Environment Waikato’s Regulatory Committee has told Mighty River Power to consult with everyone affected before it will make a decision on the company’s request to reduce minimum flows from Lake Karapiro over the summer.
Mighty River Power has asked that minimum flows be reduced from Lake Karapiro to secure power supplies to the upper North Island, should there be a long, hot, dry summer. There will be increased reliance on the Waikato hydro system to provide generation to meet peak electricity demand in the Region because of repairs to the Otahuhu station, restrictions on Huntly station operations when the river heats up, and a growth in regional demand which exceeds generation capacity.
Environment Waikato agreed to the company’s request late last year, subject to a number of conditions. However this year the Council is concerned that third parties have not been sufficiently consulted, while the company wants to begin the trial next month for a five month period.
Hamilton City Council representative, general manager of Works and Services Sally Davis, said the application had “a significant impact on the residents, ratepayers and visitors” to the city. Last year the City Council had been asked for its approval in mid February after the three month trial had begun in early January.
She said the city had not seen reports made in May on the effects of last year’s trial and was being put under undue pressure and haste to make a response without the opportunity to consider the implications and brief its councillors.
Amongst the likely effects were the risk of exposure of bridge piles, especially at the Fairfield Bridge, where timber piles were designed never to be exposed to the air. Last year some jetties were dry and non-functional during the trial, boat ramps had to be extended to function at low water levels, and stormwater outfalls became more obvious.
There were problems at the waste water treat plant where pumps had to be overhauled because of access to water, she said.
Bank stability and erosion could also be affected. There were also effects on recreational users, especially the Waipa Delta, and low flows could expose unsightly areas along the riverbank, where the city had made a significant investment in developing and linking riverbank walkways.
Environment Waikato councillors expressed concerns about many aspects of the proposal. Chairman Jim Howland said the Council had to consider not only if people would be able to launch their boats, but also if they would have any power this summer. Cr David Peart said the Council was faced with a difficult situation, and while there were emerging issues about summer power usage there were also issues about the lowering of the river level.
Cr Lois Livingston said many Hamilton people did not leave the city any more in summer and the proposal would affect their use of the river. She was also concerned about effects on water contamination levels.
The Committee has asked the company to consult further and wants to hear from both the company and the third parties on their views before a decision is made.