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 contains 10 polygons illustrating the area of land adjacent to a water body which is subject to flooding during a range of possible design events: 1 in 10 (10%) AEP floodplain 1 in 20 (5%) AEP floodplain 1 in 25 (4%) AEP floodplain 1 in 50 (2%) AEP floodplain 1 in 100 (1%) AEP floodplain Designated flood event floodplain 1 in 200 (0.5%) AEP floodplain 1 in 500 (0.2%) AEP floodplain Maximum channel capacity Probable maximum flood 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. Blackwood River – Augusta, Bridgetown, Nannup and Boyup Brook Townsites. Bow River - Bow Bridge Townsite. Capel River - Capel Townsite. Chapman River – Geraldton Townsite. Coblinine River & Dorderyemunning Creek - Wagin Townsite. Collie River - Collie Townsite. Denmark River - Denmark Townsite. Fitzroy River - Fitzroy Crossing Townsite. Five Mile Brook - Bunbury Townsite. Gascoyne River - Carnarvon Townsite and the Lower Gascoyne (contains both pre and post-stage 2 Carnarvon flood mitigation works mapping: refer to "COMMENTS" field). Greenough River – Indian Ocean to Walkaway. Gribble Creek - Kalgoorlie Townsite. Harding River - Roebourne Townsite. Irwin River - Dongara Townsite. Margaret River – Margaret River Townsite. Nullagine River – Nullagine Townsite. Preston River - Boyanup and Donnybrook Townsites. 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. Wagin Townsite. Willyung Creek – Albany Townsite. Yakamia Creek – Albany Townsite. The dataset also covers the following areas: However, these are not design flood events, they are major historical or alternative scenario flood events that have been used (instead of the design flow, if present) to set planning & development guidelines as part of the floodplain management strategy. Refer to "FPM Historical Extent of Flooding" metadata for more details. Cohn Creek - Merredin Townsite. Corrigin Townsite. Gordon River - Tambellup Townsite. Turkey Creek - Warmun Aboriginal Community (contains both design and historical information). Yakamia Creek – Albany Townsite (contains both design and alternative scenario information). Glossary: Annual exceedance probability (AEP) - the likelihood of occurrence 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 lifetime. The 1 in 100 AEP flood has been generally adopted in Australia and overseas as the basis for floodplain management planning. Flood fringe - the area of the floodplain, outside of the floodway where development could be permitted provided it is compatible with flood hazard and building conditions provide an adequate level of flood protection. These areas are generally covered by still or very slowly moving waters during a 1 in 100 (1%) AEP flood. Floodplain - the portion of a river valley next to the river channel which is covered with water when the river overflows its banks during major river flows. The term also applies to land adjacent to estuaries which is subject to flooding. Floodway - the river channel and a portion of the floodplain where a significant flow or storage of water occurs during floods. If the floodway is even partially blocked then the natural flooding regime of th area may be detrimentally impacted with flood levels being raised and affecting areas which may not have been previously affected. Development in floodways is to be avoided wherever possible. 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 formerly known as FPM Floodplain Area (DOW-054)

