Annual inundation extent of Commonwealth environmental water

Brief description

Annual data mapping of the maximum extent of Commonwealth environmental water delivered each water year (June to July) to floodplain, wetlands and rivers of the Murray-Darling Basin. and wetland inundation). Annual polyline layers representing the watercourses watered by Commonwealth environmental water (CEW)

The data are contained within an ESRI Geodatabase and consist of annual maximum extent rasters and feature class datasets (polylines) which are to be used together to represent the maximum annual extent of Commonwealth environmental water. These data support the evaluation of Commonwealth environmental water by the Flow-MER program.

note: Although open libraries do exist to read ESRI Geodatabases (e.g. in QGIS, R, Python) we will make these data available in a more open form soon (or on request).. e.g. a zipped collection of GeoTIFF

###Inundation maps

The inundation maps are derived from observation and acquittal reporting aligned to mapping of water from Sentinel-2 sattelite imagery during dates of watering actions. Each inundation layer has been compiled from multiple sources including new mapping from Sentinel-2 imagery, inundation maps for NSW inland floodplain wetlands prepared by NSW DCCEEW , mapping provided by Flow-MER Area-scale project teams and aerial image interpretation. Mapping was conducted at 10m resolution (Sentinel-2) and rescaled to 25m pixels to align with previous Landasat based work providing a continuous annual record from the start of the program in 2014.

The layers were compiled for the Long Term Intervention Monitoring (LTIM) project and its successor the Monitoring Evaluation Research project (Flow-MER). Both programs were tasked with monitoring and evaluating the contribution of Commonwealth environmental water to outcomes in the Murray Darling Basin. The dataset has been prepared at the annual scale, where a process of pixel coding has been applied to attribute contribution and or influence, as outlined below:

* pixel value = 1. Pixel is likely to be other water (derived from the WoFS dataset) (discontinued)
* pixel value = 2. Pixel is likely to have been influenced by Commonwealth environmental water with high certainty (may include water from other environmental sources).
* pixel value = 3. (not used)
* pixel value = 4. Pixel may have been influenced by Commonwealth environmental water but with low certainty (may include water from other environmental sources). The low certainty classification may have been due to: (a) flood/wet conditions where direct attribution had a high degree of uncertainty, (b) lack of images for assessing inundation during environmental watering actions, (c) highly heterogeneous landscape coupled with a lack of field validation and (d) the inundated ares were already wet and the objective of the action was to increase persistence.
* pixel value = 5. Other environmental water (where collated). Note this dataset is likely to be incomplete and should not be viewed as ALL other environmental water. (discontinued)
* pixel value = 6. Coorong lower lakes. Coded differently simply to facilitate analyses.

Pixel Values 1 and 5 not added since 20/21 (deprecated as not reliable and not used)


###Watercourses watered maps
The linework representing these maps are derived from the ANUDEM (version 5.3.0 3 November 2016) derived raster streams, and vectorised to be usable in vector line feature format. They are initially informed and modified by the coincident locations of AusHydro V2 Watercourse feature class. The features have been organized into specific Feature Class subtypes based upon both the inputs from the AusHydro V2 Watercourse feature class and their behaviour within the AHGF stream network relationships.
NetworkFlowSegment:corresponds to an existing blueline stream from AusHydro Watercourses
NetworkArtificialFlowSegment: corresponds to a stream flow "connector" from AusHydro V2 Watercourses. These are additional stream segments that represent logcial stream flow direction when compared to the AHGFMappedStreams.
NetworkWaterAreaSegment: these are logical stream flow connectors through AHGFWaterbodies.
All of these features participate in the connected stream flow topology.

The maps contain only those segments which were considered to have been influenced by Commonwealth environmental water.

Compiled by the Flow-MER Basin scale project.

2014-2019 data based on information from the Long Term Intervention Monitoring (LTIM) project.

##Citation
CEWH (2025) Annual maximum extent of Commonwealth environmental water. Flow-MER Program. Commonwealth Environmental Water Holder, Australian Government Department of Climate Change, Energy, the Environment and Water. Sourced from https://data.gov.au/data/dataset/annual-inundation-extent-of-commonwealth-environmental-water on [date-sourced].

## Acknowledgement
We acknowledge the First Nations peoples as the Traditional Owners and Custodians of the lands, waterways and skies of the Murray-Darling Basin. We respect their continuing connection to culture and Country, and we thank them for their knowledge and science and the values reflected in these data.

Full description

Cew Inundation and Watercourses watered 2014-2024_updated_15Feb2025.zip - Esri Geodatabase of annual maximum extent of Commonwealth environmental water
metadata_flow-mer_annual_extent_CEW - Metadata