Uganda Atlas of Our Changing Environment - GRID-Arendal

Kooki hills in Kibaale-Bukoora, Rakai District
The degraded hills of Kooki in Rakai District
The most common morphology of the hills comprise of
round to flat summits that abruptly descend on steep
convex and straight slopes, ending in relatively gentle and
moderately concave pediments. The pediment slopes show
an abrupt steepening in their lower sections adjacent to
valley floors which are often swampy.
Gemorphologically, Kooki hills are thought to result
from an upwarped Buganda plateau during early
Tertiary, after a long quiescence from the Karoo era
and subsequent reduction of the plateau landscape by
denudation process to a very low relief, the African
Surface in this Buganda part of Uganda which, therefore,
is sometimes called Buganda surface. The uplift resulted in
an elevated and dissected plateau consisting of a series of
flat-topped hills or their remnants and intervening valleys.
Thus, the landscape was dissected by the rejuvenated
drainage system, leading to a dissected plateau in form of
the present ridges and hills. In some cases, the Kooki hills
are related to the Kigezi-Ankole surfaces (highlands), but
generally, Rakai hills are regarded as an upwarping of the
Buganda surface.
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The soils in the Kooki area are dominantly of Ferralsols
type and its associations. This is the most dominant
soil type in Uganda, covering about 2/3 of the country.
This is a class of soils considered to be the oldest on
earth; the soils are characterized by low fertility levels
and are deeply weathered and leached with little
mineral reserves remaining. Generally, soil distribution
varies with slope morphology, in that at the summits,
moderately deep to shallow soils often occur; but on
the steep convex and straight slopes, soils become very
thin with depths varying from bare rocky or weathered
regolith surfaces to only a few centimeters deep. Further
down on the concave and pediment slopes, respectively,
soil depths increase appreciably often reaching depths of
over 150 cm.
On the hill summits and steep upper and middle slopes,
the soils are Plinthic Ferralsols and Hyperskeletic
Leptosols. These associations are dominantly shallow,
loose and skeleteral, with high proneness to erosion.
Most of the former summit laterite capping has been
removed leaving behind disintegrating boulders and relics
Rakai District Local Administration (2007)