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Original article: https://theconversation.com/flooding-incidents-in-ghanas-capital-are-on-the-rise-researchers-chase-the-cause-254000
Urban flooding is a major problem in the global south. In west and central Africa, more than 4 million people were affected by flooding in 2024. In Ghana, cities suffer damage from flooding every year.
Ghana’s president, John Dramani Mahama, has established a task force to find ways of improving flood resilience in the country. This is partly driven by an increase in flooding incidents in cities such as Accra and Kumasi in the last decade.
We are urban planning and sustainability scholars. In a recent paper we analysed whether flooding in Accra, Ghana’s capital, was caused by climate change or poor land use planning.
We conclude from our analysis that flooding is caused by poor and uncoordinated land use planning rather than climate change. We recommend that the physical planning department and other regulatory agencies are equipped to ensure the effective enforcement the relevant land use regulations.
Mixed push factors
The Accra metropolitan area is one of the 29 administrative units of Ghana’s Greater Accra region. It is the most populous region in Ghana, with over five million residents, according to the 2021 Housing and Population Census.
We interviewed 100 households living in areas such as Kaneshie, Adabraka and Kwame Nkrumah Circle. These areas experience a high incidence of floods. Representatives of agencies such as the Physical Planning Department of the Accra Metropolitan Assembly, the National Disaster Management Organisation and the Environmental Protection Agency were interviewed too, about:
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the nature and areas most prone to flooding in the study area
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the frequency of flooding
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land use planning and regulations and their influence on flooding.
About 40% of the people we interviewed attributed flooding to both weak enforcement of land use regulation and changes in rainfall patterns. Most of the households (52%) said floods in Accra were the result of weak enforcement of land use regulations, while 8% blamed changes in land use regulations.
We also analysed recorded data on flood incidence and rainfall. We found no correlation between increased rainfall and flooding. For example in 2017 there was a decrease in rainfall, but an increase in flooding.
This finding points to the fact that rainfall isn’t the only factor contributing to flooding in the city.
The agencies and city residents reported that between 2008 and 2018, they could see that more people were encroaching on the city’s wetlands by building homes and commercial infrastructure. This has changed the natural flow of water bodies. The Greater Accra Metropolitan and its environs has major wetlands such as Densu Delta, Sakumo Lagoon and Songor Lagoon.
Interview respondents noted that the siting of unauthorised buildings and the encroachment on buffer zones of water bodies in the city could have been averted. They blamed political interference in the enforcement of land use regulation. The government makes the situation worse in two ways, they said:
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planning standards and regulations are neglected in the development process. The processes involved in acquiring development permits are cumbersome and expensive, so people go ahead and develop without permits.
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regulatory institutions and authorities are ineffective. This is clear from the fact that planning happens chaotically. No attention is given to the ecological infrastructure that’s needed.
The way forward
We conclude that land use malpractices remain the dominant causes of flooding in Accra. They include:
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poor disposal of solid waste, which eventually blocks drains and results in water overflow during heavy rains
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building on wetlands as a result of non-compliance or non-enforcement of land use regulations.
There is an urgent need for Ghana’s cities to adopt best practices in waste management. These include recycling of plastic waste and composting for urban agriculture. An environmental excise tax was introduced in 2011 to fund plastic waste recycling and support waste management agencies.
The increasing encroachment on wetlands should be addressed through the strict enforcement of buffer regulations. Planning authorities and the judiciary can collaborate on this. The city must also encourage green infrastructure, like rain gardens, green roofs, permeable pavement, street trees and rain harvesting systems.
Research has shown these to be environmentally sustainable and cost-effective approaches to managing storm water.
Another suggested approach is the introduction of the polluter pays principle in city management. This is a system where city residents who are involved in the pollution of the environment are made to pay for the cost of mitigating the impact. Residents who dispose of waste indiscriminately and encroach on wetlands would be made to pay for the cost of the environmental degradation. Cities such as Barcelona and Helsinki have applied this principle in the management of their industrial discharge and contaminated waste.
Finally, there should be incentives for city residents to promote environmental sustainability. For example, a deposit refund system has been introduced in several states in the US and Australia. In this system, consumers are made to pay a deposit after purchasing items that can be recycled, such as plastic bottles, and the deposit is reimbursed to the consumer after the return of the empty bottles to a retail store.
The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.