Riddolls, B.W. 1971 Engineering geological site investigations Karioi hydro-electric project. Lower Hutt: New Zealand Geological Survey. New Zealand Geological Survey report EG 120 25 p.
Abstract: A number of drill holes have been sunk and trenches excavated, to obtain engineering geological data for the proposed scheme. Further work is necessary to obtain information on the permeability of ground at dam sites and along the canal. Material for dam construction and canal linings will be supplied from the widespread superficial deposits of ash and volcanic breccia. Seismic surveys would enable thicknesses to be determined in areas lacking exposures. (auth)