Flooding in Ghana: Mitigating the effects, minimising fatalities

Flooding is one of the most damaging natural disasters expected to be exacerbated in the future due to climate change, population growth and intensive urbanisation. 

It has been estimated that there were 175 floods globally, with direct economic losses of $44,767 billion, affecting 577,066,696 people and 7,910 deaths in 2022 alone.

In Ghana, flooding has been a recurring phenomenon dating back from the 1930s up to today.

This natural disaster has brought about social, economic and environmental consequences, with loss of life and properties running into several billions of Ghana cedi when it occurred. 

We can recall the June 3, 2015, flood incident in Accra where 154 people lost their lives and properties worth millions of cedis that were not spared.

It must be understood that floods cannot be stopped completely and creating resilience to flooding is crucial in our flood preparedness.

Flood control/mitigation measures

Flood mitigation measures fall into two distinct categories.

A consequence of the Akosombo Dam spillage

These are structural and non-structural measures. 

Structural measures include the construction of dams, levees, flood control reservoirs, bank protection and so on.

The hydraulic structures are quite expensive to design, construct and maintain, can take years to complete the construction and the likelihood of their negative impacts to the environment.

Additionally, these structures cannot be easily altered after construction.

It must be remembered that in 2001, in New Orleans, because of the failures of levees, there were 1,836 fatalities, mostly from flooding. In Ghana, the Volta River Authority had to spill excess water from the Akosombo and Kpong dams to avoid dam breaks, owing to heavy rainfall and increased volume of water to the dams in September 2023, which led to catastrophic consequences to downstream communities.

These two scenarios show how structural measures if breached, can lead to the inundation of communities downstream of these hydraulic structures.

Non-structural measures include flood forecasting and warning, increasing the resilience of flood-prone areas, implementation of Natural Flood Management (NFM), including low-impact development (LID) and Sustainable Drainage Systems (SuDS) and reducing risk through evacuation and so on.

Flood forecasting and warning to city dwellers require the collaborative efforts of the Hydrological Services Authority (HSA), academia, private sector and the Meteorological Agency. I hope there is a team at the HSA coordinating the efforts.

The wetlands and other floodplains serving as sinks for excess runoff are being depleted by businessmen and other encroachers to the admiration of the Lands Commission and the Ministry of Local Government, Chieftaincy and Religious Affairs (MLGCRA).

I suggest the Flood Managers at the Ministry of Works, Housing and Water Resources (MWHR), NADMO, CSOs and other stakeholders should engage these two institutions to halt the degradation and restore the wetlands.

The sustainable way is to plant resilient tree species to serve as sinks for water and carbon, reduce greenhouse gases and mitigate climate impacts.

In our urban settings, there is a high degree of paved areas in and around households, thereby reducing water penetration in case of heavy downpours.

This phenomenon creates increased runoff and eventually causes flooding.

So the narrative of excessive pavements must change.

Drainage

Our drainage systems are really not sustainable, since the hydrology of the urban settlements has changed over the years.

Flooding event in an urban centre

Urban catchments have been altered due to human developments and most of the drainage systems are inadequate to contain the urban flood. 

Additionally, most of the drainage systems have been silted, especially with plastic waste.

The MMDAs should encourage and motivate industry players to make recycling and composting a major part of solid waste management while communities along the drainage systems are educated as well.

In addition, Flood Managers at the MWHR must ensure the continuous desilting of all major and minor drains in communities.

One area that must be critically looked at is stationary vehicles, especially small cars and tricycles and their impacts on flooding.

In the recent floods in Valencia, Spain, most of the flow pathways were obstructed by vehicles and hindered the flow of water, killing over 300 people.

All flood-prone areas must be mapped, and vehicles, tricycles and containers that would impede the flow of the runoff should be removed and taken to safer grounds. 

The writer is a Hydrologist/ Environmental Engineer; Executive Director, 
Gant Institute of Hydrology & Environmental Management/Senior Lecturer (PT), 
Kumasi Technical University.
UP 249, KNUST
E-mail: a.oseitwumasi@gmail.com