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The aqueduct that can be seen today, east of the Akko-Nahariya road, was built during the late Ottoman period to supply water to Acre. The aqueduct was built by Suleiman Pasha in the years 1814–1815. The aqueduct, as seen in the diagram below, starts at the Cabri Springs to the north, ca. 70 meters above sea level, and runs south ca. 14 kilometers to Acco (at sea level), yielding a slope of 5 meters per kilometer, or 0.5%. North South
Schematic diagram of the aqueduct
For part of the aqueduct’s length there was an open water channel supported by tall arches (above, 1). The height of the aqueduct was, for example, ca. 12.5 meters at the section that passed over the Yasaf stream. In sections close to the ground, the channel was enclosed with a stone cover to prevent the entry of dirt to the system.
A covered channel An open channel The arches crossing the Yasaf stream
Approximately two kilometers before Acre, the aqueduct ceased to be an open channel and the water entered into an underground pipe. This pipe was constructed of either earthenware or stone modules. The typical module was 60 cm long, 35 cm wide and 35 cm high. One end (“male”) had a projecting flange; the other (“female”) had a socket, so that two modules could be fitted together. The seal between the modules, and within the cavity of the pipe, was made of a coating of a clay-like cement.
A stone pipe module Pool on the top of a siphon tower Stones of an arch
At the outskirts of the city, water towers were built that operated according to Pascal’s Law of Fluid Pressure (a reverse siphon). At the top of each tower was an open pool.
The purposes of these towers and their pools were:
(1) To supply water to higher points in the city without pressure loss.
(2) To function as an air relief valve to prevent a pressure surge resulting from a sudden cessation of the water flow.
(3) To allow the outlet of water for irrigation at several points along the aqueduct without the loss of water pressure.
(4) To allow the settling of solid contaminants to the bottom of the pool. (5) To make possible the efficient identification of blockage locations in a specific section of the pipe.
Inside each tower was a narrow cavity with stone protrusions or hollows that served as footholds, making it possible to ascend to the pool above to perform periodic maintenance.
The towers which remain standing until today are (from north to south):
1. Al-Bahja siphon tower – This is the chute within the grounds of today’s Manof youth facility (Diagram, 2). This is the endpoint of the long, arched segment of the aqueduct above ground. From here, the aqueduct descends at a slant into an underground pipe that carries the water to where the aqueduct enters into the Old City wall. The pipe, consisting of modular units, continues southward.