The Yaéré floodplain, located in the Logone watershed south of Lake Chad, is highly vulnerable to recurrent flooding that threatens local populations and the regional economy. This study quantifies the floodplain’s hydrological dynamics over a 40-year period (1984-2024) by analysing 683 cloud-free Landsat images to map surface water changes. The results reveal substantial hydrological variability, with flooded areas ranging from complete absence (0 km2) to a record maximum of 17,559 km2 in October 2022, and an average flooded extent of approximately 1630 km2. Flooding exhibits a pronounced seasonal pattern, peaking mainly in September and October, corresponding to key rainfall periods and river inflows critical for ecosystem functioning. Strong interannual variability is evident, contrasting exceptionally wet years such as 1999, 2022, and 2024 with notably dry periods including 1984, 1987, and 2007. Since 2019, a discernible increase in extreme flood events suggests intensifying precipitation trends consistent with regional climate change. Anthropogenic factors also shape the flood regime, notably the Maga dam and associated dykes constructed in the 1970s, which have modified natural inundation patterns and downstream hydrology. Diachronic mapping of flooded zones provides an essential tool for identifying areas of significant hydrological change, supporting targeted ecological restoration and risk management efforts. These findings offer critical insights for adaptive management of this vulnerable wetland in a changing climate. Integrating this remote sensing data into local and regional policy frameworks can enhance flood forecasting and early warning systems, improving community resilience to extreme hydrological events. Ultimately, this study contributes to the sustainable management of water resources and flood risk reduction in the Lake Chad basin, fostering more effective responses to future climatic uncertainties.
References
[1]
Bryzek, J.A., Veselka IV, W.E. and Anderson, J. (2024) State Role and Involvement in Determining Wetland Mitigation Performance Standards in the United States. EcologyandSociety, 29, Article 30. https://doi.org/10.5751/es-14530-290130
[2]
Sarwar Hossain, M. and Szabo, S. (2017) Understanding the Social-Ecological System of Wetlands. In: Wetland Science, Springer, 285-300. https://doi.org/10.1007/978-81-322-3715-0_15
[3]
Bullock, A. and Acreman, M. (2003) The Role of Wetlands in the Hydrological Cycle. Hydrology and Earth System Sciences, 7, 358-389. https://doi.org/10.5194/hess-7-358-2003
[4]
Delclaux, F., Seignobos, C., Liénou, G. and Genthon, P. (2010) Water and People in the Yaéré Floodplain (North Cameroon). In: Floodplains: Physical Geography, Ecology and Societal Interactions, Nova Publishers, 1-27.
[5]
Castellarin, A., Di Baldassarre, G. and Brath, A. (2011) Floodplain Management Strategies for Flood Attenuation in the River Po. River Research and Applications, 27, 1037-1047. https://doi.org/10.1002/rra.1405
[6]
Devitt, L., Neal, J., Coxon, G., Savage, J. and Wagener, T. (2023) Flood Hazard Potential Reveals Global Floodplain Settlement Patterns. Nature Communications, 14, Article No. 2801. https://doi.org/10.1038/s41467-023-38297-9
[7]
Jacobson, R.B., Lindner, G. and Bitner, C. (2015) The Role of Floodplain Restoration in Mitigating Flood Risk, Lower Missouri River, USA. In: Geomorphic Approaches to Integrated Floodplain Management of Lowland Fluvial Systems in North America and Europe, Springer, 203-243. https://doi.org/10.1007/978-1-4939-2380-9_9
[8]
Ogawa, H. and Male, J.W. (1986) Simulating the Flood Mitigation Role of Wetlands. Journal of Water Resources Planning and Management, 112, 114-128. https://doi.org/10.1061/(asce)0733-9496(1986)112:1(114)
[9]
Acreman, M. and Holden, J. (2013) How Wetlands Affect Floods. Wetlands, 33, 773-786. https://doi.org/10.1007/s13157-013-0473-2
[10]
Guaita García, N., Martínez Fernández, J. and Fitz, C. (2020) Environmental Scenario Analysis on Natural and Social-Ecological Systems: A Review of Methods, Approaches and Applications. Sustainability, 12, Article 7542. https://doi.org/10.3390/su12187542
[11]
Lallemant, D., Hamel, P., Balbi, M., Lim, T.N., Schmitt, R. and Win, S. (2021) Nature-Based Solutions for Flood Risk Reduction: A Probabilistic Modeling Framework. One Earth, 4, 1310-1321. https://doi.org/10.1016/j.oneear.2021.08.010
[12]
Lloréns, J.L.P. (2008) Impacts of Climate Change on Wetland Ecosystems.