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. Both the floodway and flood fringe make up the 1 in 100 (1%) annual exceedance probability (AEP) floodplain, however there are areas where the floodplain exists, but the floodway and flood fringe does not. In such situations, a different floodplain management strategy applies (for example, the Swan River between the Narrows and Canning Bridges). This dataset contains four lines - Floodway limit, Extent of 1 in 100 (1%) AEP flooding, Extent of floodway & Extent of study. The Floodway limit, Extent of floodway and Extent of 1 in 100 (1%) AEP Flooding and Extent of study line types are boundaries which appropriately overlay over the "FPM 1 in 100 (1%) AEP Floodway and Flood Fringe Areas" (polygon) dataset. 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, Northam, York and Beverley Townsites. Blackwood River – Augusta, Bridgetown, Nannup and Boyup Brook Townsites. Brunswick River - Greater Bunbury Coblinine River & Dorderyemunning Creek - Wagin Townsite. Collie River - Collie Townsite. Chapman River – Geraldton Townsite. Denmark River – Denmark Townsite. Gascoyne River - Carnarvon Townsite and the Lower Gascoyne. Gribble Creek - Kalgoorlie Townsite. Harding River - Roebourne Townsite. Irwin River - Dongara Townsite. Lower Collie River - Greater Bunbury. Preston River - Donnybrook Townsite. Serpentine River, Peel, Birrega & Oaklands Drains, 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 (Peel Main Drain), east to South Western Highway (Serpentine River) and north to Wungong Brook (Birrega Drain). Swan River, Canning River and Tributaries: Perth - 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, Henley Brook, Jane Brook, St Leonards Creek, Susannah Brook (Swan River) and Southern River/ Wungong Brook (Canning River). Toby Inlet – Quindalup Townsite. Vasse-Wonnerup Estuaries, Broadwater and New River - Busselton Townsite. For further information on flooding and floodplain management in Western Australia, please refer to our Water Facts publications: Flooding in Western Australia (Water facts 13) and Floodplain Management (Water facts 14). This information is available at the following addresses: https://www.wa.gov.au/system/files/2022-11/Water-facts-13-Flooding-in-Western-Australia.pdf https://www.wa.gov.au/system/files/2022-11/Water-facts-14-Floodplain-management.pdf Glossary: Annual exceedance probability (AEP) - the likelihood of occurrence 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 lifetime. The 1 in 100 AEP flood has been generally adopted in Australia and overseas as the basis for floodplain management planning. Flood fringe - the area of the floodplain, outside of the floodway where development could be permitted provided it is compatible with flood hazard and building conditions provide an adequate level of flood protection. These areas are generally covered by still or very slowly moving waters during a 1 in 100 (1%) AEP flood. Floodplain - the portion of a river valley next to the river channel which is covered with water when the river overflows its banks during major river flows. The term also applies to land adjacent to estuaries which is subject to flooding. Floodway - the river channel and a portion of the floodplain where a significant flow or storage of water occurs during floods. If the floodway is even partially blocked, then the natural flooding regime of the area may be detrimentally impacted with flood levels being raised and affecting areas which may not have been previously affected. Development in floodways is to be avoided wherever possible. 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.

Historically, low-lying land adjacent to rivers and coastlines has been favoured for settlement as they provided sources of fresh water, food, transportation and waste disposal. These areas become affected by flooding during sufficiently heavy or prolonged rainfall, high tides or storm surges and cyclones. In the north-west of the State flooding is most likely to be caused by the summer monsoon or tropical cyclones while floods in the south-west are more likely to occur in response to heavy winter rainfalls. While historical flood records and information extend as far back as 1830, detailed information on peak flood levels is typically limited to the last few decades. This dataset shows the area of inundation (polygons), i.e., the floodplain area that has occurred during the major flood events in Western Australia. Note: To see the full scope of the historical flood mapping, 3 dataset layers are required to be loaded in the following order: FLOODPLAIN DATASET LAYERS:
FPM Historical Flood Levels (m AHD) FPM Historical Extent of Flooding FPM Historical Floodplain Area The major flood events that are covered in this dataset are: Bow Bridge Townsite (June 1988) Corrigin Townsite (January 1982) Esperance Townsite (January 2007) Kupungarri to Willare (including Dales Yard & Mount Joseph gauging stations) - Fitzroy River (January 2023) Lake Grace Townsite (January 2006) Merredin Townsite (February 1979) Perth (February 2017) Tambellup Townsite (January 1982) Warmun Aboriginal Community (March 2011) York Townsite (July 2021, August 2022) Other major flood events that have occurred in the past include: Blackwood River (1945, 1955, 1963, 1964, 1982) Collie River (1945, 1963, 1964, 1974, 1982) Fitzroy River (1983, 1986, 1991, 1993, 2002, 2011) Gascoyne River (1960, 1961, 1980, 1995, 2000, 2010) Greenough River (1888, 1927, 1953, 1971, 1988, 1999, 2006) Moore River (1934, 1955, 1961, 1995, 1999) Murray River (1862, 1945, 1955, 1964) Preston River (1964, 1967, 1974, 1983, 1990, 2011) Swan River (1862, 1872, 1945, 1955, 1964, 1983) The historical flood information is used in the Department of Water and Environmental Regulation's floodplain management activities to ensure that floodplains are managed for the benefit of the whole community, minimising the risk and damages and protecting environmental values. Floodplain mapping datasets and floodplain development strategies for rivers and major watercourses in Western Australia are also available from the Department of Water and Environmental Regulation. GLOSSARY:

Annual exceedance probability (AEP) - the likelihood of occurrence 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 lifetime. 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 river overflows its banks during major river flows. The term also applies to land adjacent to estuaries 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.

