Modelling of Drainage Basin in Udi-Awgu Cuesta, Southeastern Nigeria Using Remote Sensing and GIS

International Journal of Research and Scientific Innovation (IJRSI) | Volume VII, Issue XI, November 2020 | ISSN 2321–2705

Modelling of Drainage Basin in Udi-Awgu Cuesta, Southeastern Nigeria Using Remote Sensing and GIS

 Ejemeyovwi Danny Ochuko
Associate Professor, Faculty of The Social Sciences, Department of Geog. & Reg. Planning, Delta Slate University, P.M.B.1, Abraka, Nigeria

ABSTRACT
GIS and remotely sensed enhanced multi-spectral data of Digital Elevation Model (DEM,), Landsat ETM+ digital Image and aerial photos to generate hydrologic mops for basin morphometric studies. Measurement of properties to evaluate parameters (Indices,) was carried out for Udi-Awgwu Cuesta Regions, South Eastern Nigeria. The analysis was carried out using digitized hydrological maps geo referenced using 4 points (resampled and merged) and the sub mqp of the study area extracted and incorporated into the GIS spatial data base in a GIS environment. The interpreted images are superimposed to create appropriate information platform to generate hydrological maps for analysis, interpretation and classification at sub basins level of water divided concept. The mapping of the drainage networks was followed by fieldwork (ground truthing) for confirmation of field observations during pre and post interpretative phases using the basic interpretative element of colour, lone, shape, pattern, shadow, site and association.. There is observed increased in network and basins in the enhanced data(ETM and DEM) than the aerial Photos due to higher resolving power( resolutions). There are major implications of the properties and parameters represented by six factors of reduced ranked variables evaluated with their implications include: basin circularity (RC) values of 0.62- 0.74 approaches one (1) tend to indicate basin pear shape with geological and hydrological tendencies of the uniform infiltration which does not overflow, as it takes long time for excess water to reach the basin outlet. The relief of 750m indicates high gravity water flow, high erosion tendencies, high infiltration arid high run-off conditions while the drainage density (Dd) between 0.85 and 0.95 depicts high permeable subsurface under sparse vegetation cover arid of medium relief subject to high erosion. The low values (0.52-0.62) of the bifurcation ratio (Rb) indicates low structural complexity and high permeability subsurface with attendant subsurface erosion. Cumulative stream length (between 830-1019.6) is indicative of fairly low value that characterized medium relief permeable bedrock and low structural disturbance depicting absence of geologic influence in the area. The various landforms associated with geo- fluvial processes in the upland area area ridges, undulating plateau, rills and gullies with rough to smooth rounded tops while in the lowland area are found sedimentary veneers (weathered, eroded loose earth materials) transported downwards and are responsible for the developments of fluvial deposition features of rolling plains, foot slopes, narrow valleys with main valley floor at the end of erosional plain.

Keywords: Geology, Drainage, Basin Morphometry, Landforms, GIS/Remote Sensing.

1.0 INTRODUCTION

Topographical base maps produced from aerial photos available to Nigeria researchers, are on the scale of 1:50,000 and until new ones with large scales are produced, the need still exists for the maps to be improved upon (using various enhancement procedure and techniques) to make them more useful for geomorphologic and hydrologic investigations. This study further explore the enhancement techniques of aerial photography and satellite data adopted by Ebisemiju, 1978) and Reddy et al., (2004) and digital analyses of satellite data was applied by Reddy et al, (2004); Das and Makheijee, (2007) and Koul et al, (2007) among ethers for morphometric studies whose results actually portray true field data.

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