The National Water Carrier
The completion of the largest water project in Israel, the National Water Carrier, was the culmination of a continuous process of developing the Israeli water resources guided by Levi Eshkol. With the construction of the National Carrier in the late 1950’s and early 1960’s, this system became a single network linking most of the regional water projects throughout the country.
The decision to implement the Jordan Project, which became known as the National Water Carrier, was adopted by the government of Israel in 1956.
The National Carrier, Israel’s water lifeline, was designed by Tahal and constructed by Mekorot. Construction was completed in June 1964 at a cost of about IL 420 million (at 1964 prices).
Since its inauguration, the National Carrier has been transporting water from Lake Kinneret as well as ground water admixed in it on its way from the Kinneret in the north of Israel to Mitzpe Ramon in the south.
The idea of a National Water Carrier was preceded by several proposed comprehensive solutions for the water problems of Israel. The first appeared in the 1902 book "Altneuland" by Theodore Herzl, prophet of the Jewish State. In his book, Herzl discusses utilizing the sources of the Jordan for irrigation purposes and channeling sea water for producing electricity from the Mediterranean Sea near Haifa, through the Beit Shean and Jordan valleys - to a line parallel to Jordan and the Dead Sea. A well-known plan for the water economy is included in the book by Professor Walter Clay Lowdermilk, "Palestine, Land of Promise", published in 1944. Prof. Lowdermilk of the U.S., a world renowned land conservation expert, was invited to Palestine by the British Mandatory Government to conduct a survey for airports. He utilized the opportunity to also conduct a thorough survey on developing the country. His book served as the basis for the detailed water resource plan prepared by James Hayes, an engineer from the Tennessee Valley Authority of the U.S., at the invitation of the settlement institutes in Israel.
The plan deals with utilizing all water sources in Israel - about 2 billion cu.m. per annum - for irrigation and production of electricity. Main features of the plan: Diverting part of the Litani River water to the Snir (Hatsbani) River, to be further conveyed by means of a dam and canal to the area south of Tel-Hai, from where it would be "dropped" to produce electricity. The plan also calls for the water to flow from Tel-Hai to the Beit Netofa valley which would become the national water reservoir, of about one billion cu.m. volume (about one quarter of the Kinneret’s volume). An electricity generating station is to be located at the reservoir’s outlet, and from there the water is to flow in an open canal to Rafiah. On its way south, the canal is to "collect" water from wadis and streams, including the waters of the Yarkon River.
The plan also calls for channeling the Yamuk River into Lake Kinneret, in order to prevent a rise in its salinity due to diversion of the Jordan, and construction of a joint Israeli-Jordanian dam about 5 km. East of Kibbutz Sha’ar Hagolan.
The Hayes plan was supposed to be implemented in two stages, over a 10-year period, but "fell through" due to economic unfeasibility and lack of cooperation on the part of Jordan.
Another famous "water plan" was that of Eric Johnston, who served between 1954-1957 as the "water envoy" of U.S. President Dwight D. Eisenhower. According to this plan, Jordan and Yarmuk water was to be divided between Israel (40 percent), Jrodan (45 percent) and Syria and Lebanon (15 percent). In accordance with international law, each country would retain the right to utilize the water flowing within its borders, if it causes no harm to a neighboring country. As the Johnston Plan constitutes a compromise between the interests of the concerned countries, the water of a river which crosses the territory of several countries is to be divided between these countries. While the "Johnston Plan" was accepted as fair by Arab water experts, Arab politicians rejected it out of hand.
With the inauguration of the National Water Carrier in 1964, some 80 percent of its water was allocated for agriculture, and 20 percent for drinking water. However, as time passed, an increasing percentage was consumed as drinking water, so that by the early 1990’s the National Carrier was supplying half of the drinking water in Israel. According to forecasts, by the year 2010 some 80 percent of the National Carrier will be directed for drinking water. The reasons for the forecast growth in the share of the total National Carrier water consumed as drinking water:
1. Population growth in Israel, primarily in the center of the country.
2. Increased domestic water use, due to a rising standard of living.
From Local Water Supply to a Nationwide Network
The State of Israel actually began to implement the plan as early as 1953. However, since at that time, before the Six Day War, the Jordan formed the border between Israel and Syria, the plan was frustrated due to Syria’s opposition. Many fire fights occurred in 1953 in the region with repeated complaints lodged against Israel by Syria at the United Nations.
