Region
Ewaso Ng'iro and Lagh Dera
The Ewaso Ng'iro (Ewaso Nyiro North) is a Kenyan river that rises on Mount Kenya and the Aberdares, flows east through Laikipia, Samburu and Isiolo, and spreads into the Lorian Swamp. Below the swamp its dry-season bed runs through Wajir and Garissa counties into Somalia, where it is called Lagh Dera.
Course
The Ewaso Ng'iro starts at Thome, near Nanyuki in Laikipia County, where the Naro Moru River from Mount Kenya meets the Ngarinyiru from the Aberdare range (Wikipedia: Ewaso Ng'iro). It is fed partly by Mount Kenya's glaciers and flows east. Below Saricho it spreads into the Lorian Swamp, a large wetland (Wikipedia: Ewaso Ng'iro).
The catchment crosses seven dry and semi-dry districts: Meru, Laikipia, Samburu, Isiolo, Wajir, Marsabit and Garissa (Wikipedia: Ewaso Ng'iro). Below the swamp the river is seasonal; its bed through Somalia is called Lagh Dera (Wikipedia: Ewaso Ng'iro). Wajir and Garissa are two of the three counties of former North Eastern Province, where most people are Somali (Wikipedia: North Eastern Province).
The name comes from the Maasai language and means "river of brown (muddy) water" (Wikipedia: Ewaso Ng'iro). Its upper basin covers about 15,200 km² (Wikipedia: Ewaso Ng'iro).
Water and wildlife
The river is the largest of Kenya's five water catchments (Wikipedia: Ewaso Ng'iro). Its water keeps the Samburu, Shaba and Buffalo Springs national reserves green in dry country (Wikipedia: Ewaso Ng'iro). It also feeds Lake Ol Bolossat, the only lake in central Kenya, which was declared a protected area in 2018 (The Star, Feb 2018; The Standard).
Less water downstream
Studies of the basin report that its tributaries dry up more often in the dry season, rain has become less reliable, and low-season flow has fallen (Wikipedia: Ewaso Ng'iro). Much of the water is taken for irrigation in the upper catchment, where the population has grown fast, leaving less for herders and wildlife downstream (Wikipedia: Ewaso Ng'iro; NETWAS, 2005). The African Development Fund puts Kenya's renewable fresh water at under 650 m³ per person per year, one of the lowest in the world (Wikipedia: Ewaso Ng'iro). A 2026 study in Hydrology and Earth System Sciences looks at water in the basin (HESS, 2026).
For Somalia's main rivers, see the Jubba River and the Shabelle River.
Sources
Sources
- Wikipedia: Ewaso Ng'iro · en.wikipedia.org
- Wikipedia: North Eastern Province · en.wikipedia.org
- The Star, Feb 2018 · the-star.co.ke
- The Standard · standardmedia.co.ke
- NETWAS, 2005 · web.archive.org
- HESS, 2026 · hess.copernicus.org
- Wikidata Q1757939 · wikidata.org
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