JARID, SHATT AL-

also spelled Chott Djerid, large saline lake in southwestern Tunisia, occupying a salt-flat basin of about 1,900 square miles (4,900 square km). The lake is covered with water only in the lowest areas, except after periods of heavy rains. The lake forms, together with Shatt Al-Fijai (Fedjadj) and Shatt Al-Gharsah (Rharsa) in Tunisia and Chotts Melrhir and Merouane in Algeria, a depression that was formerly an arm of the sea and that extends nearly 250 miles (400 km) westward from the Gulf of Gabes. This depression's floor reaches 52 feet (16 m) and 69 feet (21 m) below sea level in Jarid and Gharsah lakes, respectively. The extensive salt flats of Shatt Al-Jarid have been an important source of phosphates since discovery of the mineral there in 1949. Tawzar (Tozeur) and Naftah (Nefta), the main oases towns on the lake's periphery, are noted for their date-palm production.