Residents have been asked to share their local knowledge to help create flood plans.
The Campbelltown Southern Catchments Flood Study covers the Mansfield Creek and Spring Creek catchments leading into the Georges River, including sections of Airds, Ambarvale, Bradbury, Rosemeadow and St Helens Park.
It aims to capture local flooding information such as floodwater depths, locations and speed so that Campbelltown Council can improve its understanding of flooding in the catchment.
A questionnaire has been created so residents can help the council with historical flooding data.
Campbelltown mayor George Brticevic said long-term Macarthur residents had a lot of valuable knowledge to share.
"Flood modelling is an important resource for emergency services and for the council when assessing the need for flood mitigation measures or making future planning decisions," he said.
"There is a wealth of local knowledge in our community, particularly among long-term residents, so I encourage you to complete the questionnaire and share your experiences and any photos or videos from past flooding events."
Locals have until Friday, August 27 to complete the survey, which is available at campbelltown.nsw.gov.au.