Geographical Analysis of Gully Erosion Site in Ekwueme Square, Awka Using Remote Sensing and GIS Techniques

Abstract

This research work focused on the Geographical Analysis of Alex Ekwueme Square Gully 
Erosion Site Awka, employing advanced techniques in Remote Sensing and Geographic 
Information Systems (GIS). Key findings include a V-shaped head indicating subsoil 
resistance, a trapezoidal mid-section suggesting increased bank erosion, and a flat-tailed end 
signifying initial intense runoff. The site's elevations varied from 90m to 103m at the head, 
indicating erosion-resistant subsoil. Elevations at the tail ranged from 58m to 64m, showcasing 
a consistent cross-section profile and intense surface runoff during initial development. The 
gully site is located at the foot of the Ifite hill, sloping towards the Obibia River. Slope analysis 
revealed inclined landscapes ranging from 0° to 21.5°, contributing to surface runoff and 
erosion. The highest slope regions, predominantly facing eastward and north-eastward, 
converge in the gully site, indicating potential for increased gully erosion. Land use and land 
cover changes from 2012 to 2023 revealed urban development encroaching on vegetated areas, 
with built-up areas increasing from 0.51 sq.km. in 2012 to 0.83 sq.km. in 2023. The vegetation 
class suffered significant spatial losses, indicating an increasing trend of urban development 
impacting densely vegetated areas. Over the period the gully's length fluctuated, peaking at 
1,384m in 2018, which prompted Nigeria Erosion and Watershed Management Project 
(NEWMAP) to commence GRASS project. This research paper recommends establishing 
monitoring systems using remote sensing and GIS technologies to track changes in the gully 
site over time.