The Central Plains Water Enhancement Scheme is a community irrigation scheme which will provide water to an irrigable area of 60,000Ha within a command area of over 100,000Ha of the Canterbury Plains between the Southern Alps to the west, State Highway I and the Waimakariri and Rakaia Rivers.
The scheme, which will be built in stages, will utilise run-of-river water from both the Rakaia and Waimakariri rivers supported by stored water from Lake Coleridge.
With a current estimated construction cost of $385 million (excluding on-farm costs), the Central Plains Water Scheme is a significant construction project for the South Island.
The Waimakariri and Rakaia Rivers will be linked via a 56km headrace canal running around the foothills and water from the canal will be distributed by gravity feed throughout the 60,000Ha by over 500kms of underground piping. Water within the canal will be about 4m deep and approximately 25m wide at the surface.
The first Stage will comprise 20,000Ha between the Rakaia and Selwyn Rivers. The footprint of future stages is likely to be within the Hororata, Greendale , Darfield, Kirwee and Sheffield areas. Farmer demand will dictate the extent and timing of development.