Built in a steppe like, semi-arid zone, the city of Kairouan, when it was founded, had scarce drinking water resources. Thus, from the outset the city was faced with the problem of water supply. In 734-741 the caliph of Damascus ordered his governor in Kairouan to build fifteen or so water reservoirs in the vicinity to supply the population with drinking water.

Two monumental basins as well as a few cisterns have survived the centuries and provide us now with an example of these majestic hydraulic installations, considered to have been the largest during the Middle ages. They cover an area of 11.000m2 and had a capacity of 53.000m3. In the middle of the large circular basin, 127,7m in diameter and 4,8m deep, stood an octagonal tower where the Emir came to rest.

Today, the complex, recently enriched with new installations excavated during terracing work, has been turned into a park with facilities for visitors.