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NSW Flood Data Portal

Flood study

Jewells Wetland Flood Study

The Jewells Wetland Flood Study has been prepared for Lake Macquarie City Council (Council) to define the existing flood behaviour in the Jewells Wetland catchment and establish the basis for subsequent floodplain management activities. The primary objective of the Flood Study is to define the flood behaviour of the Jewells Wetland catchment through the establishment of appropriate numerical models. The study has produced information on flood flows, velocities, levels and extents for a range of flood event magnitudes under existing catchment and floodplain conditions. Specifically, the study incorporates:

  • Compilation and review of existing information pertinent to the study and acquisition of additional data including survey as required;
  • Development and calibration of appropriate hydrologic and hydraulic models;
  • Determination of design flood conditions for a range of design event including the 50% AEP, 20% AEP, 10% AEP, 5% AEP, 2% AEP, 1% AEP, 0.5% AEP and PMF event; and
  • Presentation of study methodology, results and findings in a comprehensive report incorporating appropriate flood mapping.

Additional Information

Field Value
Title Jewells Wetland Flood Study
River Basin 211 - Macquarie Tuggerah
Publication Date 1 September 2013
Themes Land and Resource Management
Spatial Extent
© OpenStreetMap contributors
Council/LGA Lake Macquarie City Council
Author/ Prepared by BMT WBM Pty Ltd
Publish date 27 March 2017
Update date 27 March 2017
Place Name Jewells Wetland
Approval State Approved
Submitted for approval 27 March 2017
Submitted by John Silk
Approved 28 March 2017
Approved by silkj
Data Comment

Report only; no other data. Legacy data; may have been superseded.

Additional information about the Catchment: The Jewells Wetland catchment is a significant catchment located in the north-east region of the city of Lake Macquarie. The catchment occupies a total catchment area of around 21km2, extending from the ring of townships along the catchment ridgeline, including Dudley, Whitebridge, Charlestown, Mount Hutton, Tingira Heights, and Floraville, draining through a number of creek systems to the coastal outlet at Nine-Mile Beach, Redhead. In addition to the Jewells Wetland catchment, the study also incorporates the neighbouring Freshwater Creek catchment which encompasses an additional area of some 3km2. Evident in the catchment topography are the numerous sub-catchments typically defined by relative steep upper catchments emanating from the ridgeline running around the hill top suburbs of Tingira Heights, Mt Hutton, Charlestown and Whitebridge. The main flowpaths through the catchments are generally well-defined draining through to the low-lying Jewells Wetland and on to the coastal outlet. The lower Jewells Wetland (Crokers Creek) is an Intermittently Closed and Open Lake or Lagoon (ICOLL), which are a characteristic feature of the NSW coastline. An ICOLL has an intermittent connection to the ocean, being terminated periodically by an accumulation of marine sediment in the form of an entrance berm. The entrance berm typically undergoes a period of building during heavy seas, in which the berm level is raised, reducing the connectivity between lake and ocean. Catchment runoff following rainfall events is the natural process through which the entrance berm overtops and scours (entrance breakout), increasing connectivity between lake and ocean. It is noted that the entrance system consists of a number of potential channels that can scour through the main barrier at the front on Nine-Mile Beach. Under flood conditions, the ability of these channels to scour and convey floodwater from the system has a potentially significant effect on peak flood levels, particularly in the lower catchment below Kalaroo Road. A significant proportion of the catchment is urbanised consisting of a mix of predominantly residential and some commercial land use. The Bennetts Green and Gateshead estates represent the main commercial/industrial centres within the catchment. The predominant land uses within the catchment can be summarised as approximately 50% natural catchment, 35% urban residential and 7% commercial/industrial. Given the nature of the catchment topography, the majority of urban area is located on typically higher ground. However, some development has encroached on the floodplain areas of the key tributary particularly around Windale and Gateshead. The lower lying areas around Jewells Wetland are largely undeveloped. However some tourist park and retirement communities along Kalaroo Road are located on relatively low-lying land immediately adjacent to the entrance channels at the downstream end of the catchment.

Identifier 7c90126a-f4fd-406f-9293-85b894490e63