Joseph Callaway

Household cistern. Cap still in place, this cistern set into the floor of an Iron Age I house at Ai remained undisturbed for nearly 3,000 years—until it was excavated by American archaeologist Joseph Callaway in the 1960s. Bell-shaped in design (see drawing), this cistern was carved from bedrock. In the Ai region, bedrock is a combination of two types of impermeable stone, both of which are distinctly visible here: thin layers of hard Cenomanian limestone at the bottom of the cistern, and a thick layer of Senonian chalk at the top.

Beneath two houses at Ai, a network of interconnected cisterns gave the extended family living there an abundant supply of stored rainwater (see plan). The pioneering Israelites introduced cistern building to the area on a widespread basis, as they did agricultural terraces.