Ord
17.2 River outflow from the region

Supporting information

The volume recognised in the water accounting statements (7,286,990 ML) represents the combined volume of water outflow from the Ord River to the Cambridge Gulf and the Keep River to the Timor Sea during the 2011–12 year.

The total annual volume of flow observed during the 2011–12 year at the most downstream station along the rivers that flow into the sea, is given in the following table.


Volume of flow measured at the most downstream station during the 2011–12 year along rivers that flow into the sea

Catchment

Station

Discharge (ML)

Quality codes

Ord River

Ord River - 809339

6,682,461

1,2

King River - 809314

180,629

1,2,12

 

Subtotal

6,863,090

12

Keep River

Keep River - G8100225

272,800

41,91,141

Sandy Creek - G8100210

151,100

150

 

Subtotal

423,900

150

Total surface water flow out of region

7,286,990


 

Quantification approach

Data source

Department of Water, Water Information database (Ord River catchment data); Department of Land Resource Management, Hydstra database (Keep River catchment data).

Provided by

Department of Water and Department of Land Resource Management.

Method

The total volume of water that flows out to sea is the sum of the available volume of outflow from the four rivers that flow into the sea:

  • Ord River
  • King River
  • Keep River
  • Sandy Creek.

The river outflow was estimated using instantaneous discharge data (L/s) collected at the most downstream gauging station (nearest to the outlet to the sea) along a river. These data were converted to daily volume data (ML) to determine the total annual discharge (in ML) at each station during the 2011–12 year.

Assumptions, limitations, caveats and approximations

It is assumed that the river outflow to the sea is equal to the volume of discharge measured at the most downstream station along a river, i.e. there is no adjustment made for the contributing area below the gauging station used to calculate the outflow.

Uncertainty information

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


Department of Water quality codes for flow data
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


The Department of Land Resource Management assigns quality codes to flow data in accordance with the following table:


Department of Land Resource Management quality codes for flow data
Quality code Description
41 Good rating
91 Satisfactory rating
141
Poor rating
150
Rating under review—not quality coded
255
No data


The total volume of water that outflows into the sea from the Ord River catchment (Ord and King rivers) has a quality code of 12. The total volume of water that outflows into the sea from the Keep River catchment (Keep River and Sandy Creek) has a quality code of 150. These quality codes indicate the lowest quality of data recorded for all the station data for the respective catchments.