At the end of that year, the U.N. decided to enjoin Israel from diverting the Jordan waters. As a result, the original plan of the National Carrier was amended and it was decided to base it mainly on water of Lake Kinneret, which was designated as the northern and primary natural reservoir of the National Carrier, from which the water is pumped and carried southward.
This change in the plan was significant, involving the use of large quantities of energy (electricity), since its construction involved lifting water from 209-213 meters below sea level to an elevation of 151 meters above sea level. To convey the water to the highest point of the National Carrier, near Eilabun, a difference of about 370 meters in elevation had to be overcome. This was achieved by means of two large pumping stations: Sapir (Tabgha) and Tsalmon.
Lake Kinneret covers an area of about 168 sq. km., containing 4 billion cu.m. of water. The lake receives most of its water from the Jordan, formed by the confluence of its three major tributaries; the Dan, which "contributes" some 250 million cu.m. per annum; the Snir (Hatsbani), with an average annual contribution of some 150 million cu.m., and the Hermon (Banias) River, contributing an annual average of about 120 cu.m. to the Jordan.
The Kinneret thus receives in an average year about 520 million cu.m. of water from its major tributaries. Together with minor tributaries, flood waters and other sources, the total average annual inflow into the Kinneret from its catchment basis amounts to about 850 million cu.m., 65% of which is from the Jordan and its tributaries, and 35% from all other sources. Some 300 million cu.m. of this water - evaporates.
About 500 million cu.m. of water is available for pumping from the Kinneret in an average year. Of this, about 400 million cu.m. is pumped into the National Water Carrier.
The Underwater Pipeline
Water enters the National Water Carrier through a pipeline, several hundred meters in length, submerged in the northern part of Lake Kinneret. The water passes through the pipeline into an intermediate reservoir on the shore, then to a pumping station through an inlet tunnel. The underwater pipeline is composed of 9 "sausages" - pipes joined by means of an internal cable which is "threaded" through them. This connection method gives them the appearance of a sausage. Each such "sausage" is composed of 12 concrete pipes 5 meters long and 3 meters in diameter. As these pipes were cast on shore, they were encased in steel pipes. Each of these huge "sausages", about 56 meters long when joined, and weighing about 300 tons, was then sealed at the ends and floated out into the lake. Quality tests were performed on the "sausages" while they were floating, following which they were towed into their designated position by two tugs and submerged by the controlled opening of the air valves at the sealed ends. Divers carried out the final joining of the pipes at the lake bottom.
A huge winged star-shaped "cap" was mounted in a vertical section of the underwater pipe in order to take in water from all directions.
Sapir Pumping Station
The Sapir Pumping Station, on the shore of Lake Kinneret, is named in memory of Mr. Pinchas Sapir, one of the prominent members of the Labor Movement and who managed Mekorot in the 1940’s. After the founding of the State of Israel, Mr. Sapir became Minister of Trade and Industry and subsequently Minister of Finance.
On its way to the Sapir (Taghba) pumping station in the northwestern part of Lake Kinneret, the water passes through an intermediate equalizing reservoir before entering the sumps of the pumping station which is excavated in its entirety in a mountain cavern. The sumps, intermediate reservoir and the Kinneret function as communicating vessels whose water level is identical to the level of the Kinneret. A vertical pump draws the water from each sump, transmitting it to the main horizontal pump.
Three horizontal pump units are located in the main pump hall, each composed of the two above mentioned pumps and two motors. The hall measures 20 x 80 meters and is 21 meters high, its shape resembling a giant egg. The total height of the hall with the pump sump reaches 40 meters. Each of the 20,000 kW units has a pumping capacity of 6.75 cu.m. per second, driven by powerful motors of 30,000 horsepower each. Electricity is supplied through a special switching yard which brings electric power cables into the station through a cable tunnel. The switching yard contains many electric poles supplied by overhead high tension lines.
