Volcanic Soil Trucked Out Of Tauranga
Tuesday, March 14, 2006
Volcanic Soil Trucked Out Of Tauranga Golf Course
Electricity company Powerco will lay power cables to future proof the new growth area of Tauriko next week, but first 1000 square metres of volcanic soil must be removed to allow the cables be installed correctly.
Powerco spokesperson Neville Goodwin says ‘volcanic sand’ has been found near Tauranga Golf Course and needs to be removed because it will not allow heat to be dispersed from power cables into the surrounding earth.
Goodwin says soil samples were taken and sent to Wellington for analysis, where tests revealed a high level of thermal resistivity. To find this type of soil in this location was unexpected. Soil at the opposite end of Cameron Road (city end) does not have the same characteristics.
“Cables generate heat when carrying an electric current and usually that heat is dissipated into the surrounding earth. But volcanic soil has a high ‘thermal resistivity’, which means it’s not efficient at transferring heat. If heat is not drawn away from the cable, it could overheat at high usage times.”
To fix the problem, Powerco will dig a trench along the cable path – 600m of which is alongside the golf course – and remove 1000 cubic metres of soil from it. Crushed lime will be used to fill around one metre of the trench depth, with the cable running through the middle of it. Another half-metre of topsoil will be used to close the trench in.
“The installation of lime was recommended by the cable manufacturer. Lime is a denser mass and it works well to dissipate heat. It also retains moisture better than soil, and that aids in transferring the heat,” Goodwin says.
Tauranga Golf Course will be closed for five days from March 13-17 while the work is being done. While the trench is open, sewer and stormwater infrastructure will be laid using the same trench. There will be no damage to the golf course.
Goodwin says Powerco contractors will be working long days and into the night to get the work finished in five days, but it is preferable to disrupting the golfers any longer than necessary. There may be minor disruptions along the Cameron Road footpath near the golf course.
Powerco is laying a pair of two kilometre long 33,000 volt cables from Cameron Road (opposite Maleme Street) through to The Lakes subdivision, at a cost of around $1.2 million.
However they will only run at 11,000 volts until the power demand from the new residential and commercial subdivisions at Tauriko increases. Eventually a substation will be built to service the new community and the new cables will be energised at 33,000 volts to supply the new substation.