Group Title: significance of tropical cyclone rainfall in the water supply of south Florida
Title: The significance of tropical cyclone rainfall in the water supply of south Florida
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THE SIGNIFICANCE OF TROPICAL CYCLONE RAINFALL
IN THE WATER SUPPLY OF SOUTH FLORIDA













BY

DONALD BRANDES


A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL
OF THE UNIVERSITY OF FLORIDA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS
FOR THE DEGREE OF DOCTOR OF PHILOSOPHY



UNIVERSITY OF FLORIDA


1981




































Copyright

DONALD BRANDES

1981






























Dedicated to Pam, Mom, Dad, Adam, and Fred.















ACKNOWLEDGEMENTS


I wish to thank my wife, Pam, for her patience while

I neglected her in order to do my academic work, and for

her assistance in processing data and typing for this

dissertation and other projects that I have worked on during

the last several years.

Thanks to my committee, Dr. James Henry, Dr. Robert

Marcus, Dr. William Weismantel, Dr. Earl Starnes, and

Dr. Daniel Spangler, for their help and understanding and

the time which they have spent with me on this research

and other matters. A special thanks to my committee

chairman, Dr. David Nlddrle, for his very prompt and

thorough critiquing of all my written work. His promptness

has contributed substantially to the earlier completion of

this document.

Thanks to Dr. E.C. Pirkle for giving me the opportunity

to teach in the physical sciences program for several years.

Thanks also to Paul Hebert, of the National Hurricane

Research Center, and the following personnel of the South

Florida Water Management District for their cooperation and

suggestions regarding various segments of this research:

Abe Kreitman, Ernie Gallego, Beatrice Fisher, Alan Fox,

Jim Lane, George Marband, and Ray Burgess.













TABLE OF CONTENTS



ACKNOWLEDGEMENTS ....................................... iv

LIST OF TABLES ................................ ........ vii

LIST OF FIGURES ........................................ .. viii

ABSTRACT ................................................ ix

1 INTRODUCTION AND DEFINITION OF PROBLEM ....... ..... 1

Tropical Cyclones ............................... 2
Destructive Effects of Tropical Cyclones ........ 5
Modification of Hurricanes ......................... 5
Problems of Successful Tropical Cyclone
Modification ...................................... 7
Importance of Tropical Cyclone Rainfall ......... 9
Public Concern for the Environment .............. 10

2 LITERATURE CONCERNING THE BENEFICIAL ASPECTS
OF HURRICANES ..................................... 13

3 HURRICANE SUPPRESSION ............................. 19

Damage Caused by Hurricanes ...................... 19
Cloud Seeding ..................................... 21
Unpredictability of Hurricanes .................. 25

4 RESEARCH DESIGN ..................................... 30

Study Area ...................................... 31
Organization and Methodology .................... 31

5 TROPICAL CYCLONE RAINFALL ......................... 35

Data Sources .................................... 35
Selection of Stations ........................... 38
Determining if Rain is Caused by a Tropical
Cyclone ........... .............................. 40
Previous Studies ................................ 42
Criteria for Determining Rainfall Source ........ 45
Some Discarded Assumptions .................... 45
Procedures ..................... ............. 48
Analysis of Tropical Cyclone Rainfall ........... 49
Summary and Discussion of Rainfall Data ...... 49
Possible Indications of Climatic Change ....... 64









6 WATER FROM TROPICAL CYCLONE RAINFALL ............... 71

Methodology for Estimating Infiltration .......... 72
Methodology for Estimating Impoundable
Surface Water .................................... 78
Methodology for Estimating Evapotranspiration .... 79
Estimates of Water from Tropical Cyclone Rainfall 80

7 WATER SUPPLIES IN THE SOUTH FLORIDA WATER
MANAGEMENT DISTRICT ............................... 87

Origin of the SFWMD ............................. 87
Water Management Goals in the SFWMD .............. 90
Present and Projected Water Demand in the SFWMD .. 91
Significance of Water Supply and Demand
Projections ........................................ 96

8 IMPLICATIONS OF REDUCED RAINFALL FOR
WATER MANAGEMENT PLANNING .......................... 100

General Implications for Water Management
Pol icy ............................ ....... ... 100
Implications for the Water Use and
Supply Development Plan .................. ....... 102
Conservation ..................................... 103
Wellfield Development .......................... 104
Backpumping .................................... 105
Demineral ization ........................ ..... 106
Deep Aquifer Storage .......................... 106
Increased Lake Okeechobee Storage .............. 107
Wastewater Reuse ................................ 108
Forward Pumping ................................ 109
Weather Modification ........................... 110
Thin Films over Storage Areas .................. 110
Water Importation ............................... 111
Additional Water Conservation Areas ............ 112
Reclamation and Systems Optimization ........... 112
Closing Comment ................................ 112

9 SUMMARY AND CONCLUSIONS ............................. 114

APPENDICES

A HURRICANE RAINFALL PER STORM ...................... 119

B TROPICAL STORM RAINFALL PER STORM .................... 123

REFERENCES CITED .......................................... 127

SUPPLEMENTARY BIBLIOGRAPHY ............................... 135

BIOGRAPHICAL SKETCH ...................................... 151














LIST OF TABLES


DATES OF HURRICANE AND TROPICAL STORM RAINFALL ......
t-TESTS OF RAINFALL DATA--INDIVIDUAL STATIONS .......
SATELLITE IMAGERY .... ........................... ....


4 TROPICAL
5 TROPICAL
6 TROPICAL
7 TROPICAL
3 TROPICAL
9 TROPICAL
O TROPICAL
1 TROPICAL
2 TROPICAL
3 TROPICAL
4 TROPICAL
5 TROPICAL
6 TROPICAL
7 TROPICAL
8 TROPICAL
9 TROPICAL
O TROPICAL
1 TROPICAL
2 TROPICAL
3 TROPICAL


CYCLONE RAINFALL--ALL STATIONS .............
CYCLONE RAINFALL--ARCADIA ..................
CYCLONE RAINFALL--AVON PARK ................
CYCLONE RAINFALL--BARTOW ...................
CYCLONE RAINFALL--BELLE GLADE ..............
CYCLONE RAINFALL--EVERGLADES CITY ..........
CYCLONE RAINFALL--FELLSMERE ................
CYCLONE RAINFALL--FORT LAUDERDALE ..........
CYCLONE RAINFALL--FORT MYERS ...............
CYCLONE RAINFALL--FORT PIERCE ..............
CYCLONE RAINFALL--HOMESTEAD ................
CYCLONE RAINFALL--ISLEWORTH ................
CYCLONE RAINFALL--KISSIMMEE ................
CYCLONE RAINFALL--LA BELLE .................
CYCLONE RAINFALL--MIAMI ....................
CYCLONE RAINFALL--MOORE HAVEN ..............
CYCLONE RAINFALL--OKEECHOBEE ...............
CYCLONE RAINFALL--ORLANDO ..................
CYCLONE RAINFALL--PUNTA GORDA ..............
CYCLONE RAINFALL--WEST PALM BEACH ..........


JUNE RAINFALL--ALL STATIONS ....................
JULY RAINFALL--ALL STATIONS ................
AUGUST RAINFALL--ALL STATIONS .......................
SEPTEMBER RAINFALL--ALL STATIONS ....................
OCTOBER RAINFALL--ALL STATIONS ......................
NUMBER OF HURRICANES AND TROPICAL STORMS PER YEAR ...
TROPICAL CYCLONE RAINFALL BY YEAR--ALL STATIONS .....
CORRELATION COEFFICIENTS ............................
t-TESTS OF RAINFALL DATA--ALL STATIONS ..............
INCHES OF RAINFALL PER TROPICAL CYCLONE .............
POLYGON SPECIFICATIONS ..............................
OBSERVATION WELL INDEX ..............................
WATER FROM HURRICANE RAINFALL .......................
WATER FROM TROPICAL STORM RAINFALL ..................
ANNUAL FRESH WATER DEMAND ...........................
NET BALANCE BETWEEN CONSUMPTION AND SUPPLY ..........


vi















LIST OF FIGURES


1 THE SOUTH FLORIDA WATER MANAGEMENT DISTRICT ........ 32

2 WEATHER STATIONS ............................. ...... 39

3 HURRICANE "GLADYS" ................. ................ 44

4 TROPICAL STORM "AMY" ..................... ... .. 44

5 MEAN RAINFALL 1919-1978
HURRICANES AND TROPICAL STORMS ................... 61

6 MEAN RAINFALL 1919-1978
HURRICANES & TROPICAL STORMS AND ANNUAL ............ 62

7 RAINFALL BY YEAR ................................. 67

8 POLYGONS AND OBSERVATION WELLS ..................... 74

9 IMPOUNDABLE CATCHMENT AREAS ...................... 85


viii
















Abstract of Dissertation Presented to the Graduate Council
of the University of Florida in Partial Fullfillment
of the Requirements for the Degree of Doctor of Philosophy

THE SIGNIFICANCE OF TROPICAL CYCLONE RAINFALL
IN THE WATER SUPPLY OF SOUTH FLORIDA

By

Donald Brandes

June 1981

Chairman: Dr. David Niddrie
Major Department: Department of Geography



Hurricanes and tropical storms are an important part

of the hydrologic cycle in South Florida. Although these

storms may cause damage to coastal properties and endanger

lives, they also bring rainfall to recharge water supplies.

If hurricanes fail to influence the rainfall of this region,

either because of human intervention by weather modification

or because of possible natural climatic change, the water

budget is affected.

The study of tropical cyclone rainfall for a sixty-year

period from 1919 through 1978 reveals that the amount of

rain from hurricanes has declined significantly in the last

several decades. This decline is discussed in relation to

its effects on water supply and management in the South

Florida Water Management District. Although declining

supplies and increasing consumption portend severe chronic











water shortages in the region, the knowledge that hurricanes

do not bring as much rain as water management officials had

thought should allow more effective use of surface storage

reservoirs.
















CHAPTER 1

INTRODUCTION AND DEFINITION OF PROBLEM



"Water supply, with everything these words imply
In relation to land use, population growth,
agricultural expansion, and maintenance of
environmental quality, is a major issue in South
Florida." William B. Storch, Chief Engineer,
Central and Southern Florida Flood Control
District (1973, p. 1).



Water is a vital natural resource. It is necessary for

human existence and is used in large quantities in our

society. In Florida, water is usually obtained by pumping

it from a river or lake or from a well which penetrates an

aquifer. Both surface and ground sources are replenished by

rainfall which may occur at places quite distant from the

eventual pumping site. Rainwater which falls in the

Interior of the state usually flows toward the coast.

Surface flow in rivers to the Gulf of Mexico and Atlantic

Ocean is easily observable. Within the ground, however, the

water also flows toward the coast. This underground flow

from the interior of the peninsula to the coastal zone

provides a source of fresh water for coastal area wells and

protects aquifers from the osmotic encroachment of salt.

As populations grow, their need for water increases.

The population of Florida tends to be concentrated along the








coast where fresh water supplies are least plentiful. Salt

water intrusion into depleted aquifers is a problem for many

communities and urban wellfields must frequently be moved

further inland to find new sources of fresh water.

The same communities which suffer osmotic salt

intrusion also face the possibility of severe damage to

property and loss of life from tropical cyclones between

June and November. The effects of these violent seasonal

storms, however, are not entirely maleficent. They bring

rain to replenish the water supply even though they may

destroy shops and homes.



Tropical Cylones



A cyclone is an atmospheric circulatory system in

which the winds rotate into a low pressure vortex. In the

Northern Hemisphere, this circulation is counterclockwise,

while in the Southern Hemisphere it is clockwise. The term

"tropical cyclone" refers to such a circulation which

develops over tropical waters. Tropical cyclones are storms

in which the energy to drive the circulation is derived from

the latent heat of condensation of water vapor. They are

distinguished from extratropical cyclones which are driven

primarily by the contrasts of temperature and moisture

typically associated with cold and warm fronts (Neumann

et al. 1978).








