Flood Studies

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Throsby Creek floodplain - Maryville early 1900's

Council has carried out flood studies in the major local catchments of Newcastle to estimate:

  • Flood extent
  • Flood depth and velocity
  • Flood level
  • Provisional hazard

This is the first step in the process of planning for future floods and these studies create the platform for the Flood Management Plans.

View the studies

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.

Reports

 View the mapFlood prone land map for the Throsby, Styx and Cottage Creek catchments

The Flood Study investigates flood behaviour for the urban areas upstream of Hexham Swamp where Ironbark Creek drains the suburbs of Elermore Vale and Wallsend. The creek is predominantly a natural channel with associated floodplain of open spaces and sports fields. During rare storm events these floodplains can spill into urban areas causing overland flow flooding. Wallsend CBD is located where a broad natural channel and floodplain converges to a narrow canal with adjacent commercial development on the floodplain. Significant flood risk is evident for the CBD where flooding has been recorded approximately every decade since the late 19th century.

Report

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Flood prone land in the Ironbark Creek catchment

The upper catchment of Dark Creek includes the bushland behind Jesmond Park and the suburbs of Callaghan and North Lambton. Flows from the upper catchments converge at the Jesmond commercial area and flow in a concrete open channel through Burmingham Gardens until meeting Ironbark Creek at Fletcher Park. The capacity of the drainage system and open channel is exceeded during large storm events and flooding of residential areas and the Jesmond Commercial Area is common and has been mapped.

Report

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Flood prone land in the Dark Creek catchment

A Lower Hunter River Flood Study was completed in 1994 for the reach extending from Newcastle Harbour up to Green Rocks. Then an update of the Flood Study was completed in 2008 to include more up to date topography of the Hexham area. The study found that there are parts of the Newcastle Area vulnerable to Hunter River floods including Beresfield, Tarro, Hexham, Shortland and Sandgate. Areas surrounding Newcastle Harbour are less flood-prone during Hunter River floods because river flows are adequately stored in the floodplain of the Harbour and Fullerton Cove. More recent residential development in Fletcher and Maryland fringes Hexham Swamp and has been built above the predicted flood levels of the Hunter River to reduce flood risk.

Report

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 Lower Hunter River in flood

The harbour of Newcastle experiences elevated sea levels due to coastal storms causing large waves, galeforce winds and extreme tides. These storms are commonly referred to as East Coast Low events. These factors can combine to cause Storm Surge up Newcastle Harbour that floods low areas along the foreshore. Suburbs such as Stockton, Carrington, Wickham, Honeysuckle and Kooragang are particularly sensitive to Storm Surge.

Report

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 Newcastle Harbour post June 2007 storm event - one of the most severe East Coast Lows on record

Newcastle West is changing. Redevelopment of infrastructure and private property is happening in flood prone land surrounding Cottage Creek. City of Newcastle has undertaken a detailed study of flood behaviour in the area around Marketown, Wickham Interchange and Honeysuckle to inform how flood risks can be reduced. A number of options were investigated and it was found that improving conveyance of flood water in the Cottage Creek channel is the preferred option (Option E). City of Newcastle are now working with Developers and the State Government to pursue this option. Measures to improve the conveyance include channel widening and bridge replacements. 

A number of studies have been completed over the years prior to the preparation of the flood studies. Supporting documents include:

  1. PBP (1996). Lower Hunter Valley Floodplain Management Study: Assessment of Strategic Options for Community Consultation (DRAFT). Prepared for Port Stephens and the City of Newcastle.
  2. PBP (1997). Lower Hunter Valley Floodplain Management Study: Volume A - Assessment of Strategic Options for Community Consultation Summary Report (DRAFT). Prepared for Port Stephens and the City of Newcastle.
  3. PBP (2001). Lower Hunter Valley Floodplain Management Study: Volume B - Planning Implementation Strategy (DRAFT). Prepared for Port Stephens and the City of Newcastle.
  4. PBP (2001). Lower Hunter Valley Floodplain Management Study: Volume B - Planning Implementation Strategy (DRAFT), Summary Report. Prepared for Port Stephens and the City of Newcastle.
  5. PBP (2007). Wallsend Floodplain Risk Management Study and Plan. Prepared for the City of Newcastle.