An ingenious idea to build artificial glaciers at lower altitudes using pipes, gravity and night temperatures could transform an arid landscape into an oasis. The idea crystallized in his mind one morning as Sonam Wangchuk was crossing a bridge in the Indian Himalayas. The engineer from Ladakh, in the Jammu region of north India, was already a famous problem solver. But addressing the water shortages that threatened life in his mountainous home had started to feel like an intractable problem until he saw the chunk of ice: still hanging, improbably, beneath the bridge, long after the shards around it had melted. In that moment, he says, "I understood that it was not the warmth of the sun that was melting the ice on the ground. It was direct sunlight."

What Wangchuck saw reflected in the ice that day was realised four years ago, when he unveiled his first "ice stupa", an artificial glacier that towered surreally over the otherwise arid landscape, and for which in December he received a prestigious £80,000 innovation prize. It is the latest solution to an old problem in the Himalayan foothills. Despite its breathtaking scenery, life in Ladakh has always been hard. It is a desert at 10,000 feet, receiving on average just 50mm of rainfall each year. "The only reason people can live there is the glaciers," Wangchuk says. Each winter, titanic shelves of ice form at high altitudes and melt throughout the spring, flowing downwards into the streams that are the veins of civilisation on the mountain. It also has the benefit of resembling the Buddhist stupas – religious sites used for meditation and worship and the stupas are simple.

They are formed by running pipes below the frost line, at which temperature the water hovers between a liquid and solid state. Then the pipes turn skywards, spraying the water into -20C air, using the bitter cold to freeze it as it falls to earth. The first prototype, stretching 20 feet high, was built in October 2013, and expected to melt by the beginning of May. It lasted eighteen days longer. A second much larger stupa was grown near a forest of 5,000 trees, and kept them watered throughout the driest months until 6 July. Those two stupas were funded by crowd sourcing donations. Last year, Wangchuk was awarded a Rolex innovation grant, money he will use to create the next generation of ice towers. 20 more, each 100 feet high, are in the works.

Source: https://www.theguardian.com/environment/2017/apr/22/the-ice-stupas-of-ladakh-solving-water-crisis-in-the-high-desert-of-himalaya