Cry (1967) has stated that no other type of atmospheric

circulation has a greater variety of form, structure, and

movement than tropical cyclones, and that they undergo

radical changes of structure and associated weather from

the time they form over warm tropical waters to when they

dissipate or become modified over land or colder water.

Alaka has described the developmental phases of tropical

cyclones as follows:

The weakest stage is the "tropical disturbance"
in which rotary circulation is slight or absent
at the surface, but possibly better developed
aloft. There are no closed surface isobars and
no strong winds. Disturbances of this type are
common in the tropics. Next in intensity is the
"tropical depression" which is associated with
one or more closed surface isobars and with
sustained winds equal to or less than Beaufort
force 7 (32-38 miles/h). When the winds are
Beaufort force 8-11 (39-72 miles/h) we have a
"tropical storm". Finally, the strongest stage,
with winds of Beaufort force 12 ( 73 miles/h),
is the "hurricane." (Alaka, 1968, p. 1)

Although the term "tropical cyclone" may be used to

refer to storms of varying intensity, ranging in wind speeds

from below force 7 to greater than force 12, it is used in

the present study to indicate only those storms with force 8

winds or greater. Such disturbances have been defined by

Alaka as tropical storms and hurricanes. This usage is

consistent with that found in meteorological literature.

The structure of a tropical cyclone has been described

by Riehl (1963) as that of a simple heat engine. First,

convergence of surface air toward the center of the storm is

initiated by relatively low atmospheric pressure in that









region. Secondly, when air arriving at the storm center

begins to rise, it cools owing to reduced pressure at higher

altitudes. When rising air is cooled below its dewpoint,

clouds form and latent heat of condensation is released from

the water molecule into the atmosphere. Release of latent

heat at certain places within the storm enlarges the

temperature and pressure differentials found between its

different parts and levels, and thus provides impetus for

more convergence of surface air toward the storm center.

The difference between the low central pressure in a

tropical cyclone and the relatively higher atmospheric

pressure surrounding the storm, provides great enough

temperature gradients to raise the cyclone to tropical storm

intensity, but is not sufficient to make the storm develop

into a hurricane. According to Malkus (1957), the formation

of the so-called "eye" is Instrumental in achieving

hurricane-force winds. When warm air in the center of the

storm begins to descend instead of rising, the increase in

atmospheric pressure at lower altitudes causes the air to

become significantly warmer than it would be if released

latent heat of condensation were the only mechanism. This

descending air in the center of the storm thus explains both

the relatively calm weather associated with the eye of a

hurricane and the very violent conditions which prevail

immediately adjacent to it.

Tropical cyclones form over large bodies of warm water

and are common to all tropical oceans except the South









Atlantic (Niddrie, 1964). During their early stages in

tropical latitudes, they tend to travel from east to west

with the easterly winds. Later, they may recurve poleward

and thence toward the east under the influence of

mid-oceanic high pressure cells and prevailing westerly

winds of the middle latitudes (Dunn, 1967).



Destructive Effects of Tropical Cyclones



The damage which tropical cyclones can cause is widely

recognized and often the subject of scientific inquiry.

The seriousness of the threat of hurricanes to life and

property is such that the National Oceanic and Atmospheric

Administration (NOAA) maintains a center in Miami, Florida,

devoted exclusively to hurricane research.

The danger of tropical cyclones is as well known to

the general public as to the scientific community. Editors

for newspapers, television, and radio, always seeking

sensational stories, are eager to proclaim "devastation" and

"disaster" when a hurricane makes landfall. The reading

public has been further educated by the best-selling novel,

Condominium (McDonald, 1977), which vividly and accurately

portrays the type of disaster that could result from a

severe hurricane making landfall along the southwest coast

of Florida.








Modification of Hurricanes



The popular notion that the role of hurricanes is only

destructive has prompted scientists to consider numerous

schemes to weaken or divert them as means of preventing or

reducing damage. To date these schemes have consisted

primarily of physical experiments based on the ability of

certain powdered particles to nucleate moisture and release

latent heat into the storm system.

Cloud seeding with silver iodide has been attempted on

several occasions (Braham & Neil, 1958; Simpson, Ahrens, &

Decker, 1963; "Science--Meteorology," 1963; Simpson, J.,

1967; Simpson, R.H., 1969; "Project Stormfury . ," 1971;

NOAA, 1971a). Carbon dust, dropped from an airplane, has

been used to interrupt solar radiation above a hurricane

(Gray, 1973). Proposals have also been made to apply films

of various types to the ocean surface in order to reduce

evaporation and interrupt the hurricane's supply of moisture

and heat (Kazmann, 1972; Wilson, 1973). Obvious problems

of maintaining the integrity of a film on a stormy ocean

surface and pollution remaining after the storm have,

however, prevented actual experiments with water surface

films in hurricanes.

Weakening and diverting tropical cyclones is, of

course, well intended, but, as in any instance of attempted

environmental modification, may not always lead to an

entirely favorable outcome. The solution to one problem









often leads to others. If, for example, a nuclear device

were to be used to stir local areas of the ocean, bringing

cool water to the surface and thereby removing the

hurricane's main energy source, obvious auxiliary damage

would be caused by the explosion. The marine environment

would be severely affected and land areas would be subject

to radioactive rain, making that procedure clearly an

unattractive solution to the hurricane problem.

Another proposal for utilizing nuclear devices to

control hurricanes is the detonating of a bomb within the

storm in order to disrupt its circulatory organization.

Unfortunately, this procedure would require a device of such

immense power that the bomb would do far more damage than

the hurricane would have done if left alone. According to

one authority, it has been shown that, "A mature hurricane

of moderate strength and size releases as much condensation

heat energy through its cloud systems in a day as the

nuclear fusion energy of about 400 20-megaton hydrogen

bombs" (Simpson & Simpson, 1966, p. 1045).



Problems of Successful Tropical Cyclone Modification



The possibility of modification causing increased

damage is obvious and usually addressed at least implicitly

in any literature which discusses means for suppressing

hurricanes. It is usually assumed that continued research

will eventually result in a dependably safe means of









suppressing the great storms. That assumption may be

correct insofar as direct damage from the storm is

concerned, but it does not take into account the fact that

adverse consequences may result even from completely

successful attempts to suppress tropical cyclones.

If hurricanes were artificially dissipated at sea or

diverted away from land areas, precipitation falling in the

areas which would have been in the storms' paths would

presumably be reduced. This loss of rainfall could be

significant for inhabitants of a hurricane-prone region.

Hurricanes and tropical storms are part of the hydrologic

cycle in certain tropical and subtropical areas such as the

Caribbean Basin and Florida. Water supplies in those

regions may be significantly affected by the occurrence or

non-occurrence of hurricanes.

The spectacle of the hurricane's immediate fury and the

damage resulting from flooding and high winds overshadow the

fact that life-giving rain also comes with the storm. The

hurricane's rain may remain in the ground, recharging

aquifers, for years after the storm's damage has been

repaired. Although hurricane damage may be intense in some

localities, beneficial rainfall is widespread. The dangers

that coastal areas face in the event of a major hurricane

are obvious. The problems caused by preventing hurricanes

and thereby losing their rainfall are much less obvious, but

may in fact be more severe.








Hurricane modification may never become feasible but it

is still necessary to consider what might happen if

hurricanes fail to arrive, for the simple reason that they

are already striking Florida much less often than they did

in the past. This may be a cycle that will reverse itself

in the 1980's or it may be part of a longer term trend, but

what is clear is that relatively few hurricanes have hit

the Peninsula of Florida during the last thirty years.

Regardless of what causes a decrease in hurricanes, it still

affects the water budget, so it is imperative to understand

the importance of hurricanes as a source of terrestrial

water.



Importance of Tropical Cyclone Rainfall



Economic development and population increase in Florida

are mainly concentrated along the east and west coasts of

the peninsula. Every major city in South Florida is located

in the coastal zone. Coastal populations depend upon rain

falling many miles inland for their water. The demands thus

placed on coastal aquifers in Florida already exceed locally

sustainable supplies. If Florida were deprived of hurricane

rainfall, shortages of fresh water in coastal areas could

become even more acute. Although damage potential from

hurricanes is quite considerable in the coastal zone, it may

become relatively unimportant if severe chronic water









shortages affected local economies and population-carrying

capacities.

Impacts on interior regions, as well as the coastal

zone, must also be considered. Storm tides penetrate inland

only a few miles, with the height of the surge dissipating

one to two feet for each mile traveled over a flat surface

(NOAA, 1976). Hurricane-force winds likewise persist only a

few miles inland. For example, the maximum sustained winds

of "Carla," 1961, an unusually intense hurricane, decreased

from 175 mph at landfall on the Texas coast to less than 75

mph by the time the storm center had traveled 15 miles

inland (Friedman, 1975). Lesser storms will carry hurricane

force winds lesser distances inland. The eye of Hurricane

"David," 1979, traveled along the entire eastern coast of

Florida and then impinged on parts of Georgia and South

Carolina, but very few places, even along the barrier

islands of those three states, experienced winds greater

than 50 mph (NOAA, 1979). In contrast, the rain resulting

from "David's" influence covered the entire peninsular

portion of Florida and penetrated hundreds of miles inland

into several neighboring states. A former director of the

National Hurricane Center has stated that, "Most hurricanes

that cross a coastline drop the major portion of their rain

at inland stations after winds diminish below hurricane

force" (Simpson & Simpson, 1966, p. 1047).

Although tropical cyclones are both large and violent,

the area of extremely violent weather associated with such








a storm is small compared to the area in which rain is

stimulated by the disturbance. A given location may

frequently experience rainfall and unsettled weather

resulting from hurricanes, but rarely be exposed to

hurricane-force winds.



Public Concern For The Environment



During the last two decades, concern for the environ-

ment has become a popular theme in the United States,

prompting the passage of numerous legislative bills by the

federal government as well as by many states. Foremost of

these laws is the National Environmental Policy Act of 1969

(NEPA). This Act requires that Environmental Impact

Statements (EIS) be filed for all major federal actions

significantly affecting the quality of the human environment

(U.S. Congress, 1970). Although some criticism may be

leveled at NEPA for delaying projects and increasing their

expense, the law serves the much needed purpose of requiring

that the environment be taken into account in making

decisions which will affect it. Federal courts have given

NEPA a broad interpretation and have applied its mandate

strictly (Krupensky & Weismantel, 1979).

The EIS requirement can be used as an effective

instrument for protecting the public from adverse

consequences developing from suppressing hurricanes. It

may, however, be left to an outside party to point out the








problems of loss of rainfall associated with successful

hurricane suppression. The existing EIS for the

experimental Project Stormfury ignores this issue. Prepared

by the Weather Modification Division of NOAA it states,

"There is no evidence at this time that any adverse effects

have occurred or may be expected to occur as a result of

these experiments" (NOAA, 1971a, p. 3). The present

research addresses the matter of how much water comes from

hurricane rainfall and provides some of the information that

would be needed to produce a more comprehensive evaluation

of the impact of hurricane modification or natural climatic

change that causes the amount of rainfall from hurricanes to

dec ine.















CHAPTER 2


LITERATURE CONCERNING
THE BENEFICIAL ASPECTS OF HURRICANES


There is a very large body of literature concerning

hurricanes. Most of it, however, concerns their destructive

effects and the means to cope with those effects.

Beneficial aspects are rarely discussed at length.

Tannehill (1952), one of the few writers to comment on

"tropical storms that are beneficial," devotes only one

page to that topic in a 308-page book. He states:

Not all tropical cyclones are destructive: in
fact many of them are beneficial. Rains
accompanying them revive crops and replenish
supplies of storage water. Even in the most
destructive hurricanes, areas some distance from
the storm center, where winds are not dangerous,
receive beneficial rains. (Tannehill, 1952, p.
130)

Although Tannehill was one of the most knowledgable

experts of his time on the topic of hurricanes, he offers

only two rather dated references to support his statement.

