Freshwater Consumption as a Percentage of Local Average Annual Precipitation
Source: USGS Water Use Data (1985-1990)
Map Description:
This map shows average annual freshwater consumption from all sources (residential, agricultural, industrial, etc.) as a percentage of local average annual precipitation. Average annual freshwater consumption was determined for the six year period between 1985 and 1990. Average annual precipitation was determined for the 30 year period between 1960 and 1989 and includes snowfall. Sample measurements were weighted and averaged for each 8-digit hydrologic unit. The map legend indicates the following percentage ranges: Greater than 150%, 100% to 150%, 75% to 100% and less than 75% (which includes areas where precipitation exceeds freshwater consumption). The map is a useful indicator of where demands for freshwater may be creating pressures on water supply, at least in terms of water supplied through precipitation.

Cautions for this Product:
Though it may indicate areas where annual demand for water exceeds annual precipitation, there are, of course, many other factors affecting water availability. The map is also misleading in the fact that the freshwater consumed may not originate at or near the location of the precipitation.

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