KARAPIRO DAM

Press, Volume LXXXIII, Issue 25084, 16 January 1947, Page 8

KARAPIRO DAM

BIG JOB NEARING COMPLETION

WORKERS MOVING ON TO MARAETAI Construction of the Karapiro dam, on the Waikato river about five miles south of Cambridge, is nearly completed, with the removal of the lower coffer dam, one of the two temporary dams which were built to form an area in which the main concrete dam could be constructed. While the dam was being constructed, any seepage was pumped out of the construction area, but as soon as the structure was finished pumping of seepage from the uppbr coffer dam ceased, and the water was allowed to mount against the upstream face of the main dam, reaching river level several weeks ago. Pumping of seepage through the lower coffer dam ceased just before Christmas, and the water around the power-house has risen to river level. Work will begin within the next few days on removing this coffer dam, so that, when the water is allowed to flow through the first turbine, probably toward the end of March, it will have a free passage out into the main river channel.

Most of the demolition of the lower coffer dam will be done by a large' dragline, but a number of concrete grout layers within the dam will be broken with small explosive charges. Above the dam the radial cableway which delivered the concrete to the arch of the dam and a 10-ton crane have been dismantled to allow the removal of part of the bank of the old river in front of the intake and spillway sections. About 70,000yds of soil have to be excavated in this area to facilitate the free flow of dammed water into the turbines. Installation of Generator Installation of the first 30.000-kilo-watt generator is still incomplete, but it is not expected that any major delay will occur on this side of the work. Along the banks of the river, where the shores of the new Karapiro lake will be, work has been proceeding for about a month in clearing the scrub and trees from the proposed lake level down for 30ft. The' clearing on the terrace formation along the river bank is being done by a special type of roller fitted with blades. This cut? up the scrub, which later will be burned. In other rougher parts the clearing is being done by scrub-clearing gangs, and hand cutting has also to be done where there are any large trees. With the slackening of work at Karapiro and .the increasing call for labour at the Maraetai project further up the Waikato, the married men’s huts at Karapiro are being moved on specially designed trailers to the construction village at Mangakino at the rate of two a day. About a third of these huts have already been moved.