sentences:  In the second half of the 19th century about 65 km² of the estuary's lowlands have been embanked and reclaimed, largely for agricultural purposes.In the late 1930s, transatlantic air traffic was dominated by flying boats, and a flying boat terminal was located at Foynes on the south side of the Shannon Estuary.However, it was realised that developing technology would require a permanent runway and airport.