[13]
Moritz, M., Laborde, S., Phang, S., Ahmadou, M., Durand, M., Fernandez, A., et al. (2016) Studying the Logone Floodplain, Cameroon, as a Coupled Human and Natural System. AfricanJournalofAquaticScience, 41, 99-108. https://doi.org/10.2989/16085914.2016.1143799
[14]
Scholte, P. (2005) Floodplain Rehabilitation and the Future of Conservation & Development. Adaptive Management of Success in Waza-Logone, Cameroon. Tropical Resource Management Papers.
[15]
Sighomnou, D., Nkamdjou, L.S. and Liénou, G. (2002) La plaine du Yaéré dans le Nord-Cameroun: Une expérience de restauration des inondations. In: Gestion intégrée des ressources naturelles en zones inondables tropicales, IRD Éditions, 375-384. https://doi.org/10.4000/books.irdeditions.8565
[16]
Raimond, C., Garine, É. and Langlois, O. (2013) Ressources vivrières et choix alimentaires dans le bassin du lac Tchad. IRD éditions.
[17]
Westra, T. and De Wulf, R.R. (2009) Modelling Yearly Flooding Extent of the Waza-Logone Floodplain in Northern Cameroon Based on MODIS and Rainfall Data. InternationalJournalofRemoteSensing, 30, 5527-5548. https://doi.org/10.1080/01431160802672872
[18]
Ziébé, R. (2015) Fisheries in the Waza Logone floodplain: An Analysis of the Status of the Fisheries Sector and Mitigation of Conflicts within the Sector in North Cameroon. PhD Thesis, Leiden University.
[19]
Béné, C., Neiland, A., Jolley, T., Ovie, S., Sule, O., Ladu, B., et al. (2003) Inland Fisheries, Poverty, and Rural Livelihoods in the Lake Chad Basin. Journal of Asian and African Studies, 38, 17-51. https://doi.org/10.1177/002190960303800102
[20]
Fernández, A., Najafi, M.R., Durand, M., Mark, B.G., Moritz, M., Jung, H.C., et al. (2016) Testing the Skill of Numerical Hydraulic Modeling to Simulate Spatiotemporal Flooding Patterns in the Logone Floodplain, Cameroon. Journal of Hydrology, 539, 265-280. https://doi.org/10.1016/j.jhydrol.2016.05.026
[21]
Jung, H.C., Alsdorf, D., Moritz, M., Lee, H. and Vassolo, S. (2011) Analysis of the Relationship between Flooding Area and Water Height in the Logone Floodplain. Physics and Chemistry of the Earth, Parts A/B/C, 36, 232-240. https://doi.org/10.1016/j.pce.2011.01.010
[22]
Murumkar, A., Durand, M., Fernández, A., Moritz, M., Mark, B., Phang, S.C., et al. (2020) Trends and Spatial Patterns of 20th Century Temperature, Rainfall and PET in the Semi-Arid Logone River Basin, Sub-Saharan Africa. Journal of Arid Environments, 178, Article 104168. https://doi.org/10.1016/j.jaridenv.2020.104168
[23]
Naah, E. (1990) Hydrologie du grand Yaéré du nord Cameroun. Thèse de Doctorat es-sciences, Université de Yaoundé.
