As part of a plan to rehabilitate and stabilize the structures along the waterline begun several months before the December 2010 storm, a series of deep and shallow test drillings were conducted to acquire data on the subsoil within the inner harbor. Following the storm, further drillings and probes were conducted along the promenade (Fig. 1B: Drilling C) and within the inner harbor (Fig. 1B: Drillings A and B). In April 2012, work began on renovating the rockery along the promenade (see Fig. 1B), a probe trench was made behind the shoreline, at the base of the rockery, and probes were excavated.

On 11–13 December 2010, a massive storm battered the coast of Israel, recording wind gusts of 100–110 km per hour and waves up to 13.7 m high (average wave height of 7.2 m, based on data from the Israel Oceanographic and Limnological Research Institute). The storm caused widespread destruction to ancient and modern buildings and installations in Caesarea. Many ancient structures on the coast to the north of the harbor were exposed and damaged: the foundations of the high-level aqueduct were laid bare and the four southern arches were in danger of collapsing; a section of the Byzantine sewage-pipe outlet (length 6–8 m) collapsed and was washed into the sea together with part of the western corner of the Byzantine northern wall; the western end of the northern Hellenistic/Herodian wall sustained severe damage; and buildings and installations on the coastal cliff near the shoreline were exposed and collapsed onto the beach, leaving piles of dressed building stones, mosaic tesserae, and large quantities of potsherds. The inner harbor sustained widespread destruction to historic and modern buildings, today used for commercial purposes, and to the seafront promenade: significant erosion was observed in the foundations of the Helena and Crusader restaurants, some of which had collapsed even before the storm (see Fig. 1B); in the ancient harbor, previously excavated probes and probe trenches near the round and square towers were opened up (Raban 1998: Fig. 2); the modern eastern jetty was broken into several pieces and the sea wall on top of it, built of reinforced concrete (thickness 1 m), disintegrated and was washed unto the sea bed to the east of the jetty; inside and outside the area of the ancient harbor, a layer of sand (thickness c. 2 m) from the sea bed was washed away revealing many ancient finds.

To the east and west of the current drillings, excavations were conducted in the past by the Combined Caesarea Expedition. After processing and analyzing the excavation finds in Area I to the east of the inner harbor and Area T to the west of the Round Tower (see Fig. 2), the expedition’s archaeologists estimated that during the Herodian period, the inner harbor covered an area of 150 × 250 sq m (Raban 1998; Raban and Holum 1991). In the inner harbor’s previous excavations, 12 core drillings were extracted with a manual drill (Raban 1996:635). The upper third of the sand cover in the center and south of the harbor was identified as aeolian sand, while the lower two-thirds are of marine origin. This data suggests the formation of a dune in the northern part of the area, while in the central and southern parts, a shallow lagoon was formed that was subject to repeated flooding. In 2000, a geoarchaeological study was conducted by the Combined Caesarea Expedition, led by Raban and Goodman-Tchernov, in order to investigate the possibility of flooding and damage to the shoreline by tsunami waves. In recent years, this research has been continued by a joint delegation of the School of Marine Sciences at the University of Haifa, the Hunter College New York and the Israel Antiquities Authority’s Marine Archaeology Unit. Preliminary findings from this research suggest that there may be a significant link between such waves and the flooding and blockage of the inland harbor (Holum et al. 1992; Goodman-Tchernov et al. 2009).

In 2009, a series of drillings were carried out by Agassi Rimon Engineers Ltd, funded by the Caesarea Development Corporation and supervised by the Israel Antiquities Authority’s Marine Archaeology Unit. The drilling series was divided into two groups that included dozens of shallow drillings to a depth of c. 1 m below sea level, and deep core drillings down to 10 m below sea level. Following sedimentological analysis of the cores, reports on the findings were submitted to the Caesarea Development Corporation and the Israel Antiquities Authority for engineering planning purposes (Soil Drilling Reports: Nos. 18944/2009, 19083/2010, 9645/2011, Israel Antiquities Authority archives). The drillings were carried out on the floor of the promenade (4.5 m above sea level), which was set as the zero measurement point. Within the area of the Crusader restaurant, three drillings to 1 m below sea level found a layer of clean sand at the bottom. Drillings to 1 m below sea level in and around the Helena restaurant also found a layer of clean sand at the bottom. The deep drillings (Fig. 1B: A, B) contained fine, clean sand to a depth of c. 3 m below sea level. At 3.0–3.5 m below sea level, a layer of clay-bearing sand appeared that yielded Byzantine pottery. At 3.5–6.0 m below sea level, a layer of clean sand was found. At 6 m to c. 7 m below sea level, the natural kurkar bedrock was encountered together with kurkar sand and kurkar lenses. Following the results of the drilling, it was decided to build an underground retaining wall (slurry wall) consisting of adjacent supporting pillars; the pillars were drilled and cast to a depth of 10 m below sea level (Land Drilling Report No. 18944/2011, Israel Antiquities Authority archives). Three additional drillings conducted on the south jetty to the west of the citadel found kurkar plates interposed with sand layers at a depth of 1.0–4.5 m below the top of the jetty (see Fig. 1B:C). Due to the extensive damage to the Crusader restaurant building, it was decided to demolish the building to the level of the promenade and rebuild it. After it was demolished, dozens of pillar drillings were conducted under the supervision and documentation of the Israel Antiquities Authority’s Marine Archaeology Unit. The drillings were bored c. 3 m apart to a depth of 3 m below sea level through a layer of clean sand with clay underneath. In addition, deep drillings (Drillings 10–50; Fig. 3) were bored along the western shoreline wall in order to build a slurry wall. It should be noted that in all the drillings, at a depth of 6–7 m below sea level, the same layers were found in the subsoil and bedrock.         

