If the bogs of Ireland could be drained then they could be used to grow this raw material without affecting the existing agricultural output of the country. In 1811–1812 Alexander Nimmo surveyed and mapped over 76,000 acres (30,700 ha) of land on the Iveragh Peninsula for the Bogs Commission. Over 17,000 acres (7,000 ha) of this were on the sea shore area of the Laune River, Lower Maine River, and Castlemaine Harbour. These stone and earthen banks still prevent high tides flooding much of this land. The banks vary from 1 m to over 5 m in height. Sluice gates allow water drain out at low tide and prevent rising tides from flooding the land. The banks run from the townland of Tullig near Cromane, to Killorglin, part way up the Laune, around the area of Callinafercy, up both sides of the Maine River and along the north side of Castlemaine Harbour, part way to Inch. Various major repairs are evident where large rocks and concrete have replaced the stone and earth, although much of the original banks are still intact.