Mount Hutt Ski Field Pumping System

In May 2014 Think Water Timaru was contracted by the Mt Hutt Ski Field to install a pumping system into a well at their ski field; the water is to be ponded and used to make snow.

The particulars provided for the well are:

  • Drilling: Washington Exploration Ltd
  • Site coordinates 43°29’27.61”S / 171°32’28.21” E. Elevation 1736 (Google Earth)
  • Bore diameter 250mm to 60 metres, 200mm to 120 metres
  • Total bore depth 170 metres from ground level
  • Static water level 63 metres from ground level
  • Recommended flow rate of 22 litres/sec
  • Drawdown at the above flow rate to 93 metres from ground level
  • Delivery to a pond sited at 1735 metres above sea level

The pump selected was a Grundfos SP77-11 c/w 37 Kw motor. For ease of installation and to keep costs down the pumping system was installed on 112metres of 100mm series 200 Crusader hose. The temperature on the day was rather cool and blustery and small stones (not sand) were being picked up by the wind and blown around. The bore itself was located in a trench which offered some protection from the wind but it was still cold.

Installed pumping system
Pumping system installed

To explain some of the oddities of the job:

  • the well is sited at 1736 metres above sea level,
  • the ski headquarters (HQ) is sited at 1600 metres above sea level, (which is 136 metres below the wellhead) and
  • the well has a total depth of 170 metres.
Crusader Hose
Crusader hose being installed

This means the bottom of the well is 34 metres lower than ski HQ and the pump is sitting at a level around 25 metres above ski HQ. The static water level is 73 metres above ski HQ. Confused yet?

During the process of fitting the cables to the Crusader hose, they did encounter a slight drawback; the temperature probe cable was attacked by a swarm of kea’s, (the parrots, not the cars) and they removed the outer sleeve in a number of places before we could drive them away. The team then had to heat shrink some patches on the cable which held the installation up for about half an hour – but we soon had the pumping system in the well out of harm’s way!!