McLean, J.D. 1986 The Waiau (Canterbury) hydro prefeasibility study. Lower Hutt: New Zealand Geological Survey. New Zealand Geological Survey report EG 408 88 p.
Abstract: The Ministry of Works and Development is conducting a pre-feasibility study of an area of the hydroelectric potential of the Clarence, Waiau and Hurunui Rivers in north Canterbury. This predominantly 'desk-study' report considers the geology of the project area in relaiton to potential sites of power development structures. (A separate NZGS report discusses seismotectonic hazards of the area.) For the purpose of the report the extensive (c.5000 km2) project area is divided into eight separate areas and the engineering geological conditions thought to be present at each of the possible dam sites, canal and tunnel reoutes is described. Suitable investigations for the next (feasibility) stage of the study are recommended. Strong, hard Torlesse 'greywacke' is the predominant rock type and forms all of the mountain ranges as well as the potentiallly exploitable river gordges. Hilly areas of low relief underlain by both hard and soft Tertiary rocks while unconsolidated Quaternary gravels infill the low-lying Hanmer and Culverden basins as well as the main river courses. Several major faults, commonly displaying active traces, cross the area in a north-east trending direction. The various canal route options linking the three rivers are discussed. Some of these transverse gentle to moderate slopes underlain by Tertiary or Quaternary age rocks; other routes over steeper and more rugged Torlesse 'greywacke' slopes, are generally considered less suitable. Possible sources of suitable construction materials are indicated but some, particularly impermeable dam core material, have yet to be identified.