Drawing from Fassig (1929) Tannehill comments:

. 60 percent of the storms that affected
Puerto Rico from 1899 to 1928, inclusive, were
beneficial. Only 10 percent were overwhelmingly
destructive, while 30 percent were locally
destructive but beneficial in some parts of the
island. In the majority of Puerto Rican
hurricanes during this period, losses caused
by the winds of the storm were insignificant
compared with the great benefits to crops and
municipal water supplies. (Tannehill, 1952,
pp. 130-131)









Tannehill's other reference is Visher (1922). Vlsher

makes only a brief comment that the rains brought by

hurricanes are "often very welcome." Further reading of

Tannehills's book, however, reveals another benefit which

may result from hurricanes. On several occasions when

fruit trees have been stripped of their leaves by high

winds, the trees have reblossomed and produced a second

crop of fruit.

Bowden (1974) also devotes a small part of a

book-length monograph to the beneficent hurricane. He was

apparently surprised when two long time residents of St.

Croix "pointed out that hurricanes brought welcome rain

to the islands." Bowden states that:

This conception of the beneficent hurricane
is surprising, at first glance. But it must be
remembered (1) that the cautious scholar R.B.
Stone wrote in 1942 "that it Is not minimizing
the danger from these storms to say that they
rarely strike with great severity," and (2) that
many if not a majority of the hurricanes that
have come within 100 miles of the islands in
the last 100 years have brought copious rains,
frequently to parched agricultural lands.
. there is a strong possibility that the 48
known hurricanes that have passed over or close
to these dry islands (Virgin Islands) in the
last 100 years may, on balance, have been more
beneficial than detrimental. (Bowden, 1974, p.
72)

Bowden offers no systematically acquired evidence

to support the concept of the beneficent hurricane and

cites only one literary source concerning the topic, the

aforementioned book by Tannehill. He further states that it

is a "minority view" and that his informants were "not old









enough to have experienced the last major hurricane of 1928

on St. Croix" (Bowden, 1974, p. 72).

Sugg (1968) has examined the rainfall data from

tropical cyclones which have moved over drought-stricken

areas and has provided numerical evidence of the beneficence

of hurricane rainfall. Although he establishes that

hurricane rainfall may be of great value in ameliorating

drought, he fails to observe that it may be a part of the

normal water supply for an area. Sugg states, "It is quite

obvious that rains, to be most beneficial, must fall on

drought-stricken areas" (Sugg, 1963, p. 39).

After presenting a well documented case in order to

demonstrate the benefits of hurricane rainfall, Sugg goes

on to mention briefly several other supposed benefits.

Although his approach to the "other benefits" is less

scientific than his treatment of rainfall, his comments draw

attention to the wide variety of impacts which a hurricane

may generate. Sugg's "other benefits" are 1) abnormal

migrations of fish and crustaceans, resulting in larger

catches for commercial fisherman, 2) destruction of slum

areas, 3) suppression of rodents and insects by damaging

their breeding grounds, and 4) Influencing historical

events by sinking warships.

It is arguable whether the effects of hurricanes

mentioned by Sugg are actually beneficial. Abnormal

migration of fish and crustaceans may be accompanied by

higher than normal mortality rates. Destruction of slum








areas deprives poor people of homes. Destruction of

rodent and insect breeding areas in one place is probably

accompanied by their replacement elsewhere. The evaluation

of whether historical events have been Influenced favorably

or unfavorably depends very much upon the background of the

observer. Although Sugg has titled his article "Beneficial

Aspects of the Tropical Cyclone," he has demonstrated no

definite benefit other than the cessation of drought.

An earlier article by Sugg (1967), although not

directed primarily at the beneficial aspects of the tropical

cyclone, is more effective in demonstrating an unexpected

gain resulting from a hurricane. In his study of the

"Economic Aspects of Hurricanes," he has observed that

short term booms have been recognized as a result of

insurance compensation in hurricane disaster areas in

the United States.

An example of a short term economic gain resulting

from a hurricane strike is given by Parades (1978). While

studying citizen responses to Hurricane "Eloise," 1975, in

Panama City, Florida, Paredes encountered the proprietor

of a beachside tavern, who told of throngs of construction

workers who frequented his establishment during the clean-up

and rebuilding following the storm. Paredes' study revealed

that the tavern operator was not the only person to benefit

from the storm. Thirty percent of the respondents to his

survey expressed the opinion that Hurricane "Eloise" had

beneficial effects on the local economy.








Short term increases in spending have also been

observed immediately before a hurricane strikes. Anderson

(1972) has stated that hurricane warnings cause people to

take actions to prepare for the storm. Those actions often

consist of purchasing items which are perceived to be useful

during a hurricane, thus certain businesses will experience

brisk sales as a result of the hurricane warning even though

the storm might not in fact strike that locale.

Weaver (1968) has written about a variety of benefits

which may be derived from hurricanes. Favorable

developments which Weaver cited as resulting from hurricanes

include: (1) Sugg's observation of short term booms

resulting from insurance compensation, (2) rainfall, and

(3) increased rate of economic development and improvements

to resource management. The third item referred

specifically to events which occurred on the island of

Grenada after Hurricane "Janet," 1955. Weaver showed that

the storm's damage caused the Forestry Department and

Fisheries Division to be created and the Department of

Agriculture to be revitalized. Furthermore, he stated that

the hurricane initiated improvements in transportation and

communication facilities and a shift from nutmeg and cacao

to more lucrative bananas as the principal export.

The body of literature concerning the beneficial

aspects of hurricanes is small, but even the few works

cited here indicate the diversity of favorable results

which a hurricane may generate. Much of what is said in






18

the cited works is of a speculative nature and very little

is supported by thorough scientific inquiry. The need for

further research concerning non-destructive aspects of

hurricanes is clearly justified by the paucity of existing

literature pertaining to that topic and its speculative

character.















CHAPTER 3

HURRICANE SUPPRESSION



Damage Caused by Hurricanes



In the continental United States from 1925 to 1970,

hurricanes were responsible for 4911 deaths and the

destruction of $7.5 billion in property (Brinkman, 1975).

Compared to other natural hazards, hurricanes rank second in

both the number of fatalities and value of property damage.*

The harmful effects of hurricanes are further emphasized by

their concentration in a narrow zone along the coastlines of

the Atlantic Ocean and the Gulf of Mexico.

Historical records bear witness to the damage which can

result from severe hurricanes. A storm tide which inundated

Galveston, Texas, in 1900 is said to be responsible for the

loss of 6000 lives. In 1909, 350 lives were lost to a storm

in Louisiana and Mississippi. In August and September of

1915, separate hurricanes struck Galveston, Texas, and

Burwood, Louisiana, each causing the loss of approximately

275 human lives. Similar losses of life are reported for



*Tornadoes killed 8037 people during the same time
period, and floods caused $9.2 billion in damages from 1925
to 1969 (Brinkman, 1975).









storms of 1919 and 1926 in Florida. Over 1800 persons are

estimated to have died in the September 1928 hurricane in

which wind-driven waters from Lake Okeechobee overflowed

into populated areas. Over 400 persons are known to have

perished in the "Labor Day Storm" of 1935 in the Florida

Keys and along the Gulf of Mexico coast to Tampa. Hurricane

"Audrey" in 1957 took 390 lives. In more recent years,

deaths in the United States have been fewer, owing to

advance warning and evacuation of people from exposed

locations, but property damage continues to grow as a result

of increasing urbanization (NOAA, 1971b) in areas where

building codes and land use controls do not effectively

minimize hazard risks.

Brinkman's summary of hurricane hazards in the United

States indicates how rapidly population and urban

development are increasing in areas subject to hurricane

violence. Dury (1977) has further warned that past

estimates of the danger from hurricanes are probably too

low. His application of statistical techniques to data

derived from hurricanes occurring from 1900 through 1972

yields results which prompted him to forecast that:

"Prospects for hurricane-related flood damage in a single

event within the next quarter century appear to be grim

indeed" (Dury, 1977, p. 257). It is little wonder that men

seek to suppress these great storms.








Cloud Seeding



A variety of techniques for suppressing hurricanes are

available. Suggestions which include the use of nuclear

devices are so obviously infeasible that no actual

experiments have been performed using those means, and

relatively little research regarding evaporation suppression

or blocking of insolation has been performed. The single

means for suppressing hurricanes which is most frequently

studied by scientists and discussed by the public at large

is cloud seeding.

Cloud seeding is accomplished by artificially applying

certain finely particulated materials to potential rain

clouds or clouds already producing rain. This procedure is

an outgrowth of Langmuir's (1947) studies of the role of

nuclei in creating droplets of water from clouds. Most

commonly silver iodide, and occasionally dry ice or other

substances, are spread into clouds to increase the number of

available hygroscopic nuclei. It is hypothesized that this

practice should increase the quantity of rainfall derived

from a given cloud. Opinions about its effectiveness vary

and research concerning the efficacy of cloud seeding as

means of increasing long term rainfall has not yet yielded

conclusive results (Kazmann, 1972).

In hurricane seeding, the goal is not to increase

precipitation but rather to modify the storm so as to reduce

its intensity or to cause it to move in a direction away








from populated areas (Braham & Neil, 1958). Seeding of

selected portions of the hurricane is used to decrease the

temperature and pressure differences within the storm and

thereby disorganize circulation around the eye and reduce

wind speeds ("Project Stormfury . ," 1971).

The first hurricane cloud seeding experiment on record

occurred off the coast of Georgia and South Carolina in

1947. A group from Project Cirrus, a rainmaking experiment,

flew into the storm and dropped about 180 pounds of dry ice.

Unfortunately, the storm changed direction immediately after

the seeding and made landfall at Savannah, Georgia, causing

heavy flooding and considerable damage to property in

Georgia and South Carolina (Braham & Neil, 1958;

"Science--Meteorology," 1963; Niddrie, 1964; "Project

Stormfury . ," 1971).

The sudden change in direction of the 1947 storm was at

the time cited as evidence that the seeding had had a marked

effect. However, inasmuch as previous and subsequent storms

have exhibited equally erratic changes in path without

having been seeded, no definite conclusion may be drawn from

the events following that particular seeding episode (Braham

& Neil, 1958). At present, it seems unlikely that the 1947

seeding experiment had a significant effect upon the

hurricane. R.H. Simpson (1969), while he was director of

the National Hurricane Center, commented that for seeding to

be effective, it would have to be performed continuously,

rather than on a single application basis.









No further hurricane cloud seeding was attempted

until 1961. At that time the United States Weather Bureau

authorized the dropping of silver iodide into Hurricane

"Esther." Maximum wind speeds in the seeded sector dropped

by as much as 14 percent. Within hours after the seeding,

however, the storm had regained full strength

("Science--Meteorology," 1963).

During the following year, Project Stormfury was

established as a collaborative effort by the Departments of

Commerce and Defense. The express roll of Project Stormfury

is to perform research pertaining to hurricane modification

(NOAA, 1971a). This project is part of a larger effort

aimed at several aspects of research pertaining to

hurricanes. J. Simpson (1967) has described the areas of

major concentration of hurricane research. Little change

has occurred since her remarks:

No effort is currently being directed
towards operational weather modification, which
is still largely in the empirical or statistical
phase. The current work consists of background
experiments, in the following three senses of the
word:

1. "Before and after" measurements on
full-scale atmospheric systems after
introducing an artificial alteration. The
alteration is designed to be predictable
and controllable, and is at least backed
by physical hypotheses outlining its
consequences. Our Stormfury cumulus and
hurricane seeding experiments are examples.

2. Detailed observations upon situations
in which nature herself is performing
a partially controlled experiment. An
example is our study of the alterations
of airflow and convective cloud patterns









by heated islands. The measurements can be
examined in the framework of a fairly well
developed theoretical model.

