Groundwater Quality Assessment and Impact of Urbanization on the Shallow Aquifer of Douala: A Temporal and Spatial Approach for groundwater management

Código

I-EBHE0049

Autores

Huguette Christiane EMVOUTOU, Albert Franklin TCHOKOUAHA, Lambert NDONANG TCHIENGUE, Flore MBATCHOU NANA, Joseph Martial MESSOLO, Carelle DATCHOUA, Brondone TCHINDA, Lionel TCHOUDENOU, Estelle NDOME EFFOUDOU

Tema

WG 1.03: Urban Water - Urbanization phenomenon & adequate water management

Resumo

The superficial aquifer system of Douala bears a vital source of groundwater for middle-class households but faces a growing threat from increased demand for water supply. This study aims to assess the spatial and temporal dynamics of this aquifer beyond seasonal variations combined to satellite images of 1990, 2000, 2010 and 2023. A total of 105 samples of hand dug wells, natural springs and rivers were examined through physicochemical parameters and major ions. The general flow is NE-SW towards the main River locally called Wouri and the aquifer feed several rivers of the town. Classical tools of hydrogeology, evidence acidic fresh slight mineralized groundwaters, under a latent corrosiveness and a tendency to scaling with a predominant chloride groundwater type. Although 97% of water meets WHO standards and a fraction of 3% is found to be unsuitable for agriculture, water supply and health, mainly due to occasional pollution in densely populated areas. Groundwater quality index exhibits from 1990 to 2023 that land cover experienced a gradual decrease, particularly in the densely populated Douala 3 District; affecting recharge which is particularly abundant in submerged lands. Factor analysis methods decipher processes such as the weathering of silicate minerals and dissolution predominant ionic exchange. Urbanized areas are vulnerable to nitrates, and high chloride levels could increase with future urbanization. This research highlights groundwater quality and the implications of unplanned urbanization on water supplies, laying a critical foundation for proactive groundwater management in Douala.