Biology Reference
In-Depth Information
Rachel Wark of RMC Water and Environment, an environmental consult-
ing firm. Rain or shine, what few people realize is that recycled water is
often cleaner than garden-variety tap water from the delta.
A 2008 Pacific Institute report indicates that water conservation can
make a real difference in reducing demand, and yield as much new water
as 3 to 20 modest-sized new dams. The report also concludes that the ab-
solute volume of water exported from the delta is too high, especially at
critical times for ecosystem health.
The average Californian uses 154 gallons of water per day, but the lion's
share of the state's water doesn't go to urban taps and toilets—it waters
crops. On the upstream farms and orchards using more than three-
quarters of the state's water supply, steps to improve efficiencies have been
modest. Farmers and their water districts have been encouraged to shift to
less water-intensive crops, to replace flooding between crop furrows with
drip and sprinkler irrigation, and to monitor and manage irrigation more
carefully. Little accounting of the extent to which these conservation mea-
sures have been implemented on the ground has been done to date.
Cities have made similarly modest progress in conserving and recy-
cling water. During droughts in the 1970s and 1990s, urban water dis-
tricts—particularly in southern California—started installing low-flow
toilets and recycling water to irrigate golf courses. In the early 1990s, the
Irvine Ranch District experimented with running recycled water through
toilet flushing systems in new high-rise office buildings. The dual plumb-
ing systems reduced the use of drinking-quality water by up to 75 percent.
Diverted irrigation water sustains Central Valley agriculture. (Department of Water
Resources)
