Copeton Dam is a major clay core and rock fill embankment

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aqua ...

with nine radial gates and a gated concrete chute spillway across the Gwydir River upstream of Bingara in the

New England New England is a region consisting of six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York (state), New York to the west and by the ...

region of

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

. The dam's purpose includes environmental flows, hydro-electric power generation,

irrigation Irrigation (also referred to as watering of plants) is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has bee ...

, and

water supply Water supply is the provision of water by public utilities, commercial organisations, community endeavors or by individuals, usually via a system of pumps and pipes. Public water supply systems are crucial to properly functioning societies. Th ...

. The impounded reservoir is called Lake Copeton.

Location and features

Commenced in March 1968, commissioned in 1973, and completed in 1976, the Copeton Dam is a major dam on the Gwydir River, a tributary of the Barwon River, and is located approximately southwest of Inverell, between Bingara and Bundarra. The dam was built by the New South Wales Water Conservation & Irrigation Commission and the Department of Water Resources to supply water for irrigation. Water from the dam is now released directly into the Gwydir River which is used by irrigators downstream of the dam including for pecan nut farming, and for producing

cotton Cotton (), first recorded in ancient India, is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus '' Gossypium'' in the mallow family Malvaceae. The fiber is almost pure ...

, wheat,

lucerne Lucerne ( ) or Luzern ()Other languages: ; ; ; . is a city in central Switzerland, in the Languages of Switzerland, German-speaking portion of the country. Lucerne is the capital of the canton of Lucerne and part of the Lucerne (district), di ...

, vegetables, fruit trees, oil seeds and fodder as well as pastures for sheep and cattle. The dam wall comprises of rock fill and is high and is long. The maximum water depth is and at 100% capacity the dam wall holds back of water at AHD. The surface area of Lake Copeton is and the catchment area is . The gate-controlled concrete chute spillway is capable of discharging of water per day. Together with a series of diversionary weirs and regulatory works downstream from the dam, Copeton is able to provide a reliable flow of water to of land. This amount is much less than the originally planned because of higher rates of absorption and evaporation along some of the irrigation channels. Despite these overestimates irrigated agriculture in the Gwydir Valley saw the area become Australia's major cotton-producing region. Copeton Dam Storage

Upgrade of facilities

In 2007, it was decided the dam would need an upgrade for safety reasons. The A$70 million upgrade is expected to be completed during 2013 and Stage One involves the construction of a four-bay, -wide, fuse plug spillway at Diamond Bay to enable the dam to safely pass extreme floods. Once the fuse plug is installed the dam wall will be raised and the spillway gate modified.

Spillway

Unexpected erosion of hard, sound, unweathered granite in the unlined spillway discharge channel was caused by rock failure under high in-situ compressive stress. This type of erosion due to high in-situ stress has not been reported elsewhere in the world. Remedial works involved building a training wall to separate the original single spillway into a service spillway and a secondary (emergency) spillway. A concrete slab, anchored to the underlying rock was constructed in the floor of the main scour channel to provide some additional protection on those rare occasions when the secondary spillway will discharge water over this area. The smaller, more frequent flood events will be discharged through the service spillway onto more scour resistant rock which has performed satisfactorily to date. The secondary spillway will operate very infrequently and will only discharge when the capacity of the service spillway is exceeded. Geological investigations for the design of these remedial works included surface stress measurements in the unlined spillway discharge channel as well as geological mapping and diamond core drilling.

Power generation

A hydro-electric

power station A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the electricity generation, generation of electric power. Power stations are generally connected to an electr ...

generates up to of

electricity Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwel ...

from the flow of the water leaving Copeton Dam with an average annual output of . The station was completed in December 1996. The facility is managed by AGL Energy.

Recreation

Copeton Dam offers sailing, windsurfing, boating, water skiing, fishing and swimming while bushwalkers can enjoy unusual geological formations, lake and mountain views and a wide variety of plant life.

References

External links

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Copeton Dam Fishing Information & Map
{{WaterNSW , state=autocollapse Dams completed in 1976 Energy infrastructure completed in 1996 New England (New South Wales) Dams in New South Wales Embankment dams Hydroelectric power stations in New South Wales