During April 2010, a salvage excavation was conducted in the northern part of the Sultan’s Pool in Jerusalem (Permit No. A-5895; map ref. 221462/631075), prior to the installation of a sewer pipe. The excavation, undertaken on behalf of the Israel Antiquities Authority and underwritten by the Gihon Company, was directed by Y. Zelinger, with the assistance of M. Kunin (surveying and drafting), A. Peretz (field photography), C. Hersch (pottery drawing), H. Rosenstein (metallurgical laboratory) and D.T. Ariel (numismatics).
A section of the Lower Aqueduct to Jerusalem and the arches bridge that carried it were excavated inside the Sultan’s Pool (length of excavation area 25 m; Fig. 1); the aqueduct crosses the pool from the southwest to the northeast. The Lower Aqueduct, which was built during the Second Temple period, is well known from previous surveys and excavations. It begins at the Solomon’s Pools south of Bethlehem and ends at the Temple Mount. The Sultan’s Pool, which was built in the upper part of the Ben-Hinnom Valley, is located in the lowest spot of the region and was therefore used as a reservoir for floodwater. To maintain the elevation of the aqueduct that passed through the pool, a bridge was constructed to support the aqueduct over the valley. The bridge is visible in photographs taken at the end of the nineteenth century (Fig. 2); however, it was covered over with alluvium during the twentieth century. A drainage pipe (diam. 1.5 m), which was apparently installed in the 1960s and caused severe damage to the aqueduct and the bridge, passes through the excavation area.
The Aqueduct. A section of the aqueduct (length 11. 5 m, width 0.4 m, max. preserved height 0.3 m) was exposed in the southwestern part of the excavation area. Its sides (W103, W104) were built of partly dressed stones bonded with light colored mortar and coated with white homogenous plaster. Wall 103 (width c. 0.6 m, max. height 3.1 m) was built to a great depth, although it was not founded on the bedrock. Wall 104 (width c. 0.5 m, exposed height 0.9 m) was not exposed to its full height due to technical problems. At the beginning of the Ottoman period, a terracotta pipe (diam. 0.25 m; Figs. 3; 4:3), encased in a plaster cast, was installed in the southwestern most section of the aqueduct. Damage to the aqueduct occurred when two inspection points for the sewer were built on and near it; one point was constructed at the time of the British Mandate and the other was apparently built in the 1950s.
The Arch Bridge. The bridge was built of large dressed stones and was borne atop arches, four of which were exposed in the current excavation. The northeastern most arch was preserved in its entirety (width c. 2.5 m; Fig. 5). The next arch to the southwest was partially preserved, whereas the two southwestern arches were almost completely destroyed due to the installation of the drainage pipe. The height of the bridge varies in accordance with the level of the ground. Two layers of plaster that constituted the base of the aqueduct were preserved on the bridge; the sides of the aqueduct were not preserved. Clay sediment was preserved between the two plaster layers of the aqueduct, indicating that the upper plaster layer was a later repair to the aqueduct. A worn coin was discovered in the base of the bridge next to the northeastern arches (L110). It may date to the time of Alexander Jannaeus or Herod, but this is uncertain and in any case, it does not contribute to dating the time of the bridge’s construction. The bridge’s southwestern arch had survived by remains of the bridge’s base and the springer (W105; max. excavated depth 2.3 m). Two bowl fragments were discovered in the soil near the base of the bridge (L107); one is glazed and dates to the Mamluk period (Fig. 4:1) and the other is an arched-rim krater from the Byzantine period (Fig. 4:2); the foundation trench of the bridge is probably located in this spot.
Conrad Schick was the first to describe the aqueduct and the bridge that carried it when he documented the Sultan’s Pool and its surroundings in 1898. The detailed plan and sections that accompany his article enabled the reconstruction of the aqueduct and the bridge; however, they are useless for dating the remains. The Lower Aqueduct provided water to Jerusalem as of the Hasmonean period and continued to function until the Ottoman period. Due to its prolonged use and the numerous repairs made to it, it is difficult to date the different phases. The method of construction in the southwestern section of the aqueduct is similar to sections of the aqueduct that were exposed in the past and were dated to the Early Roman period. The arch bridge, however, is dated to the Mamluk period, based on the dedicatory inscription from 1320 CE that was incorporated in it (it is visible in photographs but has not yet been exposed). The Mamluk sultan al-Nasir Muhammad ibn Qalawun is referred to in this inscription. In addition, a few glazed potsherds from the Mamluk period were discovered in the foundation trench of the northern wall of the aqueduct in this excavation, which further corroborate this dating. The aqueduct was probably built originally in the Hasmonean period and crossed the channel in the Ben-Hinnom Valley on a bridge that was destroyed due to neglect or floods and a new bridge had replaced it in the Mamluk period.