Hydrologic Reference Stations

Glossary

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.

Anomaly

Annual streamflow minus the average annual streamflow.

Area

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.

Stream Length

Combined length of 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.


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