1. Lake Victoria Drainage Basin:
- Covers the largest surface area of Kenya, including parts of the western and Nyanza regions.
- Tributaries: Mara, Yala, Nzoia, and Sondu Rivers.
- Lake Victoria is the primary water source and drains into the Nile River system.
2. Rift Valley Drainage Basin:
- Located along the Great Rift Valley, stretching from Lake Turkana in the north to Lake Magadi in the south.
- Tributaries: Ewaso Ng'iro, Turkwel, and Kerio Rivers.
- Lakes: Lake Baringo, Lake Naivasha, and Lake Elementeita are part of this drainage system.
3. Athi River Drainage Basin:
- Covers parts of the Eastern, Central, and Coastal regions of Kenya.
- Tributaries: Thika, Maragua, and Athi Rivers.
- Drains into the Indian Ocean.
4. Tana River Drainage Basin:
- The largest river basin in Kenya, originating from the Aberdare Range and Mount Kenya.
- Tributaries: Sagana, Thiba, and Tana Rivers.
- Drains into the Indian Ocean.
5. Ewaso Ng'iro (North) Drainage Basin:
- Located in northern Kenya, including parts of the Turkana, Samburu, and Isiolo counties.
- Tributaries: Ewaso Ng'iro North River and its tributaries.
- Endorheic basin; water does not drain into any ocean but instead ends in the Lorian Swamp and Lake Turkana.