Volume 62, Issue 341, May - August 2026

Development of Gully Morphological Features and Soil Loss under Land Covers (LC) of Upper Imo River Basin (UIRB), South Eastern Nigeria

Chibo Christian Nnamdi^1♦, Areola AA², Okoro FC¹, Arc Ewulum NJ³

¹Department of Geography and Environmental Management, Imo State University Owerri, Nigeria
²Department of Geography, University of Ibadan, Nigeria
³Department of Architecture, Imo State University Owerri, Nigeria

^♦Corresponding Author
Chibo Christian Nnamdi, Department of Geography and Environmental Management, Imo State University Owerri, Nigeria

ABSTRACT

In UIRB and globally, gully erosion is one of the most visible environmental and geomorphic hazards, which limits the maximum function of soils and landscape. Gully initiation and development increases runoff, soil loss, flooding and aids sedimentation. This research investigated and examined the gully morphological features and soil loss under various land covers of UIRB. It examined land cover change between 2008 and 2023; assessed the gullies under various land covers of the study area, analyzed the morphological features of the sampled gullies under land cover of the study area, and quantified the amount of soil loss resulting from gully erosion in various land covers. Landsat 8 and topographical maps was processed to identify the extent of the UIRB boundary. Eighteen gully sites were systematically selected considering the land cover of UIRB. Both primary and secondary data were was utilized in the research. Primary data are gully length, width, depth area, volume and slope gradient. The data was generated by field measurement and Digital Image Analysis (DIA) of the Landsat image of 2008 and 2023. The morphological properties obtained through measurement are the gully length, width and depth, while the gully areas, and soil loss were derived. The research identified five land covers in the study area between 2008 and 2023. All the identified land covers showed a wellobserved change (gain/loss) within the time of study. The built-up area with 6.99% gain e showed the greatest gain in LC, while farmland with 12.79% loss indicated the highest loss in LC. Assessment done on the gullies in various LCs showed that none of the gullies in UIRB originated from water bodies. Built up areas and farmland has the greatest number of gullies found in them, containing 77.8% (39.8% each) of all the gullies in the study area. Built up areas and farmland are the two land covers that experience greatest attack of gully erosion with 22.55km2 and 24.17km2 respectively. Wetland has the least land (0.8km2) attacked by gully erosion in the study area. The greatest gully spread was observed in farmland with 28.1% spread while the least spread was observed in wetland and water bodies (12.3% each). Soil loss computed in various land covers showed that the greatest soil loss was observed in forest cover (39%), built-up area (35%) loss, and the least soil loss was observed in wetland cover (4%). Gully morphological parameters were observed to vary across land covers of the study area, with built-up area and farmland being mostly under gully attack and forest cover and built-up areas being the covers with greatest soil loss in UIRB.

Keywords: Upper Imo River Basin, Morphological, Soil Loss, Land Cover

Discovery, 2026, 62, e13d3263

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Published: 21 May 2026