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Ord

                                                                                                   

14.2 Surface water flow out of region

                             

Supporting information   


The volume recognised in the water accounting statements (2,971,718 ML) represents the volume of water outflow from the Ord River to the Cambridge Gulf, and the volume of water outflow from the Keep River to the Timor Sea. The volume recognised in the water accounting statements is the sum of the Ord River and Keep River components.

The breakdown of outflow from the Ord and Keep rivers is provided in the table below.

 

Catchment

Gauge station

 Discharge (ML)
Ord River

Ord River @ Tarrara Bar (No. 809339)
King River @ Cockburn North (No. 809314)

 2,777,389
89,581
 

Ord River Subtotal

 2,866,970
Keep River

Keep River @ Legune Road Crossing (No. G8100225)
Sandy Creek @ Legune Road Crossing (No. G8100210) 

 2,346
102,402
 

Keep River Subtotal

 104,748

Total surface water flow out of region

 2,971,718

 

Quantification approach   


Data sources

Western Australian Department of Water: Water Information (WIN) database, Hydstra database.
Northern Territory Department of Natural Resources, Environment, The Arts and Sport: Hydstra database.

 

Data provider

Bureau of Meteorology.

 

Method

The outflow to the sea is calculated as the sum of the annual discharge from the following gauging station locations:

  • Ord River @ Tarrara Bar (Gauge No. 809339)
  • King River @ Cockburn North (Gauge No. 809314)
  • Keep River @ Legune Road Crossing (Gauge No. G8100225)
  • Sandy Creek @ Legune Road Crossing (Gauge No. G8100210).

 

Uncertainty

Derived from measured data. A description of the uncertainty is below.

The Western Australian Department of Water assigns quality codes to flow data in accordance with the following table:

Quality code Description
1 Very good record
2 Very good record—corrections applied
3 Good record—corrections or estimations applied
4 Estimated record—good
5 Estimated record—fair
6 Estimated record—poor
10 Estimated record—not reviewed/quality not known
11 Theoretical rating
12 Estimated rating

Flow data provided by the Western Australian Department of Water was quality coded as follows:

  • flow data for site 809314 was quality coded ‘2’
  • flow data for site 809339 was quality coded ‘4’ from 1 July 2009 to 21 June 2010
  • flow data for site 809339 was quality coded ‘10’ from 22 June 2010 to 30 June 2010.

The Northern Territory Department of Natural Resources, Environment, The Arts and Sport assigns quality codes to flow data in accordance with the following table:

Quality code Description
Blank All recorded data is continuous and reliable
? Data not quality coded
* Unverified Telemetry Data (use with caution)
NA No available record

Flow data provided by the Northern Territory Department of Natural Resources, Environment, The Arts and Sport was quality coded as follows:

  • flow data for site G8100225 was quality coded ‘Blank’ from 1 July 2009 to 3 September 2010
  • flow data for site G8100225 was quality coded ‘NA’ from 4 August 2009 to 9 August 2010
  • flow data for site G8100225 was quality coded ‘*’ from 10 August 2009 to 30 June 2010
  • flow data for site G8100210 was quality coded ‘?’ from 1 July 2009 to 30 June 2010.

 

Assumptions, approximations and caveats/limitations

  • It is assumed that the measured flow at the gauging stations is equal to the amount of water that eventually flows out of the region. In some cases, the location of the gauge is many kilometres from the coast.
  • Quality codes quoted above represent the lowest quality coded data in the data-set, and is not representative of the entire data-set used in the calculation.