rise in sinkholes wreaking havoc along the coast of the Dead Sea.

Workers had stopped tending the date grove, fearing the earth might swallow them up.

The Dead Sea is shrinking, and as its waters vanish at a rate of more than one metre a year, hundreds of sinkholes, some the size of a basketball court, some two storeys deep, are devouring land where the shoreline once stood.

The date trees line a section of a two-lane desert road - a main north-south artery that cuts through Israel and the Palestinian West Bank - that was shut down six months ago when a gaping hole opened up beneath the asphalt.

Once a rarity, hundreds of new sinkholes are appearing every year, and the rate is expected to rise. Officials have not come up with a figure for the extent of the damage, but power lines have been downed and caravans and bungalows engulfed. On at least one occasion, hikers were injured falling into one of the pits.

"It's not a problem we can handle alone," said Dov Litvinoff, mayor of the Tamar region that covers the southern half of the Dead Sea in Israel.

The main reason the sea is shrinking is because its natural water sources, which flow south through the Jordan river valley from Syria and Lebanon, have been diverted for farming and drinking water along the way. Mining operations account for the remaining 30 percent of the deterioration, according to Israel's parliamentary research group.

Relocating infrastructure is a temporary solution, the mayor said. The sinkholes will only stop when the waters of the Dead Sea are restored, and that requires an international initiative, since it also borders Jordan and the West Bank.

Even with everyone on board, he said, it would take decades to reverse the ecological damage to the ancient salt lake, which sits more than 400 metres below sea level, the lowest point on dry land, a basin baking in the blazing heat.

The World Bank is promoting a much-discussed project to desalinate waters from the Red Sea to pump the brine by-product into the Dead Sea, but it is unclear whether the project will take off, and environmental groups say it would represent a drop in a bucket.

DISSOLVING SALT CAUSES CAVITIES

The Dead Sea is a favorite spot for tourists, who enjoy floating effortlessly in its highly salted waters and treating their skin with the mineral-rich mud that lines its shores. But two popular beaches have been forced to close and officials fear tourism could start to be more seriously affected.

It also supports a huge mining industry. Israel Chemicals (ICL) and Jordan's Arab Potash Company extract minerals like fertiliser potash and flame-retardant bromine for export around the world.

It takes less than an hour to drive the length of the lake, which is linked to the Sea of Galilee in the north by the River Jordan. Eighty years ago it would have been a single, 70 km (43 mile) lake. Today the bottom third has dried up and what is left is kept alive artificially by ICL as evaporation pools.

But sinkholes are not appearing in Jordan where the coast is steeper, said Guy Dunenfeld, head engineer for the Tamar regional council. The Israeli shore is flat, he said, and waters recede at a much faster pace as a result.

Deep beneath the newly exposed land is a 30-meter layer of salt formed over thousands of years. Without the Dead Sea waters to protect it, fresh water from rain or desert flash floods seeps underground and dissolves the salt layer, creating a cavity that eventually collapses, sucking in the ground.

The Geological Survey of Israel has started to monitor small contour shifts in the ground with satellite images that could signal forming sinkholes.

"They have on a few occasions given us about a week's notice, including the sinkhole that wrecked the highway," Dunenfeld said. "But there is nothing we can do with the information other than to send teams out, fill in each new hole with dirt and fix the damage after it occurs."

That is something, but not enough to reassure the workers at the palm grove, who remain too scared to return. (Editing by Luke Baker and Peter Millership)

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