Strategic Assessment of Florida's Environment
(SAFE)
Agricultural Water Supply Withdrawal
Explanation of Indicator
The state of Florida depends on its water resources for
drinking
water, for agriculture, for industry, and to support
wildlife
habitat. Unfortunately, nearly all human activities
may
adversely affect Florida's water quality and quantity.
In
addition, the state is expected to grow at a rate of
three
percent annually, with most of the growth along coastal
areas
where water resources are already being threatened by
over-
consumption, contamination, and saltwater intrusion.
In 1990, the agricultural water supply (irrigation and
non
irrigation) withdrawal of water throughout the state was
3,895
million gallons per day or about 52 percent of the fresh
water
used daily. This includes fresh water drawn from both
the
surface and the ground, as well as reclaimed waters. It
includes
the irrigation of grasses, ornamentals, and commercial
crops as
well as non-irrigation withdrawal for things such as
livestock
drinking, wash down, and fish farming.
In recent years, the data for this indicator was
calculated by
multiplying the number of acres irrigated by the
quantity of
irrigation water required to optimally grow each crop
and
adjusted by computer modeling. Though these figures
are
estimates, they are assumed to be quite accurate. The
earlier
figure are somewhat less accurate, primarily because the
methods
of data collection and modeling have improved over the
years.
Source
The Water Resources Division of the U.S. Geological Survey
(USGS)
is the lead office for this information. The USGS
publishes a
report, Water Withdrawals, Use, and Trends in Florida, every
five
years which contains this information. It is
prepared in
cooperation with the Florida Department of
Environmental
Protection and the water management districts, relying on
them
for much of the raw data. The publication is prepared by
Richard
L. Marella, who can be contacted at USGS, 227 North
Bronough
Street, Suite 3015, Tallahassee, Florida 32301, or at (904)
942-
9500.
Data Characteristics
This information can be obtained in a hard copy format from
the
Water Resources Division of the USGS.
There are no additional costs associated with obtaining
this
information. The information is collected throughout the
year by
both the Department and the water management
districts,
statewide, but it is compiled for the above mentioned
publication
approximately every five years by the USGS.
Overall Assessment
As the state's population grows so will the need for
large
volumes of good quality water. The percent change in total
water
withdrawal will reflect our ability to more efficiently
conserve
and utilize this limited resource. When data on
quantities of
water withdrawn are only collected every 5 years, anomalies
may
exist for that year, which could lead to an
incorrect
interpretation. If a given year has above or below
normal
precipitation (extremely wet or dry), or has an event
like a
hurricane, the water use value will most likely be skewed
for
that year.
In addition, the data used to calculate this information is
not
only based on actual meter readings as explained above.
However,
this is the best information currently available and is
thought
to be relatively accurate.
Analysis of Indicator
Agricultural water supply withdrawal has increased from
375
million gallon per day in 1950 to 3,805 million gallons per
day
in 1990 or an increase of over ten times. This is a
total
increase of 915 percent over this forty year period. Some
of the
water management districts are now requiring irrigators to
meter
and record their water-use. However, not all water
management
districts are doing this, and within each district metering
and
recording will depend on the capacity of the system. Since
data
collection is not required for all water management
districts,
the data may not reflect all agricultural withdrawals.
Agricultural Water Supply Withdrawal
