Gully erosion has reached alarming proportions in south-eastern Nigeria, prompting the use of geospatial information technology to map a gully erosion site in Oron, Akwa Ibom State, for effective remediation and control. The use of dual frequency Leica GPS 1200 provided ground controls in the vicinity of the gully head. The formation and growth of gullies causes large amounts of sediment to be released into receiving streams, polluting sources of water supply for the rapidly growing urban population. The obtained data were downloaded and processed using Leica Geo Office 8.3 before being exported to Arc GIS 10.1 and Auto CAD Civil 3D 2013 for terrain analysis-DEM. In addition, the Leica Total Station TS 06 was used for topographic mapping. The defined runoff contributing area aided in calculating the maximum discharge (using the Rational method). The computed runoff of 33.919m3/s accounts for the rapid rate of gully headscarp retreat of 1.2 m/day prior to intervention by the state government during the month of July. The findings were put to use in the design of gully control structures.
Author (s) Details
Dr. Charles Udosen
Department of Geography, University of Uyo, Uyo, Nigeria.
Mr. Okon Efiong Ubom
Shell Petroleum Development Company Ltd, Uyo, Nigeria.
Mr. Abasi-Ifreke S. Etok
Akwa Ibom State, College of Arts and Sciences, Nung Ukim, Ikono, Nigeria.
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