7. Gisborne Region
7.1 Catchment #53: Waiapu
This catchment has:
- no existing hydro-electric power stations,
- no controlled lake storage.
Table 10: Hydropower Opportunities in the Waiapu Catchment with High to Medium Confidence of Proceeding in the Next 20 Years.| Name | MW | Average Energy Production (GWh p.a.) | Public Reference |
| Mata | 15 | 67 | T&T 1978 |
| Waingakia Diversion | 15 | 65 | T&T 1978 |
| Waitahaia | 7 | 31 | T&T 1978 |
7.1.1 Mata (16/2)
A short distance downstream of its confluences with the Waitahaia River the Mata River is joined on its left bank by the Mangaohiroa Stream. At this point the river channel narrows to be flanked by steeply rising banks with rock outcrops, forming a suitable site for a dam. The scheme comprises a 40m high dam with pipelines extending to penstocks feeding water to a power station with an estimated generating capacity of 15MW giving approximately 67GWh p.a. (50% plant factor).
7.1.2 Waingakia Diversion (16/9)
Waingakia Stream affords potential for a "diversion" type hydro scheme making use of the substantial fall able to be gained by diverting flows through to the Mata River. With a catchment area of 49.6km², Waingakia Stream has an estimated long term mean flow in the reach of interest of 6m³/s, and by utilising head of up to 260m, an annual generation output of up to 65GWh would be achieved from a 15MW generator (50% plant factor).
7.1.3 Waitahaia (16/14)
The considerable natural fall in the upper reaches of the Waitahaia River affords potential for a "diversion" type hydro scheme very similar in concept to that previously outlined for the Waingakia Stream. Although the flow in the Waitahaia River at a convenient diversion site exceeds that of the Waingakia Stream, the economically developable head is less than half as much, with the result that the Waitahaia Scheme is estimated to have a generating capacity of about 7MW, giving approximately 31GWh p.a. (50% plant factor).
7.2 Other Opportunities in this Region
7.2.1 Prohibited
There are no known prohibited opportunities.
7.2.2 Undefined
With the isolation of some parts of the region and the stringy electricity distribution lines in the region there are areas where micro hydro electric generation is likely to be attractive in the future. Such distributed generation would avoid the need to upgrade old or undersized distribution lines where there are few electricity users.
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