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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 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 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 Clarrie Hall is and the catchment area is . The uncontrolled chute spillway is capable of discharging . The estimated completion cost was 34 million.〔 In April 2013, an upgrade of Clarrie Hall Dam commenced, and included widening the existing spillway crest to and raising the existing spillway inlet walls and embankment parapet wall by . 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 over the dam spillway. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Clarrie Hall Dam」の詳細全文を読む スポンサード リンク
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