RETIRED Water Observations from Space 25m 2.1.5

Brief description

This record was retired 29/03/2022 with approval from S.Oliver as it has been superseded by eCat 146257 DEA Water Observations Water Observations from Space (WOfS) provides surface water observations derived from satellite imagery for all of Australia from 1986 to the present. The WOfS product allows users to get a better understanding of where water is normally present in a landscape, where water is seldom observed, and where inundation has occurred occasionally. WOfS displays the detected surface water from cloud-free Landsat observations for the whole of Australia.

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Maintenance and Update Frequency: asNeeded

Statement: The Water Observations from Space product (WOfS) is a key component of the National Flood Risk Information Portal (NFRIP), developed by Geoscience Australia (GA). The objective of Water Observations from Space is to analyse GA's historic archive of satellite imagery to derive water observations, to help understand where flooding may have occurred in the past, and hence help inform on areas under threat of flooding in future. WOfS is being developed in parallel with the National Flood Studies Database system which will provide Flood Study documentation and reports to a wide range of users. Both systems will be delivered via the internet through the NFRIP portal. Satellite imagery has been used to map floods around the world for several years. Organisations such as the Colorado Flood Observatory in the USA and several state-based agencies in Australia regularly provide satellite-based flood extents for major flood events. GA developed a flood mapping methodology in 2008-2009 that was extensively used for the major Australian flood events since 2010, providing emergency service agencies with regional flood extent information. The Phase 1 outputs from the NFRIP were delivered to the public in November 2012, including a proof of concept of WOfS. This displayed surface water extents for three study areas, including the original derived extents and the cumulative summary product. Subsequent stakeholder feedback has shown that the most desirable information is the summary product, providing and understanding of the long term dynamics of surface water. The Phase 2 outputs from the NFRIP (release in April 2014), included the release of WOfS v1.0, which is accessible to the public as a web service from the NFRIP and from http://eos.ga.gov.au. The current version of WOfS has separated the individual time slices from the derived summary statistics. The time slices, termed Water Observation Feature Layers (WOFLs) are contained in WO_25_2.1.5, while the summary statistics are contained in WO-STATS_25_2.1.5.

Notes

Purpose
The primary purpose of the WOfS product is to help understand where flooding may have occurred in the past. This has application in emergency management and risk assessment. The product has many secondary uses. For example the WOfS product provides an indication on the permanence of surface water in the Australian landscape by showing where water is observed rarely in comparison to where it is often observed. This has application in water management and mapping. WOfS has also been used for wetland analyses, water connectivity and surface-ground water relationships. As the WOFLs have been separated from the derived statistics in this version, WOfS is most useful for performing analyses requiring the investigation of surface water extent for particular times rather than over long term time series.