The Sassandra river, which flows in the western part of Côte d'Ivoire, is one of the most affected by hydropower developments, with three dams constructed along its course. The objective of the study was to evaluate the physical health of the Sassandra River prior to and following the construction of the Buyo and Soubré hydroelectric dams. To achieve this, satellite images from four years were selected: 1990, 2005, 2015, and 2025. Using these images and field data, mapping and remote-sensing tools were employed to determine several river–environment parameters, including riparian vegetation, width, sinuosity, width–depth ratio, slope, and the confinement index, among others. The vegetation on the east bank decreased from 72% in 1990 to 60% in 2025, with a slight recovery after 2005, while the vegetation on the west bank increased from 64% to 79%, at the expense of bare soil and cultivated areas. In terms of morphodynamics, the balance between erosion and accretion varied along the river: there was substantial accumulation upstream of the Buyo Dam, while the intermediate zone experienced increased erosion since 2005. The river’s morphology, particularly its meandering character (SI = 2 upstream; 1.4 in the highly sinuous zone; 1.15 downstream), shows an evolution influenced by the dams, with a decrease in sinuosity during the construction of the Soubré Dam, followed by recovery in 2025. The confinement index (> 1.5) and the width/depth ratio (< 12) suggest relative stability of the channel, modulated by river dynamics.
| [1] | I. Yuksel, “Barrages et hydroélectricité pour un développement durable,” Sources d’énergie Politique 4 du Plan économique, vol. 4, p. : 100-110. |
| [2] | E. F. Moran, M. C. Lopez, N. Moore, N. Müller, and D. W. Hyndman, “Sustainable hydropower in the 21st century,” Proc. Natl. Acad. Sci. U.S.A., vol. 115, no. 47, pp. 11891–11898, Nov. 2018.View Article PubMed |
| [3] | H. Merritt and A. Barragán-Ocaña, “The impact of market factors on the development of eco-friendly energy technologies: the case of bioethanol,” Clean Techn Environ Policy, vol. 25, no. 2, pp. 313–321, 2021.View Article PubMed |
| [4] | B. Li, Z. Liang, Z. Bao, J. Wang, and Y. Hu, “Changes in streamflow and sediment for a planned large reservoir in the middle Yellow River,” Land Degrad Dev, vol. 30, no. 7, pp. 878–893, Apr. 2019.View Article |
| [5] | S. A. Brandt, “Classification of geomorphological effects downstream of dams,” CATENA, vol. 40, no. 4, pp. 375–401, Aug. 2000.View Article |
| [6] | S. Arroyo, “Channel improvement of the Rio Grande below El Paso,” Mexican Federal Civil Engineer, 1925. |
| [7] | J. W. Stanley, “Retrogression on the Lower Colorado River After 1935,” T. Am. Soc. Civ. Eng., vol. 116, no. 1, pp. 943–954, Jan. 1951.View Article |
| [8] | S. L. Malhotra, “Effets des barrages et des déversoirs sur le régime des rivières,” in Proc. Int. Assoc. Hydraul. Res., 4ème réunion, |
| [9] | H. H. Chang, Fluvial processes in river engineering, Reprint ed. Malabar, Fla: Krieger Publ, 1992. |
| [10] | N. L. Poff, J. D. Olden, D. M. Merritt, and D. M. Pepin, “Homogenization of regional river dynamics by dams and global biodiversity implications,” Proc. Natl. Acad. Sci. U.S.A., vol. 104, no. 14, pp. 5732–5737, Apr. 2007.View Article PubMed |
| [11] | B. Alldredge and G. Moore, “Assessment of riparian vegetation sensitivity to river hydrology downstream of a major texas dam: assessment of riparian vegetation sensitivity to river hydrology,” River Res. Applic., vol. 30, no. 2, pp. 230–244, Feb. 2014.View Article |
| [12] | Gouvci, “Le barrage de Soubré : un projet structurant à impact direct.” Accessed: Sept. 23, 2025. [Online]. Available: https://www.gouv.ci/_actualite-article.php?recordID=13427 |
| [13] | Cienergie, “Mise en eau du barrage de Gribo-Popoli.” [Online]. Available: https://www.cinergies.ci/2024/03/02/mise-en-eau-du-barrage-de-gribo-popoli/ |
| [14] | OFB (Office français de la biodiversité), “L’altération de l’hydromorphologie d’un cours d’eau à l’origine de dysfonctionnements,” Office français de la biodiversité, France, RecueilHydro, 2010. |
| [15] | G. Girard, J. Sircoulon, and P. Touchebeuf de Lussigny, Aperçu sur les régimes hydrologiques de Côte d’Ivoire 1970. in ORSTOM (Office de la Recherche Scientifique et Technique d’Outre-Mer). 1970. |
| [16] | B. Konan, “Modélisation et gestion intégrée des ressources en eau dans le bassin versant du Sassandra (Côte d’Ivoire),” Thèse de doctorat 3ème cycle, Université d’Abobo Adjamé, Abidjan, Côte d’Ivoire), 2001. |