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 envirionmental and ecological considerations are not addressed. This dataset contains 10 polygons …Show full descriptionThe 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 envirionmental and ecological considerations are not addressed. This dataset contains 10 polygons illustrating the area of land adjacent to a water body which is subject to flooding during a range of possible design events: 1 in 10 (10%) AEP floodplain 1 in 20 (5%) AEP floodplain 1 in 25 (4%) AEP floodplain 1 in 50 (2%) AEP floodplain 1 in 100 (1%) AEP floodplain Designated flood event floodplain 1 in 200 (0.5%) AEP floodplain 1 in 500 (0.2%) AEP floodplain Maximum channel capacity Probable maximum flood 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. Blackwood River – Augusta, Bridgetown, Nannup and Boyup Brook Townsites. Bow River - Bow Bridge Townsite. Capel River - Capel Townsite. Chapman River – Geraldton Townsite. Coblinine River & Dorderyemunning Creek - Wagin Townsite. Collie River - Collie Townsite. Denmark River - Denmark Townsite. Fitzroy River - Fitzroy Crossing Townsite. Five Mile Brook - Bunbury Townsite. Gascoyne River - Carnarvon Townsite and the Lower Gascoyne (contains both pre and post-stage 2 Carnarvon flood mitigation works mapping: refer to "COMMENTS" field). Greenough River – Indian Ocean to Walkaway. Gribble Creek - Kalgoorlie Townsite. Harding River - Roebourne Townsite. Irwin River - Dongara Townsite. Margaret River – Margaret River Townsite. Nullagine River – Nullagine Townsite. Preston River - Boyanup and Donnybrook Townsites. 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. Wagin Townsite. Willyung Creek – Albany Townsite. Yakamia Creek – Albany Townsite. The dataset also covers the following areas: However these are not design flood events, they are major historical or alternative scenario flood events that have been used (instead of the design flow, if present) to set planning & development guidelines as part of the floodplain management strategy. Refer to "FPM Historical Extent of Flooding" metadata for more details. Cohn Creek - Merredin Townsite. Corrigin Townsite. Gordon River - Tambellup Townsite. Turkey Creek - Warmun Aboriginal Community (contains both design and historical information). Yakamia Creek – Albany Townsite (contains both design and alternative scenario information). 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. Flood fringe - the area of the floodplain, outside of the floodway where development could be permitted provided it is compatible with flood hazard and building conditions provide an adequate level of flood protection. These areas are generally covered by still or very slowly moving waters during a 1 in 100 (1%) AEP flood. 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. Floodway - the river channel and a portion of the floodplain where a significant flow or storage of water occurs during floods. If the floodway is even partially blocked then the natural flooding regime of th area may be detrimentally impacted with flood levels being raised and affecting areas which may not have been previously affected. Development in floodways is to be avoided wherever possible. 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 Floodplain Area (DOW-054)

