The River, the Dams and our Water
- Before any of the Dams were constructed the Ord River had been measured to flow at a peak of up to one and a half million cubic feet per minute (this roughly equates to metropolitan Sydney’s daily water consumption passing by in about 22 seconds).
- Diversion Dam constructed between 1959 and 1962 and contains the waters of Lake Kununurra.
- Main Ord Dam constructed between 1969 and 1972 and contains the waters of Lake Argyle.
Diversion Dam comprises 20 radial arm gates each about 15 metres wide and 13 metres high and weighing 95 tonnes.
- 15 tonnes of water per second escapes for each 100mm that each gate is raised.
Approximately 63% of the stored water is wasted to the ocean to “maintain” the “wetland” that has been developed by the damming of the Ord River.
- Currently only 334 gigalitres of the roughly 11,000 gigalitres of water stored in Lake Argyle is allocated for irrigation.
- Volume of water in Lake Kununurra (Diversion Dam) is roughly 90 million cubic metres.
- Volume of water in Lake Argyle (Main Ord Dam) is roughly 11,000 million cubic metres.
- We could drain Lake Kununurra (Diversion Dam) and refill it from Lake Argyle once a week and never run out of water.
- The annual Kununurra rainfall is about 800 mm which falls during the “wet” season usually between December and March.
- In the year 2000 we received nearly double our annual rainfall (1480 mm) In that year Lake Argyle was at one stage overflowing the spillway by about 9.8 metres.
- After the high rainfall of the wet season 2000 Lake Argyle overflowed for the whole year until the next wet season (all of 2001).