flood (river) distributary [chapter]

2014 Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik  
Channel planform dynamics were analyzed for the River Nun; a major distributary of the River Niger from 1985 to 2015 using GIS and Remote sensing applications. Satellite imagery of the area from 1985, 1995, 2005, and 2015 were analyzed by means of GIS and used to determine the planform characteristics and changes in width, sinuosity, and shoreline migration rates. The channel planform dynamics were determined by comparing sequential changes in the position of the shorelines in these years.
more » ... n these years. Sinuosity adjustments during the study were small and range between 1.74-1.76. The initial sinuosity (1.74 in 1985) increased to 1.75 in 1995 and then increased to 1.76 in 2015. Channel expansion is observed to be the dominant planform process, owing to periodic floods within the study area. The river's channel width barely expanded from 1985 to 1995 (by 0.1 %). However, there is a constant increase in expansion within the study years that by 2005-2015 expansion had increased to 9%. The bank erosion was prevalent. Mean erosion rates ranged from Original Research Article Akana and Adeigbe; JGEESI, 22(1): 1-11, 2019; Article no.JGEESI.49541 2 0.7 m/year in 20 years to 2m/year in 30 years . In the 1 st 10 years (1985)(1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995) less than 0.1 m of deposition was observed. The mean erosion rates ranged from 1.3 to 1.6 m/year on the left side and 2.8 to 3.8 m/year on the right side of the channel. Mean accretion rates of 1.2 m/year on the left side and 1.8 m/year on the right side were observed. The channel is observed to move generally towards the east (right).
doi:10.1007/978-3-642-41714-6_61765 fatcat:cmyc34o3n5fppo3tcrn2rndgxq