- ,u11 ,?:u u Mr Ingical and
I'TT IrVY w t ,.r.. 1
SOUTHWEST FLORIDA WATER MANAGEMENT DISTRICT
Derrill S. McAteer
J. R. Graw
Thomas M. Van der Veer
Joe E. Hill
N. Brooks Johns
S. C. Bexley
Ronald B. Lambert
Latimer H. Turner
I_l_- __ I "" "I1
"-~ F; ~_ ~ 5
--,ufrmiHdLiuni, i I i wi 1.
I L I I i I
WATER IN ADEQUATE QUANTITIES.EQUATES WITH
HEALTHY FLORIDA ECONOMY
In/est Xentral Florida, we depend upon water -- an adequate supply of
it -- for our physical and economic health. Almost all of our major industries
and commercial pursuits are water-dependent enterprises:
Few industries depend so heavily upon irrigation as Florida's
citrus growers. Their crops represent about $1 billion in cash
receipts to the Florida economy annually.
Our vegetable farmers and ornamental horticulturists likewise
must have sufficient water for irrigation. Their cash receipts bring
approximately $486.2 million to the state each year.
Many Florida ranchers and dairymen need large quantities of
water to maintain improved pastures during the annual dry months.
These industries generate cash receipts totalling $510 million.
The phosphate industry, with more than 11,000 employees and
a payroll of $137 million has an estimated impact on florida's
economy of $3 billion yearly. From central Florida's phosphate
mines comes an indispensable component of the fertilizer America's
farmers must have to avert a world-wide food shortage. Yet, to
keep these mines operating, to keep this valuable ore moving to
port, requires massive quantities of water: about 251 million gallons
A I- ^^s~
_^ l^ \
, I0 L
Even our multi-million-dollar tourist tra depends indirectly
upon water. According to a Florida Department of Commerce survey,
the state's primary attraction for tourists is water, water sports,
and water-related activities. And 27.2 million visitors spend
$8.8 billion in Florida each year.
Finally, and with probably the most immediate importance to
each of us personally, is Public Water Supply. Distribution of
water to millions of persons by city and county water systems is
not only of deep personal importance to those users, but is also
big business and big money providing these local governments with
much needed additional income. L.ets.f water means more hook ups,
more income, more dollars in circulationand a healthier city or
county budget. Such uses throughout the District total something
like 217.4 million gallons per day. Pinellas County alone averages
77.9 MGD and St. Petersburg averages 34.5 MGD. AhVW AWIR4 l' Al A.
IS THERE ANYONE IN THE DISTRICT WHOSE livelihood does not depend, directly
or indirectly, upon the health of these industries?
IF THERE ISN'T SUFFICIENT WATER to sustain these industries and jk46
employees, can a store manager, a realtor, a trucker banker hope to prosper?
If retail sales decline, where will advertising dollars and sales commissions
come from? If the general economy declines, how will tax revenues --- and
public service programs supported by tax dollars --- be affected?
THIS IS NOT A DOOMSDAY PREDICTION of an imminent water shortage that could
cause these industries (and all the offices and businesses that are related to
them in th4s complex economy ofeowurs to collapse or to force massive layoffs.
THIS IS, HOWEV, AN EMPHATIC STATEMENT that water is a valuable natural
resource. For Floridans, it is our economic lifeblood. We can no longer assume
that a sufficient water supply will always be available. If we are all to
prosper, this precious resource must be managed properly to insure that all our
domestic and industrial needs are met.
HOW CAN THE WATER RESOURCE BE PROTECTED?
"A THOUSAND GALLONS PER DAY PER ACRE" has been repeated so often in public
hearings at the Southwest Florida Water Management District regarding consumptive
use of water that is has almost become a slogan. Where did the figure come from?
From data compiled from years of research by the District and the U. S. Geological
FIRST, IT'S NECESSARY to establish how much water there is
before we can talk about how much is available for human use. There
are three natural sources of water: (1) Precipitation (rainfall);
(2) Ground Water (water that exixts or flows into an area beneath
the ground); and (3) Surface Water (rivers and streams).
BECAUSE DISTRICT BOUNDARIES are based upon natural watershed
Basins, there are no rivers originating outside the District and
flowing into the District and hydrologic data indicates that there
is virtually no round, ater inflow into the District. Therefore,
our only source of water in this part of Florida is rainfall. ffm
Sjecords of the Geological Survey and the U. S. Weather Service tell
us that, on a District-wide basis, we-wi44 average 52 inches of
precipitation per year.
il(lii _1 iiiil i i ilil
NOW, WC HAPPENS to the rain after it ias? The Geological
Survey, through the use of continuous recorders on District rivers,
tells us that 2.3 trillion gallons flow into the Gulf during an
average year. That's the equivalent of 13 inches of rain falling on
the District's 10,000 square miles.
