GIS-BASED EVALUATION OF SAND MINING IMPACTS ON GEOMORPHOLOGICAL CHANGES ALONG THE IMO RIVER BANK, NIGERIA (1980–2025)
Keywords:
Geomorphology, Erosion, Morphology, Fluvial, DepositionAbstract
Sand mining has become one of the major anthropogenic activities altering river morphology and accelerating riverbank instability in many developing countries. This study evaluated the impacts of sand mining on geomorphological changes along the Imo River, Nigeria, over the period 1980–2025 using Geographic Information Systems (GIS) and remote sensing techniques. Multi-temporal satellite imagery and spatial analysis were employed to examine riverbank dynamics, while the Digital Shoreline Analysis System (DSAS) was used to quantify riverbank migration, erosion, and deposition rates. Cross-sectional analyses were further conducted to assess changes in channel morphology associated with prolonged sediment extraction. The results revealed significant geomorphological changes along the Imo River, characterized by widespread riverbank erosion, channel widening, and localized sediment deposition. Between 1990 and 2020, approximately 18.03 km² of land was lost through erosion, compared with only 1.98 km² gained through deposition. Erosion rates varied considerably along the river corridor, with maximum retreat rates reaching approximately −10 m yr⁻¹, particularly within sections experiencing intensive sand mining activities. The observed morphological changes indicate that continuous sediment removal has altered channel geometry, disrupted sediment balance, and increased riverbank instability, thereby heightening the vulnerability of adjacent communities to flooding, land degradation, and infrastructure damage. The study demonstrates the effectiveness of integrating GIS, remote sensing, and DSAS for long-term monitoring of sand mining impacts on river systems. It recommends strengthened regulation of sand mining activities, continuous geomorphological monitoring, and sustainable river basin management strategies to mitigate environmental degradation and promote the sustainable use of riverine resources along the Imo River.
References
[1] Ahmed, M. F., Binh, D. V., Kantoush, S. A., Park, E., Doan, N. L. P., Tuan, L. A., Nguyen, V. D., Vu, T. H., Nguyen, B. Q., Ngoc, T. A., Tung, N. X., & Sumi, T. (2025). Intensified susceptibility to riverbed incisions under sand mining impacts in the Vietnamese Mekong Delta: A long-term spatiotemporal analysis. Geomorphology, 470, 109535. https://doi.org/10.1016/j.geomorph.2024.109535
[2] Abdulazeez, A. (2016). A review on the impact of river and inland sand mining on Nigerian river basins.
[3] Adeniji, O., Okereke, C., & Nwosu, C. (2019). Impact of sand mining on river morphology and aquatic ecosystem: A case study of Imo River, Nigeria. Environmental Geology, 78(2), 305–317.
[4] Amangabara, T. G. (2015). Drainage morphology of Imo Basin in the Anambra–Imo River Basin area, Imo State, Southern Nigeria. Journal of Geography, Environment and Earth Science International, 3(1), 1–11. https://doi.org/10.9734/JGEESI/2015/17114
[5] Chang, H. (2008). River morphology and river channel changes. Transactions of Tianjin University, 14, 254–262. https://doi.org/10.1007/s12209-008-0045-3
[6] Corenblit, D., Piégay, H., Arrignon, F., González-Sargas, E., Bonis, A., Davies, N. S., Ebengo, D. M., Garófano-Gómez, V., Gurnell, A. M., Henry, A. L., Hortobágyi, B., Martínez-Capel, F., Steiger, J., Tabacchi, E., Tooth, S., Vautier, F., & Walcker, R. (2024). Interactions between vegetation and river morphodynamics. Part I: Research clarifications and challenges. Earth-Science Reviews, 253, 104769. https://doi.org/10.1016/j.earscirev.2024.104769
[7] Damseth, S., Thakur, K., Kumar, R., Kumar, S., Mahajan, D., Kumari, H., Sharma, D., & Sharma, A. K. (2024). Assessing the impacts of river bed mining on aquatic ecosystems: A critical review of effects on water quality and biodiversity. HydroResearch, 7, 122–130. https://doi.org/10.1016/j.hydres.2024.01.004
[8] Darby, S. E., & Sear, D. A. (2008). River management and environmental sustainability. Geological Society, London, Special Publications, 283, 1–11.
