The Department of Water and Environmental Regulation produces floodplain mapping of rivers and major watercourses and provides floodplain development advice to ensure that proposed floodplain development has adequate flood protection and does not impact on the existing flood regime of the area.

This advice is related to major river flooding only. Other issues, such as stormwater drainage and environmental and ecological considerations are not addressed.

This dataset comprises polygon areas showing land where development controls maybe applied to ensure an adequate level of flood protection is provided to proposed development. Information on flooding or flood levels outside of these areas is not currently available.

Links to the associated strategy diagrams and general notes on the available floodplain mapping are located under field name ‘STRATEGY’ in the attribute table.

Note: To see the full scope of the floodplain mapping, 12 dataset layers are required to be loaded in the following order:

FLOODPLAIN DATASET LAYERS:
FPM Flood Level Points (m AHD) FPM Flood Level Contours (m AHD) FPM 1 in 100 (1%) AEP Floodway and Flood Fringe Line FPM Extent of Flooding FPM Levee Banks FPM Location of Cross Sections FPM 1 in 100 (1%) AEP Floodplain Development Control Area FPM Map Index FPM Bridges FPM Special Development Condition Area FPM 1 in 100 (1%) AEP Floodway and Flood Fringe Area FPM Floodplain Area

The dataset covers the following areas:

• Avon River - Toodyay to Beverley.

• Balingup Brook - Balingup Townsite.

• Bandy Creek - Esperance Townsite.

• Blackwood River – Augusta, Bridgetown, Nannup and Boyup Brook Townsites.

• Bow River - Bow Bridge Townsite.

• Capel River - Capel Townsite.

• Chapman River – Geraldton and Nabawa Townsites.

• Coblinine River & Dorderyemunning Creek - Wagin Townsite.

• Cohn Creek - Merredin Townsite.

• Collie River - Collie Townsite.

• Corrigin Townsite.

• Denmark River - Denmark Townsite.

• Exmouth Townsite.

• Ferguson River - Preston River to northwest of Dardanup Townsite.

• Fitzroy River - Fitzroy Crossing Townsite, Fitzroy Crossing Townsite to Willare and Noonkanbah.

• Five Mile Brook - Bunbury Townsite.

• Gascoyne River - Carnarvon Townsite, the Lower Gascoyne and Gascoyne Junction.

• Gingin Brook - Gingin Townsite.

• Gordon River - Tambellup Townsite.

• Greenough River – Indian Ocean to Walkaway.

• Gribble Creek - Kalgoorlie Townsite.

• Harding River - Roebourne Townsite.

• Irwin River - Dongara Townsite.

• Karratha Townsite.

• Lake Grace Townsite.

• Leschenault Estuary / Collie River/ Preston River/ Brunswick River/ Eedle's Gully (Greater Bunbury Region) - Collie River from Leschenault Estuary to just east of South Western Highway, Preston River from Leschenault Estuary to Donnybrook-Boyup Brook Rd, Brunswick River from Collie River to just east of South Western Highway, Eedles Gully from Preston River to Bunbury Aerodrome and Leschenault Estuary from Bunbury to Binningup.

• Margaret River – Margaret River Townsite.

• Moore River - Moora Townsite and Bennies Road area.

• Murchison River - Kalbarri Townsite and North West Coastal Hwy to Jack Hills.

• Nullagine River – Nullagine Townsite.

• Port Hedland Townsite.

• Serpentine River, Murray River and the Peel Inlet / Harvey Estuary - Peel Inlet / Harvey Estuary to Pinjarra and south to the Darling Scarp (Murray River) and Peel Inlet / Harvey Estuary to Wellard and east to South Western Highway (Serpentine River).

• Swan River, Canning River and Tributaries: Fremantle to Walyunga National Park (Swan River) and Canning Bridge to Brookton Highway (Canning River). Tributaries include Bennett Brook, Blackadder Creek, Ellen Brook, Helena River, Jane Brook, St Leonards Creek, Susannah Brook (Swan River) and Southern River/ Wungong Brook (Canning River).

• Toby Inlet – Quindalup Townsite.

• Turkey Creek - Warmun Aboriginal Community.

• Vasse-Wonnerup Estuaries, Broadwater and New River - Busselton Townsite.

• Willyung Creek – Albany.

• Yakamia Creek – Albany Townsite.

Glossary:

• Annual exceedance probability (AEP) - the likelihood of occurance of a flood of a given size or larger in any one year; usually expressed as a percentage.

• 1 in 100 AEP flood - this means that there is a 1 in 100 (or 1%) chance of a flow of this size or larger occurring in any one year. This flood has a 50% chance of being experienced at least once in a person's life time. The 1 in 100 AEP flood has been generally adopted in Australia and overseas as the basis for floodplain management planning.

• Floodplain - the portion of a river valley next to the river channel which is covered with water when the rier overflows its banks during major river flows. The term also applies to land adjacent to estauries which is subject to flooding.

• Australian Height Datum (AHD) - is a geodetic datum for altitude measurement in Australia. It was adopted in 1971 by the National Mapping Council as the datum to which all vertical control for mapping is to be referred. The datum is based on the mean sea level (1966-1968) being assigned the value 0.000m on the Australian Height Datum (AHD) at 30 tide gauges around the coast of the Australian continent.

This dataset was formally known as FPM 1 in 100 (1%) AEP Floodplain Development Control Area (DOW-032)