Assessing The Impact of Sea Encroachment in Ilaje, Ondo State, Using Optical Satellite Imagery Analysis and Shuttle Radar Topography Mission
Research Article  ·  Published: 20 August 2026
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Journal of Geoscience and Earth Observation
Volume 1, Issue 2, 2026: 101-112
Research Article Open Access

Assessing The Impact of Sea Encroachment in Ilaje, Ondo State, Using Optical Satellite Imagery Analysis and Shuttle Radar Topography Mission

1 Department of Surveying and Geoinformatics, Federal University of Technology, Akure 340001, Ondo State, Nigeria
* Corresponding Author: Blessing Banji Adewumi, [email protected]
Volume 1, Issue 2
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Abstract

This study assessed the impacts of sea encroachment in Ilaje Local Government Area of Ondo State, Nigeria, using multi-temporal optical satellite imagery and the Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM). This study analyzed past and recent shoreline change trends, simulated elevation-based vulnerability to flooding, and predicted the potential effects of sea-level rise. Landsat images from 1995, 2000, 2005, 2010, 2015, 2020, and 2025 were analyzed to identify the shoreline, and shoreline changes were calculated using the End Point Rate (EPR) and Linear Regression Rate (LRR) in the Digital Shoreline Analysis System (DSAS). Elevation-based vulnerability maps were modeled using the SRTM DEM, and future inundation was projected using sea-level rise data. Results showed that erosion was more severe along the Ilaje coastline, with over 70 percent of the shoreline retreating at different rates, while only small sections experienced accretion. The inundation model, assuming a conservative rise of 0.269 m, indicated that more than 555 km$^2$ of land could be submerged, and a 1m rise could flood over 650 km$^2$ by the year 2150, an event that would affect settlements such as Ayetoro, Ogogoro, and Gbeke Eke. These findings emphasize why Ilaje communities are at risk of land loss, displacement, and livelihood impacts. The analysis concludes that sea intrusion poses a significant threat to the coastal ecosystem in Ilaje. This study recommends integrating the coastal zone into planning efforts, restoring mangroves as natural barriers, adopting stricter measures to prevent unsustainable human activities, and maintaining ongoing geospatial monitoring as part of a sustainable strategy for change.

Graphical Abstract

Assessing The Impact of Sea Encroachment in Ilaje, Ondo State, Using Optical Satellite Imagery Analysis and Shuttle Radar Topography Mission

Keywords

coastal management sea encroachment Ilaje sea-level rise shoreline change inundation models

Data Availability Statement

Data will be made available on request.

Funding

This work was supported without any funding.

Conflicts of Interest

The authors declare no conflicts of interest.

AI Use Statement

The authors declare that no generative AI was used in the preparation of this manuscript.

Ethical Approval and Consent to Participate

Not applicable.

