Engineering Geology for the Snowy Mountains Scheme
Fig. 9.—Tumut Pond Dam Site
At higher levels the bed-rock becomes partly obscured by a thin discontinuous cover of soil and scree. The bed of the river channel is occupied by large boulders. A diamond drill hole was sloped under the river bed from each bank and penetrated fresh jointed but otherwise sound granite. At river level the granite is almost fresh, but weathering progressively increases up the valley walls. On the left bank this is mostly only slight, with limited zones of moderate weathering extending down to about 60 feet from the surface
at the highest levels of the abutment, with limonite staining on joints of otherwise fresh rock extending down about 170 ft. On the right abutment the weathering is rather similar, but near the top of the abutment the slope flattens and forms a rather narrow spur, and under this spur weathering extends slightly more deeply and is somewhat more intense than on the left bank.
Fig. 10.—Tumut Pond Dam Site
