Hydrologic Reference Stations
This glossary defines the key terms used on the Australian Network of Hydrologic Reference Stations portal.
- Annual Average
Average of the annual total streamflow volumes (within each water year) over the stated period of record.
- Annual Baseflow
The component of streamflow supplied by groundwater discharge in a water year.
- Annual Total
Total streamflow volume per water year.
Annual streamflow minus the average annual streamflow.
The catchment area derived from the Australian Hydrological Geospatial Fabric catchments (including contributing overland flow and internally draining areas).
- Cease to flow
Number of zero flow days within each year.
- Daily Q10
10 Percent of the time, the daily streamflow is below the Q10 value in each water year.
- Daily Q50
50 Percent of the time, the daily streamflow is below the Q50 value in each water year.
- Daily Q90
90 Percent of the time, the daily streamflow is below the Q90 value in each water year.
- Event Analysis
Histograms showing the frequency and magnitude (volume) of events.
- Flow Duration Curve
A curve showing percentage of time streamflow magnitude exceeds certain value.
- Hydrologic Reference Station
A hydrologic reference station is located in an unregulated catchment with minimal land-use change upstream. It has a high-quality long streamflow record with a frequently verified rating table. The gauge has been well maintained. See the Station Selection Guidelines page for more information.
- Long-term streamflow trend
A unidirectional change in the magnitude of the streamflow variable. The trend may be increasing or decreasing.
- Max Elevation
Maximum elevation within the Australian Hydrological Geospatial Fabric derived catchment boundaries
- Min Elevation
Minimum elevation within the Australian Hydrological Geospatial Fabric derived catchment boundaries
- Runoff Rate
The percentage of rainfall volume that becomes streamflow after losses such as evaporation within the catchment.
- Longest Stream Length
The length of the longest stream within the catchment of Hydrologic Reference station derived from the contributing streams from the Australian Hydrological Geospatial Fabric MappedStream features.
- Water Year
The Water Year begins with the month recording minimum average monthly flow over the period of the data. If the beginning month is a month from January to June, the nominal year of the Water Year is the same as the calendar year of the beginning month. For months July to December, the nominal year is the year following the calendar year of the beginning month. For example, a water year starting in July 1997 is nominally Water Year 1998.
Water Information System Kisters (WISKI) contains Watercourse level and discharge time-series data and ratings collected from approximately 3500 measurement stations across Australia. This data can be accessed via Water Data Online http://www.bom.gov.au/waterdata/. Except for Victoria, all discharge data are directly uploaded from the water agencies. For Victoria, the rating tables in WISKI are used to compute discharge from the water levels at the time-step provided by the agencies. The discharge data are then accumulated to a daily total at 9am for the previous 24 hours.