River flooding, especially flash floods, are a serious and frequent problem in Samoa and in particular Apia where steep catchments with rapid flood onsets are subject to frequent heavy rainfall events. The April 2001 flood event inundated large parts of Apia urban area within a negligible time lag from the beginning of the intense rainfall. The surrounding watersheds responded to the flash floods with combined overbank/overland flow. Approximately 5,000 local residents were directly affected by the flood.
The flooding is mainly caused by urban extension activity in a floodplain environment. Only considerate flood plain management strategies and urban development planning strategies adapted to flood drainage are sustainable flood reduction methods. These are of high importance for the future of Apia, the principle centre of population, administration, and commercial acitivty in Samoa.