By the end of the Roman period, and largely as the result of late Romano-British activity, somewhat over one-half of the tidal wetlands of the inner Severn Estuary between Gloucester and Awre had been embanked and drained. Little reclamation occurred during the medieval period, but early modern-modern times witnessed substantial further activity, leaving scant active salt marsh today. The Romano-British reclamations are recognized on the basis of archaeological evidence and, where direct evidence of settlement is lacking, by the degree to which the reclaimed areas are depressed below the level of the contemporary active marshes along the tidal river. Despite the similarity in the amount of available wetland on both banks, most of the Romano-British reclamations are to be found on the left bank of the Severn, and most of these carry a settlement directly on the alluvium. This distribution pattern points to significant differences in the organization and use of land between the two banks of the river and, when combined with other evidence, suggests that wetland reclamation on the left bank was mostly a feature of the development of large villa estates, with the alluvial settlements representing substantial, outlying farmsteads. Iron-making based on rich ores imported from the Forest of Dean occurred at all the wetland and near-wetland settlements on the two banks, and locally may have taken place on an industrial scale. At Awre on the right bank, however, an early iron-making tradition seems to have survived to a late Roman date.