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Cite This Article

APA Style
Adewumi, B. B., Tata, H., & Awoleye, K. D. (2026). Assessing The Impact of Sea Encroachment in Ilaje, Ondo State, Using Optical Satellite Imagery Analysis and Shuttle Radar Topography Mission. Journal of Geoscience and Earth Observation, 1(2), 101-112. https://doi.org/10.62762/JGEO.2026.327931
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TY  - JOUR
AU  - Adewumi, Blessing Banji
AU  - Tata, Herbert
AU  - Awoleye, Kolawole Daniel
PY  - 2026
DA  - 2026/08/20
TI  - Assessing The Impact of Sea Encroachment in Ilaje, Ondo State, Using Optical Satellite Imagery Analysis and Shuttle Radar Topography Mission
JO  - Journal of Geoscience and Earth Observation
T2  - Journal of Geoscience and Earth Observation
JF  - Journal of Geoscience and Earth Observation
VL  - 1
IS  - 2
SP  - 101
EP  - 112
DO  - 10.62762/JGEO.2026.327931
UR  - https://www.icck.org/article/abs/JGEO.2026.327931
KW  - coastal management
KW  - sea encroachment
KW  - Ilaje
KW  - sea-level rise
KW  - shoreline change
KW  - inundation models
AB  - This study assessed the impacts of sea encroachment in Ilaje Local Government Area of Ondo State, Nigeria, using multi-temporal optical satellite imagery and the Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM). This study analyzed past and recent shoreline change trends, simulated elevation-based vulnerability to flooding, and predicted the potential effects of sea-level rise. Landsat images from 1995, 2000, 2005, 2010, 2015, 2020, and 2025 were analyzed to identify the shoreline, and shoreline changes were calculated using the End Point Rate (EPR) and Linear Regression Rate (LRR) in the Digital Shoreline Analysis System (DSAS). Elevation-based vulnerability maps were modeled using the SRTM DEM, and future inundation was projected using sea-level rise data. Results showed that erosion was more severe along the Ilaje coastline, with over 70 percent of the shoreline retreating at different rates, while only small sections experienced accretion. The inundation model, assuming a conservative rise of 0.269 m, indicated that more than 555 km$^2$ of land could be submerged, and a 1m rise could flood over 650 km$^2$ by the year 2150, an event that would affect settlements such as Ayetoro, Ogogoro, and Gbeke Eke. These findings emphasize why Ilaje communities are at risk of land loss, displacement, and livelihood impacts. The analysis concludes that sea intrusion poses a significant threat to the coastal ecosystem in Ilaje. This study recommends integrating the coastal zone into planning efforts, restoring mangroves as natural barriers, adopting stricter measures to prevent unsustainable human activities, and maintaining ongoing geospatial monitoring as part of a sustainable strategy for change.
SN  - pending
PB  - Institute of Central Computation and Knowledge
LA  - English
ER  - 
BibTeX Format
Compatible with LaTeX, BibTeX, and other reference managers
@article{Adewumi2026Assessing,
  author = {Blessing Banji Adewumi and Herbert Tata and Kolawole Daniel Awoleye},
  title = {Assessing The Impact of Sea Encroachment in Ilaje, Ondo State, Using Optical Satellite Imagery Analysis and Shuttle Radar Topography Mission},
  journal = {Journal of Geoscience and Earth Observation},
  year = {2026},
  volume = {1},
  number = {2},
  pages = {101-112},
  doi = {10.62762/JGEO.2026.327931},
  url = {https://www.icck.org/article/abs/JGEO.2026.327931},
  abstract = {This study assessed the impacts of sea encroachment in Ilaje Local Government Area of Ondo State, Nigeria, using multi-temporal optical satellite imagery and the Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM). This study analyzed past and recent shoreline change trends, simulated elevation-based vulnerability to flooding, and predicted the potential effects of sea-level rise. Landsat images from 1995, 2000, 2005, 2010, 2015, 2020, and 2025 were analyzed to identify the shoreline, and shoreline changes were calculated using the End Point Rate (EPR) and Linear Regression Rate (LRR) in the Digital Shoreline Analysis System (DSAS). Elevation-based vulnerability maps were modeled using the SRTM DEM, and future inundation was projected using sea-level rise data. Results showed that erosion was more severe along the Ilaje coastline, with over 70 percent of the shoreline retreating at different rates, while only small sections experienced accretion. The inundation model, assuming a conservative rise of 0.269 m, indicated that more than 555 km\$^2\$ of land could be submerged, and a 1m rise could flood over 650 km\$^2\$ by the year 2150, an event that would affect settlements such as Ayetoro, Ogogoro, and Gbeke Eke. These findings emphasize why Ilaje communities are at risk of land loss, displacement, and livelihood impacts. The analysis concludes that sea intrusion poses a significant threat to the coastal ecosystem in Ilaje. This study recommends integrating the coastal zone into planning efforts, restoring mangroves as natural barriers, adopting stricter measures to prevent unsustainable human activities, and maintaining ongoing geospatial monitoring as part of a sustainable strategy for change.},
  keywords = {coastal management, sea encroachment, Ilaje, sea-level rise, shoreline change, inundation models},
  issn = {pending},
  publisher = {Institute of Central Computation and Knowledge}
}

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CC BY Copyright © 2026 by the Author(s). Published by Institute of Central Computation and Knowledge. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.
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