Local Setting
The study area is situated within the basement complex of south-western Nigeria within the coordinate of latitude N6°56'00" - 6°58'00" and longitude E3°56'00" - 4°00' over land area of approximately 10km2. The climate is monsoonal type (Ojo, 1997), with double maxima rainfall peaking in June and September. The months of December and January are relatively dry. The average temperature is about 30°C throughout the year. Humidity is about fifty percent all year round. The climatic condition is reflected in the vegetation, which is lowland rain forest except where human interference has reduced it to secondary forest.
The rivers flows in NE-SW direction and their tributaries forms a dense sub-dendrite like pattern. The principal rivers appear to be controlled by the topography of the area, i.e. they flow in lowlands and specific channels. The leading river and their major tributaries are perennial while majority are active only during the wet season.