The strategic importance of building flood resilience in the Greater Dakar Region

Submitted by C40 Cities Finance Facility (CFF) | published 8th Jul 2021 | last updated 21st Oct 2021
Flooded city centre

Flooded city centre (Photo by Martinez Codina)

Introduction

Flooding is considered to be one of the most common and severe natural and climate-induced disasters worldwide (World Bank, 2020b). Senegal has been experiencing many climate change impacts over the past few years. Flooding has been identified as one of Senegal’s main and most serious disaster risk which is amplified by a changing and unpredictable rainfall pattern (GFDRR, n.d). The number of people affected by floods in Senegal has increased five-fold from 170,000 in 1999 to over 900,000 in 2009, with most of them being based in the Greater Dakar region (Schaer, Thiam & Nygaard, 2018). The existing socio-economic conditions that prevail in Senegal and Dakar can be partly explained by the (WorldAtlas, 2019) numerous flood-related losses (GFDRR, 2014). 

This report* explores the importance of flood resilience in Dakar. It includes sections on: Climate change in Senegal; Cost of floods; Why flood management interventions are so important in Dakar; A multi-pronged approach to address floods; and, CFF’s work in Dakar.

*A summary of the report can be found below. Download the full publication from the right-hand column for more details.

Causes of floods and exacerbating factors in and around Dakar

The scale of floods experienced in and around Dakar are the confluence of many factors. These can be summarised as follows:

  • Discriminatory planning under colonial rule
  • Rapid urbanisation
  • Land use changes
  • Limited services and infrastructure

Changes in land use can be largely explained by rapid urban sprawl in Dakar. The hardening of surfaces are attributed to an increase in the expanse of land covered by continuous residential, commercial, industrial, and services (such as airport and port) areas. The hardening of surfaces affects natural drainage patterns and increases surface runoff. A very small proportion of the Dakar area contains green urban spaces, bare soil, agricultural area, forest and shrublands as well as land without any current use (see Figure 3, pg. 8). The rapidly decreasing surface area that supports natural drainage and infiltration coupled with the lack of drainage infrastructure to effectively manage the evacuation of surface water exacerbate the impact of floods in Dakar during high rainfall events.


Land use changes

The causes of floods and exacerbating factors enumerated above are further compounded by climate change which presents an even greater challenge. This highlights the urgency of flood adaptation measures and the need to grow the call to action louder in the Greater Dakar region. 

Economic losses associated with floods

West Africa, whilst it contributes a marginal portion of the global total emissions, faces some of the most rapid climatic changes. Floods represent a major threat to the development gains made to date and the future socio-economic potential of West African countries (World Bank, 2019). The damage to assets, loss of lives and economic production loss associated with floods – pluvial and fluvial – in 2017 in the coastal regions of Senegal, Benin, Cote d’Ivoire, and Togo is estimated at US $1.45 billion representing over 2% of their combined GDPs (World Bank, 2019). This is a significant loss on an annual basis due to pluvial and fluvial floods in coastal areas. These figures are an underrepresentation of the total cost of floods throughout these countries, which at the time of writing was not available. It is estimated that floods – pluvial and fluvial – experienced in 2017 along the coast1 cost the Senegalese economy a total of $230 million which is equivalent to approximately 1.4% of its GDP. The costs were calculated based on damage to assets, loss of lives, and economic production losses. 

To put this in context, almost every year, there is about 1.4% of the economy that is wiped out. This leads to a larger share of people becoming further entrenched into poverty and climate vulnerability, thereby limiting their ability to bounce back from future climate shocks and stresses. To effectively address poverty reduction and climate resilience, addressing floods will have to be at the core of this work. Without an approach centred on improved urban planning whilst addressing floods, larger swathes of the population will be made more vulnerable to the impacts of a rapidly changing climate. 

Devastating floods were experienced across the country in 2009, especially in the Greater Dakar region. It is estimated that approximately 380,000 people were affected by the floods with over 30,000 damaged houses in Dakar, most of which have been rendered uninhabitable and abandoned since (GFDRR, 2014). The damage and losses experienced amounted to roughly US $ 82 million in losses and damage in the Greater Dakar region. 


Why are flood management interventions are so important in Dakar?

Adaptation Options

Recognising that the prevention and management of floods occur within complex political, regulatory, and institutional spaces, this report is by no means all-encompassing but rather takes a stance on advocating for a coherent, multi-faceted and intergovernmental transversal approach and the use of proven and cost-effective solutions.

It is acknowledged that there are major structural works that would be required in and around Dakar to build flood resilience and deliver on the backlog of services. Firstly, this report does not provide an analysis of the nature and scale of such infrastructure but rather provides a lens through which to plan and design such infrastructure. Secondly, the argument put forward relates to the transversal intergovernmental coordination that is required to deliver comprehensive flood interventions. Thirdly, numerous low-cost, high-opportunity interventions are proposed that could be put in place to limit the impact of floods. Each approach has to be adequately contextualised and further investigated for the prevailing context in the Greater Dakar region. 

  • Future- and climate-proofing of infrastructure: To safeguard the lives and livelihoods of citizens, it is of critical importance that all public infrastructure is planned with an understanding of the impact of future climate and future demand. The principle underpinning the decisionmaking process for climate-proofing of investments into public infrastructure is to determine whether the planned infrastructure will perform as intended under present and future climate risks (UNDP, 2011). This avoids locking in high levels of investments, which often public infrastructure projects require, into projects that will buckle under future climate scenarios (UNDP, 2011). 
  •  Comprehensive and holistic approach to addressing floods: In accelerating the pace of development to bridge the service delivery gap, government agencies should break away from siloed planning and implementation. The cost of siloed planning and implementation is far too high with the side effect of potentially higher poverty incidence. The local and regional government should work in a transversal manner that is representative of all technical departments to plan, oversee, and implement all infrastructure projects
  • Low-cost high-impact solutions: There are many structural and non-structural options that can be pursued to build flood resilience in the Greater Dakar region whilst accelerating climate resilience. Low-cost high-impact solutions should be prioritised. For maximum benefits, options such as those presented below need to be planned and implemented using a climate change lens and using a transversal working approach:
    • Zoning ordinance for limited type of land use
    • Floodplain management (including zoning)
    • Sponge city
    • Green roof
    • Coastal vegetation restoration
    • Sustainable urban drainage solutions
    • Routine clean-up and maintenance of waterways

Conclusion

Floods have and will continue to constrain socio-economic development in Senegal and in the
Greater Dakar region and entrench a greater share of the population into poverty. In the face of a rapidly changing climate, floods of increased intensity and frequency will deepen
the vulnerability of the Dakarois population to future climate-related hazards and economic shocks (such as the one brought on by the Covid-19 crisis) and limit their ability to bounce back. The widespread lived experience of floods thus far cannot become the way of life. An integrated approach to urban planning is paramount for the City to effectively deliver on poverty reduction, service delivery and infrastructure development in the Greater Dakar region.