The flour-mill compound, which includes five buildings (A–E; overall length 72 m, 750 sq m; Fig. 1), was examined and documented in the current excavation. The buildings, whose walls are built of kurkar, were constructed across 15 channels (M1–M15) that conveyed water from the northern streambed of the Na‘aman toward the marsh that extended south of the compound. The buildings’ plans and the quality of construction are not uniform. The easternmost mill (A) is the only separate structure that was not built as part of the series of mills; Buildings B and E were erected in an organized and meticulous manner, whereas in Buildings C and D, a variety of masonry stones in secondary use were used and no uniform floor level was maintained. Arches that survived in Buildings B and C divided the interior and bore wooden beams that supported a flat roof, which probably consisted of tamped soil mixed with lime. None of the roofing elements survived in Buildings A, D and E, but it seems that they too made use of arches and flat roofs.
The water flowed to the buildings in open channels of various widths (width 5–10 m, depth 1.0–1.5 m) that were dug in the ground. Their bottom was lined with wadi pebbles and small bridges were built above them, allowing passage between the buildings in the compound. The channels (length 7.8–9.6 m, width c. 0.7 m, depth 1 m) beneath the buildings had a slight incline (c. 0.3 m). They were paved and lined with stone slabs, sealed with a layer of gray plaster and covered with stone slabs that were incorporated in the floors of the buildings. The southern section of each channel—which terminated in a rectangular nozzle-like opening—was built in the shape of a funnel for the purpose of increasing the water pressure: a slope of 15–20 cm was created for a distance of c. 1 m and in the last half meter, the channels become narrower by c. 0.5 m. A cell (c. 6 sq m, height c. 1.6 m) was built at the outlet of each channel, in the southern façade of the buildings. A horizontal paddle wheel was installed in each cell at a height of 3–20 cm above its floor; it was powered by the water that flowed into the channel’s aperture.
Seven of the cells (M1, M2, M5, M12–M15) were excavated to their full depth and parts of the paddle wheels were found in most of them. A nearly intact paddle wheel (inner radius 1.3 m, outer radius 1.8 m; Fig. 2) was uncovered in Cell M15: the paddles and its exterior shell are made of iron while the inner axles are made of oak. Each of the paddle wheels operated a pair of millstones that was installed at floor level in the building. The foundations of all fifteen pairs of millstones were discovered in the buildings, alongside the openings where the axles that connected the paddle wheels to the millstones were placed; fragments of millstones in secondary use were found throughout the compound and used as a foundation for a later concrete floor.
A large quantity of finds was recovered from the buildings, including pottery vessels, glass artifacts and coins, dating from the second half of the nineteenth century to the second half of the twentieth century, which define the time when the buildings were in use. Earlier objects included small cannonballs from the Napoleonic siege of ‘Akko, which may evince the demolition of the mill that had stood there by the retreating French army; a fragment of a glazed Egyptian pottery vessel from the Mamluk period (thirteenth–fourteenth centuries CE), the only one of its kind to be discovered so far in ‘Akko; and two Ayyubid coins (twelfth century CE) that were found in the fill levels, underlying the buildings. It can be concluded, on the basis of the scant finds that the mills did not operate prior to the middle of the nineteenth century CE.
One of the channels that conveyed water to the mills was revealed in a probe excavated at the northern façade of Building C. On its bottom, which was lined with fieldstones, were potsherds and coins that dated its use to the end of the nineteenth century CE and the first half of the twentieth century CE. A probe excavated below the bottom of the channel, alongside the western wall of Building B and opposite the openings of Channels M7–M9 (Fig. 3) contained a layer of sand (thickness c. 0.3 m) that covered a paved level (L209) of meticulously dressed flagstones (0.3×0.6 m) that were carefully set in place. The flagstones abutted two sections of walls that were aligned north–south; the western one (W1) extended below Channels M7 and M8, and the eastern one (W2) was located beneath the western wall of Building B. A small amount of ceramics from the Crusader period (thirteenth century CE) was found in the foundation trench of W2, indicating the date of the walls and the pavement that abutted them, although the function of the walls and the pavement remains unclear.
The complex of flour mills in the Riduwan Gardens—where fifteen sets of millstones operated—is the largest of its kind from the Ottoman period, known to date in Israel.
The abundance of water from Nahal Na‘aman was utilized for operating a large number of millstones in the compound simultaneously, even though some of them belonged to several phases. The technology of utilizing water at the site also differed from that of other known mills of the Ottoman period, which made use of penstocks (arubot) or sluices. Despite the historical evidence with regard to flour mills in ‘Akko prior to the middle of the nineteenth century CE, the findings from the excavation indicate that the mill compound operated exclusively in the second half of the nineteenth century CE and the first two decades of the twentieth century CE.