The Ondiri swamp. Logs are used to facilitate the safe crossing across the peat.
The Southern Bypass
has crossed many topographical regions on its path around the city. The
17.1 billion project begins from Mombasa Road to Kikuyu. One of the
fascination structures is the 121m box culvert that will allow the
smooth flow of water from the Ondiri Swamp a few metres across that is
the only quaking bog and the second deepest wetland in Africa after
Doula in Cameroon.
Truant boys dig off the macrophytes making a hole in which they dive and swim underneath the floating peat. If you do not identify the light from where you dived in, you will float away to darkness. - Mr.Wainina of MCDI (Standard Digital)
The MegaProjects Kenya team incharge of this the Southern Bypass project
came across this interesting swamp that has a history dating back to
the colonial times. Ondiri swamp lies at some 1km from the Kikuyu
township and is an important source of the Nairobi river. This swamp
difers from any other because it has a covering of macrophytes growing
above the water. This mud like cover known as peat can hold a human
being's wight at some points on the surface and a jump on the surface
sets of a series of waves across, a clear sign that one is 'standing on
water'.
The peat has some grass cover which has fooled some to
forget and plunge into the deep dark waters below. A series of wood
planks has been laid ontop to aid in crossing accross but at some point
in the middle of the lamp one has to be careful.
The water moving below the peat is very clean are clear.
Ecosystem
destruction in Ondirí wetland dates back to the colonial era, which was
marked by extensive deforestation. Currently the ecosystem is highly
threatened by various activities within both the wetlands and riparian
land. This includes dumping of solid waste and uncontrolled water
abstraction. There are several water pumps around the wetland, which are
not metered meaning that it is impossible to gauge the level of water
abstraction.
In addition, there are fears that the water in the
wetland has been reducing. But again the out flowing river does not have
a gauging station. Kikuyu town also lacks a sewerage system, which
increases the likelihood of pollutants seepage from septic tanks.
Previous conservation initiatives mainly fencing and tree planting by
forest departments in the 1990’s collapsed due to lack of community
ownership of the process and enforcement.
A
quacking bog is made up of a layer of vegetation floating over water.
You can walk on the vegetation, but if you jump up and down the whole
bog quakes.
The Ondirí wetland is oval in shape
and local legend has it that it used to be an open lake in the early
part of the last century and indeed the name itself is Gikuyu corruption
of old lake (Undirí). However as deforestation and subsequent erosion
accelerated, the lake came to be covered with floating reeds on peat
such that now it has an extensive reed mat that covers more than 95
percent of the wetland to form a quacking bog, the only one in the
country. A quacking bog is made up of a layer of vegetation floating
over water. You can walk on the vegetation, but if you jump up and down
the whole bog quakes (Macharia and Thenya, 2007).
Ondirí is a
unique and an important wetland. As noted earlier, Ondirí is Kenya’s
only quaking bog and the second deepest wetland in Africa after Doula in
Cameroon. But despite the size and benefits of Ondirí wetland to this
country it has received only scant attention from researchers, writers,
natural resource environmental management and the large conservation
driven organizations. Equally the governments both central and local
have done little to conserve the wetland for posterity. Media mention of
this wetland is also scattered and limited in scope.
The
lake came to be covered with floating reeds on peat such that now it
has an extensive reed mat that covers more than 95% of the surface
The
major diatoms at Ondiri Swamp were Amphipleura pellucida, Navicula
gawaniensis, Pinularia tropica, Eunotia tenella, Melosira ambigua,
Nitzschia subrostrata, Surirella sp., Eunotia pectinalis, Cyctotella
iris, Nitzschia latens and Strauroneis phoenicenteron which are mainly
associated with larger and more open wetland. The younger level was
dominated by Navicula tenella, Navucula el Kab, Nitzschia linearis,
Navicula halophila, Gomphonema gracile, Navicula. salinicola, Frustulia
rhomboides Eunotia pectinalis and Hantzschia amphioxys which are
associated with smaller wetlands.
References: Paleoclimate of Ondiri Swamp - Julian Awuor Ogondo, Standard Media
Acknowledged Source: MegaProjects Kenya Blog
