Iraq is growing the most from 21.6 to 74.75. Syria is not growing very much only from 14.8 to 30.43. Turkey is already the largest population at 62.2 but is growing even more to 97.92. Turkey will Still need the most water and Syria will need a lot less then Iraq and Turkey.
Agriculture needs water the most with a water withdraw of 39.38 cubic km. Second but a lot less is Industry at 1.97. Last and close to industry is domestic at 1.35. Iraq needs the most water for agricultre even if they may not have it.
Iraq gets about as much water from inside as outside the country. It gets 35.20 cubic km internally and 40.22 externally. Water that comes from outside is the Tigris and Euphrates. It is only a bit more than internal water.
Iraq uses almost two times as much renewable water (75.42 cubic km) as withdraw water (42.70 cubic km). This means Iraq gets a lot of water from the Tigris and Euphrates
Turkey has the largest population. Then Iraq is second and Syria is a lot lower than the other two. This shows Turkey does need the most water and Syria probably needs the least. Iraq needs a decent amount.