| River | Kolars (1994)(km3∙year−1) | Kliot (1994) (km3∙year−1) | Altinbilek (1997)(km3∙year−1) | Beaumont (1998)(km3∙year−1) | UN (2010)(km3∙year−1) | Current study(km3∙year−1) |
| Tigris | 29.20 | 40.00 | 31.90 | 38.2 to 61.0 | ---- | 42.844 |
| Euphrates | 17.00 | 16.00 | 15.50 | 25 to 28.1 | ---- | 29.225 |
| Total | 46.20 | 46.00 | 47.4 | 58.2 to 89.1 | 77 | 72.069 |