Did you know…
At normal full supply level the area of the lake formed by the Ord Dam is 980 square kilometres and impounds 10.7 million mega litres (8.6 million acre feet) of water, over 18 times the volume of water contained in Sydney Harbour! If the lake ever does flood to its maximum capacity then the volume will more than triple – Sydney Harbour could be filled more than 70 times.
Kununurra forms the hub around which the Ord River Irrigation Project revolves. Centred in the Eastern Kimberley, the area not only provides incomparable tourist attractions, but a massive intensive agricultural development, made possible by the construction of the two dams.
Ord River Irrigation Project Statistics
Present area under irrigation (2008): 13,000 hectares
Water used (2008): 171,500 megalitres
Ultimate irrigation area: 45,000 hectares
Potential water usage: 587,000 mega litres / year
Population of the Ord Valley: Approximately 6,000
Average annual rainfall (mostly falls November to March): 787mm / 31 inches
Average annual evaporation: 2,700mm
Average annual flow of Ord River at Dam site: 4,400,000 mega litres
Total length of the Ord River: 650km
Catchment area (Ord and other rivers south of Lake Argyle): 46,200 square kilometres
Kununurra Diversion Dam (Completed 1963)
Length of dam including levees: 5km
Storage volume: 100,000,000 cubic metres
Distance from main Ord Dam (Lake Argyle): 55km downstream
Ord River Dam (Completed 1971) / Lake Argyle (Filled 1974)
Length at crest: 335m
Height from river bed: 98.5m
Volume of clay core: 243,000 cubic metres
Total material: 1,903,000 cubic metres
Full storage capacity – volume: 10,700,000,000 cubic metres
Surface area at storage: 980 square kilometres
Maximum flood level – volume: 34,655,000,000 cubic metres
Surface area at flood: 2,072 square kilometres
Maximum depth in flood: 63m
Highest level to date (7 April, 2011): 101.36.m AHD*
Lowest level to date (4 January, 1991): 78.58m AHD*
(*AHD – Australian Height Datum)