| [17] | L. Congedo, “Semi-Automatic Classification Plugin: A Python tool for the download and processing of remote sensing images in QGIS,” JOSS, vol. 6, no. 64, p. 3172, Aug. 2021.View Article |
| [18] | D. H. N’Da, E. K. N’Guessan, M. E. Wajda, and A. Kouadio, “Apport de la télédétection au suivi de la déforestation dans le Parc National de la Marahoué (Côte d’ivoire),” Bulletin - Société Française de Photogrammétrie et de Télédétection, p. 1734, 2008. |
| [19] | R. Caloz, T. J. Blaser, and G. Willemin, “Création d’une ortho-image à l’aide d’un modèle numérique d’altitude : influence des modes de ré-échantillonnage radiométrique,” Télédétection et cartographie., pp. 17–30, 1993. |
| [20] | A. S. Sahu, “Identification et cartographie des zones inondées dans la partie Purba Medinipur du bassin du fleuve Keleghai, en Inde : méthodes RS et SIG,” Revue internationale des géosciences avancées, vol. 2, no. 2, pp. 59–65. |
| [21] | S. K. McFEETERS, “The use of the Normalized Difference Water Index (NDWI) in the delineation of open water features,” International Journal of Remote Sensing, vol. 17, no. 7, pp. 1425–1432, May 1996.View Article |
| [22] | A. Garnier, S. Dufour, L. Lespez, S. Caillaut, and D. Delahaye, “Analyse spatiotemporelle de la dynamique fluviale d’un cours d’eau sahélo-soudanien entre 1967 et 2007. Le cas du Yamé au pays Dogon (Mali, Afrique de l’Ouest),” Revue internationale de géomatique, vol. 24, no. 3, pp. 279–306, Sept. 2014.View Article |
| [23] | E. Wiederkehr, S. Dufour, and H. Piégay, “Localisation et caractérisation semi-automatique des géomorphosites fluviaux potentiels. Exemples d’applications à partir d’outils géomatiques dans le bassin de la Drôme (France),” geomorphologie, vol. 16, no. 2, pp. 175–188, July 2010.View Article |
| [24] | G. J. Brierley and K. A. Fryirs, Eds., Geomorphology and River Management: Applications of the River Styles Framework, 1st ed. Wiley, 2004.View Article |
| [25] | L. B. Leopold and M. G. Wolman, River channel patterns, braided, meandering and straight. in Geology Survey Paper,. 1957.View Article |
| [26] | P. E. Ashmore, “How do gravel-bed rivers braid ?,” Can. J. Earth Sci., vol. 28, no. 3, pp. 326–341, Mar. 1991.View Article |
| [27] | D. Knighton, Fluvial Forms and Processes, 0 ed. Routledge, 2014..View Article |
| [28] | G. Petts, “Appliedriver morphology, edited by D. Rosgen. Woldland Hydology, Pagosa Springs, CO, 1996. ISBN 0-9653289. Stream Reconnaissance Handbook, edited by C.R. Thorne. John Wiley & Sons, Chichester, 1998. ISBN 0-471-96856-0.,” Regul. Rivers: Res. Mgmt., vol. 15, no. 4, pp. 373–374, July 1999.View Article |
| [29] | A. Regos, M. Ninyerola, G. Moré, and X. Pons, “Linking land cover dynamics with driving forces in mountain landscape of the Northwestern Iberian Peninsula,” International Journal of Applied Earth Observation and Geoinformation, vol. 38, pp. 1–14, June 2015.View Article |
| [30] | F. C. Aguiar, M. J. Martins, P. C. Silva, and M. R. Fernandes, “Riverscapes downstream of hydropower dams: Effects of altered flows and historical land-use change,” Landscape and Urban Planning, vol. 153, pp. 83–98, Sept. 2016.View Article |
| [31] | R. Mukherjee, R. Bilas, S. S. Biswas, and R. Pal, “Bank erosion and accretion dynamics explored by GIS techniques in lower Ramganga river, Western Uttar Pradesh, India,” Spat. Inf. Res., vol. 25, no. 1, pp. 23–38, Feb. 2017.View Article |
| [32] | S. Dragićević et al., “Spatial and Temporal Variability of Bank Erosion during the Period 1930–2016: Case Study—Kolubara River Basin (Serbia),” Water, vol. 9, no. 10, p. 748, Sept. 2017.View Article |
| [33] | R. Islam, Md. N. Islam, and M. N. Islam, “Impacts of Bangabandhu Jamuna Multi-purpose Bridge on the dynamics of bar morphology at the Jamuna River in Bangladesh,” Model. Earth Syst. Environ., vol. 3, no. 3, pp. 903–925, Sept. 2017.View Article |
| [34] | T. Takagi, T. Oguchi, J. Matsumoto, M. J. Grossman, M. H. Sarker, and M. A. Matin, “Channel braiding and stability of the Brahmaputra River, Bangladesh, since 1967: GIS and remote sensing analyses,” Geomorphology, vol. 85, no. 3–4, pp. 294–305, Mar. 2007.View Article |
| [35] | S. Bandyopadhyay, K. Ghosh, and S. K. De, “A proposed method of bank erosion vulnerability zonation and its application on the River Haora, Tripura, India,” Geomorphology, vol. 224, pp. 111–121, Nov. 2014.View Article |
| [36] | S. S. Biswas and P. Pani, “Changes in the hydrological regime and channel morphology as the effects of dams and bridges in the Barakar River, India,” Environ Earth Sci, vol. 80, no. 5, p. 209, Mar. 2021.View Article |
