How to build better ice towers for drinking water and irrigation

There’s a better way to build a glacier.

During winter in India’s mountainous Ladakh region, some farmers use pipes and sprinklers to construct building-sized cones of ice. These towering, humanmade glaciers, called ice stupas, slowly release water as they melt during the dry spring months for communities to drink or irrigate crops. But the pipes often freeze when conditions get too cold, stifling construction.

Now, preliminary results show that an automated system can erect an ice stupa while avoiding frozen pipes, using local weather data to control when and how much water is spouted. What’s more, the new system uses roughly a tenth the amount of water that the conventional method uses, researchers reported June 23 at the Frontiers in Hydrology meeting in San Juan, Puerto Rico.

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“This is one of the technological steps forward that we need to get this innovative idea to the point where it’s realistic as a solution,” says glaciologist Duncan Quincey of the University of Leeds in England who was not involved in the research. Automation could help communities build larger, longer-lasting ice stupas that provide more water during dry periods, he says.

Ice stupas emerged in 2014 as a means for communities to cope with shrinking alpine glaciers due to human-caused climate change (SN: 5/29/19). Typically, high-mountain communities in India, Kyrgyzstan and Chile pipe glacial meltwater into gravity-driven fountains that sprinkle continuously in the winter. Cold air freezes the drizzle, creating frozen cones that can store millions of liters of water.

The process is simple, though inefficient. More than 70 percent of the spouted water may flow away instead of freezing, says glaciologist Suryanarayanan Balasubramanian of the University of Fribourg in Switzerland.

So Balasubramanian and his team outfitted an ice stupa’s fountain with a computer that automatically adjusted the spout’s flow rate based on local temperatures, humidity and wind speed. Then the scientists tested the system by building two ice stupas in Guttannen, Switzerland — one using a continuously spraying fountain and one using the automated system.

After four months, the team found that the continuously sprinkling fountain had spouted about 1,100 cubic meters of water and amassed 53 cubic meters of ice, with pipes freezing once. The automated system sprayed only around 150 cubic meters of water but formed 61 cubic meters of ice, without any frozen pipes.

The researchers are now trying to simplify their prototype to make it more affordable for high-mountain communities around the world. “We eventually want to reduce the cost so that it is within two months of salary of the farmers in Ladakh,” Balasubramanian says. “Around $200 to $400.”