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Journal of Environmental Hydrology
ISSN 1058-3912 |
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Electronic Journal of the International Association for
Environmental Hydrology
JEH Volume 16 (2008), Paper 32 Posted October 11, 2008 GENERATION OF DIGITAL ELEVATION MODELS (DEMs) FOR GULLIES IN ONDO-STATE, NIGERIA
A. Adediji ABSTRACT Gully development is a significant problem at Ode-Irele, Lipanu, Akotogbo and Ajagba town in the Irele Local Government Area (LGA) of Ondo-State, Nigeria. To better understand gully development and features, digital elevation models (DEMs) are derived to establish gully morphometric attributes such as surface slope, catchment area, average depth and width, as well as cross-sectional area and volume of material/soil eroded. The DEM for each of the study gully catchments was derived from the values of the spot heights and coordinates of each point obtained through the use of GPS and processed using Surfer software. The values of slopes in the study gully catchments ranged from approximately 0o58’27" at Lipanu to 4o51’31" at Ajagba. The DEMs of gullies at Idogun, Ajagba and Ado quarter showed slopes that appeared steeper than the gully at Lipanu. The slope shapes are dominantly convex which implies that overland flow will be generated from all sides of the slope. The convexity of most of the gully catchments coupled with the termination of drainage channels, as well as poor roads and drains maintenance by the community and government, have led to the development of large deep gullies at Ode-Irele, Akotogbo and Ajagba. The development of gullies could be minimized by encouraging planting of cover grasses in adjacent areas rather than paving of the surface, which makes the ground impervious. Reference: A. Adediji, M.O. Ibitoye, and O. Ekanade. 2008. Generation of digital elevation models (DEMs) for gullies in Ondo-State, Nigeria. Journal of Environmental Hydrology, Vol. 16, Paper 32. CONTACT: A. Adediji Department Of Geography Obafemi Awolowo University Ile-Ife, Nigeria E-mail: remiadediji2003@yahoo.co.uk |
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