International Journal of Research and Scientific Innovation (IJRSI) | Volume VII, Issue XI, November 2020 | ISSN 2321–2705 www.rsisinternational.org Page 69 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 mqpof 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 innetwork 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 representedby 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. I.INTRODUCTION opographical 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 photographyand satellite data adopted by Ebisemiju, 1978) and Reddy et al., (2004) anddigital 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. The aim of this research work is to use satellite remotely sensed multispectral data of digital elevation model (DEM) and Landsat ETM+) and Aerial photos to generate hydrologic maps for measurement of morphometric properties to evaluate parameters (indices) using digital analysis. The specific objectives include to: • Generate hydrological maps using remotely sensed data i.e. Landsat enhanced thematic mapper (ETM+) and digital elevation model (DEM), data, and aerial photos. • Generated hydrological maps to digitally map the drainage basins and stream networks to generate morphometric properties. • evaluate parameters (indices) in the drainage basins to present their implications and • identify the various landforms in the area and adduced reasons for their formations II. STUDY AREA The study area is a part of the Udi-Awgu cuesta in Enugu State, South Eastern Nigeria, The Udi-Awgu Cuesta is located in Udi and Awgu LGAs of Enugu State, Nigeria within the sector of the impressive Nsukka-Okigwe Cuesta running through North-South direction on the cuesta is bounded in the east by the Cross river plan and on the west by the Anambra/Mamu lowlands. The Udi-Awgu section of the cuesta is referenced by latitudes 6° 00 ʹ N and 6° 20 ʹ N as well as longitudes 7° 02ʹE and 7°31ʹE with approximate area extent of 4,200 km 2 . (fig. l - 3) T