Victoria - 1 in 100 Year Flood Extent

Brief description

## **Abstract**

This dataset and its metadata statement were supplied to the Bioregional Assessment Programme by a third party and are presented here as originally supplied.



Polygon data delineating modelled statistical flood extent with an Average Recurrence Interval (ARI) of 100 years. For historical/actual flood extents, refer to 'Historic_extent' layer. Also known as the 1 in 100 year flood layer, it is used, among other things, in the creation of 'Land Subject to Inundation' areas as used in Planning Scheme Zones. The 1 in 100 year data is not restricted. This data is part of a group of layers depicting a range of statistical ARI extents. Current layers include 5, 10, 20, 30, 50, 100, 200, 500, 1000 year intervals, each in a separate dataset. The layer called EXTENT_PMF represents areas of 'probable maximum flood' and is also part of this group. The data is statistically derived using hydrological models, historic flood extents and heights.

## **Purpose**

Mainly used for municipal planning and risk assessment. The EXTENT_100Y_ARI layer is deemed the most appropriate to use for determining areas at risk of flooding. This layer directly inputs into the Land Subject to Inundation overlay. (LSIO)

## **Dataset History**

Lineage: Primary



Positional Accuracy: Precision: 5m to 100m Initial data, flagged as 'modified = 20000101' varies in accuracy, and should be treated with caution, particularly at scales less than 1:25,000. Data with 'modified' values later than 20000101 are quite accurate and mostly sourced from flood studies. This data is suitable to use at township and parcel level. Reliability field provides clues to the accuracy, where a value of 1 is best and 3 is worst.



Attribute Accuracy: Attributes are verified and should be accurate. Overall reliability of the source material is indicated in RELIABILITY field, where 'HIGH' is good and 'LOW' is poor quality source information.



Logical Consistency: Attributes are consistent with other related layers e.g. flood height contours



Data Source: Flood data dates back to mid 1800s and historically has been predominantly located in DNRE Floodplain Management. Some data is located in Water Authorities.



Completeness: Floodplain Management Unit mapping conventions on definitions of flood mapping height data will be followed.



Additional Metadata: Recommend liaison with Floodplain Management Unit to clarify use of this layer

Refer to mapping reports for each major data capture effort to be kept at DNRE Floodplain Management Unit.

## **Dataset Citation**

Victorian Department of Environment and Primary Industries (2014) Victoria - 1 in 100 Year Flood Extent. Bioregional Assessment Source Dataset. Viewed 05 October 2018, http://data.bioregionalassessments.gov.au/dataset/6e59ed35-3fde-48e3-8135-eb05263ce4aa.

Full description

Victoria - 1 in 100 Year Flood Extent - Data File