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 ...

with nine radial gates and a gated concrete chute spillway across the

Gwydir River Gwydir River (locally wɑe̯də, a major inland perennial river of the Barwon catchment within the Murray–Darling basin, is located in the Northern Tablelands, North West Slopes, and Orana districts of New South Wales, Australia. Th ...

upstream of

Bingara Bingara (Aboriginal for 'creek') is a small town on the Gwydir River in Murchison County in the New England region of New South Wales, Australia. Bingara is currently the administrative centre for the Gwydir Shire that was created in 2003. The ...

in the

New England New England is a region comprising 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 Can ...

region of

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

, Australia. The dam's purpose includes environmental flows,

hydro-electric Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined an ...

power generation,

irrigation Irrigation (also referred to as watering) 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 been devel ...

, 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. Thes ...

. 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 Inverell is a large town in northern New South Wales, Australia, situated on the Macintyre River, close to the Queensland border. It is also the centre of Inverell Shire. Inverell is located on the Gwydir Highway on the western slopes of the ...

, 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 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 cellulose, and can contain minor pe ...

, wheat, lucerne, 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 A fuse plug is a collapsible dam installed on spillways in dams to increase the dam's capacity. The principle behind the fuse plug is that the majority of water that overflows a dam's spillway can be safely dammed except in high flood condition ...

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 generation of electric power. Power stations are generally connected to an electrical grid. Many ...

generates up to of

electricity Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as describ ...

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