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T HE L AND

Iraq’s terrain consists mostly of low-lying plains and desert. The north and northeast are mountainous; marshes cover parts of the southeast, along the border with Iran.

spring because of rains in the north. However, in the 1950s the Samarra Dam was built in central Iraq. When the river level is par- ticularly high, the dam helps divert water into the Tharthar Reservoir, where it can be stored for later use. Like the Tigris, the Euphrates River also originates in Turkey. It flows first through Syria and then enters Iraq in the northwest, running through the country for 743 miles (1,196 km). The Euphrates flows along a channel that is roughly parallel to that of the Tigris. As they flow through Iraq, the two rivers are between 25 and 100 miles (40 and 161 km) apart. Eventually, the Euphrates joins the Tigris at Al Qurnah.