Perkerra River
The Perkerra River is a river in the Great Rift Valley in Kenya that feeds the freshwater Lake Baringo. It is the only perennial river in the arid and semi-arid lands of the Baringo County. The Perkerra river supplies water to the Perkerra Irrigation Scheme in the Jemps flats near Marigat Township, just south of the lake. Catchment The river has a catchment area of . It rises in the Mau Forest on the western wall of the Rift valley at , dropping down to at its mouth on the lake. The catchment area has steep slopes on the hillsides, flattening out lower down. Most of the water comes from the hill slopes, where annual rainfall is from to . The region around the lake is semi-arid, with annual rainfall of and annual evaporation rates of to . Land use changes In the late 1800s the alluvial plains near the lake were occupied by the Njemps people, an ethnic group related to the Maasai. They used a brushwood barrier to raise the level of the river and let the water flow over the flat ground. The barrier would be destroyed by the seasonal floods, needing to be replaced, but the