Environment Waikato has worked with Mighty River Power and Genesis to assess the effect of hydro electric power generation structures and operating regimes on the river system. Both companies have provided additional information to Environment Waikato and an assessment has been produced (Mulholland and Hamilton, 2001)
It has been agreed that there are a range of factors affecting the need for works at any location. The assessments have taken into account technical material, but judgement has still had to be applied. The dominant factors in all zones are considered to be natural.
In working through the issues on a zone-by-zone basis, the relevant technical material has been reviewed and a summary of the most relevant factors made. Assessments of the contributor effect of land uses and hydro electric companies has been made and is detailed in section 16. The four zones affected are Lake Taupo, Upper Waikato, Middle Waikato and Lower Waikato.
Significant capital works, that are yet to be fully scoped and defined, are of concern to the companies. Environment Waikato intends to refine funding policies and justification for these works on a case-by-case basis.
The overall outcome of the combined contributor assessments is that hydro electric companies should meet about five percent of the overall Project Watershed budget as a Contributor to the need for the works or services. This is in addition to the cost to the companies as general ratepayers.