Drainage Channels. A channel with a convex ceiling (L154; exposed length 5.5 m, width 0.30–0.35 m, height c. 0.8 m), oriented northeast-southwest, was exposed in Squares D/E17 and D18. The floor of the channel consisted of plaster mixed with potsherds and its sides were built of one course of ashlars (W173, W182), upon which no plaster was discerned. Debesh construction, composed of mortar/cement and small stones, was built on the sides. The channel had an incline of 1.5%, a relatively slight gradient, which was likely to cause blockages. Channel 154 was founded on a floor of small and medium stones (L153) that was placed on the sand. The western side of Floor 153 ended in a straight line. The floor was probably part of an early channel whose walls had been robbed. A larger channel (L150; exposed length 9 m, width 0.45–0.50 m, height 1.2 m; Fig. 2) was discovered to the west of Channel 154; it had cut through Channel 154 and therefore postdated it. Channel 150, aligned northeast-southwest, was set directly on the sand and its ceiling was arched. The earlier channel’s floor was used at the northeastern end of Channel 150. The channel’s floor consisted of plaster mixed with potsherds and its sides were built of two courses of kurkar ashlars (W171, W172) that had no plaster coating. A vault of plaster/cement and small stones was constructed on top of the sides. The channel was built at an incline of 3.7%, as customary in sewage systems today. The GPR tests in the area revealed that the earlier channel drained a southern region of the tell and the later channel drained an area, further north on the tell. The replacement of the early channel with the later one probably occurred due to the increase in the volume of drained substance and also because of an error in the gradient of the early channel. Later pits dug into the channels (L116, L125) damaged them. The pits contained potsherds dating to the Byzantine period (fifth–seventh centuries CE; below) and coins from the middle of the fourth century CE (below). Based on the ceramic artifacts, the channels presumably went out of use at the end of the Byzantine period.
A stone wall (W300; exposed length 2 m, width 0.55 m) was uncovered in Square C17; oriented north–south, it was preserved three courses high. The wall served as a retaining wall for sand fill that was deposited to its east. The drainage channels were founded on this sand and it seems that the sand was meant to absorb liquids from the channels. Layers of alluvium that had washed down from the tell were discovered west of W300.
A drainage system, constructed in a similar manner and dating to the Roman period, was exposed in Rome, mostly beneath the Via del Velabro. The system in Rome is bigger because it served a considerably larger population than that of Yavne, and it was constructed inside the city limits, unlike the system at Yavne, which was built on the fringes of the tell, outside the residential area of the Byzantine period settlement (Lamprecht H.O. 1987. Opus Caementitium Bautechnik der Römer. Düsseldorf). 
An Industrial Building with Glass Furnaces. Remains of the northeastern corner of a building were exposed in Squares C23/24. The walls of the building (W231, W232; width 0.7 m, preserved height 0.25–0.30 m) were built of small and medium stones. Inside the building were two circular glass furnaces (L159—diam. 1.1, preserved height 0.6 m; L160—diam. 1.5 m, preserved height 0.4 m); Furnace 160 was only partially exposed. Glass slag was discovered throughout the entire excavation area. The southern part of W231 had been damaged in an early period due to the digging of a channel (L138), at whose bottom stones were uncovered. Both W231 and Furnace 159 were damaged during the modern era by a backhoe-dug ditch. The floor of Furnace 159 and its sides were built of fired clay; the floor protruded out beyond the sides of the furnace. A ventilation pipe, designed to provide oxygen for combustion, penetrated the side of the furnace; it consisted of Gaza-type jars that dated to the Late Byzantine period (Figs. 3, 4). The jars were inserted one inside the other after their bases and rims were removed (Fig. 5; Mayerson P. 1992. The Gaza ‘Wine’ Jar [Gazition] and the ‘Lost’ Ashkelon Jar [Askalônion]. IEJ 42:76–80). Two of the jars that composed the pipe were preserved in situ.
Furnace 160 was built of fired clay. Several stones discovered to the east of the furnace may be the remains of a wall that was meant to reinforce the outside of the furnace, or perhaps they were remains of auxiliary installations connected to the furnace.
Pottery kilns, similar to the glass furnaces, were discovered in Yafo; they were used until the third century CE (ESI 14:81–83). A similar glass furnace, dating to the sixth century CE, was exposed in Apollonia (I. Roll and E. Ayalon 1989. Apollonia and the Southern Sharon. Tel Aviv).
