Application of Remote Sensing and GIS in Sinuosity and River Migration Analysis of the Lower Parts of River Niger in the Niger Delta

S Tombra Akana ,Edirin Akpofure

doi:10.7176/jees/9-4-08

Abstract

This research is financed by the African Union in collaboration with Pan African University Life and Earth Sciences (including health and Agriculture), Ibadan, Nigeria and University of Ibadan, Ibadan Nigeria. Abstract Sinuosity and river migration analysis of the lower parts of the River Niger in Niger Delta from Onitsha to the coast has been done using various Landsat images during 1985 to 2015. The transect method was used for the river shifting measurement. The study area consists of a stretch characterized by uneven meandering and migration. Consequently, the adjacent areas are susceptible to flooding that causes significant losses of crops, property, livestock, and human lives. During the study period, the channel pattern moved from a sinuous-straight to straight-sinuous pattern with sinuosity reducing in the upper portions of the channel. It was found that in the upper portions of River Niger, the west bank of the channel was subjected to more erosion and that the river is migrating towards the west. In the lower portions of the River Niger, the east bank is subjected to more erosion and thus the channel is migrating towards the east. The width of the meander belt ranged from less than 1km to 4.9 km with an average of about 2km. Based on the findings of this study, it is suggested that the flood protection structures are crucial for the west bank in the upper reaches and the east bank in the lower portions of the channel in the study area. It is further suggested that these structures be constructed outside the meander belt of the river. Keywords : Sinuosity. Channel migration. Meander belt. Channel pattern. GIS. Landsat images. DOI : 10.7176/JEES/9-4-08 Publication date : April 30 th 2019

Highlights

Rivers are important as the conveyor of the products of continental denudational processes to the major sinks, and as a natural resource for a wide range of human activities and uses especially transportation, recreation, irrigation, fishing, water and energy supply
4.1 Analysis of sinuosity of meanders In 1985, the River Niger averagely was a straight-sinuous channel with a sinuosity parameter less than 1.5 for most of its segments
From 1995 till the end of the study period (i.e., 2015), the sinuosity of the River Niger is observed to increase as the years progress moving it to a predominantly sinuous channel with portions of braiding in some sections (Figure 3; table 1)

Summary

Introduction

Rivers are important as the conveyor of the products of continental denudational processes to the major sinks (oceans and lakes), and as a natural resource for a wide range of human activities and uses especially transportation, recreation, irrigation, fishing, water and energy supply. Investigations carried out by Ebisemiju (1994) in the Elemi river basin, southwestern Nigeria suggested that small intermittent streams in the seasonally wet humid tropics have a tendency to develop very sinuous channels characterized by compound and highly convoluted loop He presented that the dominant factor controlling the degree of sinuosity is channel bank resistance to lateral erosion as influenced primarily by the nature of riparian vegetation and secondarily by the percentage silt/clay in channel bank sediment. Alluvial rivers are inherently dynamic in nature, responding to the variation in water and sediment inputs (Yang et al 1999) Alterations in these inputs either natural or anthropogenic result in changes in the planform/channel pattern, sinuosity, and braiding index (Knighton 1984)

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