For many years the coastline of Dublin Bay lay along the seaward side of the Rock Road, fringed by salt-marsh which was covered at high tide. The construction of the Dublin - Kingstown Railway in 1834-35 cut off an area of approximately 19 hectares between Merrion Gates and Blackrock. Much of this area was drained for development or amenity purposes, but the marsh survived because it was fed by three streams, drainage from the road and by a well.

Some time before 1876 an elaborate drainage system was built, with a sluice gate beneath the railway line at Williamstown, which was so effective that the marsh was cultivated during both World Wars, until this operation became uneconomic.

A culvert was built in 1964 on the northern side to prevent flooding. An Taisce acquired the Reserve in 1971,and are now assisted in its management by a Management Advisory Committee which represents several interested organisations and strongly supported by the Friends of Booterstown.

The marsh was badly affected by an oil spillage in 1985, since when there has been considerable discussion to find the optimum management strategy to apply, especially following the re-discovery there of a rare plant, Puccinellia fasciculata. This plant, known as Borrer's salt-marsh grass, is extremely rare in Ireland, and needs very specific conditions only found in a marsh like Booterstown. It is, of course, protected by law, and is one of the treasures of the Reserve, though suppressed by flooding.