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We are pleased to announce that the journal CATENA has published an article on the genesis and monitoring of urban gullies studied in the Democratic Republic of Congo. Prof. Dr. Jean Poesen from the Department of Geology, Soil Science, and Geoinformatics at UMCS is a co-author of this publication:
Ilombe Mawe G., Lutete Landu E., Makanzu Imwangana F., Hubert A., Dille A., Bielders C. L., Poesen J., Dewitte O., Vanmaercke M., 2024. What controls the expansion of urban gullies in tropical environments? Lessons learned from contrasting cities in D.R. Congo. Catena, 241, 108055. https://doi.org/10.1016/j.catena.2024.108055
Urban gullies (UGs) are becoming an increasingly significant issue in many tropical cities across the Global South. Studying these geo-hydrological threats requires a deep understanding of the pace and controlling factors of these processes. Thus, the authors examined the expansion rates of a representative sample of UGs in Kinshasa (n = 17) and Bukavu (n = 29), two contrasting cities in the Democratic Republic of Congo. Long-term expansion rates (10–17 years) were reconstructed, distinguishing between headcut retreat and sidewall widening, and environmental factors that could explain these rates were analyzed. Total expansion rates range from 12.6 to 863 m² per year. Most changes occur through sidewall widening. In Kinshasa, characterized mainly by sandy soils, contrasts in expansion rates are primarily correlated with the features of the upslope drainage areas of the gullies. Particularly, road density and a hypothetical runoff index (combining drainage area, land use, and soil characteristics) explain a significant part of the observed differences. In Bukavu, such trends are less apparent. This is likely due to the clayey nature of the soils, which offer more resistance against gully erosion, resulting in generally smaller and less active UGs. Moreover, the already low infiltration rates of these soils probably make the relative impact of urbanization on runoff production smaller. The results also indicate that UGs located in recent landslides have higher gully expansion rates. The mechanisms behind this remain poorly understood. Overall, this publication opens promising perspectives for modeling and predicting gully expansion rates in urban environments, but may also contribute to more effective stabilization efforts for these forms.
Publication list of Institute staff
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