The Lake Illawarra, Mt Warrigal and Oak Flats catchments are all located on the southern side of Lake Illawarra and include the suburbs of Mt Warrigal, Warilla, and Oak Flats, along with a small portion of Blackbutt and Shellharbour City Centre. The study area is within the Shellharbour Local Government Area (LGA) and includes a number of small catchments, all less than 2 km² in area.

These catchments have a history of frequent hazardous flooding events. The area experiences flooding from floodwaters rising from Lake Illawarra as well as localised heavy downpours causing hazardous stormwater overland flows. This area also includes the Shellharbour City Centre Wet Basin, a prescribed dam as defined by the NSW Dam Safety Committee with a significant flood consequence category.
 
The most recent flooding event occurred in March 2011, when excessive rainfall resulted in major flooding. This caused widespread damage to the entire Shellharbour LGA and particularly affected Lake Illawarra, Mt Warrigal and Oak Flats. These areas also experienced flood damage during November 2013, and again in March 2014.

The NSW Office of Environment and Heritage is responsible for coordinating floodplain management funds in accordance with the NSW Government Flood Prone Land Policy. Priorities are assessed and funds are allocated to assist Councils in the preparation of floodplain risk management plans and the implementation of these plans. Funding was granted for the 2013/2014 financial year to undertake a flood study of the Lake Illawarra, Mt Warrigal and Oak Flats Catchments, and the flood study was adopted by Council in February 2020. The flood study defines the nature and the extent of flood behaviour and will also assist us and key emergency personnel in creating community awareness of the potential effects of flooding.