The term withdrawal uses defines the water that is withdrawn from its source (a river, lake or groundwater supply), piped or channelled to many different locations and users (e.g., household and industrial uses, thermal and nuclear power generation, irrigation and livestock watering), and then is collected again for return to a lake, river or into the ground. Withdrawal uses are measurable as quantities of intake, discharge, and consumption. Water intake is the amount withdrawn from the source for a particular activity over a specific period of time. It represents the demand imposed by that particular use on the water source at a given location. Table 4.1 shows the regional water intake in Canada for each major activity. Usually, however, most of the water taken out is returned at or near the source. This is called water discharge. Water consumption is the difference between water intake and water discharge. Consumption removes water from a river system and makes it unavailable for further use downstream (Environment Canada, 1993a).
KeywordsSteam Transportation Sewage Fishing Dian
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