GIS-Based Study of Prioritized Gully Erosion and Flood Locations in Ebonyi State

D.c Onuoha ,Nwabueze I Igu ,Rotimi Oluwole

doi:10.7176/jees/10-2-11

Abstract

Gully erosion and flood is a major environmental disaster in south eastern part of Nigeria. This study adopts Geographic Information System (GIS) as a tool in the identification of flood and gully erosion locations in Ebonyi State. 31 flood and erosion locations were identified using GPS receiver and field ground investigation. Gully erosion and flood severity map was produced using the SRTM (Shuttle Radar Topographic Mission), which was imported into the ArcGIS platform. The result shows that gully erosion sites were well dispersed around Ajali Sandstone geological Formation. The slope characteristic was ascertained to be greater than 15 o which encourages flood and gully erosion activities. The flood and erosion severity map produced showed risk and vulnerability of settlements and infrastructure while the observation on site showed loss of properties, economic trees, biodiversity and obstructed access; thus endangered human existence. This study therefore recommended public enlightenment on their role in flood and erosion control, enlistment of geologists, environmental managers and other experts in flood and erosion control planning for better understanding of the terrain before adopting any measure of control. Also the production of gully and flood severity map for other areas within the south-eastern Nigeria is necessary to enable better control of these environmental hazards. Keywords : Gully Erosion, Flood Locations, GIS DOI: 10.7176/JEES/10-2-11 Publication date: February 29th 2020

Highlights

Erosion is a natural geological process in which soils and bedrocks are detached and transported away by water, wind or glacier (Posen et al, 2011)
In the Nigeria environment water is the main agent of erosion
The simplest form of erosion is as raindrop which involves detachment of soil particles

Summary

Introduction

Erosion is a natural geological process in which soils and bedrocks are detached and transported away by water, wind or glacier (Posen et al, 2011). Erosion is a worldwide phenomenon involving several geological processes tending to reduce land surface to equilibrium (Allen, 1997). It is the part of normal processes of denudation associated with climatic factors and hydrological cycles. Erosion processes are usually gravity driven and are related to second law of thermodynamics which states that there is always a tendency towards increase in entropy in any natural system. This implies that every natural system always strives to achieve a lower energy state and this induces breakdown (Angrist and Hepler, 1967). It devastates the land and crops, destroys infrastructure such as roads and houses and has occasionally resulted in loss of lives

Aim and Objectives

Findings

Impacts of flood and gully erosion