Dartmouth Dam
Encyclopedia
Dartmouth Dam is a large dam
on the Mitta Mitta River
in the north-eastern portion of the Australian state
of Victoria
. The dam creates the artificial Lake Dartmouth, storing water from the Victorian "High Country's" snow fields for summer release into the Mitta Mitta (and the downstream Lake Hume
) and subsequently into the greater Murray River
for irrigation.
Construction was started in 1973 and completed in 1979 at a cost of $139 Million. The dam is constructed with an earth core and rock filled walls, rising to a height of 180 metres making it Australia's highest dam. It has a capacity of 3,906 gigalitres (or 3906000 Megalitres), or approximately 6.7 times the capacity of Sydney Harbor. It can release a maximum outflow of approximately 10,000 megalitres per day in normal operation. The dam's inflow and outflow capacity is quite small considering its size, meaning that its levels vary little compared with some other dams on the Murray and their tributaries.
The dam is a popular recreational trout
fishery, being regularly restocked by the Victorian Department of Primary Industries. Since its completion in 1979, the dam has spilled over only twice – once in 1998, and again in 1999. The 1998 overflow came, largely coincidentally, soon after a major accident in which two steel beams entered the turbine
s of the (unattended) 200 MW hydroelectric generators
installed in the dam. The resulting force ruined the power station and the dam's control systems, making it impossible to gradually release water from the near-capacity dam by conventional means. An improvised system, placing large pipes over the spillway to siphon water over it, was soon installed, but the inflow from an unusually wet spring was such that the dam would have overflowed anyway, leading to a spectacular cascade over the huge rock steps formed when the rock used for the dam itself was quarried from the valley walls.
A subsequent investigation could not find any explanation for the presence of the steel beams.
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...
on the Mitta Mitta River
Mitta Mitta River
The Mitta Mitta River is a major tributary of the Murray River in Australia and the source of approximately 40% of the Murray's flow.The river's headwaters include Victoria's highest mountain, Mount Bogong, with the Mitta Mitta itself forming at the confluence of the Cobungra River and the Big...
in the north-eastern portion of the Australian state
Sovereign state
A sovereign state, or simply, state, is a state with a defined territory on which it exercises internal and external sovereignty, a permanent population, a government, and the capacity to enter into relations with other sovereign states. It is also normally understood to be a state which is neither...
of Victoria
Victoria (Australia)
Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....
. The dam creates the artificial Lake Dartmouth, storing water from the Victorian "High Country's" snow fields for summer release into the Mitta Mitta (and the downstream Lake Hume
Lake Hume
Lake Hume is an artificial lake in Australia formed by the Hume Weir east of Albury-Wodonga on the Murray River just downstream of its junction with the Mitta River. The small towns of Tallangatta, Bonegilla and Bellbridge are located on the shores of Lake Hume...
) and subsequently into the greater Murray River
Murray River
The Murray River is Australia's longest river. At in length, the Murray rises in the Australian Alps, draining the western side of Australia's highest mountains and, for most of its length, meanders across Australia's inland plains, forming the border between New South Wales and Victoria as it...
for irrigation.
Construction was started in 1973 and completed in 1979 at a cost of $139 Million. The dam is constructed with an earth core and rock filled walls, rising to a height of 180 metres making it Australia's highest dam. It has a capacity of 3,906 gigalitres (or 3906000 Megalitres), or approximately 6.7 times the capacity of Sydney Harbor. It can release a maximum outflow of approximately 10,000 megalitres per day in normal operation. The dam's inflow and outflow capacity is quite small considering its size, meaning that its levels vary little compared with some other dams on the Murray and their tributaries.
The dam is a popular recreational trout
Trout
Trout is the name for a number of species of freshwater and saltwater fish belonging to the Salmoninae subfamily of the family Salmonidae. Salmon belong to the same family as trout. Most salmon species spend almost all their lives in salt water...
fishery, being regularly restocked by the Victorian Department of Primary Industries. Since its completion in 1979, the dam has spilled over only twice – once in 1998, and again in 1999. The 1998 overflow came, largely coincidentally, soon after a major accident in which two steel beams entered the turbine
Turbine
A turbine is a rotary engine that extracts energy from a fluid flow and converts it into useful work.The simplest turbines have one moving part, a rotor assembly, which is a shaft or drum with blades attached. Moving fluid acts on the blades, or the blades react to the flow, so that they move and...
s of the (unattended) 200 MW hydroelectric generators
Dartmouth Power Station, Victoria (Australia)
Dartmouth Power Station is a hydroelectric power station at Dartmouth Dam on the Mitta Mitta River in Victoria, Australia. Dartmouth has one turbo generator, with a generating capacity of 180 MW of electricity, the largest single hydroelectric turbine in Australia...
installed in the dam. The resulting force ruined the power station and the dam's control systems, making it impossible to gradually release water from the near-capacity dam by conventional means. An improvised system, placing large pipes over the spillway to siphon water over it, was soon installed, but the inflow from an unusually wet spring was such that the dam would have overflowed anyway, leading to a spectacular cascade over the huge rock steps formed when the rock used for the dam itself was quarried from the valley walls.
A subsequent investigation could not find any explanation for the presence of the steel beams.