Water System (Zone 3)
Beersheba’s massive water system was constructed inside the city walls sometime during the ninth century BCE, ensuring a plentiful supply of water in the event of a siege. The excavators have debated whether the system provided water for the daily needs of the city, for as its reservoirs could only be refilled a few days each year, drawing water daily would risk the possibility of not having enough water to endure a sudden lengthy siege. At any rate, the well outside the city would supply the city’s daily needs.
The water system’s reservoirs, cut into bedrock deep beneath the city, were replenished by intermittent flood waters from the Nahal Hebron, located north of the tell, through feeder tunnels, while additional water was collected from rain run-off. Today the Nahal Hebron runs some 150 meters north of the tell and seven meters below the feeder tunnel, so it is reasonable to assume the course of the wadi has shifted over the past three millennia.
The feeder tunnel deposited water from the Nahal Hebron into two regulating chambers. In its original design, the water had to make two 90-degree turns, which served to reduce the speed of the flood waters and filter out silt and stones. During the second phase of the water system, an S-shaped stone channel was added. This meant the feeder system was no longer required to reduce the speed of the water, as the new design was adapted for a smoother, but more limited continuous water flow. From the regulating chambers, the water then flowed into another feeder tunnel that narrowed into a chute into the reservoir system.
The walls and floor of the reservoirs appear to have been finished with a 10-centimeters-thick layer of hydraulic plaster. The system consisted of a central compartment with five additional compartments branching off from it. The fourth side of the central compartment was fed by the feeder tunnel. Dividing the reservoir into smaller spaces was designed to reduce the likelihood of the roof collapsing; however, the roof did collapse, probably during the spate of earthquakes that rocked the region during the mid-eighth century BCE, destroying the entire Stratum IV city. The water system was likely repaired when the Stratum III city was built, this time with additional stone supports to prevent the roof from collapsing again, along with modifications to the feeder tunnels. The new walls reduced the storage capacity of the reservoir by about 100 cubic meters, but apparently succeeded in preventing another collapse. During the final stage of reconstruction, a wall was built that sectioned off the reservoir closest to the staircase from the rest of the system. This represented a massive shift in the function of the water system, for instead of collecting flood water from outside the settlement, the system now served as a cistern for runoff water from the stairwell. This system was probably used during the Persian period, when Beersheba had a much smaller population with significantly reduced water needs. The relative stability of much of the Persian period also mitigated the likelihood of storing excessive amounts of water for a siege. The water system appears to have fallen out of use before the late-second century BCE.
Access to the water was granted by way of a flight of stairs descending some 15 meters below street level. The staircase likely included some sort of a balustrade to protect people from falling as they carried heavily filled water jars up the stairs. The shaft was carved from brittle rock, so slanted retaining walls were built to support the stairs. The shaft appears to have been built from the bottom up, so the builders would have needed ladders and scaffolding to create the stairs. An additional shaft allowed access to the water system while during its construction and restoration. The shaft is hewn into the natural chalk rock and leads from one of the regulating chambers in the feeder system to the lower outer slope of the mound, just outside the city’s fortifications. This shaft would have been used to bring in construction materials and remove debris during construction of the reservoir system. The shaft was likely reopened during the second phase of the system, when support walls were added to fix the system’s collapsed roof. Once the construction was completed, this shaft was blocked off and covered in soil to prevent its discovery.