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.