Hydro Spill
Ohakuri
Mighty River Power owns and operates nine hydroelectric power stations on the Waikato River. As a responsible user of valuable natural resources we are committed to managing the water resources of Lake Taupo and the Waikato River as efficiently as possible. Our goal is to see that as water passes through each of our power stations as much of it as possible is used to generate electricity. Most of the time we are able to achieve this. However, from time to time and for various reasons water is released from a dam without generating electricity, which is known as "spill".
On this website, you will find weekly reports on spill from any of our nine hydro stations and the reasons for it. The reports comply with the standards recently agreed by the industry.
The reports record the amount of spill that has occurred at each of our hydro electric power stations for that week equivalent to the amount of energy that could have been generated if spill had not occurred. The units are gigawatt hours (GWh). In an average year the Waikato hydro electric power stations generate a combined total of 4,120GWh.
Mighty River Power has a regulatory requirement for daily spills of water down the Aratiatia rapids to meet recreational and tourism demands. Other spills on the Waikato River are usually caused by weed blockages or the sudden failure or planned maintenance of generation plants - identified by the categories in the hydro spill tables.