The 20th century has been characterized by an exponential population growth, with a high density in coastal zones. The aim of this work is to study the impact of land use changes on the hydrological cycle, and possible consequences in marine environment. The study has focused on the relationship between coastal urbanisation and submarine groundwater discharge (SGD) that may cause an alteration in the biogeochemical cycles of marine ecosystems. An analysis of land use changes, historical salinities and nutrients data in the Maresme (Barcelona) coastal zone have revealed that the percentage of urban and forest zone land use has increased since 1990, corresponding to a decrease of nutrients in coastal waters through SGD. These impacts may cause changes in coastal biogeochemical cycles, like the decrease in chlorophyll concentrations. Results denote the correlation between land use, coastal aquifer dynamics and the effects of SGD in coastal environments.