Featured Image: Ladakh (Trần Trung Toàn Thiện on Unsplash).
Ladakh is a cold desert plateau in India where villagers are dealing with water shortages caused by shrinking glaciers, consequently meltwater comes later in the year. Ladakh is situated in India, surrounded by Pakistan and China, close to the Himalayas. The mountains are taller than the plateau itself, and therefore block most of the rain clouds so the region gets meagre amount of rain and snow. On average about 100 mm annually.
“The gap between a late winter snowmelt and springtime glacier melt is yawning ever wider,” Sonam Wangchuk a local monk explains. April and May are a crucial time when farmers need water the most for their newly planted crops (otherwise the crops will not mature by the time winter sets in). The snow from the winter has already melted before spring, leaving glaciers as the only water source. The glaciers have retreated far up the mountains so those are melting too late. And then in August, there’s a lot of melt, plus occasional bursts of rain from monsoon clouds, which lead to flash floods. To mitigate the water shortage in spring, Wangchuck, who is also an engineer started building ice stupas with a couple of his students in 2015. Stupas help to alleviate seasonal water shortages by storing meltwater from winter months in ice structures at an altitude lower than the natural glaciers and higher than the cultivated fields.
By mid-September a smaller stream flows throughout the winter steadily (also relies on reducing the velocity of river water) but wastefully.
An ice stupa uses piping to divert stream water. This technology is quite simple. At night, when the air is sub-zero they open the nozzle. The fine spray is freezing as it is falling. A cone of ice is rising around the pipe, tapering toward the top. The water is shot upwards through a vertical pipe and a sprinkler like a geyser and freezes in vertical layers in a conical structure that resembles Buddhist stupas. Ice Stupas were named after this type of Buddhist shrine. Due to their vertical shape and steeper sides, these ice mounds have less surface area exposed to sunlight. And by the reason of the high volume and the previous effect they can reside low while remaining frozen much longer, through the winter. This is the most important advantage of these ice reservoirs.
Marcus Nüsser conducted a Study of Assesses Efficacy of Artificial Glaciers in Alleviating Water Scarcity in Ladakh.
A challenge of the ice stupa, Nüsser explained, is that since they rely on pipes, “they need a relatively sophisticated intake system that is not blocked during the cold seasons.” And local climate must include frequent freeze-thaw cycles to have the successful formation of large quantities of ice.
High-density plastic pipes, buried under the ground, below the frost line to prevent freezing, divert water by gravity from the upper stream area to preferred locations, using the hydraulic head, produced by the altitudinal difference between intake and outflow. Then before the final section of the pipe then rises a narrower vertical pipe with a sprinkler fixed on top sprays out a fountain of water due to hydrostatic pressure which freezes on contact with cold air. The ground is previously plastered with clay to reduce its permeability and to prevent rapid seepage during the melting phase in spring. Branches of seabuckthorn and barbed wire are laid around the initial structure to provide additional surfaces for ice aggregation.
So the team built a 23 m-tall ice cone, which contained roughly one million liters of water, and it lasted till August. On a sunny day, it could give roughly 50,000 liters of water. In 2019 they’ve built 26 ice stupas across Ladakh, this year some of them are 30 m tall, and more are planned for the winter. Each will supply 10 million litres of water a year and irrigate 25 acres of land. As of now, the inventor is preparing a pipeline to create 50 more ice stupas that will provide 10 million liters of water a year.
The benefits are it doesn’t require a lot of space and the installation is flexible and locations in close vicinity to settlements and field. On the other hand, there have been protests against the project as it abstracts water from the main stream, thereby reducing water availability for downstream communities and households, according to Nüsser.
But now, high in the Himalayas, a desert is turning green.
- http: //icestupa.org/