A Guide to Nairobi’s Rivers and Streams

By Albert Gicheha and Don Pablo

Most of the big cities found in Asia, Europe, North America and parts of Africa are located on the banks of big rivers. This is due to the fact that the cities began as villages, then towns near major rivers so as to guarantee supply of water. You’ll also have noticed that the big cities have landmark bridges over such big rivers. Nairobi is not blessed with big rivers – or bridges – but instead, it has a maze of smaller rivers and streams, collectively referred to as the Nairobi River Basin.

The main drainage systems of Kenya

A feature of the streams and rivers in Nairobi is that they all flow eastwards. The Western half of Nairobi marks the start of the ascent up the Rift Valley escarpment while the Eastern half is a flat plain. The rivers therefore flow by gravity to the East. All these rivers and streams join the main river of the Basin – the Nairobi River – near Dandora and Ruai which then proceeds to join the Athi River. Another feature of the rivers in Nairobi is that most informal settlements are located along river valleys, as will be shown later in this article.

We will now embark on a brief journey that details the main rivers in Nairobi, their respective sources, the areas traversed by these rivers and their significant tributaries, starting with the Northern most going South.

1. Gathara-ini River and Kiu River

Gathara-ini is the river that lends its name to the Kasarani area. It starts off in Kiambu at Kanunga area where after a few kilometres, it lays its first claim to fame by being the river dammed at Paradise Lost Resort. It then crosses Kiambu Road at Thindigua and flows on the Northern side of the Windsor Golf and Country Club, past the Northern bypass and onto Kamiti road. Gathara-ini is the first big river one crosses from Roysambu on the way to Kamiti and Kahawa West.

Gathara-ini crosses Thika road as you approach Githurai from the city. Further downstream, it forms the boundary between Githurai Kimbo and the Northern side of Mwiki. It then flows through sparsely populated areas before crossing the Eastern bypass, where it joins the Nairobi river near the Ruai sewage treatment plant. The other big river that one crosses before the Kahawa West turn is the Kiu river which then passes between Githurai and Kahawa barracks on Thika road. The Kiu River joins the Kamiti river, the stream between Kahawa Barracks and Kenyatta University, and after the Eastern by pass, it joins Nairobi river further upstream from where Gathara-ini joins.

2. RuiRuaka River

This river derives its name from the Kikuyu word Ruirwaaka meaning ‘the river of women’. It lends its name to two major areas: Ruaka town upstream and the Ruaraka area further downstream. RuiRuaka starts its journey from the highlands near Limuru and flows southwards to the East of Limuru road past Ruaka town where you find the Ruaka falls past Two Rivers mall and Rosslyn Riviera onto Runda, Karura forest before emerging on Kiambu road before Ridgeways. .The river flows side by side to its major tributary the Karura river which lends its name to Karura in Kiambu county and Karura forest downstream it flows through the river valley one crosses past Village Market, through Gigiri before traversing the Karura forest where you find the Karura falls and emerging on Kiambu road after the CID headquarters.

RuiRuaka and the Karura river confluence as they it the Thika Highway between the General Service Unit (GSU) Headquarters and Rosters roundabout. The river then forms a distinction between EABL-Ngumba area and Baba Ndogo. Further downstream it flows in the Lucky Summer area and joins the Nairobi River at Dandora phase 5.

3. Mathari and Gitathuru Rivers

These two rivers flow side by side for quite a distance before finally merging. The Gitathuru flows from Limuru and it’s the river that is next to Wangige town. It then flows along the Lower Kabete valley, next to the UON School of Business and proceeds to Kitisuru. Gitathuru flows through the deep river valley one crosses whilst using Peponi Road past Oil Libya. The Gitathuru River continues to flow through the Western portion of the Karura forest, crossing Limuru road at the Belgian Embassy. It flows through the river valley one crosses after the Muthaiga junction and proceeds to form the Southern border of the Karura nature trail. The river emerges on Kiambu Road and one crosses it after the Muthaiga police station on your way to Kiambu. Gitathuru flows through the Muthaiga golf club before crossing Thika Road next to Utalli college and NYS Headquarters.

The sister Mathari River flows upstream next to Kingero shopping centre in the Kabete area. It forms a natural boundary between Loresho and Lower Kabete where it is dammed. It is the river on Lower Kabete road that one crosses before the intersection between the Westlands-Red Hill bypass. Mathari River then flows through Spring Valley emerging at Peponi road just before Oil Libya. It proceeds through Highridge and Muthaiga area behind Getrudes Hospital and emerges on Thika road after the Pangani interchange. The River continue to flow on the southern side of Pangani and Mathari Hospital before emerging into the expansive Mathari valley where it finally meets up with the sister river Gitathuru.

Mathari River then continues to flow and forms a boundary between Huruma and Mathari North estates before crossing Outering road where it forms a boundary between Kariobangi North and Baba Ndogo. It passes other major slums of Korogocho and Ngomongo before joining Nairobi River at Dandora phase 4.

