Digging deep for a drink
Rodriguez well brings water to the polar desert
Posted February 4, 2007
“Water, water everywhere / Nor any a drop to drink.”
South Pole residents can relate to the famous lament of this mariner, surrounded by undrinkable water.
The station sits on top of a two-mile-thick ice sheet, which stretches to the horizon in every direction, gently rolling like a calm sea. And while snow and ice blanket the region, no drinking water exists in the polar desert.
Unlike the ancient mariner in Samuel Taylor Coleridge’s poem, however, residents have the benefit of engineers who have created the Rodriguez well to harvest enough liquid water from the ice to meet their needs. But the emphasis around station on water conservation and the allotment of two two-minute showers a week serve as reminders that the water that flows from the station’s taps isn’t easy to come by.
“We create a Rod well, which is a cavity deep in the ice where we melt ice to create our own drinking water,” said Brad Coutu, South Pole facilities, engineering, maintenance and construction manager.
This cavity is formed about 250 feet beneath the surface by maintaining a pool of heated water throughout the well’s lifespan. The bulb-shaped pocket gradually expands as the walls continually melt away, creating a constantly renewing source of water that Coutu said can produce up to 1 million gallons.
A submersible pump and series of hoses cycle the water up the ice shaft and through heat exchangers, while siphoning a portion of the flow for the station’s use before sending the rest back down to the well. Coutu estimated that the system gives one gallon of water to the station for every two gallons it reheats and returns to the well.
“The lifespan of a well is about seven years depending on the amount of people down here and the water usage,” Coutu said. “Once the well gets to be over 500 feet deep, it takes too much energy to pull the water up and recirculate it.”
The current well was created during the 2001-02 season at a depth of 180 feet and currently rests 435 feet beneath the surface, where it is now melting ice made of snow that fell around 500 A.D, according to John Rand, who provides engineering assistance focused on South Pole issues. He said current projections look like it could function for two more years.
As it takes about a year for a new Rod well to develop, Coutu is already leading the effort to prepare the infrastructure for the next Rod well.
“Before we use it, we have to wait until it has enough water for us to take some out of it and still have enough to recirculate for its continuous growth,” Coutu said.
Rod wells have been used at the South Pole station since 1995. The first water well was installed by Cold Regions Research and Engineering Laboratory engineers. The Rod well system was developed by Army engineer Raul Rodriguez at Camp Century in Greenland during the early 1960s.
Surface snow melting, which required a constant snow-gathering effort, served as the Rod wells’ predecessor at the South Pole.
“I’d say Rod wells are 80 percent more efficient, especially when it comes to labor. A snow melter is very labor intensive,” Coutu said.
“Once the Rod well is made, the hard work is done for the next several years. Besides maintenance and preventative maintenance operations, it’s essentially like your water supply at home you don’t even know it’s there. You turn the faucet on — and out comes water.”