Historically, low-lying land adjacent to rivers and coastlines has been favoured for settlement as they provided sources of fresh water, food, transportation and waste disposal. These areas become affected by flooding during sufficiently heavy or prolonged rainfall, high tides or storm surges and cyclones. In the north-west of the State flooding is most likely to be caused by the summer monsoon or tropical cyclones while floods in the south-west are more likely to occur in response to heavy winter rainfalls. While historical flood records and information extend as far back as 1830, detailed information on peak flood levels is typically limited to the last few decades. This dataset contains the available surveyed peak flood level information for major flood events that have occurred in Western Australia. The flood levels are referenced to the Australian Height Datum (AHD). Note: To see the full scope of the historical flood mapping, 3 dataset layers are required to be loaded in the following order: FLOODPLAIN DATASET LAYERS: FPM Historical Flood Levels (m AHD) FPM Historical Extent of Flooding FPM Historical Floodplain Area Major flood events that have occurred in the past include: Blackwood River (1945, 1955, 1963, 1964, 1982) Collie River (1945, 1963, 1964, 1974, 1982) Fitzroy River (1983, 1986, 1991, 1993, 2002, 2011) Gascoyne River (1960, 1961, 1980, 1995, 2000, 2010) Greenough River (1888, 1927, 1953, 1971, 1988, 1999, 2006) Moore River (1934, 1955, 1961, 1995, 1999) Murray River (1862, 1945, 1955, 1964) Preston River (1964, 1967, 1974, 1983, 1990, 2011) Swan River (1862, 1872, 1945, 1955, 1964, 1983) The historical flood information is used in the Department of Water and Environmental Regulation's floodplain management activities to ensure that floodplains are managed for the benefit of the whole community, minimising the risk and damages and protecting environmental values. Floodplain mapping datasets and floodplain development strategies for rivers and major watercourses in Western Australia are also available from the Department of Water and Environmental Regulation. Note: The ‘Event’ dates in the attribute table are derived from various sources, including Department of Water and Environmental Regulation's Floodplain Management Section reports, records and plans, historical newspaper articles, flood survey information, Bureau of Meteorology rainfall intensity records, on-site flood information and information provided by locals. It is not always possible to obtain an exact date when the flood event has occurred because in some cases the floodwaters may take several days to subside, peaking at different times at various locations over the course, or historical records may only refer to the month or year of the event. However, considering the above date variations the ‘Event’ dates are listed as follows: 22nd December 2010: The day, month and year of the flood event (or rainfall) are known. August 1963: The month and year are known. Exact date unknown. 1954: The year is known but the month and day are unknown. Glossary: Annual exceedance probability (AEP) - the likelihood of occurrence 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 lifetime. 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 river overflows its banks during major river flows. The term also applies to land adjacent to estuaries 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.

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 …Show full descriptionThe 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 envirionmental and ecological considerations are not addressed. Both the floodway and flood fringe make up the 1 in 100 (1%) annual exceedence probability (AEP) floodplain, however there are areas where the floodplain exists but the floodway and flood fringe does not. In such situations, a different floodplain management strategy applies (for example, the Swan River between the Narrows and Canning Bridges). This dataset comprises two polygons - Flood fringe, and Floodway. The flood fringe is that part of the floodplain where development may be considered acceptable subject to certain building conditions that will provide adequate flood protection. The floodway is that part of the 1 in 100 (1%) AEP floodplain where development that is considered obstructive to major flows is not acceptable as it would increase flood levels upstream. No new buildings are acceptable in the floodway. 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, Northam, York and Beverley Townsites. Blackwood River – Augusta, Bridgetown, Nannup and Boyup Brook Townsites. Brunswick River - Greater Bunbury Coblinine River & Dorderyemunning Creek - Wagin Townsite. Collie River - Collie Townsite. Chapman River – Geraldton Townsite. Denmark River – Denmark Townsite. Gascoyne River - Carnarvon Townsite and the Lower Gascoyne. Gribble Creek - Kalgoorlie Townsite. Harding River - Roebourne Townsite. Irwin River - Dongara Townsite. Lower Collie River - Greater Bunbury. Preston River - Donnybrook Townsite. Serpentine River, Peel, Birrega & Oaklands Drains, 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 (Peel Main Drain), east to South Western Highway (Serpentine River) and north to Wungong Brook (Birrega Drain). Swan River, Canning River and Tributaries: Perth - 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, Henley Brook, Jane Brook, St Leonards Creek, Susannah Brook (Swan River) and Southern River/ Wungong Brook (Canning River). Toby Inlet – Quindalup Townsite. Vasse-Wonnerup Estuaries, Broadwater and New River - Busselton Townsite. For further information on flooding and floodplain management in Western Australia please refer to our Water Facts publications: Flooding in Western Australia (Water facts 13) and Floodplain Management (Water facts 14). This information is available at the Department of Water and Environmental Regulation's website at the following address: http://www.water.wa.gov.au/Publications/Find+a+publication/default.aspx - Under 'Find a publication' click on 'Series Browse' (3rd column from the left) and scroll DWERn to 'Water Facts' and select '+' button located on the right of the heading to open the PDF's 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. Flood fringe - the area of the floodplain, outside of the floodway where development could be permitted provided it is compatible with flood hazard and building conditions provide an adequate level of flood protection. These areas are generally covered by still or very slowly moving waters during a 1 in 100 (1%) AEP flood. 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. Floodway - the river channel and a portion of the floodplain where a significant flow or storage of water occurs during floods. If the floodway is even partially blocked then the natural flooding regime of th area may be detrimentally impacted with flood levels being raised and affecting areas which may not have been previously affected. Development in floodways is to be avoided wherever possible. 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.

