TITLE:
Geomorphology and Hydrology of the Benin Region, Edo State, Nigeria
AUTHORS:
Catherine Imhangulaya Ikhile
KEYWORDS:
Geology, Physiography (Relief) and Geomorphology, Geomorphic Processes, Weathering, Drainage Processes, Landforms, Surface Water Hydrology and Water Resources
JOURNAL NAME:
International Journal of Geosciences,
Vol.7 No.2,
February
26,
2016
ABSTRACT: This paper examines the
geomorphology and hydrology of the Benin Region, Edo State, Nigeria. The major
landform features and processes of the region are highlighted. This region is a
strategic and significant landscape in Nigeria. Information was gathered on the
various aspects of the landscape, including the Geology, Physiography (Relief)
and Geomorphology, Geomorphic processes, Weathering, Drainage processes,
Landforms, Surface Water Hydrology and Water Resources. The Benin Region is
underlained by sedimentary formation of the South Sedimentary Basin. The
geology is generally marked by top reddish earth, composed of ferruginized or literalized clay sand.
Geologically, the Benin Region comprises of 1) the Benin formation; 2)
alluvium; 3) drift/top soil and 4) Azagba-Ogwashi (Asuba-Ogwashi) formation.
Several parts of the region are surrounded by the Benin historical moats. The
region has been described as a tilled plain in the south western direction. The
local relief of the region is 91 m. Boreholes records in the Benin Region show
evidence of deep chemical weathering overtime. Soil profile reveals that the
region is composed mainly of
reddish brown sandy laterite. Intermittent layers of porous sands of sandy
clays may reach a large depth as
found in the borehole drilled in the region. These are products of deep
chemical decay of the original parent rock materials. Three river systems drain
the Benin Region. They are the Ikpoba River, the Ogba River and Owigie-Ogbovben
River systems. The mean annual discharge of Ikpoba River for 1982-1983 and
1993-2002 was 1411 mm/yr, which was 1.019 × 109 m3 with a mean annual baseflow of 1256.23 mm (0. 907 × 109 m3).
This constitutes 87.65% of the total flow. It has a mean annual surface runoff
of 225.18 mm (0.112 × 109 m3)
or 24.4 % of the total discharge. The water resources of the region include
surface water and underground water.