| 87 Opuha Dam benefits are substantial South Opuha. Lindy Andrews The environmental and economic benefits of South Canterbury’s Opuha Dam are undeniably substantial, with its positive downstream impacts poised to grow well into the future. A 2006 study by the Aoraki Development Trust and the Ministry of Economic Development (MED) evaluated the dam’s net economic benefit to the South Canterbury economy at an impressive $185 million. Today, the dam’s annual gross economic contribution exceeds $1 billion, with a net economic benefit of $315 million. Opuha Dam has undoubtedly helped propel South Canterbury into economic prosperity. “Irrigated land is productive land,” Opuha Water Chief Executive Bjorn Triplow points out, highlighting the benefits to dairying, horticulture, arable cropping, sheep, beef, deer farming, and specialist seed growing. The dam was commissioned in 1998 and was purchased in 2007 to become fully owned by its farmer shareholders. It provides irrigation for 16,000 hectares in South Canterbury, spanning the McKenzie and Timaru Districts. A 50-metre-high zoned earth dam, Opuha sits at the confluence of the North and South Opuha Rivers. It features a single hydro turbine and a 710-hectare lake that stores up to 74 million cubic metres of water. The dam also generates renewable hydroelectricity and offers extensive recreational opportunities. While some water in Lake Opuha is used for irrigation and town supply, its environmental function is of utmost importance. Water storage is prioritised for release into the Opuha River, which flows into the Opihi River, ensuring minimum environmental river flows are always maintained, particularly during times of drought and low natural flows. Opuha’s Environmental team, which is led by Julia Crossman, and includes a freshwater specialist, monitors more than 60 sites across Lake Opuha, its rivers, and tributaries. Water is also released from the bottom of the dam in annual artificial freshes, which mimic natural high river flow events and help remove nuisance species like RURAL SERVICES » Opuha Water didymo from the river. “Before the Opuha Dam was built, the rivers would frequently dry out, leaving pools of stranded fish,” Bjorn says. “The dam allows minimum river flows to be maintained year-round.” The lake level throughout the year is regularly reviewed by the Opuha Environmental Flow Release Group, consisting of representatives from Environment Canterbury, the Timaru and McKenzie District Councils, Fish & Game, the Department of Conservation, Federated Farmers, and Te Runanga o Arowhenua. This group ensures community-based input into the decisions made regarding the use of water from Lake Opuha. Looking ahead, the irrigation season appears promising. “Heading towards the summer months, Lake Opuha is at 100% of its operational level with no Monitor and control your critical on-farm infrastructure from anywhere. Agricultural Solutions halosystems.co.nz Operated by our skilled and knowledgeable sta , we have a comprehensive range of modern plant and equipment to fulfill all your needs. Residential Subdivisions Commercial Developments Drainage Demolition Residential Site & Foundation Preparation Driveways & Landscaping Rock Walls P 0800 773 2002 E admin@pse.co.nz W www.pse.co.nz STANDOUT TRADE SERVICES Level Electrical Geraldine T: 03 693 9399 E: geraldine@levelelectrical.nz W: geraldine.levelelectrical.nz current water restrictions required. Recent rain and snow events have put us in a good position,” Bjorn notes. He emphasises that Opuha Water’s legacy is set to flow well into the future. “We recognise the significance of this asset to South Canterbury and the importance of taking a generational approach. “The Opuha Dam stands as a testament to the region’s commitment to sustainable development, balancing economic growth with environmental stewardship.”
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