The Dead Sea / The drying of the sea caused the formation of hundreds of dangerous pits
Zafarir Rinat
The sharp drop in the level of the Dead Sea, which has worsened in recent years, is causing negative environmental effects, including, apparently, the formation of hundreds of sinkholes around the sea that endanger the infrastructure of buildings and roads in the area.
Recent studies carried out by the Geological Institute and the Geophysical Institute have confirmed the researchers' assumption that there is a connection between the formation of the pits and the drop in sea level. The conclusions of the studies were presented last week as part of a special gathering of professionals on the future of the Dead Sea held by the Ministry of Environment and the Ministry of Infrastructure.
The level of the Dead Sea has dropped by 20 meters over the last century. During the last years its rate of decrease is more than a meter per year. This is due to the utilization of the water sources in Jordan, the Sea of Galilee and the Yarmouch for the benefit of man, and the drying of its southern part for industrial purposes.
Dr. Danny Wax from the Geological Institute stated that until now more than 600 pits are known to have formed, mainly along the western coast of the Dead Sea. Some of them reached a diameter of up to 30 meters and a depth of 15 meters.
The early assumption of the researchers was that a decrease in the level of the Dead Sea also causes a decrease in the level of saline groundwater around the sea, resulting in the infiltration of fresher groundwater. These dissolve layers of salt that are under the ground. This creates a cavity into which the upper layer of soil collapses and a large pit is created without any prior warning. By drilling into the ground that reached a depth of 24 meters, and using a geophysical instrument capable of distinguishing what is happening under the ground, the researchers were able to prove that there is a layer of salt 11 meters thick and near it higher concentrations of fresh water. Apparently the fresh water penetrates through cracks in the ground towards the salt layer and causes the melting, and then the collapse of the top soil layer. On the other hand, no salt layer was discovered on the northwest coast of the sea, and no pits were discovered in this area either.
The holes in the Dead Sea have already caused the closure of a parking lot near Kibbutz Ein Gedi. The Vice President of the Dead Sea Industries, Yoel Goldwasser, who participated in the conference last week, said that a large pit had also formed in the factories a short distance from one of the warehouses. Recently, Jordanian researchers also reported on the formation of pits that damaged the road used by the potash plants in Jordan. They recommended abandoning an entire area on the central coast of the sea due to fear of the formation of additional pits.
The experts of the Geological Institute are under a lot of pressure from industry and tourism officials and from the localities in the area to prepare a risk map that will make it possible to assess the location of cavities in the ground that could lead to the formation of a pit. This map is currently being prepared. Today, the Geophysical Institute operates a special device that can locate with a relatively high probability cavities that have already been created underground. At the same time, the geologists formulated a series of recommendations for preventive treatment of the pothole problem. Among other things, they suggest trying to pump the fresh groundwater through drilling to prevent it from flowing towards the salt layers. Another suggestion is to locate the salt layers and dissolve them proactively. The space created as a result of this operation can be filled with compacted soil. In order to implement these suggestions, comprehensive studies must be carried out. In any case, it seems that the implementation of the proposals will be carried out on a point-by-point basis, mainly in places where various infrastructure facilities are planned to be built.
The drop in sea level caused additional negative effects besides the pit phenomenon. In the second half of the 70s, the connection between the northern part of the sea and the southern part was severed, which became a series of industrial ponds that are used by the Dead Sea factories in Israel and the potash factory in Jordan to produce raw materials.
According to geologist Eli Raz, who lives in Kibbutz Ein Gedi, there is a fear of deterioration in the climate conditions in the Dead Sea region because a higher level of sea water was a moderating and cooling factor for the desert climate. Another phenomenon related to the drop in sea level is the formation of large mudflats in the northwest of the sea. These surfaces cause serious damage to the Ein Pesha nature reserve area, and they cut off access roads to the area.
The Ministry of Regional Development has recently renewed its efforts to build a canal that will carry water from the Gulf of Eilat to the Dead Sea through the territory of Jordan. This plan was previously discussed
Mainly in the context of utilizing the flow of water for energy production and operating a seawater desalination facility, but now the ministry is presenting the plan as also intended to save the Dead Sea by injecting water into it that will cause the level to rise.
However, according to geologists, the Yamim Canal may have far-reaching effects on the Dead Sea, some of them negative. Dr. Itai Gabrieli from the Geological Institute, who commented on this at the conference, said that the mixing of Red Sea water and Dead Sea water may result in the creation of a gypsum suspension in the sea, and the development of tiny animals. Another problem is the development of hydrogen sulfide which may create a problem for factories and require special treatment to neutralize it. Gabrieli summarized the expected changes: "It is difficult to say whether all the changes will be positive or negative, but it is clear that it will not be the same Dead Sea, but a sea with a different composition."
The Palestinians will build the irrigation canal
Gideon Bromberg, one of the directors of the Mediterranean branch of the world's largest environmental organization "Friends of the Earth", warns against further plans to utilize water in the Dead Sea's catchment basin that may exacerbate the damage to the sea and further lower its level.
Bromberg, who spoke at a conference on the Dead Sea that took place last week, noted that the Jordanians are about to operate a dam in the Arnon River to utilize the polluted water in it. This stream is one of the water sources of the Dead Sea on the Jordanian side. The Palestinians are planning to build a dam on the Oja River, which until now flowed into Jordan and from there to the Dead Sea. The Palestinians also have a plan to build a canal parallel to Jordan that will use water from the area for irrigation purposes.'
{Appeared in Haaretz newspaper, 20/12/2000{
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