Its average course is forty kilometers even if the maximum length of its bed reaches 150 kilometers.
It collects its water basin upstream by a series of wadis draining the Nara region and Jebel Tazza, all being retained by the dam Sidi Saad, located about 45 kilometers southwest of Kairouan. Downstream of the dam, a series of wadis flow into the Wadi Zeroud, flowing to a zone located about ten kilometers south-east of Kairouan where it ceases to be a single wadi and splits into several parts some of which joined the sebkha Kelbia.
The rainfall reduced the region led to the near-absence of water in summer but also to floods in autumn, when rain falls during a short period of time. Construction of the dam has allowed the irrigation of farmland and helped prevent flooding, but, however, reduced the level of groundwater also overexploited.
