Wivenhoe Dam

The Lake Wivenhoe is a reservoir in the southeast of the Australian state of Queensland. The Wivenhoe Dam is located on the middle reaches of the Brisbane River just above the confluence of the Locker Creek. He is about 23 km northwest of Ipswich away. The driving distance from the city center of Brisbane is about 80 km.

The Lake Wivenhoe was designed to prevent the usual on the Brisbane River flash floods and as a water reservoir in the early 1970 's. The flooding of Brisbane in 1974 made ​​the need for a flood protection for the cities in southeast Queensland clearly. The lake serves as a water reservoir for the Wivenhoe Power Station.

The Wivenhoe Dam is a gravity dam, which consists of earth and rock, and is 2.3 km long and 50 m high. It has a concrete outlet with five steel gates. The 12 m wide and 16.6 m high gates are among the largest of its kind in the world. The dam also has an emergency overflow, which prevents overfilling.

The reservoir has a storage capacity of 2,610 million cubic meters, of which 1,160 million m³ serve as a drinking water reservoir. The surface with full back is 109.4 km ² and the coastline length of 462 km. 200 properties were purchased in order to get the 337.5 km ² of land that were needed for the dam and the reservoir. The hydrological catchment area of the reservoir is about 7020 km ² and receives an average rainfall of 940 mm / year. The volume of the reservoir is about twice as large as that of the port of Sydney and about seven times as large as that of the Advance Town Lake on the Nerang River on the Gold Coast. The Lake Wivenhoe also covers a portion of the water requirement of the Gold Coast.

Purpose

The dam was built in response to floods that devastated Brisbane in 1974. It was built in the late 1970s and early 1980s for several purposes: In addition to the flood protection it considers even drinking water for Brisbane and its surroundings before and serves as the lower reservoir of a pumped storage power station, the Wivenhoe Power Station. The upper memory is the Atkinson Lake, about 30 km north-west of Ipswich with a capacity 28.7 million m³ and a dam, which corresponds to the type of the Wivenhoe Dam.

At normal water level of the reservoir supplied via pipeline and the Tarong Power Station and Tarong North Power Station. In drought but it only provides the water for the Tarong North Power Station.

Construction

Wivenhoe was first in 1890 and then again in 1933 as the site of a dam drawn into consideration. Further investigations began in the mid 1960s. In November 1971, the government gave approval to begin the construction preparations. The purchase of land for the reservoir began in March 1973. 1976 granted the government's approval for the pumped storage power plant. The total cost of the power plant project amounted to 450 million Australian dollars. In March 1977, the first construction contract was issued. The dam was built by the Queensland Water Resources Commission.

In June 1983, the partially completed dam prevented a potentially dangerous flash flood, could have caused the damage can that would have met them at the great flood in Brisbane in 1893. In 1985, the construction was completed.

Flood protection

At high tide, the dam can hold 1,450 million cubic meters of additional water or 225 % of its base capacity. After the statutory water drainage plan of this water must be drained within 7 days after reaching the 100 % -owned filling degree. Between April 2004 and September 2008, a further lowering system with tri- backup dam was built on the west side of the dam for improved flood protection. 2007 pointed to a safety study that the Wivenhoe Dam ANCOLD the rules (Australian National Committee on Large Dams, dt: "Australian National Committee on big dams " ) did not meet adequate flood capacity.

January 2011

The largest ever recorded inflow volumes in the reservoir occurred in January 2011. On 11 January 2011 the Lake Wivenhoe reached its highest water level recorded so far, 191 % and rising. He held back the water and so reduced the downstream destruction. Since it is a heaped gravity dam, he is not built for a water overflow over the crown. Such a spillover involves the risk of leachates, which can ultimately lead to the collapse of the entire dam. To prevent this, the Wivenhoe dam received a second emergency overflow. In the flood peak water level reached a value of 60 cm below the emergency spillway.

Treated waste water

2006 were introduced into the reservoir contingency plans for additional discharge of treated wastewater from the Western Corridor Recycled Water Scheme. 60,000 m³ of treated wastewater should be introduced into the lake in early 2009. Increased rainfall in 2008 and a public outcry ensured that these plans were again shelved.

Fauna

The reservoir itself is threatened Australian lungfish. Anne Kemp, a scientist from the University of Queensland, assumes that there were about 800 copies in the lake in 2010, but many were washed away when the outlets were opened. Furthermore, it is the number of food animals, such as molluscs and shells, not enough to feed the Australian lungfish in the lake.

Stable populations of lung fish living in the lakes of southeast Queensland since 1896 and so for over 100 years. Originally they found these fish only in the river systems of the Mary River and the Burnett River. Because of the continued threat of their natural habitat, they were also used in other river systems, such as that of the Brisbane River between the years 1895 / 1896. This procedure improved the chances of survival of this species.

Recreational facilities

The Lake Wivenhoe also offers opportunities for camping and other recreational outdoor activities. Tent sites there are at Captain Logan Camp and Lumley Hill Camp. The guarded Camping at Captain Logan Camp has hot showers, restrooms and picnic areas. Adjacent to find playgrounds, kiosk rental boats and a slipway for boats at Logan Inlet. More picnic areas are available at the Cormorant Bay, in Hamon Cove and at the Spillway Common.

Activities

For sport fishing, you need a special permit ( Permit Stocked impoundment ). Swimming is allowed without restrictions. Similarly, the operation is permitted by rowing and electric boats, but pets are not permitted on or in the lake.

Statistics

• Valley height: 23 m
• Crown height: 79 m
• Building volumes: 4 million m³ (rock pile ) and 140,000 m³ ( concrete)
• Drain Valves: 2 x diameter 1.5 m
• Average annual evaporation: 1.872 mm