Flood Risk Assessment Scope and Sources of Flooding

A FRA must consider the flood risk from all sources of flooding where the proposed development is located within or in proximity to the fluvial (river) flood plain, the coastal flood plain or the flood inundation area of a reservoir. It should then identify measures that can be adopted to control and mitigate the flooding to the development or elsewhere as a result of the development. The main sources of flooding (under the implementation of the EU Floods Directive in Northern Ireland) are: • Fluvial – flooding from watercourses, either natural or man-made and either open or culverted. Such flooding is normally caused when channel or culvert capacity is exceeded and water flows out-of-bank onto the natural flood plan. • Coastal – flooding from the sea when water levels exceed the normal tidal range and flood onto low lying areas along the coastline. • Pluvial – flooding which results from excessive rainfall, generating overland flow that overwhelms existing drainage systems and / or collects in low lying areas.