Hydrological and water quality assessment of the Aghien Lagoon hydrosystem (Abidjan, Cote d'Ivoire)

To face the difficulties involved in supplying freshwater to Abidjan (Cote d'Ivoire), the Aghien Lagoon connected by a channel to the Potou-ebrie lagoon is a potential resource for production of drinking water. A hydro-meteorological network was installed with the objective of assessing the sustainability of the lagoon in terms of both quantity and quality, and 10 sampling campaigns were conducted between June 2015 and December 2016 to evaluate the water quality. Even if the annual flow of the two peri-urban tributaries is just equivalent to the volume of the lagoon, the large daily inflow by the channel can secure the future quantitative demand. Unfortunately, the main tributaries in the peri-urban zones have lacked sanitation services and present numerous markers of pollution. Even if the water quality status of the lagoon remains quite good with respect to total nitrogen and total phosphorus, it nevertheless presents a high potential risk of eutrophication.