Chichester Dam is a dam in the Hunter Region of New South Wales

New South Wales

New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...

 approximately 21.6 km (13.4 mi) north of Dungog

Dungog, New South Wales

Dungog is a country town on the Williams River in the upper Hunter Valley in New South Wales, Australia. Located in the middle of dairy and timber country, it is the centre of the Dungog Shire Local Government Area and at the 2006 census it had a population of 2,102 people. The area includes the...

. It was constructed between 1917 and 1926 as a supply of drinking water for the Hunter Region by damming the Chichester River

Chichester River

The Chichester River is a river of the state of New South Wales in Australia. It is dammed by the Chichester Dam.-References:...

. The dam contributes about 35 percent of the lower Hunter region's water supply. Its catchment is largely located within the Barrington Tops National Park

Barrington Tops National Park

Barrington Tops is a National Park in the Hunter Valley, approximately north of Sydney in New South Wales, Australia. The nearest towns are Scone, Singleton, Dungog, Gloucester and East Gresford....

, and covers 197 km² (76.1 sq mi), receiving water from the Chichester and Wangat Rivers. The reservoir holds 21,500 megalitres of water and is connected to reservoirs in Maitland

Maitland, New South Wales

Maitland is a city in the Lower Hunter Valley of New South Wales, Australia and the seat of Maitland City Council, situated on the Hunter River approximately by road north of Sydney and north-west of Newcastle...

, Cessnock

Cessnock, New South Wales

Cessnock is a city in the Hunter Region of New South Wales, Australia, about by road west of Newcastle. It is the administrative centre of the Cessnock City Council LGA and was named after an 1826 grant of land called Cessnock Estate, which was owned by John Campbell...

 and Newcastle

Newcastle, New South Wales

The Newcastle metropolitan area is the second most populated area in the Australian state of New South Wales and includes most of the Newcastle and Lake Macquarie Local Government Areas...

by an 80 km (50 mi) long gravitation main. The wall is 254 m (833 ft) long and 43 m (141 ft) high, using a cyclopean system of interlocking concrete blocks and large boulders. The wall is anchored to the bedrock below it by 93 stressed tendons.

History

Construction began in 1917 and finished in 1926. In 1965 the spillway was lowered by 2.75 m (9.02 ft) to increase flood capacity. In 1985 the dam was post tensioned with cables and the spillway was relocated to the centre of the dam and returned to its original height. In 1995 the seepage potential was reduced under the northern abutment and in 2003 an improved dainage system for the dam's foundations was installed and the left parapet wall was raised to prevent overtopping in a major flood.