This product delivers a monthly timeseries of water surface area for On-Farm Storages (OFS) across the five key valleys of the northern Murray-Darling Basin (Border River, Gwydir, Namoi, Macquarie-Castlereagh, and Barwon-Darling). The dataset encompasses both licensed Flood Plain Harvesting (FPH) storages and other storages of interest within these regions.

OFS play a vital role in agricultural water supply by enabling farmers to store water for irrigation. Regular monitoring of these storages is essential for effective water resource management, supporting efforts to address water scarcity, ensure regulatory compliance, respond to climate variability, and promote sustainable agricultural practices.

The OFS Water Surface Area Monthly dataset enables the identification of storage fill and drawdown events over large areas, capturing responses to both natural and managed water movements.

Timeseries observations are generated from publicly available Landsat (since 1987) and Sentinel (since 2015) satellite imagery, using multispectral data and a streamlined geospatial model [2]. The full methodology is available as open-source code published by the Department [1].

References

[1] https://datasets.seed.nsw.gov.au/dataset/remote-sensing-earth-observation-water-toolkit.

[2] https://www.tandfonline.com/doi/full/10.1080/01431160600589179 (Subscription required).

Format

ArcGIS Rest Map Service

ArcGIS Feature Service

WFS (Web Feature Service)

Information about output/files

Water surface area is calculated from medium-resolution optical satellite data—Landsat (30 m, 16-day revisit) and Sentinel-2 (10 m, 5-day revisit). Due to inherent uncertainty in distinguishing wet and dry boundary pixels, the reported areas should be considered estimates.

Output

Polygon features defining On Farm Storages with a relationship class linked table of monthly mean area totals.

1. ArcGIS REST MAP SERVICE - Earth Observation - On Farm Storage (OFS) Water Surface Area Monthly

What is a ESRI map service?

https://enterprise.arcgis.com/en/server/10.5/publish-services/windows/what-is-a-map-service.htm

2. ArcGIS REST FEATURE SERVICE - Earth Observation - On Farm Storage (OFS) Water Surface Area Monthly

What is a ESRI feature service?

https://enterprise.arcgis.com/en/server/10.5/publish-services/windows/what-is-a-feature-service-.htm

3. ArcGIS REST WFS - Earth Observation - On Farm Storage (OFS) Water Surface Area Monthly

What is a WFS?

https://enterprise.arcgis.com/en/server/latest/publish-services/windows/wfs-services.htm

Dataset Attributes

POLYGON ID: Unique Identifier that links the OFS Polygon to the monthly area mean totals.

FSL AREA: Total water surface area of the storage polygon in hectares at the Full Supply Level (FSL). Note: often considered lower than the storage crest height.

YEAR MONTH: Year and Month of the observation

MAX AREA: The maximum observed water surface area (ha) observed in a storage, based on multiple observations taken throughout the month. The observed water surface area is subject to the uncertainties described in the Accuracy and Error section.