Geological Challenges in African Cities: The Expansion of Urban Gullies

A recent study has uncovered a worrying geological phenomenon affecting cities in Africa, where massive trenches known as gullies are forming in urban areas, destroying homes and businesses in moments. This phenomenon is causing the displacement of thousands of residents and poses a continuous threat to urban growth on the continent.

Gully Expansion and Its Impact

Research indicates that urban gullies in Africa are rapidly expanding in cities built on sandy soils that lack adequate drainage systems. During heavy rainfall, water accumulates on roads and surfaces, and without effective drainage systems, it seeps into open ground, leading to the formation of deep trenches that can stretch for hundreds of meters.

These trenches not only swallow homes and infrastructure but can also sometimes lead to fatalities. In the Democratic Republic of the Congo alone, an average of 118,600 people were displaced between 2004 and 2023 due to gully expansion, with displacement rates doubling after 2020.

Case Study: Kinshasa

In Kinshasa, the capital and one of the cities most affected by this phenomenon, 868 urban gullies have been recorded, extending over 221 kilometers. Researchers visited the city in November 2019 and met with a family who lost their children due to a nighttime gully collapse. These incidents highlight the imminent danger faced by residents living near gullies.

Researchers note that gully expansion is significantly linked to road networks, where roads are turned into large channels that become rivers due to accumulated water, exacerbating the problem.

Proposed Solutions and Challenges

Addressing this geological challenge requires substantial investments in drainage infrastructure. Researchers emphasize that preventing gully formation is more effective than trying to stabilize them after they have formed, which can cost more than one million US dollars per gully.

Anna Mijic, a hydrologist at Imperial College London, states that governments and private institutions need to increase their investments in adequate drainage systems. However, high costs and the maintenance of long-term solutions present major obstacles.

The Role of Community and Environment

Gina Ziervogel, a geographer at the University of Cape Town in South Africa, stresses the importance of involving affected communities in planning interventions, as their experiences can contribute to finding sustainable solutions. Governments should also prioritize sustainable infrastructure and understand the role of the environment and resources in cities, such as soil and water.

Conclusion

The phenomenon of gully expansion in African cities represents a significant geological and environmental challenge that requires immediate attention and sustainable planning. Without effective and early action, this challenge is expected to impact hundreds of thousands of residents in the coming years. Governments and concerned institutions must work together to develop strategies aimed at improving drainage systems and protecting urban areas from this escalating phenomenon.