The protection status by way of the long-standing Water Conservation Order (WCO) for the Rakaia River is being eroded by efforts by Trustpower and Environment Canterbury says the New Zealand Federation of Freshwater Anglers (NZFFA).

Federation president Dr Peter Trolove said WCOs were akin to a National Park status preserving public property for the public interest. But that protection status is being undermined.

“The situation is now an unresolved shambles with Trustpower "giving the bird" to the water harvesting formula proscribed in the Rakaia NWCO,” he said. “Meanwhile Ecan is desperately searching for a way out of its statutory duty to give effect to the Rakaia WCO.”

The shambles began at a 2012 Ecan managed hearing which determined that the Rakaia River NWCO 1988 should be amended to enable the Lake Coleridge Project (LCP) which involved storing water in Lake Coleridge in times of high flow to be later sold to contracted irrigation schemes by Trustpower based on evidence provided by Trustpower, accepted by three "Independent Commissioners", that the effects of the LCP would be minor or less than minor.

The detail of the water harvesting protocol was made very clear at the Hearing and was subsequently passed into law - The Rakaia River WCO 1988 Amended 2013.

Ecan accepted the water harvesting formula as did the Minister for the Environment at that time.

Dr Trolove submitted against the LCP. He carried out his own approximate calculations based on historical Ecan Rakaia River flow data and found in some years there would not be sufficient natural flows to store adequate volumes of water to supply the 100,000 ha of new irrigation if the proposed water storage formula was complied with.

It appeared Trustpower very soon learned that the 32 km2 Lake Coleridge could not store sufficient water even if there was enough excess flow to be harvested due to Lake Coleridge only having a maximum of 3 metres depth that was accessible for abstraction I.e. water could not be accessed below 3 metres and above this level water simply flowed back out the head of the lake.

Trustpower responded by creating "virtual storage" by claiming the total volume of Lake Coleridge would be used for storage. He described the corporate’s response has seriously flawed.

“This of course is utter nonsense which Ecan now appear to be attempting to validate,” he said. "A competent Ecan hydrologist (Wilco Terink) was asked to make his two and a half year investigation "fit" the flawed model. Unfortunately for Ecan he showed admirable personal integrity and resigned instead,” said Dr Trolove.

He said ECan heads are now generating further nonsense in a failing attempt to hide their reluctance and inability to perform their role under the RMA 1991.

Groups like the NZFFA, NZ Salmon Anglers and others find the moves irresponsible and unacceptable.

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