Tana Catchment Area Brief
Tana Catchment Area is geographically situated in the south eastern part of Kenya, lying between latitudes 0o 30’ north and 2o 30’ south, and longitudes 37o 00’ east and 41o 00’ east.
It borders with the following catchment areas. Ewaso Ng’iro North to the North, Rift Valley to the West, Athi to the Southwest and South, and Somalia and Indian Ocean to the East.
The Tana basin covers an area of 126,026 km2, which is about 21% of the area of Kenya.
River Tana (Picture by David Beatty)
The TCA has over 80% of its area classified as arid and semi-arid lands (ASAL), with mean annual rainfall being 679 mm.
Rainfall distribution is highly variable, ranging from less than 500 mm in Lower Tana to 2,400 mm in the highlands of Upper Tana. Rainfall is bimodal coming during the long rains of March – May, and short rains of October – November.
The daily temperatures range from below 10 o C in the mountain highlands to over 30o C at the coast.
Fig. 1: Map of Kenya Drainage basins
Counties covered by Tana Catchment Area
The counties include; Kirinyaga, Nyeri, Embu, Meru, Muranga, Kitui, Tharaka-Nithi, Garissa, Tana River, Lamu and parts of Machakos, Kilifi, Isiolo, Nyandarua and Kiambu.
Map showing Counties sub regional under Tana Catchment Area