Clarrie Hall Dam

Clarrie Hall Dam
File:Clarrie hall dam mount warning.JPG Lake Clarrie Hall and Mount Warning
Location of Clarrie Hall Dam in New South Wales
Location	Northern Rivers, New South Wales, Australia
Coordinates
Purpose	Water supply
Status	Operational
Construction began	1979
Opening date	1983
Construction cost	A$34 million
Owner(s)	Tweed Shire Council
Dam and spillways
Type of dam	Embankment dam
Impounds	Doon Doon Creek
Height	43 metres (141 ft)
Length	175 metres (574 ft)
Elevation at crest	61.5 metres (202 ft) AHD
Width (crest)	6 metres (20 ft)
Dam volume	243 cubic metres (8,600 cu ft)
Spillways	1
Spillway type	Ungated concrete chute
Spillway capacity	590 cubic metres per second (21,000 cu ft/s)
Reservoir
Creates	Lake Clarrie Hall
Total capacity	16,000 megalitres (570×10^6 cu ft)
Active capacity	15,000 megalitres (530×10^6 cu ft)
Inactive capacity	10,000 megalitres (350×10^6 cu ft)
Catchment area	60.2 square kilometres (23.2 sq mi)
Surface area	220 hectares (540 acres)
Max. water depth	41 metres (135 ft)
Website

Clarrie Hall Dam is a minor ungated concrete faced rockfill embankment dam with an uncontrolled concrete-lined chute spillway across the Doon Doon Creek, located upstream of the small town of Uki, in the Northern Rivers region of New South Wales, Australia. The main purpose of the dam is for water supply and it creates the artificial Lake Clarrie Hall.

Location and features

Clarrie Hall dam construction commenced in 1979 and it was opened in 1983 with the unique distinction of being full after heavy rainfall prior to the opening ceremony. It is a minor dam on the Doon Doon Creek, a tributary of the Tweed River, and is located approximately 15 kilometres (9.3 mi) south-west of Murwillumbah. The primary function of the dam is to provide storage of water for Tweed Shire's drinking water supply, by releasing water downstream into Doon Doon Creek when levels of freshwater in the Tweed River fall below 95%, which occurs mostly in winter and spring. Otherwise the natural flows of the Tweed River provide 80% of the water needs of the Shire.

The dam wall height is 43 metres (141 ft) and is 175 metres (574 ft) long. The maximum water depth is 41 metres (135 ft) and at 100% capacity the dam wall holds back 16,000 megalitres (570×10^⁶ cu ft) of water at 61.5 metres (202 ft) AHD. The surface area of Lake Clarrie Hall is 220 hectares (540 acres) and the catchment area is 60.2 square kilometres (23.2 sq mi). The uncontrolled chute spillway is capable of discharging 590 cubic metres per second (21,000 cu ft/s). The estimated completion cost was A$34 million.

In April 2013, an upgrade of Clarrie Hall Dam commenced, and included widening the existing spillway crest to 35 metres (115 ft) and raising the existing spillway inlet walls and embankment parapet wall by 2 metres (6 ft 7 in). It is expected that the upgrade will be completed during 2014.

Following heavy rainfall in the catchment area, in January 2012 the dam was at its highest level since records commenced in 1986. It was estimated that water was flowing in the range of 2 metres (6 ft 7 in) over the dam spillway.

Recreation

Lake Clarrie Hall provides valuable public recreation including swimming, sailing, boating and freshwater fishing, including sports fishing for Australian bass. Boat access for electric outboard and paddle-powered craft is available at Crams Farm, at the southern end of the waterbody. Lake Clarrie Hall has been stocked with more than 358,000 Australian bass fingerlings over the past 10 years. A fishing licence is required to fish in the lake.

High levels of blue-green algae are common on the lake surface.

See also

• List of reservoirs and dams in Australia
• Uki, New South Wales