Sudd

The Sudd expands and contracts as White Nile flow and seasonal rainfall spread across an extremely flat basin in South Sudan. Its mixture of open water, papyrus, reeds, floodplain grassland, and floating vegetation therefore has no simple fixed boundary.

Dense floating vegetation can block channels, while the wetland's waterways shift and divide across a huge area. The name Sudd comes from an Arabic word associated with a barrier or obstruction, reflecting the conditions faced by river traffic.

The Jonglei Canal was intended to divert White Nile water around the Sudd and reduce water lost through evaporation and plant transpiration. Construction stopped during Sudan's civil war, and the proposal remains controversial because it could alter grazing, fisheries, wildlife, and flood cycles.

Communities including the Dinka, Nuer, and Shilluk have long used the seasonal floodplains for cattle, fishing, and cultivation. Their movements and livelihoods are closely tied to the annual rise and retreat of water.