Sources of Fresh Water

 

Fresh Water Storage

 

Some runoff water is trapped for periods of time, for example in lakes. At high altitude, during winter, and in the far north and south, snow collects in ice caps, snow pack and glaciers. Water also infiltrates the ground and goes into aquifers. This groundwater later flows back to the surface in springs, or more spectacularly in hot springs and geysers. Groundwater is also extracted artificially in wells. This water storage is important, since clean, fresh water is essential to human and other land-based life. In many parts of the world, it is in short supply.

 

Frozen Water

 

Several schemes have been proposed to make use of icebergs as a water source, however to date this has only been done for novelty purposes. Glacier runoff is considered to be surface water.

The Himalayas, which are often called "The Roof of the World", contain some of the most extensive and rough high altitude areas on Earth as well as the greatest area of glaciers and permafrost outside of the poles. Ten of Asia’s largest rivers flow from there, and more than a billion people’s livelihoods depend on them. To complicate matters, temperatures are rising more rapidly here than the global average. In Nepal the temperature has risen with 0.6 degree over the last decade, whereas the global warming has been around 0.7 over the last hundred years.

 

 

Unit 3

 

Uses of Fresh Water

 

Introduction

Notes:

consumptive water use - использование воды c потерями

non-consumptive water use – использование воды без потерь

losses - потери

incorporate – объединять, включать в состав

deplete - истощать

sewage – сточные воды

additional - дополнительный

 

Uses of fresh water can be categorized as consumptive and non-consumptive (sometimes called "renewable"). Consumptive water use is water removed from available supplies without return to a water resources system (e.g., water used in manufacturing, agriculture, and food preparation that is not returned to a stream, river, or water treatment plant). A use of water is consumptive if that water is not immediately available for another use. Losses to sub-surface seepage and evaporation are considered consumptive, as water is incorporated into a product (such as farm produce). Non-consumptive water use is the use of water that does not deplete water supplies, e.g. fishing. Water that can be treated and returned as surface water, such as sewage, is generally considered non-consumptive if that water can be put to additional use.