The Throsby, Styx and Cottage Creek catchments have been investigated under a combined Flood Study that also includes local drainage networks of the Newcastle CBD. The catchments are mainly urban and are drained by pits, pipes and open concrete channels. In small frequent storms the drainage system manages the runoff from local catchments, however there are cases where the age of the system limits its ability to drain. At these times nuisance flooding may be experienced in some of the older suburbs. In larger events overland flow and inundation of low lying areas are common because of the low lying topography. These catchments all drain to Newcastle Harbour leaving them prone to inundation during east coast lows when heavy rainfall combines with elevated ocean levels. Hunter River flooding coming from further up in the Hunter Valley is generally not a threat to these areas because floods that come down the river dissipate once they flow into the expansive floodplain of Newcastle Harbour.
Flood prone land map for the Throsby, Styx and Cottage Creek catchments