Leaks reported in another canal

Press, 7 January 1983, Page 1

Leaks reported in another canal

PA Wellington Another small hydro power scheme in the Bay of Plenty will be investigated after reports of minor leaks in its canal wall. The Aniwhenua scheme, which uses the same river sources as the Wheao project, was completed more than a year ago and is being run by the Bay of Plenty Electric Power Board.

In calling for a committee of inquiry into the “engineering fault” said to have cause last week’s collapse of the Wheao canal, the Minister of Works, Mr Friedlander, has asked for a special report on the Aniwhenua problem.

Aniwhenua is of similar size to the Wheao and Ruahihi schemes, generating about 20 megawatts of power. These schemes are some of the estimated 47 local body hydro projects running or being built in New Zealand. Mr Friedlander confirmed on Wednesday that minor leaks had developed at Aniwhenua, but he said these occurred some time ago and there was no evidence to fear a repeat of the Wheao

and Ruahihi failures.

He had, however, decided it was appropriate that this project should also come under scrutiny. it is believed that the Aniwhenua’s scheme's canal wall sprung a leak more than a year ago and the cracks were filled with concrete. The wall has reportedly not leaked since.

Mr Friedlander met officials of the Rotorua Area Electricity Authority yesterday before going out to inspect the Wheao project site. Before the meeting, he said he was not prepared to detail what was meant by an engineering fault being the suspected cause of the canal collapse last Thursday. He said the preliminary report prepared for him by the Ministry of Works had been done in some haste and it would be up to the committee of inquiry to explore the incident in more detail. No detailed work had yet been done on assessing whether soil types were similar to those at Ruahihi, and whether this might have been a contributing factor, he said.

Soil failure was blamed for the Ruahihi canal collapse 15 months aeo The chairman of the Rotorua authority. Mr Allen Mills, welcomed the decision for an inquiry. He said the authority had “a totally open mind” on what might have caused the disaster, but could not add any detail to the suspicions of an engineering fault.

Mr Mills confirmed that the Wheao site was evacuated for a time about three weeks before the canal collapsed, after a minor leak developed in the cliff face immediately above the power station. He said the leak was filled with concrete and there was no evidence to suggest that this problem contributed to the canal’s collapse. The inquiry will begin immediately a three-person committee has been appointed, Mr Friedlander said he expected hearings to be held behind closed doors, although the report — to be produced in three months — would probably be made public. Mr Friedlander also said

that he had asked the Commissioner of Works, Mr J. I. Chesterman, to conduct a review of proceedings for small hydro schemes with a view to’improvements being made.

“In the process of preparing this report I have asked that he discuss any possible changes to the procedure with the engineering profession. contractors, and appropriate agencies.” the Minister said. Mr Friedlander said that if funds were requested to start reconstruction of the scheme, he would recommend to the Minister of Finance that a condition of financial approval be that an engineering audit of the proposed reconstruction be completed by the Ministry of Works.

The Labour Party leader, Mr Rowling, yesterday welcomed the committee of inquiry into the collapse of the Wheao power scheme. Mr Rowling said it was the “second collapse in recent months of a major scheme built by private enterprise.” He said he hoped the proposed general review of local hydro procedures would result in the injection of the Ministry of Works' expertise at an early stage in future. “This must be the last time that the Ministry of Works is asked to clean up after a private contractor, whether on small local schemes, or those on the scale of Clyde.” The Geological Society of New Zealand is concerned about the number of land failures in New Zealand during the last three years, says the society’s president, Dr Vince Neall, a Massey University soil scientist. Dr Neall said the recent collapse of the Wheao power scheme demonstrated the need for adequate geological investigations at big construction sites, particularly where volcanic materials were involved. The cause of the Wheao failure had yet to be scientifically determined, he said, but the society was concerned about the number of failures where inadequate geological investigations had been made or reports' of geological instability had not been heeded. .