PPS 15: Planning and Flood Risk
1.1 Flooding from rivers and coastal waters is a natural phenomenon that cannot be entirely prevented. It occurs when the capacity of a watercourse to convey water through an area is exceeded or when the volume of sea water arriving on land exceeds its capacity to discharge it. It may also result simply from the accumulation of rainfall on low-lying ground. The man-made environment can exacerbate the consequences of flooding, for example, where development in a flood plain places buildings and people at risk or by building in areas where existing drainage infrastructure is inadequate.
1.2 The effects of flooding on human activity are wide ranging, impacting on the economy, social wellbeing and the environment. For individuals and communities the impact can be significant in terms of personal suffering and financial loss and, even where flooding has natural causes, it can have damaging effects on the environment.
1.3 Much of Northern Ireland is low-lying and many of our rivers and streams have gentle gradients in their lower reaches. With lowland soils that are mostly clay rich and of low permeability there is the widespread potential for localised flooding, a situation reflected in the Region’s long history of arterial land drainage.
1.4 Climate change is expected to increase flood risk, indeed the experience of recent years suggests that the incidence of flooding in the Region, as at national and global level, is already increasing.
1.5 The primary aim of this PPS is therefore to prevent future development that may be at risk from flooding or that may increase the risk of flooding elsewhere.