The Waters of Euphrates and Tigris

During the Sāsānian period (3rd century CE), an elaborate feat of engineering linked the two rivers along that narrow neck by five navigable canals (the Īsā, Ṣarṣar, Malik, Kūthā, and Shaṭṭ al-Nīl canals), allowing Euphrates water to empty into the Tigris.