Darlington Point Floodplain Risk Management and Plan

A graph which shows how the discharge or stage/flood level at any particular location varies with time during a flood.

Term given to the study of the rainfall and runoff process; in particular, the evaluation of peak flows, flow volumes and the derivation of hydrographs for a range of floods.

Smaller scale problems in urban areas. They are outside the definition of major drainage in this glossary.

Inundation by local runoff rather than overbank discharge from a stream, river, estuary, lake or dam.

Inundation of normally dry land occurring when water overflows the natural or artificial banks of a stream, river, estuary, lake or dam.

Councils have discretion in determining whether urban drainage problems are associated with major or local drainage. For the purposes of this manual major drainage involves:

• The floodplains of original watercourses (which may now be piped, channelised or diverted), or sloping areas where overland flows develop along alternative paths once system capacity is exceeded; and/or

• Water depths generally in excess of 0.3m (in the major system design storm as defined in the current version of Australian Rainfall and Runoff). These conditions may result in danger to personal safety and property damage to both premises and vehicles; and/or

• Major overland flowpaths through developed areas outside of defined drainage reserves; and/or

• The potential to affect a number of buildings along the major flow path.