3. Numerical experiments based on
solutions of the hydrodynamic equations and
comparing the results with aircraft and
other observations.

We hope also, when staff permits, to embark
on some laboratory experiments. (J. Simpson,
1967, p. 95)

Cloud seeding experiments are the most highly

publicized hurricane research activity, although very little

seeding has taken place. The first hurricane to be seeded

under the auspices of Project Stormfury was "Beulah," 1963.

After "Beulah," there was not another hurricane seeded until

"Debbie," 1969 (NOAA, 1971a; "Project Stormfury . ,"

1971). The seeding of Hurricanes "Esther" and "Beulah" were

very similar. Silver iodide was dropped along the eye

wall of each storm and winds diminished for several hours

afterward as apparent results of the seeding. "Debbie"

was more heavily doused with silver iodide than were the

previous storms, as well as receiving the treatment further

out in the cloud wall, with the apparent consequence of

having greater effect upon the storm ("Project Stormfury .

S ," 1971).

The apparent success of the experiment with Hurricane

"Debbie" suggests that hurricane modification through cloud

seeding can be made into a feasible routine practice. In

R.H. Simpson's (1969) words:

The changes that occurred in Debbie were
these: The diameter of her eye had originally
been about 15 miles. Reports received at the








National Hurricane Center from aircraft
monitoring the storm indicated that, after the
seeding, the eye wall expanded to a 40-mile
diameter. The central pressure rose an
appreciable amount--which indicates a lessening
of intensity--and maximum winds decreased
somewhat. It was not a spectacular change, but
it was a change essentailly in the direction that
was predicted by the hypothesis on which we were
operating. (R.H. Simpson, 1969, p. 35)

"Ginger" in 1971 is the only other hurricane which has

been seeded under the Project Stormfury program (NOAA,

1978). The results of seeding "Ginger," however, were not

as promising as those of "Esther," "Beulah," and "Debbie."

Wind speeds in Hurricane "Ginger" actually increased after

seeding (NOAA, 1972).



Unpredictability of Hurricanes



The unpredictability of hurricanes and uncertainty

about how they will react to seeding have been major factors

which have limited the number of hurricane modification

experiments. Fear of law suits has prompted the

administrators of Project Stormfury to be very selective in

choosing a hurricane to seed ("Science--Meteorology," 1963).

Statements made by Frank (Malone, 1979), in his

capacity as Director of the National Hurricane Center,

during Hurricanes "David" and "Frederic" in 1979 illustrate

the inability even of hurricane experts to forecast

accurately the storms' movements and development. Dr. Frank

predicted on September 2 that the eye of Hurricane "David"








would come ashore during early morning hours of September 3,

somewhere between Palm Beach, Florida, and Marathon,

Florida. The eye of the storm actually crossed the coast

slightly north of Palm Beach, just outside the predicted

zone, after noon on September 3. When asked about the

apparent incorrectness of his forecast after the storm's eye

missed the center of the predicted zone of landfall by 100

miles, Frank commented that his forecast, "was about as

close as we can get. . My average forecast is plus or

minus 100 miles" (Malone, 1979, p. 1).

The "plus or minus 100 miles" degree of accuracy

applies only to very short term forecasts. When the

forecast concerns an event more than 24 hours into

the future, accuracy drops sharply. Predictions of the

movement and development of a hurricane are based upon

the observation that although the path of the storm may

sometimes be quite erratic, changes in the direction

or intensity of a hurricane do not usually occur rapidly.

The forecaster may generally assume that the direction and

intensity of a hurricane will continue with little change

for a short while. Although research is expanding the

available knowledge of atmospheric dynamics, the physical

properties of the atmosphere are not yet sufficiently

understood so as to provide any more dependable guidelines

for hurricane forecasts than the projection of current

trends and movements.









On September 7, several days after Frank's "as close as

we can get" estimate of "David's" landfall, he rendered his

opinion concerning the seriousness of the storm called

"Frederic." At that time, "Frederic" had just crossed

the island of Hispaniola and had weakened to a level of

intensity which barely qualified it as a tropical storm.

Frank proclaimed that "Frederic" posed no serious threat.

Other persons connected with the National Hurricane Center

were quoted as saying, "I would not encourage people to keep

their storm shutters up just because of Frederic." and "The

center is very weak and diffuse" (Dominican Republic . .

," 1979, p. 12). Less than a week later, 340,000 people

evacuated from coastal areas of Florida, Alabama, and

Mississippi as "Frederic" approached with 130 mile per hour

winds and 15-foot storm tides (Markowitz, 1979).

The prevailing lack of detailed knowledge concerning

the mechanisms which control hurricanes has led to the

criticism that actual experiments in cloud seeding are

premature. Only four years prior to the official advent of

Project Stormfury, a study funded through the National

Hurricane Research Project (Braham & Neil, 1958) stated

that,

It appears to the writers at this time that
the hurricane is so poorly described and that
there is so little known about the thermodynamic
and hydrodynamic processes which govern its
growth and decay, it is not possible to set down
a rational argument linking any known effect of
seeding to predicted changes in the behavior of
the storm. (Braham & Neil, 1958, p. 2)









Simpson & Simpson (1966) have responded to that

criticism by comparing hurricane modification research with

early research concerning nuclear physics:

It has been stated that one should know more
about hurricanes, be able to model any experiment
numerically using the hydrodynamic equations, and
be able to validate the assumptions before field
experiments are undertaken.
This has not been the approach of the
classical physicist, for whom the early atomic
pioneers such as Rutherford and Bohr will serve
as familiar examples. These men chose to learn
about atomic structure by conducting experiments
upon actual atoms--this is our example and
motivation in hurricane experimentation.
(Simpson & Simpson, 1966, p. 1045)

The Simpsons' analogy may be used equally well as an

argument in support of the opposing sentiment. Early

nuclear physicists cannot have imagined the immensely

destructive forces with which they were dealing. The

consequences of accidently detonating a nuclear explosion in

a laboratory placed in some large city are obvious and

should provide an insight to the possible consequences of

tampering with nature's greatest storms. By the Simpsons'

own admission, a mature hurricane releases many times the

quantity of energy released by the typical hydrogen bomb.

The first hurricane cloud seeding experiment occurred

in the same year the Langmuir's theory of raindrop

nucleation was published. Although the question of whether

seeding experiments are still premature may be subject to

debate, there is no doubt that the 1947 seeding experiment

was highly exploratory. Much too little was known about the







29

dynamic aspects of hurricanes at that time and too little

caution was exhibited in the venture. Since 1947 great

strides have been made in improving the understanding of

hurricanes. Some of that new knowledge has been derived

from cloud seeding experiments. The sum of what is known

about hurricanes is, however, still small compared to what

is unknown and, all too often, persons who are in position

to make decisions concerning the modification of weather

must act on the basis of sketchy information.















CHAPTER 4

RESEARCH DESIGN



The importance of hurricane and tropical storm

rainfall, as part of the total rainfall of South Florida, is

measured and the impact that the loss of such rainfall would

have on South Florida's water supply is evaluated. The

principal questions addressed herein are stated below.

Each question is answered in the order stated so that the

information derived from earlier inquiries may be used in

answering later questions.



I. What quantities and proportions of South

Florida's rainfall come from hurricanes and tropical storms?

II. What quantities and proportions of hurricane and

tropical storm rainfall are retained as part of South

Florida's water supply?

I II. What effects would the loss of hurricane and

tropical storm rainfall have on South Florida's long term

ability to meet water demands?

IV. What implications would the effects of deleting

hurricane and tropical storm rainfall from the water supply

have for long range water management planning In South

Florida?









Study Area



The study area is the South Florida Water Management

District (SFWMD) (Figure 1). This region is chosen because

hurricanes strike here more frequently than any other part

of the state. Both negative and positive impacts of

hurricanes are greater for this region than elsewhere.

South Florida, particularly the southeastern coastal area,

which is exposed to direct hurricane strike from the sea, is

highly urbanized. This means not only that thousands of

people and much valuable real estate face potential danger

from hurricanes, but also that there is a high demand for

water for municipal supplies and thermal electricity

generation. Inland from the coastal cities, extensive areas

of agriculture and natural wetlands also require water.

Although South Florida could have much to gain if hurricanes

did not strike, it could also have much to lose. The

hurricane is a prominent part of the hydrologic cycle in

this region.



Organization and Methodology



I. What quantities and proportions of rainfall result

from hurricanes and tropical storms in the South Florida

Water Management District?

Two types of information are used to answer this

question: A) What is the total amount of rainfall which






























STUDY AREA


THE SOUTH FLORIDA
WATER MANAGEMENT DISTRICT
L i-


FIGURE I
THE SOUTH FLORIDA WATER MANAGEMENT DISTRICT


.0O o









occurs? and B) How much rainfall comes from tropical

cyclones? After each of these measurements is acquired,

the figures are paired and used to calculate the percentage

of rainfall from hurricanes and tropical storms.



II. What quantities and proportions of hurricane and

tropical storm rainfall are retained as part of the South

Florida Water Management District's water supply?

Estimates of the amounts of infiltration and

impoundable runoff are based upon the rise of water levels

in test wells and the area of impoundment basins and their

watersheds.



III. What effects would the loss of tropical cyclone

rainfall have on the South Florida Water Management

District's ability to meet its water requirements?

Several types of information are required to answer

this question. A) What effects would the loss of hurricane

rainfall have upon long range water supplies? This is

obtained by comparing rainfall from a 30-year interval of

high hurricane activity with rainfall from a 30-year

interval of low activity. B) How much water is used in the

Water Management District? These data are obtained from

published documents. C) What will the water demands for the

future be in the Water Management District? Estimates of

future demand are based on projections of past water use

rates and population growth.







34

IV. What implications would the effects of deleting

hurricane and tropical storm rainfall from the water supply

have for long range planning in the South Florida Water

Management District?

The plans and policies of the South Florida Water

Management District are examined with respect to actions

that may be affected by a decline in rainfall.

Recommendations are made regarding indicated changes in

water management policies.
















CHAPTER 5

TROPICAL CYCLONE RAINFALL



Data Sources



Information regarding the dates and routes of

hurricanes and tropical storms was obtained from various

sources. The most useful reference was Neumann et al.

(1978) Tropical Cyclones Of The North Atlantic Ocean

1871-1977. This book contains numerous maps illustrating

the routes of tropical cyclones and textual descriptions of

the geographical and temporal distributions of the storms.

Tannehill (1952) Hurricanes contains similar descriptions

of tropical cyclone tracks and was also used extensively.

Other references which were consulted included Bruun et al.

(1962), Coastal Engineering Department, University of

Florida (1951), Dunn (1967), Haggard & White (1959), Hebert

& Taylor (1978), NOAA (1973), Schoner & Molansky (1956),

Simpson (1971), Sugg, Pardue, & Carrodus (1971), and

Tannehill (1938).

Forty-one hurricanes and forty-four tropical storms

(Table 1) influenced rainfall in the South Florida Water

Management District from 1919 through 197G. Rainfall data

are recorded for the dates on which the storms influenced














TABLE 1


DATES OF HURRICANE AND TROPICAL STORM RAINFALL


HURRICANES


Sept. 9-10
Sept. 25, 29-30
Oct. 24-25
Oct. 19-21
July 26-28
Oct. 20-21
Aug. 7- 9
Sept. 16-17
Sept. 27-29
July 29 Aug. I
Sept. 1
Sept. 4- 6
Oct. 3- 5
Sept. 2- 5
Sept. 28-29
Nov. 4- 5
July 29-30
Aug. 11-13
Oct. 6
Oct. 16-19
June 21-24


1945
1946
1947
1947
1948
1948
1949
1950
1950
1951
1959
1960
1964
1964
1964
1964
1964
1965
1966
1966
1968


Sept. 14-16
Oct. 7- 8
Sept. 17-12
Oct. 11-12
Sept. 21-23
Oct. 4- 5
Aug. 26-28
Sept. 3- 6
Oct. 15-18
May 17
Oct. 16-19
Sept. 9-11
Aug. 26-28
Sept. 9-11
Sept. 27-28*
Oct. 5- 6*
Oct. 14-15
Sept. 7- 9
June 8- 9
Oct. 2- 5
Oct. 16-19


* Hurricane "Hilda", passing and returning.


