Abstract:
The dy
namics of sediment
and freshwater discharge
into Ungwana Bay b
y
the
Tana and Sabaki Riv
e
r systems is still poorly
understood. Most
of the previous
hydrological inv
e
stigations have focu
sed on their upper
catchments (Dunne
and
Ongwenyi, 1976; Ongwenyi, 1983; Ongwen
yi, 1985). The present study shows
that the interaction of the two river
systems with the Indian
Ocean is controlled
not only by
the intensity of river dischar
ge, but also by
the
patterns of monsoon
winds and astronomical tides. This st
udy established that
the exchange of
terrigenous
sediments as well as t
hat of water between Tana and Sabaki
estuaries and the Indian Oc
ean portray both tidal and
seasonal variations. The
movement of the plumes wi
thin Ungwana Bay was
observed to shif
t in response
to changes
in the direction and intensit
y of the monsoon systems, which not only
control climate in the region, but also
influence the movement of wind-driven
coastal oc
ean currents (Johnson
et al
., 1982; Brakel, 1984). In this study the
dynamics of sediment and freshwater
supply into Ungwana Bay will be
highlighted.