Several special service tunnels lead to and from the main pumping hall. The chlorination tunnel, for example, contains devises for improving water quality by disinfecting with chlorine, while the drainage tunnel permits draining the water systems whenever necessary, such as when a malfunction occurs in the pipeline between the Sapir station and the open channel, causing water to penetrate into the station. The main pumps force the water into the automatically-operated valve tunnel.
Construction and excavation of the giant Sapir station and its tunnels, was one of the most difficult and complex tasks of the National Water Carrier project. Particular difficulties were encountered due to the size of the pump hall and the nature of the rock in which it was excavated, necessitating special precautions. At the first stage "small" tunnels were driven through at the level of the "future" ceiling, in order to cut through the entire length and width of the pumping hall. After casting the concrete roof, tunnels were excavated on the left and the right, along the future walls. The material to be excavated, composed of rock and earth, was removed at the final stage, after the sides of the tunnel were encased in concrete.
Supervision and control of the pumping station is by means of the most up to date computerized equipment. The entire station is air conditioned, and equipped with elevators and two cranes of 50 tons lifting capacity each.
From the Sapir station, the water is forced into three pipes which join to form a single pressure resistant steel pipe, 2,200m long, known as the "pressure pipe". The pressure pipe raises the water from -213 meters below sea level to an elevation of +44 meters above sea level, where it enters the open channel, known as the "Jordan Canal". The diameter of the pressure pipe varies, ranging between 2.20 to 2.80m. Its exterior is "padded" by a concrete casing and painted on the inside by a protective coating which was renewed in the winter of 1994-95. The spaces between the pipe and the excavated rock walls have also been filled with concrete, to protect the pipe from shocks.
The fourth pumping unit was inaugurated at the Sapir station in November 1991. The unit is housed above ground, since the current security situation does not require expensive protective construction. Another consideration for the addition of a fourth unit: in the event of a serious malfunction, such as a fire in the pump hall, the fourth unit will continue to operate as it is housed outside the present building. The fourth unit is not intended to increase the water flow in the National Water Carrier, but rather to augment the reliability of the water supply, due to the "aging" of the three veteran pumping units, after nearly 30 years of continuous operation. Since at certain periods it is impossible to stop pumping through the National Water Carrier, not even for a single day, the fourth unit provides an alternative during malfunctions or renovations in the other pumping units. The new pumping unit thus allows its veteran colleagues to take "time out", "renew" themselves and undergo renovations to prevent total failure of the unit systems, adapt them to technologies of the 21st century and extend their "life expectancy" for additional decades of proper operation.
Operating the four pumping units at night, when electricity is cheaper, may lower the cost of water.
The Jordan Canal
The National Water Carrier is discharged by the pressure pipe into an open canal, the "Jordan Canal", excavated along a rocky mountainside for almost all of is 17 km. length. The water in the Jordan Canal, 2.70 meters deep when full, flows by gravity. The canal is 3.15 meters deep, trapezoid in shape, with its width varying between 2.50 meters at the bottom and 12 meters at the top, and is sides have a slope of 1:1.5. Its bottom is lined with compacted ground basalt ("hizriya"), covered by a protective asphalt layer approximately 1cm thick, topped by a 10cm thick concrete layer. Special equipment was brought from the U.S. to construct the canal, adapted to its shape.
From the Jordan Canal the water flows into an operational reservoir with a capacity of about 1 million cu.m., the Tsalmon Reservoir, excavated in the Nahal Tsalmon valley. The reservoir regulates the water flowing from the canal into the pumping station.
Amud and Tsalmon Siphons
Two deep wadis intersect the course of the Jordan Canal, Nahal Amud, 150 meters deep, and Nahal Tsalmon, over 50 meters deep. To overcome these natural obstacles, it was necessary to interrupt the continuous route of the canal and carry the water through steel pipes shaped like an inverted siphon, operating on the communicating vessels principle. The water flows down into the wadi and rises again on the other side. A steel pipe 3.10 meters in diameter and 700 meters long was laid in a trench cut in the Nahal Amud canyon. The pipe, completely encased in concrete, was buried at a depth of 5 meters in the 10 meter wide trench. The work of cutting the trench and laying the pipe for the Nahal Amud, was especially difficult and complicated, as the slope of the canyon walls often approached 100 percent.
