In both ancient and modern times water was a precious commodity in the Middle East. Villages and cities were built near springs where possible, but in other cases wells were dug AND, from about 1200 B.C. to the present day, plastered cisterns collected the precious rainwater during the winter months.
Cisterns are cavities that are hewn out of the rock, or soil, and are lined with plaster so as to be able to store water. In the Middle East, the runoff from the winter rains filled them, and the stored water was used throughout the year.
In the cistern from Ashqelon, note the remnant of the small opening at the top, through which a container was lowered into the cistern to draw water.