Geo-Environmental Analysis of Remote Sensing Data: A Case Study of Ohafia Area, Southeastern Nigeria

Abstract

The main objective of this paper is to integrate the distribution of gully sites in the Ohafia area of Southeastern Nigeria using remote sensing technique. The Landsat thematic mapper (TM) data of parts of Ohafia was studied with objective of identifying the structures associated with the area and to infer their influence on the gully erosion initiation and propagation. The Landsat TM data was processed using the ILWIS 3.2 Academic and ERDAS software packages.In the course of this study, activities such as laterite excavations, bad farming practices, unplanned road construction and urbanization, wood harvesting for fuel and bush burning to clear lands for farming, among others were identified as factors that cause gully erosion. These activities, coupled with annual flooding from rain water were causing havoc and untold hardship as gullies continue to develop and expand rapidly in the area. Utilizing the opportunities offered by Remote Sensing, this research project came up with vital spatial datasets on the spatial distribution, development and impact of gully erosion in Southeastern Nigeria.The composite images gotten reveal the drainage pattern of the study area to be dendritic.The area is affected by tectonic activities on the geologic formation of the area is responsible for the increasing gully and landslide in the area. Lineament trend in the area correlated well with the measured strokes of the geologic formations.The study revealed that gully developments are more pronounced in areas with high terrain undulation and therefore affected areas should be reclaimed by extensive afforestation and other agricultural programme.

Quantitative Interpretation of Potential Field Data Covering Oml 29 and 11 Areas of Niger Delta, Nigeria

“…They obtained anomalous source depths to generally lie between 2,000 m and 10,600 m. Eke and Okeke (2016) estimated source depths of gravity and magnetic sources by utilizing the least square method. They obtained that depths of sources with density contrast vary from 1,000 m to 3, 500 m while source magnetic depths range from 2,183 m to 4,385 m. Depths to various magnetic sources, covering the lower Imo River basin were determined byChikwendu et al (2012). In their study, the shallow depth magnetic layer varies from 0.238 to 0.905 km while the deeper magnetic layer varies from 9.786 km to 14.238 km.…”