Regional office based in Embu
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, with Rift Valley to the West, with Athi to the Southwest and South, and with 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.
The Tana River is the longest river in the country, traversing 1,012 km from its source on both the Aberdares Ranges (3,990 m) and the Mt. Kenya (5,199 m above sea level) to the Indian Ocean near Kipini. The average width of Tana River is 39.3 m, with a mean depth 2.5 m. In the upstream area of Tana River, the tributaries have perennial flows while in the lower part of the catchment they have intermittent flows. In the middle the river flows in a northeastern direction, gradually changing course to flow eastwards at elevations below 500 m.a.s.l., passing through Garissa, Hola and Garsen towns into Tana delta. The river delta reaches roughly 30 km upstream from the mouth river, before entering the Indian Ocean at Ungwana Bay.
Water Resources Availability and Demand
Water Resource Availability
The upper part of TCA is classified as humid land, the central and coast areas as semi-arid lands and the rest as arid lands. The mean annual rainfall ranges from 500 mm in the north-eastern part of the area to 1,600 mm around Mt. Kenya. The catchment area average mean annual rainfall is 840 mm. The renewable water resources were estimated at 13.58 BCM/year in 2010 for TCA and the per capita renewable water resourceswas2, 369 m3/person/year. However, freshwater availabilityper capita was 1,140 m3/person/year, exceeding the global benchmark of 1,000 m3 per capita.
Total annual precipitation minus the evapo transpiration
 Total of annual surface water runoff plus sustainable yield of groundwater resources.
The available water resources, is estimated at 6,533 MCM/year in 2010
|Percentage increase over 2010 values||24%||-16%||20%|
Data source: NWMP 2030