TROPICAL STORMS


1925 Nov. 30 Dec. 1
1926 Sept. 15-17*
1928 Aug. 12-14
1930 Sept. 6-10
1932 Aug. 29-31
1934 May 26-28
1934 July 22-23
1936 June 13-15
1936 Aug. 21-22
1937 July 28-30
1937 Aug. 29-31
1938 Oct. 13-17*
1940 Aug. 2- 3
1941 Sept. 15-17
1941 Oct. 17-21
1945 Sept. 3- 5
1946 Nov. 1- 2
1947 Aug. 19-20
1947 Sept. 22-23
1947 Oct. 5- 6
1951 Oct. 1- 3
1952 Feb. 2- 3

* two storms overlapped


1953
1953
1953
1959
1960
1962
1964
1967
1968
1968
1968
1969
1969
1970
1970
1971
1972
1974
1974
1975
1976


Aug. 27-31
Oct. 3- 5
Oct. 7-10
June 16-20
Sept. 21-25
Aug. 24-26
June 5- 6
Sept. 7- 8
June 2- 6
June 17-20
Aug. 9-10
Sept. 6- 7
Oct. 1- 4
Sept. 13-15
Sept. 26-27
Aug. 10-12
Sept. 4- 6
June 24-28
Oct. 6- 7
June 26-27
Aug. 17-19


1919
1920
1921
1924
1926
1926
1928
1928
1929
1933
1933
1933
1933
1935
1935
1935
1936
1939
1941
1944
1945









Florida and summed to obtain the total rain from tropical

cyclones during the sixty-year period and for specified

shorter time intervals within that period. Although only

rainfall totals and the dates on which the rain fell are

needed to calculate how much water originates from tropical

cyclones, several other items are tabulated and compared to

hurricane and tropical storm rainfall in order to obtain a

better understanding of the relative importance of tropical

cyclone rainfall as a part of the total rainfall of the

a rea.

In addition to daily rainfall data for the dates on

which tropical cyclones were passing the study area,

rainfall is also tabulated for each calender year, and for

the months of peak tropical cyclone activity from June

through October of each year. Although the hurricane season

for Florida is officially defined as lasting from June

through November, only one hurricane and two tropical storms

influenced rainfall in South Florida in November during the

study period. This conforms to the findings of Niddrie

(1964) for tropical cyclones in the Caribbean Sea and

Atlantic Ocean from 1492 to the early 1960's. November is

therefore excluded from the hurricane season for the purpose

of this study. Rainfall data are obtained from monthly and

annual summaries of climatological data published by the

United States Government.










Selection of Stations



Although there are numerous stations within and near

the study area, few of them have existed for the entire

sixty-year period. Only one station, Bartow, a few miles

outside of the Water Management District, appears to have

remained at exactly the same site for the full sixty years.

Key West, another station with sixty years of complete

records, and very little change in location, is excluded in

spite of being within the Water Management District because

rain which falls in the Keys does not contribute to the

recharge of mainland aquifers (Spangler, 1981).

After numerous stations had been eliminated because of

location, short periods of records, or erratic records,

nineteen weather stations were found to be suitable. These

stations are Arcadia, Avon Park, Bartow, Belle Glade,

Everglades City, Fellsmere, Fort Lauderdale, Fort Myers,

Fort Pierce, Homestead, Isleworth, Kissimmee, La Belle,

Miami, Moore Haven, Okeechobee, Orlando, Punta Gorda, and

West Palm Beach (Figure 2).

Since it was not possible to use only weather stations

which had sixty years of continuous data in exactly the same

location, a series of t-tests was performed to ascertain

the degree of temporal consistency of the data from each

station. The sixty-year study period was divided into two

thirty-year intervals which were compared as Independent

samples. The mean annual rainfall at ten of the nineteen























































FIGURE 2


WEATHER STATIONS









stations was significantly different for the two intervals

at the 95% confidence level (Table 2).

It is noteworthy, however, that Bartow, the station

which had the most complete and dependable record for the

full sixty-year period, was one of the stations which the

t-test indicated as being significantly different from

itself. The differences observed between rainfall data from

the earlier half of the study period compared to the later

half thus do not necessarily indicate that the data were

affected by changes in station location. Rather, the

differences might be explained by climatic change. Analyses

of hurricane rainfall data and total rainfall for the region

indicate that significant declines have occurred in the

second half of the study period.



Determining if Rain is Caused by a Tropical Cyclone



Rainfall which occurs during the passage of a hurricane

or tropical storm center several hundred miles away may or

may not be directly related to the passing tropical cyclone.

Satellite remote sensing imagery may be used to determine

the areal distribution of clouds associated with the

tropical cyclone and reveal the areas where rainfall was

directly attributable to such a storm, but satellite imagery

exists only from 1960 to the present, and even then is

difficult to obtain for 1960 through 1968. No such record

of the continuity of cloud coverage is available for earlier














TABLE 2

t-TESTS OF RAINFALL DATA--INDIVIDUAL STATIONS
FIRST 30 YEARS VS. SECOND 30 YEARS

1919-4S 1949-78
CITY ItEAN MEAN t

Arcadia 52.50 52.28 0.522
Avon Park 53.52 52.55 2.234
Bartow 54.77 53.16 3.F46 *
Belle Glade 57.12 55.70 3.595 *
Everglades City 53.61 53.40 0.556
Fellsmere 55.93 51.82 8.991 *
Fort Lauderdale 61.56 59.74 3.901 *
Fort Myers 53.27 53.29 -0.064
Fort Pierce 52.76 52.34 1.031
Homestead 62.20 60.41 1.149
Isleworth 51.60 51.04 1.424
Kissimmee 49.93 49.24 1.723
La Belle 51.36 51.74 -1.133
Miami 57.47 57.51 -0.077
Moore Haven 49.95 49.33 1.608
Okeechobee 46.97 45.60 3.726 *
Orlando 51.06 49.89 3.254 *
Punta Gorda 50.96 49.37 3.641 *
West Palm Beach 61.78 59.40 5.919 *

CRITICAL VALUES OF t:
0.05 Confidence Level = 2.04
0.01 Confidence Level = 2.75
Significant at .01 Level


TABLE 3

SATELLITE IMAGERY

DATE STORM SATELLITE

1969 Sept. 5 T.S. GERDA ESSA 9
1969 Oct. 2 T.S. JENNY ESSA 9
1970 Sept. 14 T.S. FELICE ITOS 1
1970 Sept. 27 T.S. GRETA ITOS 1
1971 Aug. 12 T.S. BETH ESSA 9
1972 June 19 HURR. AGNES* ESSA 9
1972 Sept. 5 T.S. DAWN ESSA 9
1574 Oct. 6 T.S. (no name) SMS/GOES
19/4 June 25 Subtrop. St. (no name) SMS/GOES
1975 June 26 T.S. AMY SMS/GOES
1975 Sept. 23 HURR. GLADYS* SIS/GOES
1576 Aug. 17 T.S. DOTTIE SMS/GOES
19/9 Aug. 30 HURR. DAVID* S-.S /GOES
1979 Sept. 3 HURR. DAVID* StIS/GOES
1979 Sept. 8 HURR. FREDERIC* SMS/GCES
1979 Sept. 12 HURR. FREDERIC* SMS/GOES
1980 Aug. 5 IIURR. ALLEN* SMS/GOES
1980 Aug. 9 HURR. ALLEN* SMS/GOES

Indicates storms which passed either outside of
the study area or after the end of the study period.










times. Without direct knowledge of whether an area was

covered by clouds which emanated from a tropical system, it

is not possible to determine with certainty if rain which

fell at a given place on a certain day was the result of the

passing tropical cyclone or of other local or extra-tropical

causes.



Previous Studies



Previous studies of tropical cyclone rainfall have

failed to address the problem of whether a given observation

of rain actually resulted from a specific storm. Cry (1967)

discusses the problem of wind reducing the effectiveness of

rain collection devices but neglects the question of whether

the given sample should be considered at all. Goodyear

(1968) avoids raw climatological data by using the United

States Army Corps of Engineers "Storm Rainfall in the United

States" (1945 et seq) whenever possible. For earlier times

he draws his information directly from summaries of weather

station records, but gives no explanation of how it is known

that the rainfall is the result of tropical cyclones in

either situation. Examining the Corps of Engineers' storm

rainfall reports also discloses no statement on this topic.

Milton (1978) cites Schoner and Molansky (1956) and

Miller (1958) as having the most sophisticated networks of

data to work with, but it appears that their methodologies

for selecting the data to be used were no more advanced than










others who have written on the topic of tropical cyclone

rainfall. Schoner and Molansky list the Climatological Data

and Corps of Engineers as their data sources, just as

Goodyear does, and make no further statement regarding the

selection of data.

Miller chose to discontinue tabulating data whenever

the winds around the center of the storm dropped below

hurricane force. This practice ignores any rain which

results from tropical storms and a substantial part of the

rain resulting from dissipating hurricanes. Miller also

discusses the problems of rain-gauge effectiveness and the

possibility of orographic and extratropical influences on

hurricane rainfall. He states that hurricane rainfall data

from Florida are virtually free of orograohic and

extratropical effects. While the flatness of Florida

certainly minimizes orographic effects, the statement

regarding extratropical influences must be questioned. NOAA

satellite imagery of Hurricane "Gladys," September 23, 1975

(Figure 3), clearly shows a middle latitude frontal system

blending with the tropical cyclone.

Gentry (1964) is the only author who has been found to

discuss a means for determining the actual areas in which

rain is falling in the vicinity of a hurricane or tropical

storm. He cites the use of airborne radar for the purpose

of studying the patterns of hurricane rainbands. Gentry's

methodology is not relevant to the present project, however,

because a source of radar imagery for the appropriate time

interval could not be found.

































FIGURE 3


HURRICANE "GLADYS", SEPTEMBER 23, 1975


FIGURE 4


TROPICAL STORM "AMY", JUNE 26, 1975









Criteria for Determining Rainfall Source



Remote sensing imagery was employed in this study but

was found to be of little use because no hurricanes and only

eight tropical storms passed near the South Florida Water

Management District between 1969, the time for which the

earliest imagery could be obtained, and the end of the study

period in 1978. Other means had to be found to determine if

rainfall could be attributed to a tropical cyclone.

Several assumptions were tested as reasonable criteria

on which to base such decisions. These assumptions were

designed to provide a consistent set of criteria which could

be applied in the absence of direct evidence. The results

obtained by such criteria were compared to the conclusions

derived from remote sensing imagery (Table 3). Because of

the small number of tropical cyclones covered by satellite

imagery during the study period, several additional images

of storms which passed near South Florida during 1979 and

1980 were also used.



Some Discarded Assumptions

Although the assumptions appeared to be consistent with

known patterns of hurricane behavior, most of them could not

be applied to the present study. One assumption was that

the shape of the area, where rainfall was influenced by a

tropical cyclone, would be congruent with the shape of a









smaller area defined by specific values indicating heavy

rainfall and strong wind. It was found, however, that the

area of the South Florida Water Management District was too

small to yield the patterns of data required to determine

the shape of the intense part of the storm. A larger

network of stations is needed.

Another assumption was that if a station which reported

no rainfall on a given day lies between an area of known

tropical cyclone influence and another station or stations

which report some rainfall, it would be assumed the rain

which fell at locations beyond the dry station is not the

result of the tropical cyclone. This criterion assumes that

any station which is under the influence of a tropical

cyclone should receive at least a small quantity of rain

during a 24-hour period. It was found, however, that

relatively dry storms with poorly developed circulation,

such as Tropical Storm "Amy" on June 26, 1975 (Figure 4),

apparently pass some stations without dropping rain for

24-hour periods. Again, a denser network of weather

stations spread across a larger area would be required to

ascertain the rainband pattern for storms of the pre-imagery

era.