[24]
Olivry, J.C. and Naah, E. (2000) Hydrologie. Atlas de La Province de l’Extrême Nord Du Cameroun, Paris, IRD.
[25]
Loth, P.E. (2004) The Return of the Water: Restoring the Waza Logone Floodplain in Cameroon. IUCN.
[26]
Labara, B.K., Djaowe, A., Tajo, D., Chouto, S., Chendjou, F.X. and Tagne, R. (2020) La pêche artisanale par canaux dans la plaine du Logone: Une rentabilité source de conflits entre pêcheurs. Bulletin de la Société Géographique de Liège, 75, 83-100. https://doi.org/10.25518/0770-7576.6109
[27]
Kolaouna Labara, B.K., Chouto, S. and Laborde, S. (2022) Des scénarios stratégiques pour une réflexion prospective sur les couplages écologiques et humains dans la plaine inondable du Logone (Extrême-Nord Cameroun). Géographieetcultures, 116, 37-55.
[28]
de Noray, M.L. (2002) Waza Logone: Histoires d’eaux et d’hommes; Vivre dans la plaine inondable de Waza Logone au Cameroun. IUCN.
[29]
Mouafo, D., Fotsing, É., Sighomnou, D. and Sigha, L. (2002) Dam, Environment and Regional Development: Case Study of the Logone Floodplain in Northern Cameroon. International Journal of Water Resources Development, 18, 209-219. https://doi.org/10.1080/07900620220121765
[30]
Molenaar, J.W. and Van Santen, J.C.M. (2006) Perceptions of Water in a Changing Hydrological and Ecological Context: The Case of the Logone Flood Plains in Cameroon. The Geographical Journal, 172, 331-347. https://doi.org/10.1111/j.1475-4959.2006.00216.x
[31]
Gorelick, N., Hancher, M., Dixon, M., Ilyushchenko, S., Thau, D. and Moore, R. (2017) Google Earth Engine: Planetary-Scale Geospatial Analysis for Everyone. Remote Sensing of Environment, 202, 18-27. https://doi.org/10.1016/j.rse.2017.06.031
[32]
Olthof, I. and Fraser, R.H. (2024) Mapping Surface Water Dynamics (1985-2021) in the Hudson Bay Lowlands, Canada Using Sub-Pixel Landsat Analysis. Remote Sensing of Environment, 300, Article 113895. https://doi.org/10.1016/j.rse.2023.113895
[33]
Sakamoto, T., Van Nguyen, N., Kotera, A., Ohno, H., Ishitsuka, N. and Yokozawa, M. (2007) Detecting Temporal Changes in the Extent of Annual Flooding within the Cambodia and the Vietnamese Mekong Delta from MODIS Time-Series Imagery. Remote Sensing of Environment, 109, 295-313. https://doi.org/10.1016/j.rse.2007.01.011
[34]
Funk, C., Peterson, P., Landsfeld, M., Pedreros, D., Verdin, J., Shukla, S., et al. (2015) The Climate Hazards Infrared Precipitation with Stations—A New Environmental Record for Monitoring Extremes. Scientific Data, 2, Article No. 150066. https://doi.org/10.1038/sdata.2015.66
[35]
Deng, Y., Jiang, W., Tang, Z., Li, J., Lv, J., Chen, Z., et al. (2017) Spatio-Temporal Change of Lake Water Extent in Wuhan Urban Agglomeration Based on Landsat Images from 1987 to 2015. RemoteSensing, 9, Article 270. https://doi.org/10.3390/rs9030270
[36]
El Halim, M. (2015) Apport de la télédétection pour l’évaluation de la variation des surfaces d’eau et du couvert végétal dans la plaine du Haouz depuis 1984 jusqu’à 2014. PFE, Université Cadi Ayyad.
