Johnson, J.D. 1985 Kawarau River power investigations : engineering geological feasibility investigations at the KW13 damsite. Lower Hutt: New Zealand Geological Survey. New Zealand Geological Survey report EG 392 30 p.
Abstract: This report describes geological feasibility investigation undertaken for a possible concrete gravity dam at the KW13 dam site on the Kawarau River. Bedrock at the site consists of interlayered green and grey schist which have a well developed strength anisotropy along schistosity. Rock mass defects include widely spaced persistent joints and irregular spaced shears both subparallel and at high angles to schistosity; they are considered to be of both tectonic and gravitational origin. Surface mapping and subsurface investigations have indicated that no significant faults or major defects are present in the immediate vicinity of the dam foundations. Assessment of the rock mass indicates that there are potential problems in the left abutment associated with relaxation of the rock mass and persistent unfavourably orientated foliation shears. Significant over excavation and ground treatment will be required to provide an adequate foundation. No major foundation problems are expected in the right abutment and river channel area. South facing batters are the most unstable excavation orientation due to the influence of schistosity and foliation shears. (auth)