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How do winter rain and spring snowmelt affect the Tigris and Euphrates rivers?

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Map showing the Tigris and Euphrates river basin and its drainage network across Turkey, Syria, and Iraq, with color shading for elevation, major dams, canals, lakes, and boundaries with neighboring countries. The green areas indicate lower elevations along the river valleys, while higher elevations are shaded in brown and orange. A small locator map in the corner shows the basin's position within the Middle East. — Tigris-Euphrates river system The Tigris and Euphrates river basin and its drainage network.

The hydrological regime of the Tigris-Euphrates river system is primarily driven by winter precipitation and spring snowmelt originating in the Zagros and Taurus mountains.1

These rivers experience two distinct flood periods:
* Winter Rise: An irregular, minor increase in water levels occurs from November through March, largely fueled by seasonal rainfall.2
* Spring Flood: The primary flood period occurs in April and May, resulting from the melting of snow accumulated in the highlands during the winter months.23

The Tigris is particularly susceptible to short-term, intense flooding due to its precipitous tributaries and shorter course, which causes its peak flow to arrive approximately one month earlier than that of the Euphrates. While modern water-control infrastructure has helped mitigate the risks of these flood cycles, the sheer volume of water remains a significant factor in managing regional irrigation and protecting embankments.142