Central Plains Water Ltd (CPWL) has signed a historic agreement with TrustPower to store water in Lake Coleridge for use by its shareholders when the Rakaia River flow is low.
Doug Catherwood, chair of CPWL, in announcing the agreement said he was unaware of any other storage facility offering to release contracted water on demand in New Zealand.
“We have to book the volume a year in advance but TrustPower will release it with about a day’s notice,” he said.
The agreement follows months of discussion and has been made possible by the Government’s decision to alter the Conservation Order covering the river and lake.
“This is another big step forward for us. Lake Coleridge is an existing reservoir, and at this early stage the Coleridge Storage will support Stage 1 at least of the CPW Scheme, which involves water supply to 20,000 hectares of farming land,” Catherwood said.
TrustPower would provide 95% reliability for the scheme for Stage 1, he said. Before the agreement was signed, CPW was able to offer only 70% reliability with the run of river supply.
“This is good news for us. Ninety-five percent reliability is virtually water every day for farmers. This is a real alternative to our own water storage reservoir.”
There is potential for more stored water to be available for future stages of the CPWL Scheme.
“Research will need to be conducted before we can be assured of the reliability of the next tranche of water. We now know the reliability will be considerable and well worth pursuing. This will constitute the next phase of our discussions.”
Catherwood said having reliable alpine water was key for the viability of CPWL.
The positive impact meant that current groundwater users who are pumping from up to 200m would switch to surface water, releasing the pressure on the over-allocated groundwater usage, enabling the aquifers to be replenished and increase the environmental flows in the lowland streams.
“As our construction proceeds over the next couple of years, we will provide equal reliability for the coming stages of the CPW, without compromising environmental concerns for the river and the lake.”
The first stage of the irrigation scheme will run from near the Rakaia River bridge to near the Hororata River. It will be worth approximately $144 million.