The Mathari valley has the second largest informal settlement in Kenya. A distinct feature of the key Nairobi slums is that they are located along river valleys. Apart from Mathari slum along the Mathari River, there is Korogocho slum along the same river, Kibera slum along the Ngong River and Mukuru slums also along the Ngong River.

Mathare slums along the Mathare River valley. Most slums in Nairobi are found along river valleys (Image c/o Ghettoradio.co.ke)

Mathare slums along the Mathare River valley. Most slums in Nairobi are found along river valleys (Image c/o Ghettoradio.co.ke)

4. Nairobi River

Nairobi River, the main river of the Nairobi River Basin, starts from the Ondiri swamp in Kikuyu. Ondiri was initially called ‘Old Lady Swamp’ but local mispronunciation saw the swamp named Ondiri, a name which has stuck to date. The swamp was the first source of piped water for Nairobi as water used to flow through the pipes by gravity to the city. From Kikuyu, the river flows through Dagoretti area and crosses Naivasha road between Uthiru and Kawangware near ILRI. It then flows south of Mountain View estate and Kangemi before emerging at James Gichuru Road near Loreto Convent Msongari.

Nairobi River then flows near the Westlands-Rhapta road area and besides St Marys School before crossing the Westlands bypass near Chase Bank. It continues to flow behind Consolata School and cuts across the road at Riverside, before crossing Waiyaki way at Museum hill. Here, Nairobi River is joined by its major tributary – the Kirichwa River – which emerges from the Dagoretti area and flows through Riruta. Kirichwa is the river passing near Kingara road behind the Junction Shopping Mall and crosses the river valley across Argwings Khodek after Habesha Restaurant.

Past Argwing Kodhek, Kirichwa River flows through Kileleshwa and passes next to the Arboretum. It is the river one crosses on Arboretum Drive near the Shell petrol station. Kirichwa River finally joins the bigger brother, Nairobi River at Museum Hill. The confluence area of these two rivers was named ‘Chiromo’ which means ‘joining of two rivers’ in a Malawian language. The area was so named by Ewart Grogan, one of the early colonial settlers, who saw similarities between the area and a village he had travelled through in Southern Malawi that went by the same name.

Nairobi River now flows besides Kipande Road on one side and Kijabe Street on the other. A public park is situated along this area, which was once full of garages, but was rehabilitated when John Michuki was the Minister for Environment. The river emerges at Globe Cinema roundabout and proceeds along the southern side of the CBD on one side and Ngara on the other. It flows through Kamukunji, behind the Machakos Bus Station and Gikomba. After Gikomba, Nairobi River forms a boundary between Majengo and Shauri Moyo. The river then crosses Eastleigh First Avenue near Section 3 area.

The Moi Airbase covers a large area in this part of Eastlands and Nairobi River marks part of the Airbase’s boundary. The river also flows near or through Bahati, Jerusalem, Uhuru and Buruburu estates. The Kiambui slums occupy a small stretch of land between Moi Air Base and the river. Nairobi River crosses Outering Road and cuts through Kariobangi South estate. On your way to Dandora, Nairobi River cuts across Komarock Road and at this stage, the river is about to join with the Mathari River. Nairobi River then flows next to Dandora Phase 1, past the vast Dandora dumpsite and links up with the Mathari river at Dandora Phase 4.

Further downstream at Dandora phase 5, Nairobi River is joined by Ruaka River and becomes one big river. From Dandora, it is bordered to the North by Mwiki and to the South by Njiru, an area sparsely populated because of the extensive quarrying that takes place there. At New Njiru, Nairobi River is joined by another of the major Nairobi rivers, the Ngong River. The bigger Nairobi River crosses the Eastern by pass a short distance North of the Kagundo road intersection and flows next to the Nairobi Sewage treatment works at Ruai where treated Nairobi waste water is discharged into the river. It is also joined by the Gatharaini at this site and further upstream, the Kiu river. Nairobi River then joins Athi River after this.

5. Ngong River

Ngong River originates from the Kibiku forest, South of Ngong hills. At this point, it is known as Motoine river. It flows besides the Southern bypass between Dagoretti and Karen. The river is seen near the Ngong Road intersection with the bypass and it is the river one crosses from Lenana School on your way to Karen. Ngong River (still named Motoine at this stage) then flows through the Ngong Road Forest, emerging at Kibera where it is joined by other small streams. It flows through Kibera and is dammed at Nairobi Dam. At one point, the dam served the water needs of Nairobians and hosted various water sports, evidenced by the Sailors Club on the Langata side of the dam.

Past Nairobi Dam, the river adopts the name Ngong River and flows next to Highrise, cutting across Mbagathi road near the AP Camp. It crosses Langata Road near TMall and proceeds through Nairobi West where it can be seen near West mall. The river then flows through South C and emerges at Mombasa road next to the ICC Church. Past Mombasa Road, Ngong River flows into South B and passes near Mater Hospital. It flows for several kilometres through Industrial Area and is crossed by both Likoni road near Winners Chapel and Enterprise road from Tetra pack on the way to General Motors.

