Australia Reservoir Transparency

Australia operates one of the most comprehensive national water data ecosystems in the world. The Bureau of Meteorology's Water Storage Dashboard aggregates 281 reservoirs nationally, and Water Data Online holds ~6,000+ time series collected under the Water Regulations 2008, which legally compel water agencies to supply data to BoM. Parallel federal coverage is provided by MDBA's RiverData portal (Murray-Darling Basin: Hume, Dartmouth, Menindee Lakes, etc. updated hourly; basin-wide storage report fortnightly). State agencies provide additional layers: WaterNSW (Warragamba and Greater Sydney + regional dams), Seqwater (SEQ Water Grid: Wivenhoe, Somerset, Hinze...), SunWater (QLD irrigation storages), Goulburn-Murray Water (23 northern Victoria storages), SA Water (Mt Bold, Adelaide reservoirs daily), WA Water Corporation, and Hydro Tasmania (Gordon-Pedder system — Australia's largest storage). All 281 reservoirs tracked in reservoirs.earth have current readings.

Revised significantly upward after research. BoM Water Data Online exposes a publicly accessible OGC-compliant Sensor Observation Service v2 (SOS2 / WISKI) API at bom.gov.au/waterdata/services, with an official user guide ('Guide to Sensor Observation Services (SOS2) for Water Data Online v1.0.1' PDF) published by BoM. The API supports KVP and POX requests for station metadata, time series catalogues and observation values across 15+ parameters (water level, discharge, storage, rainfall, evaporation, groundwater, quality). Multiple mature open-source client libraries exist: the R package 'bomWater' (CRAN) and Python 'kiwis-pie' (PyPI), both downloading data directly from the documented API. The Water Storage Dashboard's stations.json is a secondary, less-formal endpoint, but the primary SOS2 service is a properly documented standards-based API. WaterNSW additionally operates a formal API developer portal (api-portal.waternsw.com.au) with three documented APIs (Water Data, Water Quality, Water Source), interactive testing console, and subscription-key authentication. MDBA RiverData provides interactive endpoints. The previous evaluation incorrectly characterised access as 'undocumented internal API'.

Conservative estimate — denominator includes long tail of small reservoirs in QLD/WA (mining/industrial storages, pastoral and station dams, smaller council water-supply impoundments) and some on-stream weirs not classified as 'storages' in BoM accounting. Methodology v1.3.0 (capacity-weighted). The BoM Water Storage Dashboard aggregates 281 reservoirs nationally (~75,000 hm³ covered) across all 6 states and 2 territories, capturing essentially every reservoir of operational significance plus state portals (Hydro Tasmania ~30 IPP storages including Gordon-Pedder, WaterNSW + Seqwater + SunWater + G-MW + SA Water + WA Water Corp). A realistic national denominator including the long tail of small private/industrial storages, smaller mining dams, and remote pastoral impoundments reaches approximately 88,000 hm³. Score = round(100 × 75,000 / 88,000) = 85. Australia's biggest reservoirs are operationally critical and all publicly tracked; the conservative discount reflects systematic gaps at the small end of the inventory.

BoM Water Data Online provides historical time series via the SOS2 API for the full operational history of each station — major storages typically have records from the 1960s-1980s, with the Water Regulations 2008 reporting framework standardising and back-filling data from 2008 onwards. The bomWater R package supports get_daily(), get_monthly() and get_yearly() functions returning multi-decadal series. MDBA RiverData publishes historical storage curves for River Murray dams (Hume from 1936, Dartmouth from 1979, Menindee from 1968). SA Water reservoir volumes dataset on data.sa.gov.au provides monthly history back to 2018; Victoria's monthly storage levels dataset on data.gov.au covers 64 Victorian storages since January 2010 with bulk download. Limitation: there is no single bulk historical archive download for all 281 BoM stations — retrieval is per-station via API, which is operationally fine but not as frictionless as a single CSV dump.

Daily updates for the full 281-reservoir BoM national dataset. MDBA RiverData refreshes hourly for River Murray system gauges (storages, releases, river heights at 60+ sites). Seqwater and SA Water publish daily; WaterNSW WaterInsights publishes near real-time. The basin-wide MDBA storage report is fortnightly. One of the higher-frequency national datasets globally — comparable to USGS NWIS for the subset of sites the latter covers, though Australia does not publish sub-daily storage volumes nationally the way USGS publishes 15-min instantaneous data.

Revised upward. BoM publishes detailed metadata for each station (station number, agency, parameter, units, quality codes) and the SOS2 manual documents quality-code semantics, units, aggregation rules and timestamp conventions. The Water Regulations 2008 framework, which obligates agencies to supply data to BoM under defined categories and quality standards, is publicly documented. MDBA publishes capacity figures and percentage-full calculations for each River Murray storage with explicit volume/capacity disclosure. State agencies publish capacity and methodology (Seqwater publishes operating rules; G-MW publishes storage operation manuals). Remaining gaps: the conversion between raw volume and percentage-full for the 281-station aggregate dashboard is not always explicitly footnoted; capacity revisions (after re-survey of sedimented storages) are sometimes silent.

All BoM, MDBA and state agency interfaces are in English. The Water Storage Dashboard, RiverData portal and WaterInsights app are modern, mobile-responsive web applications. Documentation, API specs and open-source client libraries are all English-native.