The Aghien lagoon is expected to provide drinking water for the population of Abidjan. Hydrodynamic modelling is therefore required to assess the impact of this operation, coupled with the impact of climate change, on the functioning of this lagoon ecosystem. The aim of our work is to determine the hydrodynamic parameters required for this exercise. The methodology consisted of surveying sections of the lagoon and its un-surveyed tributaries using a Work Horse Rio Grande Acoustic Doppler Current Profiler (ADCP). The results show that the effect of upwelling is clearly evident in sections 1 and 3 of the channel, with velocity vectors directed towards the Aghien lagoon. The mean velocity is around 0.42 m/s at low tide, compared to 0.385 m/s at high tide in section 03. The greatest variation in mean flow velocity was observed in section 02, with values increasing from 0.23 m/s at low tide to 0.18 m/s at high tide. However, the effect of upwelling attenuated the mean flow rates from 57.77 m3/s to 40.29 m3/s in section 2 (Mé section) and from 265.15 m3/s to 237.22 m3/s in section 3 (downstream channel). The flow in the northern part of the lagoon is low (0.007 m/s) and the velocity vectors point in opposite directions.