River and sea defences

River defences are provided at locations where watercourses are unable to contain high flows within their channels. Major sea defences are situated at Lough Foyle and Strangford Lough.

Protection, in the form of flood banks, or flood walls, is provided where serious flooding has occurred in the past, or where there is significant risk of such an occurrence in the future. These defences protect airfields, roads and railways, commercial and residential properties and valuable agricultural farmland.