The BCI stage one project in 2010 built infrastructure to use up to eight cumecs of water from the Rakaia River at Highbank.
TrustPower Limited installed intake, fish screening and pumping facilities to deliver the water to the Rangitata Diversion Race (RDR) utilising some of the existing Highbank Power Station facilities.
Water swap arrangements managed by RDR Management Limited allows the water to be delivered to a pipe network across the upper plains. The water is taken from the RDR to buffer ponds in the Highbank, Methven, Ashburton Forks, Springburn, Buccleugh, Valetta, and Mayfield areas. The upper plains distribution network consists of seven main pipelines with a total of 150km of pipe installed, delivering pressurised water to irrigators.
Stage two of the BCI project in 2015 saw the construction of a new river intake at Barrhill, and the Barrhill and Chertsey distribution lines. The Barrhill line is fed from water pumped from the river at Barrhill, and the Chertsey line via a 7km gravity line in the riverbed. The riverbed gravity line also has a small hydro generation plant incorporated to utilise water for generating electricity. A total of 75km of pipe is installed in the lower plains.
Automation and modifications to the RDR, the buffer storages, the Barrhill intake and hydro generator, and all distribution lines have been financed through a Joint Venture between BCI and local electricity lines cooperative Electricity Ashburton Limited.
A further three cumecs of water is being used through licence arrangements with the Acton Scheme in the Rakaia and Pendarves area.
BCI water is being utilised on arable, dairy and intensive pastoral farms.
Why is BCI vital for Mid Canterbury?
The BCI Project is important because Mid Canterbury farmers have few alternative sources of new irrigation water.
The upper plains has limited ground water opportunities due to water depth and over-allocation. BCI stage one will take the pressure off further allocation of the district’s ground water resources.
The project will also provide for more balanced use of the district’s water and energy resources. The use of “run of river” water in the upper plains will significantly reduce energy consumption for pumping and provide further ground water recharge in the lower plains. Electricity generation within the scheme will provide the district with a valuable source of renewable energy generation.
Over a period of time, it is expected there will be a shift from deep well use in the upper plains if a “run of river” supply is available.