| State: | Israel |
| Region: | Negev |
Nahal Zin (in Hebrew:נחל צין Arabic: Wadi al-Fikra) is one of the largest intermittent streams in the Negev, and it is commonly seen as the border between the northern and central Negev. The stream flows from the Plain of the Winds north of the Ramon Crater, passes south and at the foot of the Ben-Gurion Institute, and continues from there. In the northern Arava, the stream is dammed by an earthen embankment, flows into the drainage systems of the Dead Sea Works, and is diverted to the northern basin of the Dead Sea. The length of the stream is about 120 kilometers, and it is the second largest intermittent stream in Israel after Nahal Paran.[1] [2] Nahal Zin has several names in Arabic, a different name for each section. The first, Wadi Nafha, flows from the high Negev mountain area to the point where the wadi turns 90 degrees east (after the Nabatean city of Avdat). The second part is called Wadi Mora after Ein Mora (the bitter spring named for its brackish waters), the lowest spring in the series of springs in the wadi's gorge (after Ein Ma'arif and Ein Avdat). The third part is Wadi Fukra, which flows from the canyon of Ein Avdat to the Dead Sea (the name means the poor stream, due to the scarcity of grazing food and the few acacia trees in the wadi).
About 2 km north of the entrance to the Ein Avdat National Park, Nahal Zin forms a 'knee' where the stream turns at a right angle from north to east. The 'knee' was formed by ancient stream capture activity, where Nahal Zin captured the waters of an ancient and large stream that flowed before the formation of the Syrian-African Rift from the Edom Mountains westward to the Mediterranean Sea.
On average, about four flash floods occur annually in Nahal Zin. In 2004, a peak flow rate of 1,280 cubic meters per second was measured in the stream, the highest in Israel. In January 2010, this record was broken in Nahal Nitzana, where a flow rate of 1,420 cubic meters per second was measured. In 2007, part of the Nahal Zin channel and the erosion cliffs on both banks were declared a national park named "Sculpture Garden".[3]
Among biblical commentators, there is a debate regarding the location of the biblical Zin River. One interpretation suggests that the Zin River was located in the area of Halutza, Shivta, and Nitzana, an area that constitutes the drainage basin of today's Zin River. There is confusion between the Zin River and the Sin River mentioned in the Book of Exodus as being "between Elim and Sinai."
Naturally, the stream flows with floodwaters on average four times a year. It crosses the Negev, descends to the Arava Valley, and there splits into a giant alluvial fan that for millions of years flowed into the Sodom Salt Flat. In recent decades, Nahal Zin ends at a wide earthen dam built by the Dead Sea Works to protect the evaporation ponds from floods. Instead of flowing into the salt flat, the stream is diverted into the plant's water drainage system and redirected to the Jordan River and Nahal Arava. As a result, and due to the agricultural activity of the two settlements in the Sodom Plain, the area of the salt flat has shrunk by about 90%.
Within the boundaries of Nahal Tzin runs the Eilat-Ashkelon pipeline, a 42-inch diameter, 254-kilometer-long oil pipeline. This line was used to transport jet fuel between the Mediterranean Sea and the Gulf of Eilat. After faults were discovered in the pipeline's casing and it did not meet the requirements of the Ministry of Environmental Protection, the flow in the pipeline was stopped, and the operating company began upgrading the line. In June 2011, during the upgrade works, a backhoe hit the fuel pipeline and caused a jet fuel leak in the nature reserve. According to estimates, over one and a half million liters of fuel flowed in the Nahal Tzin streambed. The fuel pollution in the nature reserve threatened important springs downstream, necessitating quick action to save the reserve. The terrain did not allow immediate access to the leak area. To minimize the damage, initial actions were taken such as: manually closing valves, closing the area to hikers, building a barrier downstream to stop the fuel flow, and digging storage pits to collect the liquid fuel. The ecological consequences of the leak were severe: plants dried up and died, animals relying on these plants were harmed, and there was a serious concern that the pollution would be carried into the groundwater and the oases downstream due to the rains and floods typical of the area. Inspectors testified that even months after the incident, the stream reeked of fuel, Maariv, 22/07/2011}}}}. The Magistrate's Court convicted the EAPC company and several former senior officials in the company of severe pollution of Nahal Tzin and its surroundings following two leak incidents, in September and June.
The geology of the stream dictated the method of pollution treatment, and experts decided that the required action was ex situ biological treatment, meaning excavation and removal of the soil to authorized sites where the treatment would be carried out. This strategy was chosen to prevent the persistence of the pollution and the leakage of organic pollutants into the groundwater. The excavation depth was limited to 5 meters or until the bedrock of the streambed, due to concerns about the collapse of the stream banks. The utmost importance was given to completing the excavations and covering the stream with material identical to that removed before the start of the rainy season.
The excavated soil was transferred, among other places, to the Afek site, which receives fuel-contaminated soils and reduces the contaminant concentration to a level where it can be reused as cover soil in landfills. The treatment was done using biological treatment with "oil-eating" bacteria that reduced the pollution level in an environmentally friendly way. The primary advantages of the treatment are the reduction of the volume of waste landfilled, the reduction of pollution levels, and the possibility of reusing the soil. About 65% of the leaked fuel was collected in excavation operations that lasted several months.
During this time, some of the fuel seeped to a depth of more than 5 meters and penetrated the gravel aquifer that feeds Ein Akrab and Ein Tzin downstream. In light of this, EAPC, following the Ministry of Environmental Protection's guidance, proposed a long-term monitoring plan for the streambed to assess the pollution potential and its spread. The leak incident and the treatment strategy sparked many controversies and discussions among environmental experts.[4]