Overview of the project

Flooding is one of the main challenges facing the City of Dakar in terms of vulnerability to climate change, and has been identified as an emergency factor. This vulnerability of peripheral neighbourhoods can only increase with climate change, and the increased frequency of regular rainy periods.

Consequently, the Government of Senegal has made flood control one of its priorities. This is reflected in the Plan Sénégal Émergent (PSE,) and operationally defined in the Ten-Year Flood Control Program adopted in 2012. The World Bank currently estimates that the value of economic assets vulnerable to flooding in the Dakar region amounts to 40 billion Euros. In 2006, the Minister of Prevention and Public Hygiene launched a major project to modernize the Grand-Yoff sewerage system. Within this framework, the retention basin of the Zone de Captage was built to capture rainwater from the Grand Yoff catchment area and to limit the risks of flooding in case of heavy rain.

In addition, the high rate of urbanization in Dakar is also having a devastating effect on a number of aspects, including the quality of health services, the economy, the environment, and livelihoods.

The area known as the “Zone de Captage” (Abstraction Zone) is the outlet of a large watershed to which stormwater from several neighbourhoods in Dakar is pumped into Hann Bay.

The basin has a size of 7.70 ha, an average depth of nearly 2 m and a storage volume of 120 to 160,000 m3.  The CFF (C40 and GIZ) is supporting the City of Dakar in this project of hydraulic and landscape redevelopment of the stormwater retention basin. Currently, the basin is facing a number of difficulties exacerbated by the pressures of urbanization and population growth. For example, it is overgrown with:

• Aquatic plants
• Blackish stagnant water
• Dumping of various types of garbage
• Solid waste discharges
• Sewage discharges are connected to and carried to the pond by the storm drains

All of these actions have created an accumulation of water in the basin that is not only a nuisance to the residents, but also a source of disturbance, pollution and contamination to the surrounding neighbourhoods. As a result, the basin has lost its primary function (stormwater management) over time.

The project aims not only to redevelop the basin and make it functional, thereby improving flood resilience in the area and the city but also to achieve a number of associated socio-economic benefits, including reduced health risks and overall improvement of the surrounding urban space.

The main objective of CFF’s support to the City of Dakar will be to lead this project towards implementation in partnership with the Office National de l’Assainissement du Sénégal (ONAS).

The main components of the project are:

• The elimination of direct wastewater discharges: connection to the network, bringing polluting riparian activities up to standard or evacuation, creation of a plant purification system with reuse of treated water for watering riparian trees and gardening activities in the basin
• The reinforcement of the capacity of the basin (management of a ten-year rainfall) by upstream relieve (towards the niayes), deepening and creation of several floodable levels gradually in the basin
• Convergent actions better waste management
• Urban development of the surroundings (economic and cultural activities, traffic optimization, walking and family activities)

Currently, the preliminary studies (topographic, geotechnical and feasibility) are carried out. The next steps to be taken are:

• The detailed design study
• The environmental and social impact study
• The continuation of the consultation and land procedures
• The coordination of the contracting authorities and agreement
• The launching of the works contracts

The project is estimated at the sum of Seven Billion Three Hundred Million CFA Francs (7.300.000.000 FCFA)