school energy&environment

A water resource

Glaciers in dry temperate regions supply a source of water which is very important for the economy of local rural communities. The most systematic use of glacier water is to irrigate fields while the use for drinking purposes is often limited by the great amount of solid particles carried by water as these often have a greyish colour and a milky look. In the high Karakorum valleys, which are real high-altitude deserts, where rainfall varies from 200 to 80 nm per year, agriculture depends exclusively from melting of glacier water. To use this water are built canal systems that can be even several kilometres long: often the canals are built on unstable glacial deposits that need constant maintenance and continuous fixing to adapt them to glacier front variations. Also in the Alps, in Val d’Aosta or in the Rhone Valley, in the past existed a network of irrigation canals, called “bisse” or “ru”, that employed glacier melting water.
In Polar regions, instead, populations in the far North, such as Inuits, for a long time have used icebergs as a drinking water source. As these are constituted by ice from glaciers, coming hence from the transformation of snow, icebergs are made mostly of fresh water. Even in these days are periodically presented projects to exploit these precious resources, for example towing icebergs close to the coasts of countries characterised by drinking water shortages, although the costs of these operations for the time being are still higher than the benefits.