Ord
42.5 Releases from storages

Supporting Information

 

Releases from storages in the 2010–11 year
Releases from storages Volume 201011 (ML)
42.5 – Releases for hydro-electricity and subsequent downstream users

1,965,338

42.5b – Releases for the purposes of the environment (Spillway Creek)

9,969,687

42.5c – Releases from the irrigation valves

151,152

42.5d – Licensed abstraction

220

Total

12,086,397

 

 42.5d comprises abstractions of Argyle Diamond Mine (192 ML) and Lake Argyle Village (28 ML).

 

Quantification Approach

Data Source

Western Australian Department of Water.

Provided by

Western Australian Department of Water.

Method

a. Releases for hydro-electricity and subsequent downstream users

The volume of water released from Lake Argyle for hydro-electricty was estimated using the power output of the power station, measured at the terminals of the station's generators. The volume is calculated using the difference in pressure between the inlet and outlet of the power station, and the flow rates through the power station.

b. Releases for the purpose of the environment (Spillway Creek)

The volume of water released from Lake Argyle to Spillway Creek was calculated based on the water level of Lake Argyle, and stream gauging in Spillway Creek.

c. Releases from the irrigation valves (used for recreation)

The volume of water released from Lake Argyle through the irrigation valves was calculated using hydraulic rating tables, and valve opening settings recorded by the dam operators.

d. Licenced abstraction

Direct abstraction under licence from Lake Argyle is metered.

Assumptions, Limitations, Caveats and Approximations

  • Calculation of flow rates through the power station includes allowances for head losses in the tunnels, pipe work and turbines of the power station.
  • Storage–volume curves represent specifically surveyed parts of the water storage, and may not reflect the storage–volume relationship across the entire storage.
  • Water storages are subject to sedimentation and other physical changes over time, which, in turn, affects the accuracy of the storage–volume curves.

Uncertainty Information

The uncertainty estimate was not quantified.