The Llobregat River has accumulated multiple deltas through Quaternary eustatic cycles. The rapid rises
and step-wise, relatively slower falls in sea level have produced a bias towards preserving forced regressive
system tracks and eroding the high-stand system tracks with the exception of the Holocene delta. Subsurface
data indicates that the Quaternary deltas were feed by the Llobregat river and «rieras» derived from Garraf
and Collserola, but the sediment was probably redistributed by long-shore currents to form a unique delta
front. The Holocene Llobregat River high-stand delta progrades over older fluvial, flood-plain and shoreline
deposits equivalent to the older deltas now preserved at the continental margin. A number of paleo-flow
channels feeding the older Quaternary deltas illustrate the complexity for the exploitation and protection
of groundwater found in these deposits