Environment Waikato has granted resource consents for the continued operation of the Hinemaiaia Hydro Electric Power Station near Taupo.
Trustpower Ltd had applied for a series of consents to dam, take, divert and discharge water for power generation, and to discharge water and sediment and excavate sediment for lake dredging in the area for a period of 35 years. Eleven submissions were originally received from various groups including Department of Conservation, neighbours, iwi boards, Forest and Bird and the Taupo Fishery Advisory Committee when the applications were first made in 1998.
Five more submissions were received this year when consents were required for the bottom lake from Department of Conservation, Hatepe Residents Association, Mighty River Power and neighbours.
The applicant proposed to continue to operate the existing scheme at a slight increase in the take of water, as well as carrying out ongoing dredging maintenance works within the Hinemaiaia A lake. The applicant proposes that the lake reservoir will not be drawn down by more than 0.3 metres per hour except during floods or emergencies.
The Hinemaiaia A lake captures most of the sediment from the river and over time water storage capacity is reduced. It was last dredged in 1994 and the applicant says dredging will be required about every 10 years to retain storage.
Submitters’ concerns included effects on the fishery caused by the bottom dam, which creates a barrier for trout. Mitigation measures proposed could never compensate for the loss of original spawning area, the Fishery Advisory Committee said. The Department of Conservation said the operation of the scheme had adversely affected the trout fishery and angling opportunities.
Hatepe residents were concerned about accelerated erosion, damage to the fishery, and recreational amenities, violation of tangata whenua rights, and the scheme outliving its purpose. They wanted the consents granted for only eight years.
In making its decision the Hearing Committee said it was entitled to consider and seek to mitigate the effects on fisheries and did not accept that such matters were outside its jurisdiction.
Erosion downstream was occurring and fluctuations in river level, which the applicant controlled, was likely to increase existing erosion to only a minor extent. Some mitigation was required, but the Committee was prepared to allow the applicant to demonstrate their offer of goodwill in contributing to erosion control initiatives.
It imposed a requirement to install a fish pass within three years on the B dam, saying it was reasonable and justifiable, as the Taupo trout fishery was an exceptional resource. Granting the consents for the maximum of 35 years, it said the installation of a fish pass was a long-term investment which should achieve long term benefits.
The resource security period was in line with the size of the investment required, it said.