The Digital Flood Insurance Rate Map (DFIRM) Database depicts flood risk information and supporting data used to develop the risk data. The primary risk classifications used are the 1-percent-annual-chance flood event, the 0.2-percent-annual- chance flood event, and areas of minimal flood risk. The DFIRM Database is derived from Flood Insurance Studies (FISs), previously published Flood Insurance Rate Maps (FIRMs), flood hazard analyses performed in support of the FISs and FIRMs, and new mapping data, where available. The FISs and FIRMs are published by the Federal Emergency Management Agency (FEMA). In addition to the preceding, required text, the Abstract should also describe the projection and coordinate system as well as a general statement about horizontal accuracy.

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 polygons that identify existing residential developments in a defined floodway where building controls are recommended on house extensions, redevelopment and fencing. 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:

Fitzroy River – Fitzroy Crossing Townsite.

Murray River/Peel Inlet - Ballee, Yunderup and Cooleenup Islands, Culleenup Road and Pericho Close.

Glossary:

Annual exceedance probability (AEP) - the likelihood of occurrence 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 lifetime. 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 river overflows its banks during major river flows. The term also applies to land adjacent to estuaries 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 formerly known as FPM Special Development Condition Area (DOW-039)

Historically, low-lying land adjacent to rivers and coastlines has been favoured for settlement as they provided sources of fresh water, food, transportation and waste disposal. These areas become affected by flooding during sufficiently heavy or prolonged rainfall, high tides or storm surges and cyclones. In the north-west of the State flooding is most likely to be caused by the summer monsoon or tropical cyclones while floods in the south-west are more likely to occur in response to heavy winter rainfalls. While historical flood records and information extend as far back as 1830, detailed information on peak flood levels is typically limited to the last few decades. This dataset shows the area of inundation (polygons), i.e., the floodplain area that has occurred during the major flood events in Western Australia. Note: To see the full scope of the historical flood mapping, 3 dataset layers are required to be loaded in the following order:

This study delineates flood hazard areas and determines design flood levels along the Red Deer, Little Red Deer and the Medicine Rivers through Red Deer County, including Markerville. The study area includes an approximate 50 km reach of the Red Deer River, an approximate 12 km reach of the Little Red Deer River and an approximate 17 km reach of the Medicine River. The Red Deer River design discharge ranges from 1450 m³/s at the upstream study extent to 1750 m³/s at the downstream extent. The design discharges for the Little Red Deer and Medicine Rivers are 419 m³/s and 283 m³/s respectively. The study was prepared in March 2007. Flood information available after study completion may not be reflected in the current flood hazard study report or flood hazard mapping.

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 contains the location of levee banks (polylines) that mitigate the risk of flooding to the community and reduce potential property damage during major flood events. 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 - Northam Townsite. Capel River - Capel Townsite. Cohn Creek - merredin Townsite. Corrigin Townsite. Exmouth Townsite. Five Mile Brook - Bunbury Townsite. Gascoyne River - Carnarvon Townsite. Greenough River – Indian Ocean to Walkaway. Serpentine River - North of Lake Amarillo. Vasse-Wonnerup Estuaries, Broadwater & New River - Busselton Townsite. Glossary: Annual exceedance probability (AEP) - the likelihood of occurrence 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 lifetime. 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 river overflows its banks during major river flows. The term also applies to land adjacent to estuaries 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 formerly known as FPM Levee Banks (DOW-034)