A further difficulty in applying the second criterion

is found in the quality of the raw data. Weather stations

do not all record their data at the same time of day. Thus,

rain which falls simultaneously in two different locations










may be attributed to different days and rain which falls on

adjoining days may be attributed to the same day.

A third assumption was that for any location which is

known to receive precipitation from a tropical storm or

hurricane on at least one day, the period of time in which

the place was influenced by the storm will be assumed to

extend neither earlier than the last preceding dry day nor

later than the next following day without rain. Widely

spaced rainbands and erratic rainfall patterns impair the

utility of this criterion as well, particularly for

relatively dry storms.

The quality of the data (Appendices A and B) also

presents another problem. Occasionally the passage of a

hurricane may disable the rain gauge or prevent the observer

from recording each day of rainfall. Several days of

rainfall may go unrecorded or may be reported in a single

observation. Published summaries of climatological data

normally contain notes when cumulative quantities for

several days are reported, but there appear to be unnoted

instances of such reports as well, as for example at

Okeechobee in 1939 when no rain was recorded for two days

while the eye of a hurricane passed over the area, but over

three inches was recorded for the following day when the

storm center was several hundred miles away.










Procedures

Wide variability in the size, shape, intensity, and

rainfall patterns of hurricanes and tropical storms

precluded the prescription of any rigidly defined

methodology for determining whether a given observation of

rainfall was the result of a tropical cyclone system, at

least within the confines of the area chosen for this study.

A comprehensive study of the characteristics of the

peripheral regions of tropical cyclones in the North

Atlantic Ocean, Caribbean Sea, and Gulf of Mexico might

provide some definitive statements on this topic, but such a

study is beyond the scope of the present investigation.

The method used in this study was to plot each daily

rainfall value on a map and to examine the spatial and

temporal distributions of rainfall across the study area for

the several days while each storm passed. Prior to the

approach of a hurricane or tropical storm, the Water

Management District usually had several days when rain was

reported at few, if any, stations. If rain was found at a

majority of stations, the quantities would tend to be small

and randomly distributed across the area. With the approach

of a tropical system, rainfall generally increased in

frequency and quantity for several days before returning to

pre-storm levels.

The principles of spatial and temporal continuity apply

to tropical cyclone rainfall but not in the rigidly defined

manner which was prescribed by earlier assumptions. If one









or several stations report no rain on a given day, those

stations and others yet more distant from the storm center

may still be judged to be under the influence of the

tropical system if the proximity of the storm and the

general pattern of circulation around it can be used to

explain the pattern of rainfall observations.

In most instances, if rain was falling at a given

location and there was a tropical weather system centered

within 300 miles of the site, the rain was attributed to

that storm. The 300-mile maximum radius conforms to the

limit of the area for which Miller (1958) selected data.

Miller, however, used that distance as a rigid arbitrary

limit while the present findings suggest only that it is an

approximate median of the radius of the area that would be

influenced by a hurricane or tropical storm, which may

extend from 150 to 600 miles from the storm center.





Analysis of Tropical Cyclone Rainfall



Summary and Discussion of Rainfall Data

The rainfall data which have been collected for nineteen

weather stations in and near the South Florida Water

Management District are divided into twelve five-year

intervals and two thirty-year intervals as well as being

summed for the full sixty-year period. These data concern

annual rainfall and seasonal rainfall for the five-month










period of peak tropical cyclone activity for all nineteen

stations (Table 4), annual and seasonal rainfall for each

individual station (Tables 5 through 23 and Figures 5 and

6), tropical cyclone rainfall for each of the five months

of the period of peak hurricane activity (Tables 24 through

23), and years and months of individual tropical cyclones

(Table 29).

Mean annual rainfall from hurricanes for all stations

for the sixty-year period is 2.05 inches, or 3.3 percent of

the annual total rainfall and 5.8 percent of the seasonal

rainfall. Mean rainfall from tropical storms is 1.74

inches, or 3.2 percent of the annual rainfall and 4.9

percent of the seasonal rainfall. Hurricanes and tropical

storms combined comprise 3.79 inches of rain or 7.0 percent

of the annual rainfall and 10.6 percent of the seasonal

rainfall.

Mean annual rainfall from hurricanes for the individual

stations ranges from 1.60 inches (3.0 percent) at Arcadia to

2.71 inches (4.4 percent) at Fort Lauderdale. Rainfall from

tropical storms ranges from 1.19 inches (2.2 percent) at

Bartow to 2.18 inches (4.1 percent) at Fort Myers. Rainfall

from hurricanes and tropical storms combined ranges from

2.97 inches (5.7 percent) at Arcadia and 3.05 inches (5.6

percent) at Bartow to 4.66 inches (7.5 percent) at Fort

Lauderdale and 4.30 inches (7.7 percent) at Fellsmere.

Mean monthly rainfall from hurricanes and tropical storms

combined ranges from 0.1 inch or 1.8 percent for July to 1.2



















TABLE 4



TROPICAL CYCLONE RAINFALL--ALL STATIONS


NC YRS
CATES RECORD

1919 23 5
1924 28 5
192: 33 5
193 38 5
1939 43 5
1944 48 5
1949 53 5
1954 58 5
1959 63 5
1964 68 5
1969 73 5
1974 78 5


ANNUAL HURR. SEASON *
nEAn (JUNE OCT) ^
RAI;: MEAN ANNI N


52.97
56.26
57.47
53.40
54.75
57.42
53.63
53.19
56.43
53.66
53.23
43.65


HURRICANE RAI: TROP. STORM RAIN IIURR + TROP. ST.
MtEANI A!llN SEA MEAN ', AN I SEA tEAlN ANN SEA


* 33.62
* 37.43
3 36.32
- 34. 1
* 34.83
40.57
* 36.41
32.04
* 37.17
* 38.00
* 33.68
* 32.13


1919 48 30 55.38 36.20 65.4 2.36 5.2 7.9 1.63
1949 78 30 53.14 35.24 66.3 1.25 2.3 3.5 1.34


2.9 4.5 4.45 8.1 12.4
3.5 5.2 3.09 5.8 8.8


1919 78 60 54.26 a 35.72 65.3 2.05 3.3 5.3 1.74 3.2 4.9 3.79 7.0 10.6




TABLE 5



TROPICAL CYCLONE RAINFALL--ARCADIA


ANiUAL HURR.
NO YRS MEAN (JUNE
DATES RECORD RAIN MEAN

1919 23 2 48.97 28.92
1924 28 5 54.54 39.75
1929 33 5 48.93 30.41
1334 38 5 50.52 34.47
1939 43 5 55.30 39.05
1944 48 5 55.95 39.62
1949 53 5 58.98 45.80
1954 58 5 50.02 23.15
1959 63 5 56.45 35.79
1964 68 5 54.18 39.35
1969 73 5 46.94 31.93
1974 78 5 45.12 32.24

1919 48 27 52.75 35.83
1949 78 30 52.28 35.55

.1919 76 57 52.50 : 35.68


SEASON
- OCT)
3 ANN

59.1
72.9
62.2
68.2
70.6
70.8
77.7
56.3
63.4
72.6
65.2
71.5

67.9
63.0

68.0


HURRI CAIIE
MEAN % ANN

1.43 2.9
2.04 3.7
2.23 4.6
1.62 3.2
0.44 0.8
4.68 8.4
2.93 5.0
0.00 0.0
1.63 2.9
2.14 3.9
0.00 0.0
0.00 0.0

2.07 3.9
1.12 2.1

1.60 3.0


RAIN
3 SEA

5.0
5.1
7.3
4.7
1.1
11.8
6.4
0.0
4.5
5.4
0.0
0.0

5.8
3.1

4.5


TROP. STORM RAIN
MEAN % ANN 4 SEA

0.00 0.0 0.0
1.81 3.3 4.5
0.71 1.4 2.3
2.34 4.6 6.8
0.85 1.5 2.2
1.14 2.0 2.9
3.42 5.8 7.5
0.00 0.0 0.0
0.52 0.9 1.5
2.14 4.0 5.4
1.38 2.8 4.3
2.15 4.8 6.7

1.14 2.2 3.2
1.60 3.1 4.5

1.37 2.6 3.8


TABLE 6


TROPICAL CYCLONE RAINFALL--AVON PARK


ANNUAL
0O YRS MEAN
DATES RECORD RAIN

1919 23 5 52.75
1924 26 5 52.16
1923 33 5 55.54
1934 36 5 50.94
1939 43 5 56.00
1944 48 5 59.54
1949 53 5 53.17
1954 58 5 52.26
1959 63 5 58.89
1964 68 5 53.27
1965 73 5 51.70
1974 78 5 46.01

1919 48 30 54.49
1949 78 30 52.;5

1919 78 60 53.52


* HURR. SEASON *
S(JU'IF nCT) *
MEAn1 ANN

* 36.05 68.3
* 33.01 72.9 *
34.93 62.9
S32.14 63.1
* 35.39 63.2
S43.67 73.3
S3,.06 67.8
* 33.14 63.4
* 37.13 63.0
* 36.41 68.3 *
* 34.06 65.9
S31.81 69.1 *

* 36.86 67.6
*34.77 66.2

*35.79 66.9


HURRICANE
MEAN S ANN

1.41 2.7
2.64 5.1
3.21 5.2
0.E2 1.6
1.03 1.8
6.69 11.2
3.51 6.6
0.00 0.0
2.04 3.5
2.11 4.0
0.00 0.0
0.00 0.0

2.63 4.8
I.28 2.4

1.96 3.7


RAIN
3 SEA

3.9
7.0
9.2
2.5
2.9
15.3
9.7
0.0
5.5
5.8
0.0
0.0

7.1
3.7

5.5


TROP. STORM RAIN *


3 ANN

0.0
3.8
1.5
4.3
0.9
1.9
4.6
0.O
3.6
3.6
2. 1
5.7

2.0
3.2

2.6


Z SEA

0.0
5.3
2.3
6.8
1.4
2.6
6.7
0.0
5.3
5.2
3.3
8.3

3.0
4.9

3.9


* HURR
* MEAN

* 1.43
*3.84
* 2.94
* 3.96
S 1.30
* 5.83
* 6.35
* 0.00
* 2.15
* 4.28
* 1.38
2.15

* 3.22
2.72

* 2.97


+ TROP. ST.
3 ANN t SEA

2.9 5.0
7.0 9.7
6.0 9.7
7.6 11.5
2.3 3.3
10.4 14.7
10.8 13.9
0.0 0.0
3.8 6.0
7.9 10.9
2.8 4.3
4.6 6.7

6.1 9.0
5.2 7.7

5.7 8.3


HURR
MEAN

1.41
4.65
4.03
3.00
1.54
7.80
5.95
0.00
4.19
4.01
I. II
2.62

3.74
2.98

3.36


+ TROP. ST.
S ANN % SEA

2.7 3.9
8.9 12.2
7.3 11.5
5.9 9.3
2.8 4.4
13.1 17.9
11.2 16.5
0.0 0.0
7.1 11.3
7.5 11.0
2.1 3.3
5.7 8.3

6.9 10.1
5.7 8.6

6.3 9.4

















TABLE 7



TROPICAL CYCLONE RAINFALL--BARTOW


,:IIIUAL
E.AN
RAIN

53.98
56.74
60. 10
54.77
53.22
57.49
53.72
54.30
63.13
48.03
50.71
46.56

56.38
53.17

54.78


HURR. SEASON
* (JU:E OCT)
* MEAN AIIN

* 33.45 62.0
* 39.96 66.0
* 37.45 62.3
* 32.36 59..1
S32.42 60.9
* 33.01 66.1
S36.75 68.4
* 30.33 56.3
* 38.25 60.6
* 30.94 64.4
* 30.17 59.5
S23.4 600.7

