Population in the Dakar metropolitan area, estimated as close to 5 million people, is growing and putting increased pressure on already scarce water resources in this area with a hot semi-arid climate, informs Phys.org.
Senegal is one of the fastest growing economies in the African continent, and water security is key for its socio-economic development goals. As in many cities in the African continent, infrastructure development in Dakar struggles to keep up with a growing water demand for competing uses.
Khadija Mahecor Diouf, the mayor of the Golf Sud, a suburb in Dakar that has seen its population increase from 70,000 to 125,000 people in 10 years, says 50% of the households have problems with water access. And things are expected to worsen as the population doubles in the next 10 years.
As part of the Water in Circular Economy and Resilience (WICER) initiative, which supports countries to adopt circular economy and resilience principles, the World Bank Global Water Practice prepared a case study in 2021 focusing on the experience in Dakar. The Greater Dakar area has been dealing with a water deficit since 2011. The WICER case study notes that the Société Nationale des Eaux du Sénégal (SONES) has launched ambitious investment programs to secure and diversify the water supply. Dakar’s water is sourced from Lac de Guiers 300 km away, as well as from local groundwater, and more recently, desalination. Concerning sanitation, most of the metropolitan area uses onsite sanitation, primarily latrines, with only 32% of the population covered by the sewerage system.
To address water stress in a holistic manner, the Office National de l’Assainissement du Sénégal (ONAS), responsible for sanitation (onsite and sewered), as well as stormwater management, has been exploring and implementing circular economy opportunities. Experiences with the recovery of sanitation by-products include wastewater reuse for horticulturalists around Dakar, energy production from methane produced during wastewater treatment, and recovery of treated faecal sludge (biosolids), at the Cambérène WWTP and faecal sludge treatment plant. Senegal is recognized for its success in involving the private sector in service provision and key aspects of the sanitation service chain.
The government is interested in capitalizing on ONAS’ reuse experiences to further diversify the water source portfolio of Dakar and increase water supply resilience. To this effect, it requested support from the World Bank to do a study on water security. Challenges and Recommendations for Water Security in Senegal at National Level and in the Dakar-Mbour-Thiès Triangle, recently released, looks at water security challenges country-wide and in the area located between Dakar, Thiés and MBour, a triangle where more than half of Senegal’s population live, and where half of the country’s GDP is produced.
It found that deteriorating water resources and an inadequate institutional framework are threatening water security in Senegal, and will constrain future economic growth. Agriculture in the country uses surface water sources, though they do not meet the demand during low rainfall periods. Groundwater provides 85% of drinking water and water for industry, but overuse and pollution are major concerns. By 2035, water withdrawals are expected to increase by 30 to 60%, aggravating water stress.
The study finds it essential to diversify water supply sources with non-conventional resources such as desalination and wastewater recycling, and recommends implementing a circular economy approach to water security. Wastewater can be reused for aquifer recharge and irrigation, whereas wetlands and green infrastructure can help improve stormwater management and capture. The recommendations include as well measures to increase efficiency through the reduction of water losses, and strengthening governance in the Dakar-Mbour-Thiès triangle through a multisectoral and multi-actor platform.