The remaining 39 inches (52 inches of precipitation (P) minus
13 inches of Runoff (R) = 39 inches) is lost to a joint process known
as Evapotranspiration (Et): evaporation and plant transpiration.
With this dataL District hydrologists are able to use a formula
(developed decades ago) which could be used to establish a water budget:
Precipitation (P) = Runoff (R) + Evapotranspiration (Et)
P = 52 inches
R = 13 inches
Et = 39 inches
P(52) Et(39) = R(13)
There is nothing we can do to increase rainfall. There is little
we can do to reduce Et. Therefore, we have to live with the remaining
13 inches of runoff. This becomes our harvest, or crop.
Let's reduce this District-wide average of 13 inches to a figure
that is easier to see:
13 inches x 10,000 square miles (District Area)
=.2.3 trillion gallons per year
2.3 trillion gallons per year divided by 10,000
= 233 million gallons per year/square mile
233 million gallons per year divided by 365 days
= 640,000 gallons per day per square mile
640,000 gallons-per day/square mile
= 1,000 gallong per day per acre.
THUS, 1,000 GALLONS OF WAJER per day per acre'is nothing more and nothing
less than the average amount of rain which normally falls on a given area and
is not lost to evaporation or transpiration. This amount can be considered
available for man's use. It is the WATER CROP.
HOW IS THE WATER CROP USED?
A WATER BUDGET IS MUCH LIKE a household checking account, and similarly you
can't "spend" more water than Nature puts into the aquifer without obvious,
immediate effects. Just as an individual can't take more dollars out of his
account than he has deposited. Using another analogy, water in the massive
Floridan Aquifer is much like a savings account; it can be drawn down -- to a
limited extent -- during dry months or even dry years if comparable "deposits"
are made during rainy months and wet years to replenish the account. BUT WE DARE
NOT draw it down too much or for too long. We cannot,for:an extended length of
time, remove water faster than it is being replenished without upsetting the
Hydrologic Balance of Nature, that delicate equilibrium between salt and fresh
water and between ground and surface water.
IF WE CHOOSE TO IGNORE OUR WATER BUDGET and continue to remove more than is
being replenished (mining water) on a massive scale, this is what can result:
(1) As the water table aquifer level begins to drop, small domestic wells
would become gradually less effective. Water would have to be pumped from a
1 greater depth and more power would be required to lift the same quantities.
(2) Lakes and streams would also begin to show the effect. As the difference
in pressure between the artesian aquifer and the water table aquifer increases,
greater recharge takes place. The effect: lower lakes, stress on trees and
shrubs if the levels drop below root zones, rivers become creeks, and creeks
become dry runs.
(3) Salt water would begin to move inland and upward. All along our coast-
line, the fresh water of the Floridan Aquifer meets the salt water of the Gulf
and the Atlantic. Salt water underlies Florida at various depths throughout
the peninsula. Remove the fresh water, as would happen if water mining were
allowed on a continuing basis, and salt water will move to replace it. This
is what happens when a well loes salty.
A WORD ABOUT CHOICES
The Board has established the Consumptive Use rule so that all applicants
will know the yard stick being applied on a District-wide basis. Under the water
crop concept there is an average 365,000 gallons available per acre each year.
For the health, welfare, and best interests of the public throughout the
District, as well as for the protection of the water resource, that 365,000
gallon annual total water crop should not be exceeded.
But the day when man is using every 1,000 gallons from every acre in the
.District in some time in the future. Although mining of water is occurring in
some specific area, by and large there is no demand for the total water crop
throughout most of the District.
It is practical, then, that some water users primarily cities, counties,
and some major industries who own wellfields are allowed to take huge quantities
Sof water from relatively small areas. This is because there is enough runoff,
or water crop, from adjacent lands to supply the demand and prevent mining from
occurring. It is also because these consumptive users have shown that their
- use of water is for a reasonable, beneficial purpose and that it does not
interfere with any presently existing legal use and is consistent with the
It must be remembered, that the water crop is not the sole criteria upon
which the District bases its Consumptive Use Rules. The concept is a valid
water management tool, and is used by the staff and the Board in determining
the appropriatness of a request for water use. It is used as a guideline and
represents the best information presently available for establishing the total
amount of water available and regulatory levels. It is the best tool that has
been brought forward to assist the District's ;overningin protecting the
public interest and the resourcelas the law requires the Board to do. It is
a guideline that is continually being refined.
-IIIIIIYP -I- -- -- ~ -