Hancox, G.T. 1975 Tongariro power development - Moawhango diversion : completion report on the engineering geology of the Moawhango Dam. Lower Hutt: New Zealand Geological Survey. New Zealand Geological Survey report EG 213. 53 p.
Abstract: The Moawhango Dam is a key structure of the Moawhango Diversion (see Fig. 1). Water from the Moawhango River, Mangaio Stream and the Wahianoa diversion will be diverted to the Tongariro River through the 12 mile (19.3 km) long Moawhango tunnel. To gain sufficient height for this diversion a 210 ft (64 m) arch-gravity fam was being built on the Moawhango River, about 1 mile downstream from its confluence with the Mangaio Stream. Maximum storage in the Moawhango reservoir will be 92,000 acre ft (113,480,160 m /sup3/). Normal top water level will be RL 2792 ft and with a draw down capacity of about 50 ft, the "live" storage will be about 56,000 acre ft (69,074,880 m/sup3/). A mean flow of 479 cusecs (13.6 m/sup3/ / sec) will be diverted to the Tongariro River. Specifications for Moawhango Diversion and Moawhango Dam are given in Appendix 3. During excavations for the dam foundations and continuing into the early construction stages, extensive surface and sub-surface geological investigations were carried out to map and document the geology of the dam site. The results of these investigations are presented and discussed in this report. The results of earlier investigations at the present site (Arch Gravity site), and at several proposed sites downstream, have been described in a number of previous reports (see Appendix 4) and will not be discussed in detail. (auth)