Ngong River at Mombasa Road bridge

Ngong River at Mombasa Road bridge

Along this stretch, the Ngong River valley plays host to Mukuru, Fuata Nyayo and Sinai slums. It emerges at Outering road near Tassia and forms the boundary between Donholm and Embakasi estates. Ngong River then flows Northwards to Kayole-Soweto area and crosses Kangundo road, joining Nairobi river at New Njiru. At this point, Ngong River is the most polluted river in the country and cannot support any living organisms, including bacteria, as a result of navigating 12 kilometres through the Nairobi’s Industrial Area where chemical waste is discharged into the river.

6. Mbagathi River and Athi River

Mbagathi River starts out at Athi spring (so named as it is considered the starting point of the Athi river) in the Kibiku forest area of Ngong. It crosses Ngong Road at the Mbagathi bridge, past Karen Shopping Centre on your way to Ngong. It flows through Karen and it is the river that passes through Oloolua Forest. The cave system within the Ngong River valley at Oloolua is famed for being Mau Mau hideouts during the war for independence. Smaller streams from the Ngong Hills drain into Mbagathi River in Karen and it is a significant river by the time it crosses Magadi Road in Ongata Rongai near Maxwell Adventist Academy.

Mbagathi River upstream at Oloolua Forest

Mbagathi River upstream at Oloolua Forest

Mbagathi River flows past Rongai and goes on to form the Southern boundary of the Nairobi National Park. Ngong Hills is a major catchment area and as such, many streams flow down from the Hills through Karen and further downstream into the National Park. The streams within the Park all flow to join the Mbagathi River. The biggest of these streams is the Mokoyeti which is the river that crosses Langata Road between Galleria Shopping Mall and the Langata Cemetery.

One of the many streams in the Nairobi National Park that flow southwards to join the Mbagathi River

One of the many streams in the Nairobi National Park that flow southwards to join the Mbagathi River

Past the National Park, Mbagathi River emerges near Athi River town and cuts across Namanga Road. The new name for the river at this point becomes Athi River, having been joined by Stony Athi river that flows from Isinya. The river changes direction from Southwards to the North East as a natural barrier to the gravitational flow of the river is presented by the Lukenya Hills. Athi River then flows North Eastwards and is joined later on by the rivers from the Nairobi River Basin.

Satellite Image of Nairobi: 1. Mbagathi River at the Southern border of the Park 2. Ngong River 3. Nairobi River 4. Point where Ngong River joins the Nairobi River in Dandora 5. Ruai Sewage Treatment Plant 6. Athi River flowing round Mt. Kilimambogo

Satellite Image of Nairobi:
1. Mbagathi River at the Southern border of the Park
2. Ngong River
3. Nairobi River
4. Point where Ngong River joins the Nairobi River in Dandora
5. Ruai Sewage Treatment Plant
6. Athi River flowing round Mt. Kilimambogo

Having joined the Athi River, the Nairobi River Basin ceases to exist. Athi River, a big river by this stage, flows round Mt. Kilimambogo through Ukambani area and 600 Kilometres later, the journey ends at the Indian Ocean near Malindi.

Athi river flowing near the eponymous town.

Fourteen Falls

Athi river at Sabaki bridge, about a kilometer near mouth at Indian ocean

About the Author

Galimo Askumo
An explorer, an infomaniac and a hippie. I got tired of wanting to read detailed, long form articles on various topics that interest me so I decided to write about them. My username is an ode to the last two known members of my family tree which goes back 11 generations.

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  1. Chrenyan

    Loved this – if only our urban planners would plan around bringing out the beauty in this city of ours.

  2. James Keru

    Wow, wow, wow, I have read every small bit of this article and I’ve really liked it.

  3. glowia

    You’re a talented writer. Keep it up!

    • Don Pablo

      Thank you, Glowia.

  4. Evans Ogeto

    Very interesting read. I am currently working on a documentary on Nairobi and the Nairobi River and this is how I stumbled onto this article. It would be great to have you guys contribute into this.

    let me know if it’s possible.

  5. Henry Muuthia

    This is, by far, the most comprehensive article I have come across online on Kenya’s rivers. Keep up the good work.

  6. Nyokabi

    Reading this in 2020. I have always been fascinated by the river network in Nairobi. This article is very informative and inspires me to do more than just get fascinated. Thank you

  7. Eric

    Thank you very much! Been looking for this for a while now. Not the least disappointed.

  8. Gitahi

    Very good work and now i can identify with confidence the various streams/rivers i have always seen flow for years. Be blessed!

  9. Tom

    This is the most comprehensive write-up on the Nairobi River system that I have come across online. Great job, thanks for sharing.

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