Chichester Dam

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Lake Chichester
Location	New South Wales
Coordinates	32°14.2161′S 151°41.3672′ECoordinates: 32°14.2161′S 151°41.3672′E
Lake type	Reservoir
Primary inflows	Chichester River, Wangat River
Primary outflows	Chichester River
Catchment area	197 km² (76.1 sq mi)
Basin countries	Australia
Max. length	4.22 km (2.62 mi)
Max. width	580 m (1,902.9 ft)
Surface area	1.8 km² (444.790 acres)
Max. depth	43 m (141.1 ft)
Water volume	21,500 megalitres
Shore length¹	18 km (11.2 mi)
Surface elevation	156.2 m (512.5 ft)
Frozen	never
Islands	none
Settlements	none
¹ Shore length is not a well-defined measure.

Chichester Dam is a dam in the Hunter Region of New South Wales approximately 21.6 km (13.4 mi) north of Dungog. It was constructed between 1917 and 1926 as a supply of drinking water for the Hunter Region by damming the Chichester River. 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, 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, Cessnock and Newcastle 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.^[1]

[edit] 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.^[1]