* 35.61 63.2
S32.75 61.6

* 34.18 62.4


HURRICANE
MEAN ; ANN

1.42 2.6
2.26 3.
3.36 5.6
1.13 2.1
0.50 0.9
7.01 12.2
2.68 5.4
0.00 0.0
2.12 3.4
1.67 3.5
0.00 0.0
0.00 0.0

2.61 4.6
1.11 2.1

1.86 3.4


RA I N
. SEA

4.2
5.7
9.0
3.5
1.5
18.5
7.8
0.0
5.5
5.4
0.0
0.0

7.3
3.4

5.5


TROP. STORM
MEAN AfIN

0.00 0.0
2.21 3.8
0.83 1.4
2.75 5.0
0.54 1.0
1.42 2.5
1.13 2.1
0.00 0.0
1.66 2.6
1.34 2.8
O.82 1.6
1.55 3.2

1.29 2.3
1.08 2.0

1.19 2.2


RAIN *
SEA

0.0
5.5 *
2.2
8.5 *
1.7 *
3.7
3.1 *
0.0
4.3 *
4.3 *
2.7
5.3

3.6 *
3.3

3.5


HURR
MEAN

1.42
4.47
4.19
3.88
1.04
8.43
4.00
3.00
3.78
3.01
0.82
1.55

3.91
2.19

3.05


TABLE 8


TROPICAL CYCLONE RAINFALL--BELLE GLADE


AIINUAL
MEAN
RAIN


59.27
59.00
55.01
57.20
64.87
57.36
55.76
56.87
52.35
61 .00
49.85

59.06
55.86

57.21


a* HURR.
* (JUNE
* MEAN

* -----
* 38.84
* 38.34
S37.03
S37.38
* 45.44
* 44.45
* 33.56
* 39.97
* 38.77
S38.56
* 33.17

S39.43
S38.08

* 38.68


SEASON
- OCT) *
SANN *


65.5
65.0
67.3
65.4
70.0
77.5
60.2
67.9
74.1 *
63.2
66.5

66.8
68.2

67.6


HURRICANE
MEAN ANN

0.91 ----
4.03 6.8
3.40 5.8
1.32 2.4
0.25 0.4
8.45 13.0
3.57 6.2
0.00 0.0
1.84 3.1
3.14 6.0
0.00 0.0
0.00 0.0

3.06 5.2
1.42 2.6

2.24 3.9


RAIN *
% SEA


10.4 *
8.9 *
3.6
0.7
18.6 *
8.0
0.0 *
4.6
8.1 *
0.0 *
0.0

7.8 *
3.7 *

5.8 *


TROP. STORM
MEAN % ANN

0.00 ----
2.21 3.7
0.59 1.0
2.90 5.3
1.21 2.1
2.E6 4.4
4.51 7.9
0.00 0.0
2.33 4.0
1.40 2.7
0.51 0.8
1.87 3.8

1.63 2.8
1.77 3.2

1.70 3.0


RAIN *
4 SEA *


5.7
1.5
7.3
3.2
6.3 *
10.1 *
0.0
5.8
3.6
1.3
5.6

4.1
4.6

4.4


HURR
MEAN

0.91
6.24
4.00
4.21
1.46
11.31
8.08
0.00
4.17
4.54
0.51
1.87

4.69
3.19

3.94


TABLE 9



TROPICAL CYCLONE RAINFALL--EVERGLADES CITY


ANNUAL
NO YRS MEAN
DATES RECORD RAIN

119 23 0 -----
1924 26 2 47.13
1929 33 5 57.55
1934 36 5 55.67
1939 43 5 46.76
1944 48 5 58.32
1949 53 5 50.27
15,4 58 5 56.07
1959 63 5 56.53
1964 68 5 54.57
193o 73 5 52.99
1974 76 5 49.99

1919 46 22 53.90
1949 76 30 53.40

1919 76 52 53.61


* HURR. SEASON
* (JUNE OCT)
* EAN A ANII

* ----- ----
* 40.05 85.0
* 40.41 70.2
* 40.86 73.4
* 31.74 67.9
* 42.97 73.7
* 3Z.41 76.4
* 35.59 63.5
S 42.24 74.7
2 42.70 7&.2
* 39.31 74.2
* 37.07 74.2

* 39.09 72.5
39.22 73.4

39.16 73.1


* HURRICANE
* MEAN ANN

* 0.94 ----
S 3.46 7.3
* 3.38 5.9
S 3.34 6.0
S 1.61 3.4
7.01 12.0
S 1.09 2.2
0.00 0.0
S 2.13 3.8
* 2.73 5.0
S0.00 0.0
* 0.00 0.0

* 3.29 6.1
* 0.99 1.9

S 2.14 4.0


RAIN II
SSEA


G.7
8.4
3.2 *
5.1
16.3
2.8
0.0
5.0
6.4 *
0.0
0.0

8.4
2.5

5.5


TROP. STORM
MEAN : ANN

0.00 ----
3.94 8.4
2.08 3.6
5.24 9.4
0.44 3.9
2.58 4.4
2.05 4.1
0.00 0.0
2.97 5.2
2.05 3.8
1.15 2.2
1.22 2.4

2.36 4.4
1.57 2.9

1.9S 3.7


RAIN
. SEA


9.8
5.2
12.8
1.4
6.0
5.3
0.0
7.0
4.8
2.9
3.3

6. 1
4.0

5.0


HURR + TROP. ST.
MEAN ANN SEA

0.94 ---- ---
7.40 15.7 18.5
5.46 9.5 13.5
8.58 15.4 21.0
2.05 4.4 6.5
9.59 16.4 22.3
3.14 6.2 8.2
0.00 0.0 0.0
5.09 9.0 12.1
4.78 8.8 11.2
1.15 2.2 2.9
1.22 2.4 3.3

5.67 10.5 14.5
2.56 4.8 6.5

4.12 7.7 10.5


DATES

1319 23
1 24 26
1325 33
1934 36
139 43
1944 48
1945 53
1354 58
1959 63
19.4 68
1969 73
1974 78

1919 48
1949 78

1919 78


NO YRS
RECORD

S
5
5
S
5
5
5
5
5
5
5
5

30
30

60


+ TROP. ST.
SANN % SEA

2.6 4.2
7.6 11.2
7.0 11.2
7.1 12.0
2.0 3.2
14.7 22.2
7.5 10.9
0.0 0.0
6.0 9.9
6.3 9.7
1.6 2.7
3.2 5.3

6.9 11.0
4.1 6.7

5.6 8.9


NO YRS
RECORD

0
3
4


DATES

1919 -
1924 -
1929 -
1934 -
1939 -
1944 -
1949 -
1954 -
1959 -
1964 -
1969 -
1574 -

1919 -
1949 -

1919 -


+ TROP. ST.
SAtlN t SEA


10.5 16.1
6.8 10.4
7.7 11.4
2.6 3.9
17.4 24.9
14.1 18.2
0.0 0.0
7.1 10.4
8.7 11.7
0.8 1.3
3.8 5.6

7.9 11.9
5.7 8.4

6.9 10.2
















TABLE 10


TROPICAL CYCLONE RAINFALL--FELLSMERE

ANNUAL U IURR. SEASON
NO YRS MEAN (JUNE OCT) HURRICANE RAIN TPOP. STORM RAIN HURR + TROP. ST.
DATES RECORD RAIN MEAN :AN EAN P ANN ME SEA MEAN ,. ANF ; SEA II EAN t ANl ; SEA *

1919 23 5 48.o6 34.25 71.3 0.59 1.2 1.7 0.00 0.0 0.0 0.59 1.2 1.7
1924 28 S 61.67 4 1.62 67.3 4.91 7.9 11.3 3.24 5.2 7.6 8.14 13.2 13.u
1929 33 5 62.06 3 .45 62.0 2.75 4.4 7.2 1.42 2.3 3.7 4.17 6.7 10o.8
1334 38 5 59.49 35.43 64.6 A 0.93 1.6 2.4 2.95 5.0 7.7 3.88 6.5 10. *
1939 43 5 63.39 41.45 64.9 A 0.42 0.7 1.0 1.,6 2.9 4.5 2.29 3.6 5.5
1944 48 5 60.20 45.48 75.6 8.22 13.6 18.1 t 2.57 4.3 5.7 10.79 17.9 23.7 *
1949 53 4 58.25 33.05 67.0 3.90 6.8 10.2 4.24 7.3 10.9 8.23 14.1 21.1 *
1954 58 5 54.96 35.53 64.7 0.00 0.0 0.' 0.00 0.0 0.0 0.00 0.0 0.0 *
1959 63 5 55.48 35.61 64.2 1. 3 2.0 3.2 f 5.03 9.1 14.1 6.16 11.1 17.3
1964 66 4 45.14 33.24 73.6 2.55 5.7 7.7 2.20 4.9 6.6 4.76 10.5 14.3 *
1969 73 3 46.68 30.74 65.9 0.00 0.0 0.0 1.27 2.7 4.1 1.27 2.7 4.1 *
1974 78 3 46.03 29.41 63.9 0.00 0.0 0.0 1.37 3.0 4.7 1.37 3.0 4.7

1519 48 30 59.26 39.95 67.4 2.97 5.0 7.4 2.01 3.4 5.0 4.98 8.4 12.5
1949 78 24 51.83 34*.25 66.1 a 1.28 2.5 3.7 2.35 4.5 6.9 3.63 7.0 10.6

1919 78 54 55.96 37.25 66.6 2.12 3.8 5.7 2.18 3.9 5.9 4.30 7.7 11.6




TABLE 11


TROPICAL CYCLONE RAINFALL--FORT LAUDERDALE

AIINUAL HURR. SEASON *
O0 YRS MEAN (JUNE OCT) HURRICAt'E RAIN TROP. STORM RAIN HURR + TROP. ST.
DATES RECORD RAIN MEAN ANN MEAN 4 ANN SEA IEA!I % ANN SEA MEAN % ANN SEA *

1919 23 5 62.49 37.20 59.5 1.22 2.0 3.3 0.00 0.0 0.0 1.22 2.0 3.3
1924 28 4 66.14 i 40.79 61.7 7.51 11.4 18.4 3.83 5.8 9.4 11.34 17.1 27.8 *
1929 33 5 70.62 45.45 64.4 3.73 5.3 8.2 1.21 1.7 2.7 4.95 7.0 10.9
1934 38 4 58.78 36.33 61.8 1.33 2.3 3.7 2.32 4.8 7.8 4.15 7.1 11.4 *
1939 43 5 54.97 33.94 56.3 0.15 0.3 0.5 1.24 2.3 4.0 1.39 2.5 4.5 *
1944 48 3 71.61 45.70 63.8 9.50 13.3 20.8 1.99 2.8 4.3 11.48 16.0 25.1 *
1949 53 5 54.69 37.54 68.6 1.96 3.6 5.2 3.57 6.5 9.5 5.53 10.1 14.7 *
1954 58 5 62.63 33.33 53.2 0.00 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0 *
1959 63 5 57.38 38.33 66.8 1.74 3.0 4.5 2.91 5.1 7.6 4.65 8.1 12.1 *
1964 68 5 67.92 48.13 70.9 5.37 7.9 11.2 2.21 3.3 4.6 7.58 11.2 15.8
1969 73 5 59.73 33.95 56.3 0.00 0.0 0.0 1.06 1.8 3.1 t 1.06 1.8 3.1 *
1974 78 5 58.76 36.23 61.7 0.00 0.0 0.0 2.62 4.5 7.2 2.62 4.5 7.2

1919 48 26 63.65 39.13 61.5 3.91 6.1 10.0 1.85 2.9 4.7 5.75 9.0 14.7
1949 78 30 60.19 37.32 63.0 1.51 2.5 4.0 2.06 3.4 5.4 3.57 5.9 9.4

