Tigris–Euphrates river system through the central plain and combine at Al-Qurnah to form the Shatt al-Arab and discharge into the Persian Gulf. The region has historical importance as part of the Fertile Crescent region, in which civilization is believed to have first emerged. The ecoregion is characterized by two large rivers, the Tigris and Euphrates. The rivers have several small tributaries which feed into the system from shallow freshwater lakes, swamps, and marshes, all surrounded by desert. The hydrology of these vast marshes is extremely important to the ecology of the entire upper Persian Gulf. Historically, the area is known as Mesopotamia. As
Mesopotamian Marshes and two other canals were constructed south and nearly parallel to it. One, the Mother of Battles canal, was constructed to divert the flow of the Euphrates south below the Hammar Marsh. Second, the 240 km Loyalty to Leader Canal also known as the Basrah Sweetwater Canal, which originates in the lower Euphrates region, collected water from the terminus of the Gharraf River and diverted it under the Euphrates, away from the Central Marshes and below the Hammar Marshes towards Basrah. The Glory River was also constructed to divert water from the Tigris's southern-flowing distributaries east and parallel along the