Channel dynamics and hydraulic geometry of two tropical deltaic catchments in Southern Nigeria

Abstract

This paper attempts to explain the channel processes and dynamics of two river systems running through a rapidly urbanizing humid tropical deltaic environment with visible threats from industrialization and pollution. Hydraulic processes and parameters were compared with established power function relations for hydraulic geometry and it was discovered that the fundamental relations between channel-geometry dimensions, velocity, and flow can be expressed for the catchments. Ten gauging stations in each catchment were studied and results showed that the studied catchments adjust their geometry to changing discharges. High values of coefficients of determination among variables indicated that much of the downstream variation in channel width to depth ratio can be accounted for by changes in discharge. Also in this study the width/depth ratio (F) was found to be related to the percentage of silt + clay (M) in channel perimeter and that downstream hydraulic-geometry relations are in general agreement with previously published hydraulic and channel adjustment data.

Re-examination of Hydrochemistry and Groundwater Potentials of Cross River and Imo-Kwa-Ibo Intersecting Tropical Basins of SouthSouth Nigeria

“…Groundwater is assumed to be flowing from the northern highland areas of the basin towards the coastal areas in the south and beyond under the sea. The alluvial deposits and deltaic formation is formed by the Imo River [137,138] , it's tributary the Otamiri River, the River Kwa Ibo and the extensive valley of the Niger River and its tributary, the Orashi River are marked by wide sedimentary deposits which store large quantities of groundwater [139][140][141] . The groundwater potential of the areas is high and can be utilized for irrigation farming.…”

Hydraulic geometry analysis of Ceyhan River, Turkey

“…The average value of m was calculated to be 0.51, while average values of b and f were 0.20 and 0.29, respectively. Aisuebeogun et al [28] noted that widthto-depth ratio is related to percentage of silt and clay in the channel perimeter. Julien [29] described downstream hydraulic geometry in three ways such as empirical concept, theoretical developments and equivalent channel width.…”