The uses of water are many,
from drinking and cleaning to irrigating crops and landscapes.
Water is used for cooling, for recreation, and dust control.
Water is needed for restaurants, most industrial processes,
and even some religi ous ceremonies. On another level, the splash
and flow of water in streams and fountains soothes and inspires.
In one way or another, water is a part of almost everything
humans make and do. Washing a load of laundry uses 40 gallons,
filling a backyard pool takes about 25,000 gallons, growing
a pound of cotton consumes 1,000 gallons, while producing
a pound o f copper uses 20 gallons. All these water demands
are met by various supply sources including the Salt, Gila
and Colorado Rivers and groundwater pumped from beneath the
surface.
Uses where water is consumed, usually through evaporation
or plant growth, are consumptive uses. Examples include water
used for irrigation or in evaporative coolers. Non-consumptive
uses, such as bathing, hydropower generation and recreation,
do no t use up water. Used non-consumptively, the same water
can be used again and again, although some uses lower the
quality of the water. Once used, wastewater can be treated
and used again as reclaimed water or effluent.
The main categories of water use are agricultural, municipal
and industrial. In Arizona, irrigated agriculture long has
been the biggest consumptive user of water. Although it still
accounts for nearly 80 percent of all water use, agricultural
use i s declining. Municipal and industrial uses currently
are much less, but are growing rapidly. Mining activities
and cooling towers used for power generation account for most
of the remaining water use.
For a long time, water demand in Arizona has exceeded the
reliable supply of surface water and renewable groundwater.
Supply and demand have been balanced through excess pumping
of groundwater. This overdraft depletes groundwater aquifers
and cannot continue indefinitely (see Groundwater).
Growing competition for scarce water resources coupled with
laws limiting groundwater pumping have led to efforts to conserve
water and make use of effluent and Central Arizona Project
w ater (see Water Rights).
Issues Summary