The general purpose of the study “Pilot modelling of the effects of climate change in the Oka estuary, Bizkaia, for the determination of the adaptation measures to be taken in the Basque estuaries” - OKAKLIMA project - is to make an assessment of the effects caused by climate change in the dynamics of the estuaries of the Basque Country, focusing on the Oka estuary as pilot area. This first stage is essential to determine the adaptation measures to be taken to increase the resilience of the estuaries facing climate change.