EROSION AT ARAPUNI.—The above plan shows the emergency measures being taken at Arapuni. From the dam at Arapuni Lake the water flows down the headrace channel to the spillway weir and extension, where three penstock tunnels feed the turbine at the Powerhouse. The excess water falls over the spillway weir into the overflow channel, where, swirling back from the falls lower down, it is eating into the bed of the channel and constituting a serious menace to the big spillway weir. To divert the excess water in another "direction, while the bed of the channel is being protected with concrete, the diversion tunnel above the dam (drawn in dotted lines) is being made ready for use. It will then divert a portion of the supply into the old bed of the Waikato River. To relieve the situation still further two penstock tunnels (marked X) are hastily being excavated. These will drain water from above the spillway weir direct into the gorge above the powerhouse. It is estimated that the turbine will then utilise all the remaining supply and stop the fall over the spillway weir until such time as the overflow channel is protected.

Sun (Auckland), Volume III, Issue 747, 21 August 1929, Page 1

EROSION AT ARAPUNI.—The above plan shows the emergency measures being taken at Arapuni. From the dam at Arapuni Lake the water flows down the headrace channel to the spillway weir and extension, where three penstock tunnels feed the turbine at the Powerhouse. The excess water falls over the spillway weir into the overflow channel, where, swirling back from the falls lower down, it is eating into the bed of the channel and constituting a serious menace to the big spillway weir. To divert the excess water in another "direction, while the bed of the channel is being protected with concrete, the diversion tunnel above the dam (drawn in dotted lines) is being made ready for use. It will then divert a portion of the supply into the old bed of the Waikato River. To relieve the situation still further two penstock tunnels (marked X) are hastily being excavated. These will drain water from above the spillway weir direct into the gorge above the powerhouse. It is estimated that the turbine will then utilise all the remaining supply and stop the fall over the spillway weir until such time as the overflow channel is protected.