Yala Swamp

The Yala Swamp is a wetland region of about 175 km2 in Western Kenya.

Location
The Yala Swamp at the mouth of the Yala River covers about 175 km2 along the northeastern shore of Lake Victoria. The swamp contains the 1500 ha Lake Kanyaboli, a freshwater deltaic wetland with an average depth of 3 m, which is fed by the floodwaters of the Nzoia and Yala rivers and by the backflow of water from Lake Victoria. The wetland is in Siaya and Busia counties in Kenya. It acts as a filter for waters that flow into Lake Victoria from two major rivers, the Yala River and Nzoia River. It is sometimes considered the source of the Nile.

In the past the Yala River flowed through the eastern 20% of the Yala Swamp into Lake Kanyaboli, then into the main swamp, and then through a small gulf into Lake Victoria. Today the eastern part of the swamp has been drained, and the river flows directly into the 8000 ha main swamp. It is cut off from Lake Kanyaboli by a silt-clay dyke. Lake Kanyaboli now receives its water from the surrounding catchment area and from back-seepage from the swamp. The river's gulf has been cut off from the lake by a culvert, which created the 500 ha Lake Sare through back-flooding.

Ecology
The swamps harbour endangered fish species Oreochromis esculentus and Oreochromis variabilis that have disappeared from Lake Victoria itself. The Sitatunga antelope (Tragecephalus spekii) still lives in the swamps’ papyrus. BirdLife International classifies the Yala Swamp among Kenya’s 60 Important Bird Areas. Some of the birds that live there are the blue-breasted bee-eater, the papyrus gonolek, the swamp flycatcher, the papyrus canary, the white-winged swamp warbler and the Baillon's crake.

A 2005 report noted changes in Lake Sare that threatened the lake ecosystem through eutrophication and pollution. It recommended an inclusive management plan for the Yala swamp complex to prevent further degradation of the ecosystem. As of 2019 BirdLife International scored the threat to the swamp complex as high, and was pessimistic about action being taken.