[9] Essien, A. I., & Ofor, C. (2013). The physico-chemical characteristics of Imo River Estuary in southeastern Nigeria. Tropical Freshwater Biology, 21. https://doi.org/10.4314/tfb.v21i1.3
[10] Hassan, A., Mohammed, A., & Yusuf, I. (2020). Monitoring riverbank erosion using GIS and remote sensing: A case study of the Niger Delta. Journal of Environmental Management, 256, 109937.
[11] Kondolf, G. M. (1997). Hungry water: Effects of dams and gravel mining on river channels. Environmental Management, 21(4), 533–551.
[12] Mia, M., Karikar, B. A., Ali, M., Siddika, A., Saleem, S., Deo, P., Naqvi, H., Das, T., & Siddiqui, L. (2026). Assessing the impact of sand mining on channel morphology: A case study of the Raidak-II River in the Himalayan foreland. Discover Hazards, 2. https://doi.org/10.1007/s44475-026-00006-7
[13] Nnaji, C., Onyekachi, M., Nwankwo, E., Emenike, P., Chibueze, C., & Ogarekpe, N. (2023). Hydrological and morphometric characterization of Anambra–Imo River Basin using remote sensing (Preprint). https://doi.org/10.21203/rs.3.rs-3745340/v1
[14] Nwankwoala, H. O., & Agbo, F. O. (2016). Effects of sand mining on river morphology and flood risk in Southeastern Nigeria. Journal of Flood Risk Management, 9(3), 287–295.
[15] Obuba, K., & Eziaku, L. (2023). Hydrobiological characteristics and land-cover dynamics of the Imo River Estuary, Niger Delta, Nigeria. Michael Okpara University of Agriculture Repository. http://repository.mouau.edu.ng/works/hydrobiological-characteristics-and-land-cover-dynamics-of-the-imo-river-estuary-niger-delta-nigeria-7-2
[16] Ogunkoya, O., Aladesanmi, A., & Olawuyi, J. (2021). Remote sensing and GIS assessment of morphological changes in Nigerian rivers under sand mining pressure. Environmental Monitoring and Assessment, 193(4), 204.
[17] Ramesh, S., & Venkateswarlu, P. (2022). Shoreline change detection using DSAS: A review. Environmental Earth Sciences, 81(5), 120.
[18] Rhoads, B. L. (2020). Introduction. In River Dynamics: Geomorphology to Support Management (pp. 1–14). Cambridge University Press.
[19] Thieler, E. R., Himmelstoss, E. A., Zichichi, J. L., & Ergul, A. (2009). Digital Shoreline Analysis System (DSAS) Version 4.0 User Guide (Open-File Report 2008–1278). U.S. Geological Survey.
[20] Wala, C., Ugbomeh, A. P., Green, A. F., & Anaero-Nweke, G. N. (2023). Evaluation of the perceived ecosystem services provided by selected sites: The Imo River, Rivers State, Nigeria. Journal of Global Ecology and Environment, 18(1), 23–31. https://doi.org/10.56557/jogee/2023/v18i18253
[21] Yang, S., Li, J., & Zhang, H. (2019). Influence of sand mining on river bank erosion and sediment transport. Geomorphology, 326, 178–186
Downloads
Published
Issue
Section
License
Copyright (c) 2026 This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, adaptation, and reproduction in any medium, provided that the original work is properly cited.
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Authors are permitted to post their work online in institutional/disciplinary repositories or on their own websites. Pre-print versions posted online should include a citation and link to the final published version in Journal of Librarianship and Scholarly Communication as soon as the issue is available; post-print versions (including the final publisher's PDF) should include a citation and link to the journal's website.
