Dynamique de l'occupation des sols dans les bassins versants périurbains de la Kapou et de la Pala sur le flanc sud-ouest de Bangui, Centrafrique
Abstract
This article analyzes the diachronic evolution of land occupancy in the Kapou (658 km2) and Pala (102 km2) rivers peri-urban basins between 2002 and 2023. Satellite images (SPOT from 2002, Sentinel-2 from 2018 and 2023) were classified by Random Forest in QGis to feed a GIS-managed database. Ten land occupancy units were mapped: Dense Forest, Degraded Forest, Gallery Forest, Swamp Forest, Swamp, Savannah, Crop Mosaic, Palm grove, Habitat-Bare Soil, and Water. Over the 2002-2023 period, cultivated mosaics increased by 241 % (113.9 km2) in the Kapou watershed and by 45.3% (16.4 km2) in the Pala one, while the dense forest was declining at very similar absolute rates, 109.2 km2 (-32.4 %), and 13.6 km2 (-72.8 %) respectively. This forest retreat is strong around residential areas over a radius of 5 km. The average annual rate of dense forest reduction was lower from 2002 to 2018 than from 2018 to 2023 in the Kapou basin (-1.45 % and -3.11% respectively) and even more so in the Pala basin (-1.57% and -19,0 %). By treating data differently, agricultural land increase in average of 5.42 km2 per year in the Kapou watershed, and 0.78 km2 in the Pala one. Well represented in the Kapou basin, savannas remained stable during the study period (112 km2 in 2002 and 109 km2 in 2023). The other classes are not very extensive. However, the relatively sharp increase in the Habitat-Bare land class is to be connected to the expansion of cultivated areas.
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BibTeX
@article{waterendji2026dynamique,
title = {{Dynamique de l'occupation des sols dans les bassins versants périurbains de la Kapou et de la Pala sur le flanc sud-ouest de Bangui, Centrafrique}},
author = {Jean-Pascal Waterendji and Cyriaque Rufin Nguimalet},
journal = {Physio-Géo},
year = {2026},
month = sep,
doi = {10.4000/16uec},
url = {https://doi.org/10.4000/16uec},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Dynamique de l'occupation des sols dans les bassins versants périurbains de la Kapou et de la Pala sur le flanc sud-ouest de Bangui, Centrafrique
AU - Jean-Pascal Waterendji
AU - Cyriaque Rufin Nguimalet
PY - 2026
DA - 2026/09/01
JO - Physio-Géo
DO - 10.4000/16uec
UR - https://doi.org/10.4000/16uec
AB - This article analyzes the diachronic evolution of land occupancy in the Kapou (658 km2) and Pala (102 km2) rivers peri-urban basins between 2002 and 2023. Satellite images (SPOT from 2002, Sentinel-2 from 2018 and 2023) were classified by Random Forest in QGis to feed a GIS-managed database. Ten land occupancy units were mapped: Dense Forest, Degraded Forest, Gallery Forest, Swamp Forest, Swamp, Savannah, Crop Mosaic, Palm grove, Habitat-Bare Soil, and Water. Over the 2002-2023 period, cultivated mosaics increased by 241 % (113.9 km2) in the Kapou watershed and by 45.3% (16.4 km2) in the Pala one, while the dense forest was declining at very similar absolute rates, 109.2 km2 (-32.4 %), and 13.6 km2 (-72.8 %) respectively. This forest retreat is strong around residential areas over a radius of 5 km. The average annual rate of dense forest reduction was lower from 2002 to 2018 than from 2018 to 2023 in the Kapou basin (-1.45 % and -3.11% respectively) and even more so in the Pala basin (-1.57% and -19,0 %). By treating data differently, agricultural land increase in average of 5.42 km2 per year in the Kapou watershed, and 0.78 km2 in the Pala one. Well represented in the Kapou basin, savannas remained stable during the study period (112 km2 in 2002 and 109 km2 in 2023). The other classes are not very extensive. However, the relatively sharp increase in the Habitat-Bare land class is to be connected to the expansion of cultivated areas.
SN - 1958-573X
ER -