When work began on rebuilding the rockery along the promenade, a probe trench was excavated behind the shoreline, at the base of the rockery, down to 3.0–3.5 m below sea level. Dressed kurkar stones, remnants of collapsed stones and material that had accumulated on the beach during storms were removed from the trench. A layer of clean marine sand was exposed beneath the stones and under it, at a depth of 3.0–3.5 m below sea level, was a gray-brown layer of sand and clay mixed with small stones and Byzantine potsherds. Groundwater seepage caused the collapse of the trench walls, at which the deep excavation was halted and probe pits were dug (c. 5 × 7 m each probe). A layer of clean sand was uncovered down to 3.0–3.5 m below sea level in all the pits, beneath which was a gray-brown layer of sand and clay. The layer of clean sand yielded many ashlars and fragments of marble columns and large stone basins dating from the Byzantine period. Most of the pottery from 3.5–7.0 m below sea level dates from the Byzantine period, including a bowl base (Fig. 4:1), cooking pots (Fig. 4: 2, 3), jar rims (Fig. 4:4–6), rims of Gaza jars (Fig. 4:7–9), a jug rim (Fig. 4:10) and an amphora toe (Fig. 4:11). After clearing away the sand layers and uncovering the underlying clay soil layer, a sheet of geotechnical cloth was laid on which a sloping stone embankment was built (length 10–15 m, width 7 m; Fig. 5). Above it, a new rockery was built of large boulders weighing about 4 tons each.


Excavations previously conducted on the eastern jetty found that the Herodian jetty was built from a foundation of marine concrete poured into wooden caissons placed directly on leveled kurkar rock, at a depth of c. 1.4 m below sea level; the foundation rose to a height of up to 0.8 m above sea level. Layers of ashlars that formed a jetty with a maximum height of 1.7 m above sea level (Area I; Raban 1989:131–137) were placed on top of the concrete foundation. In further excavations conducted in 1989–1990 (Holum et al. 1992:92, Fig. 20), the archaeologists noted that the depth of the basin to the west of the jetty after it was deepened was c. 2 m below sea level. Based on data from the excavation of the eastern jetty and the sunken Round Tower (Area T), the excavators proposed a topographic reconstruction of the inner harbor representing a shallow sea bed at a uniform depth of 2.0–2.5 m below sea level. This suggested that only shallow-draft boats, i.e., small service crafts, were capable of entering the inner harbor (Reinhardt and Raban 2008:169, Fig. 12).

The finds from the drillings and probes conducted along the promenade and the shoreline provide further data and show that from the center of the inner harbor and the harbor entrance, the natural rock lies c. 6 m below sea level (Fig. 1C). This shows that deep-draft vessels would have been able to enter, maneuver and anchor in the inner harbor; however, only boats with a shallow draft could moor alongside the jetty, where the water was shallower. Sedimentary layers from before the construction of the port of Sebastos and after its demise and blockage accumulated on top of the bedrock. As part of the preparation of the foundation for the construction of the eastern jetty, the shallow eastern bedrock was deepened and leveled. During this work, most of the ancient architectural remains were transferred to the Herodian port. Based on an account by Josephus (Jewish Antiquities 16:5, 3 [147]), Raban suggests that Herod had a small military fleet that was built on the island of Rhodes and used for defense against pirate ships and invasions (Raban 2011:97–100). This fleet was probably moored in the inner harbor of Caesarea, which provided the best shelter. Similar to today, the construction of a large, deep-water port in the open sea would have been impossible without a sizable onshore logistics center, including a mooring or temporary harbor providing shelter for the vessels engaged in the port’s construction. The large, deep mooring basin in the area identified as Caesarea’s inner harbor was used by Herod for the ships and boats that served to transport the workforce and tow rafts and wooden caissons, which provided the foundations for the breakwaters (Raban 1998). These operations could probably only have taken place after organizing and constructing the necessary installations, in which case the inner harbor is actually the earliest anchorage in the Sebastos harbor complex.

The drillings and probes yielded valuable data for our understanding of the inner harbor and its reconstruction. The rebuilding of the rockery without the use of concrete was designed to enable the inner harbor to be reconstructed in the future and filled with water, as proposed in the Ministry of Tourism’s original plan in 1992.