Tsalmon Pumping Station
The second pumping station along the National Water Carrier, the Tsalmon station’s primary job is to lift the water another 115m; from an elevation of 37m above sea level to 12 meters, and into the Eilabun canal. The Tsalmon pumping station is also composed of three pumping units, but due to the smaller lift, they are powered by smaller motors of 11,000 kW each, while having the same discharge capacity as the Sapir units: 6.75 cu.m. per second each. Here too a switching yard is operated to supply electricity power to the station.
The Ya’akov (Eilabun) tunnel is the first tunnel constructed along the National Carrier route, in 1953. In June 1980 the tunnel was renamed the Ya’akov Tunnel, in honor of Ya’akov Gitelson, a senior Mekorot engineer.
The tunnel, 850m long with an inernatl diameter of 3 meters, passes under a range of hills near the Arab village of Eilabun, conveying the water from the open Jordan Canal to the open canal crossing the Beit Netofa Valley.
The Beit Netofa Canal
The Beit Netofa Canal conveys the water another 17 kilometers. Unlike the Jordan Canal, this canal was built with an oval cross section, chosen due to the fatty clay soil through which it runs. To prevent collapse of the canal walls, it was necessary to provide them with a moderate 1:3 slope. Thus the width of the canal is 19.4 meters, the concave bottom is about 12 meters wide and its depth, 2.60 meters, with the water flowing through it at a height of 2.15 meters. The Beit Netofa Canal, as the "Jordan Canal", was excavated by special equipment ordered from the U.S. The Beit Netofa Canal carries the water from the Ya’akov tunnel to the Eshkol reservoir, named after the late Mr. Levi Eshkol, one of the leaders of the Labor Movement and who founded and managed Mekorot during its first years.
Two reservoirs are located at the southwestern end of the Beit Netofa Valley. The fist, the "sedimentation pond", holds about 1.5 million cu.m. of water and serves primarily a sanitary function, to allow suspended matter in the water to settle to the bottom.
The water enters the sedimentation pond through an installation which distributes it along the length of the reservoir in order to slow down and regulate its flow. Below the inlet installation is a sluice that absorbs most of the sediment, which in the future will be pumped out by a sludge pumping facility.
The sludge removal facility will operate without disturbing the sedimentation process. Water moves slowly through this reservoir so that the silt and suspended matter would settle to the bottom. The water exits this reservoir over a weir, thus ensuring that only the surface water layer flows on.
The second reservoir, separated from the sedimentation pond by a dam, has a capacity of 4.5 million cu.m., and its function is to regulate the inflow from the pumping stations and open canals versus the outflow into the closed pipeline, which depends on water demand in Israel, from the north to the southern regions. This reservoir permits regulating the pumping on a weekly basis, so that it would be possible to utilize the cheaper electricity at night and on weekends, and limit the use of expensive power at peak electricity consumption hours.
The large reservoir also serves as a water storage reservoir in case failures in the National Carrier system and the pumping systems necessitate interrupting the regular water pumping. In such cases, the reservoir can supply the demand for several days, ensuring continuity of supply.
Both reservoirs are surrounded by embankments. The old Beit Netofa dam was also integrated in the system, after being adapted for its current function. Both reservoirs are connected to the open canal by two distributor installations. A special canal bypasses reservoirs and permits connecting the Beit Netofa Canal directly to the 108" pipeline.
Here the water undergoes final testing prior to entering the closed pipeline. In order to bring the water to drinking water standards, chemicals are added to it. A chlorination building and additional sanitary installations were constructed near the reservoirs and their outlet, to ensure that the water entering the pipeline meets potable water quality standards.
The 108" Pipeline
The open canal and the reservoirs connect via an inlet structure to the 108" concrete pipeline. The inlet installation contains sluice gates and strainers. The pipeline runs for about 86 km., from the Eshkol reservoir to the Yarkon-Negev system at Rosh-Ha’ayin.
The 108" pipes were manufactured by the Yuval-Gad factory in Ashkelon according to the U.S. Lock-Joint company method. Each pipe section is 5m long, with an internal diameter of 2.74 meters, weighing nearly 50 tons. The prestressed concrete pipe is made of a 4mm thick steel cylinder with an internal cladding of concrete 53mm thick and an external cladding of concrete 122mm thick.