A large ceramic assemblage, dating to Iron Age II and the Byzantine period, was discovered in the excavation. The Iron Age potsherds were discovered in soil debris, alluvium or in soil fill, mostly above the natural sand layer of Tel Yavne (L122, L136). A single pottery vessel was discovered in the fill of Channel 148. Iron Age II potsherds included bowls (Fig. 6:1, 2), kraters (Fig. 6:3–7), hole-mouths jars (Fig. 6:8, 9) and jars (Fig. 6:10, 11). The potsherds from the Byzantine period were discovered throughout the excavation area and in the pits that penetrated the channels and damaged them. The finds from Pit 116 dated to the fifth–seventh centuries CE and included bowls (Fig. 7:1, 2), a krater (Fig. 7:3), cooking vessels (Fig. 7:4–6), baggy-shaped jars (Fig. 7:7, 8), a Gaza-type jar (Fig. 7:9) and a jug (Fig. 7:10). A fragment of a base belonging to an African Red Slip bowl was discovered next to Kiln 146. A five-petal rosette (Fig. 7:11) is engraved on the bottom of its base and this vessel type dates from the beginning of the fourth to the end of the fifth centuries CE. In addition, two lamps were found in the fill above W300 in the northwestern part of the excavation area. One lamp (Fig. 8), which is very common to the Byzantine period, is triangular, with a tapered nozzle. It lacks a handle and is decorated with lines and a palm frond. The other lamp (Fig. 9) is elliptical and has a wide filling-hole that is broken, and a knob handle on the shoulder. The lamp is decorated with lines and bumpy dots; its nozzle is broken.
The Coins
Robert Kool
Eleven bronze coins were discovered in the excavation; three cannot be identified and two are coins that date to the beginning of the twentieth century. Six of the coins date to a brief period in the fourth century CE (321–363 CE). Coin No. 1 was discovered at the bottom of Pit 125, which was dug into the drainage channels and damaged them; it is likely to provide the latest date for the function of the drainage system in the fourth century CE. The other five coins were discovered in soil fills and on the surface; it should be noted that three of them date to the brief reign of Julian the Apostate, following his ascension to the rank of Augustus (361–363 CE).
1. Reg. No. 1218, L125, IAA 73196.
321–324 CE.
Rev.: [IOVI CONSERVATORI] Jupiter standing l, draped, holding a scepter with an eagle and Victory; below l.: eagle and wreath; below r.: captive: X/IIå
Æ, ↓, 2.61 g, 18 mm.
Comp: RIC 7:682, No. 34.
2. Reg. No. 1179, L116, IAA 73117.
Constans I, Thessalonica, 341–346 CE.
Obv.: [CONSTANS] PF AVG bust r., diademed.
Rev.: [VICTORIA]D[AV]GGONN two Victories standing facing each other, each holding a wreath; below the line: SMTSA.
Æ, ↓, 1.16 g, 17 mm.
Comp: LRBC 1:21, No. 860.
3. Reg. No. 1274, Surface, IAA 73120.
351–361 CE.
Obv.: [- - - ] bust r.
Rev.: [FEL TEMP REPARATIO] Virtus l., spearing a falling horseman and raised hand.
Æ, ↑, 2.88 g, 16 mm.
Comp: LRBC 1:100, No. 2632.
4. Reg. No. 1126, L116, IAA 73116 (Fig. 10:1).
Julian II, Antioch, 361–363 CE.
Obv.: DN FL CL IVLI –A]NVS PF AVG bust r.
Rev.: SECVRITAS REIPVB bull standing r.; above two stars
Below the line: ANTΓ
 Æ, ↑, 8.06 g, 28 mm.
Comp: LRBC 2:100, No. 2640.
5. Reg. No. 1261, L133, IAA 73118.
Julian II, Antioch, 361–363 CE.
Obv.: [DN F]L CL IV[LI –ANVS PF AVG] bust r., pearled diademed
Rev.: [SEC]VRITAS REIPVB bull standing r.; above two stars
Below the line: ANTB
 Æ, ↓, 6.59 g, 30 mm.
Comp: RIC 8:532, No. 216.
6. Reg. No. 1271, L136, IAA 73119 (Fig. 10:2).
Julian II, Alexandria, 361–363 CE.
Obv.: [DN CL IVLI] –ANVS [PE] AVG bust r., pearled and rosette diademed
Rev.: [VOT/X/MVLT/XX inscription within wreath.
Below the line: ALEA
 Æ, ↓, 2.66 g, 20 mm.
Comp: LRBC 2:103, No. 2853.
It seems that the excavated area, which extends southwest of the tell, was an industrial region of the Byzantine-period settlement. A pottery kiln was exposed nearby in the past (ESI 12:113). The exposed drainage system indicates that Yavne was a planned and organized city in the Byzantine period, which conveyed its sewage and waste water outside the populated area, possibly to the fields. Much of the ceramic finds throughout the excavated area dated to the Late Byzantine period, and it therefore seems that the settlement at Yavne reached its zenith in this period. The pottery finds from Iron Age II support the identity of the tell with biblical Yavne/Jabneel (Joshua 15:11).