1I 19 78 56 61.79 38.50 62.3 2.71 4.4 7.0 1.95 3.2 5.1 4.66 7.5 12.1 *




TABLE 12


TROPICAL CYCLONE RAINFALL--FORT MYERS

ANNUAL HURR. SEASON *
NO YRS MEAN (JUNE OCT) HURRICANE RAIN TROP. STORA RAIN H URR TROP. ST.
DATES RECORD RAIN MEAN ANIN MEAN % ANN .. SEA MEAN % ANN 3 SEA MEAN ; ANN SEA
ft *
1913 83 5 54.76 40.07 73.2 0.98 1.3 2.4 0.00 0.0 0.0 0.98 1.8 2.4 *
1924 28 5 52.07 3 .11 75.1 3.69 7.5 9.9 3.39 6.5 5.7 7.28 14.0 16.6
1329 33 5 52.50 34.33 65.4 2.04 3.3 6.0 2.79 5.3 8.1 4.33 9.2 14.1
1534 38 5 50.01 36.59 73.2 2.48 5.0 6.-. 3.35 6.7 9.2 5.83 11.7 15.9
1939 43 5 53.65 41.19 70.2 0.09 0.2 0.2 0.95 1.6 2.3 1.04 1.8 2.5
1944 48 5 51.47 3 .43 74.7 7.44 14.5 19.4 1.49 2.9 3.9 6.93 17.4 23.2 *
1349 53 5 52.40 42.35 a0.6 1.30 2.5 3.1 3.92 7.5 9.3 5.22 10.0 12.3
1954 58 5 52.77 34.04 64.5 0.00 0.0 0.0 0.00 0.0 0.0 0.00n 0.0 0.0 *
1959 63 5 55.36 39.54 71.4 2.53 4.6 6.4 3.34 6.0 3.5 5.8E 10.6 14.9
1964 68 5 49.67 37.10 74.7 1.bd 3.6 5.1 2.34 4.7 6.3 4.21 8.5 11.4 *
1969 73 5 55.83 37.77 67.7 1 0.00 0.0 0.0 2.13 3.8 5.6 2.13 3.8 5.6 *
1974 78 5 52.03 40.25 77.4 0.00 0.0 0.0 2.48 4.8 6.2 2.48 4.8 6.2
1919 43 30 5..24 33.28 71.9 2.82 5.3 7.4 2.00 3.7 5.2 4.82 9.0 12.6
1949 78 30 53.01 33.51 72.6 0.95 1.6 2.5 2.37 4.5 6.2 3.32 6.3 8.6

1919 78 60 53.13 38.40 72.3 1.9 3.5 4.9 2.13 4.1 5.7 4.07 7.7 10.6

















TABLE 13


TROPICAL CYCLONE RAINFALL--FORT PIERCE


TRrP. STORM1 RAI *
MEA' ANt l SEA *

0.00 3.0 0.0
3.24 6.2 5.6
0.90 1.6 2.8 *
1.31 3.4 5.8 *
2.12 4.0 7.0 *
3.57 6.4 9.7 *
3.06 5.6 8.7 *
0.00 0.0 0.0 *
3.81 6.8 10.3 *
2.35 4.3 7.1 *
0.38 1.6 2.6 *
1.24 2.6 4.4 *

1.94 3.6 6.1 1
1.89 3.6 5.7 *

1.92 3.6 5.9 *


TABLE 14


TROPICAL CYCLONE RAINFALL--HOMESTEAD


TROP. STORM
MEAN % ANN

0.00 0.0
4.10 6.3
1.34 2.1
2.62 4.0
1.59 2.4
1.98 3.0
2.19 3.8
0.30 0.0
2.37 3.6
2.70 4.4
1.02 1.8
1.71 2.9

1.94 3.0
1.66 2.8

1.80 2.9


RAIN
. SEA

0.0
10.1
3.2
5.8
3.3
3.9
5.2
0.0
5.1
5.9
2.5
4.3

4.3
4.0

4.2


TABLE 15


TROPICAL CYCLONE RAINFALL--ISLEWORTH


ANNUAL
NO YRS MEAN
DATES RECORD RAIN

1919 23 4 47.09
1924 28 4 49.48
1923 33 5 52.53
1934 38 5 53.36
1939 43 2 50.46
1544 48 5 58.03
1949 53 5 51.67
1954 58 5 47.83
1959 63 5 57.62
1964 66 5 49.99
1969 73 5 51.39
1974 78 5 47.71

1919 48 25 52.28
1949 78 30 51.04

1919 78 55 51.60


* HURR. SEASON *
(JUNE OCT) HURRICANE RAIN TRCP. STORM RAIN HURR
EAN % ANNl MEAN < ANN SEA MEAN 2 ANN t SEA MEAN

S28.85 61.3 0.94 2.0 3.2 0.00 0.0 0.0 0.94
S30.62 61.9 3.11 6.3 10.2 0.32 1.9 3.0 4.03
S33.04 62.9 3 2.21 4.2 6.7 0.33 0.6 1.0 2.53
S33.05 61.3 0.50 0.9 1.5 3.37 6.3 10.2 3.87
S34.73 63.8 0.28 0.5 0.3 t 0.38 1.8 2.5 1.16
* 41.14 70.9 6.93 11.9 16.9 1.21 2.1 2.9 8.14
* 33.78 65.4 4.45 3.6 13.2 1.17 2.3 3.5 5.62
* 26.C3 56.1 0.00 0.0 0.0 0.00 0.0 0.0 0.00
S 34.28 59.5 1.54 2.7 4.5 1.35 2.3 3.9 2.89
33.06 66.1 3.25 6.5 9.8 2.41 4.8 7.3 5.67
* 23.26 56.9 0.00 0.0 0.0 1.12 2.2 3.8 1.12
* 30.61 64.2 0.00 0.0 0.0 2.24 4.7 7.3 2.24

* 33.66 64.4 2.33 4.5 6.9 1.12 2.1 3.3 3.45
* 31.31 61.3 1.54 3.0 4.9 t 1.38 2.7 4.4 2.92

S32.42 62.8 1.93 3.7 6.0 1.25 2.4 .q i iR


DATES

1919 23
1924 28
1529 33
1934 38
1939 43
1944 48
1949 53
1354 58
1959 63
19b4 68
1969 73
1974 73

1919 48
1949 78

1919 73


10 YRS
RECORD

5
5
5
5
5
5
5
5
5
5
5
5

30
30

60


A'n!IUAL

RA IIN

47.28
52.60
56.99
53.80
52.54
55.91
54.54
51.11
56.130
49.05
55.85
47.88

53.19
52.46

52.82


- HURfR.
S(JU;NE
MEAN

* 26.22
* 33.79
* 32.59
* 31.13
30. 34
*36.8b
* 35.24
* 32.46
* 36.C2
* 32.85
* 33.26
*28.04

* 31.83
* 33.11

* 32.47


SEASON *
- OCT) *
SAtIll

55.5
64.2 *
57.2
57.3
57.8
66.0 *
64.6
63.5
65.4
67.0
59.6
58.6

59.9
63.1

61.5


IlpR I RCAlT E
E All ', AlNN

0.1 2.1
4.86 3.2
2.65 5.0
0.48 0.9
0.29 0.6
7.09 12.7
3.38 6.2
0.00 0.0
1.54 2.7
3.22 6.6
0.00 0.0
0.00 0.0

2.76 5.2
1.36 2.6

2.06 3.9


P Ill *
SEA

3.7
14.4
8.8 *
1.5 5
1.0
19.2 t
9.6 *
0.0 *
4.2 2
9.8
0.0 *
0.0 *

8.7 *
4.1

6.3 *


HURR
MEA N

0.98
10
3.75
2.29
2.42
10.66
6.44
0.00
5.35
5.56
0.88
1.24

4.70
3.25

3.97


* TRnP. ST.
Z ANN SEA

2.1 3.7
1 .4 24.0
6.6 11.5
4.3 7.4
4.6 8.0
19.1 28.9
11.8 18.3
0.0 0.0
9.5 14.5
11.3 16.9
1.6 2.6
2.6 4.4

8.8 14.8
6.2 9.8

7.5 12.2


DATES

1919 23
1924 28
1929 33
1934 38
1939 43
1944 48
1943 53
1954 58
1959 63
19o4 68
1569 73
1974 78

1919 48
1949 78

1919 73


1N YMRS
RECORD

4
1
3
5
5
5
5
5
5
5


53
30


ANNUAL HURRY.
MEAN (JUNE
RAIN MEAN

58.64 37.05
64.92 40.73
64.88 41.91
6 .97 45.02
66.20 47.65
66.87 50.66
57.83 42.27
60.39 36.82
66.63 46.03
61.04 45.63
57.63 40.82
58.93 33.51

64.53 44.67
60.41 41.66

62.20 43.11


SEASON *
- OCT) *
2 AIN

63.2 *
62.7 *
64.6
69.3 3
72.0 *
75.8
73.1 *
61.0 *
69. 1
74.8
70.8
67.1

69.2 *
69.3

69.3


HURRICANE
MEAN % ANN

0.98 1.7
2.56 3.9
3.92 6.0
3.96 6.1
0.17 0.3
8.18 12.2
1.38 2.4
0.00 0.0
1.97 3.0
4.76 7.8
0.00 0.0
0.00 0.0

3.29 5.1
1.35 2.2

2.32 3.7


RAIN
. SEA

2.7
6.3
9.4
8.8
0.4
16.1
3.3
0.0
4.3
10.4
0.0
0.0

7.4
3.2

5.4


HURR
ME AN

0.98
6.66
5.26
6.53
1.76
10.15
3.56
0.00
4.33
7.46
1.02
1.71

5.23
3.01

4.12


+ TROP. ST.
2 ANN : SEA

1.7 2.7
10.3 16.4
8.1 12.5
10.1 14.6
S2.7 3.7
15.2 20.0
6.2 8.4
0.0 0.0
6.5 9.4
12.2 16.3
1.8 2.5
2.9 4.3

8.1 11.7
5.0 7.2

6.6 9.6


+ TROP. ST. *
4 ANN % SEA *




















TABLE 16


TROPICAL CYCLONE RAINFALL--KISSIMMEE


NO YRS
RECORD

2
0
4
5
5
5
5
5
5
5
5
5

21
30

51


ANNUAL M HURRY.
MEAN (JUIE
RAIN MEAN

56.60 33.23
---- 33.76
51.57 283.2
47.46 27.60
50.91 32.55
51.59 34.19
53.51 34.36
48.72 30.54
56.44 35.53
46.65 31.25
46.31 28.12
43.74 29.47

50.92 31.26
49.23 31.65

49.92 31.49


SEASON
- OCT)
, ANII I

53.7

56. *
53.2
63.9 *
66.3 *
65.3 *
62.7
63.0
67.0
60.7 *
67.4

61.4 *
64.3

63.1 *


HURRICANE
MEAN :, ANN

1.35 2.4
2.10 ----
2.79 5.4
0.74 1.6
0.33 0.6
S.30 16. 1
4.15 7.3
0.00 0.0
1.62 2.9
2.29 4.9
0.00 0.0
0.00 0.0

2.60 5.1
1.34 2.7

1.97 4.0


RAI I
, SEA

4. 1
6.2
9.6
2.7
1.0
24.3
11.9
0.0
4.6
7.3
0.0
0.0

8.3
4.2

6.3


TROP. STORM
MEAN ., AMN

0.00 0.0
1.40 - -
0.23 0.4
3.03 6.4
1.24 2.4
0.71 1.4
1.71 3.2
0.00 0.0
2.32 4.1
2.71 5.8
0.83 1.8
1.93 4.4

1.10 2.2
1.58 3.2

1.34 2.7


RA III
SEA

0.0
4. 1
0.8
11.0
3.8
2. 1
4.9
0.0
6.5
8.7
2.9
6.5

3.5
5.0

4.3


IIURR
MEAN

1.35
3.49
3.02
3.77
1.56
9.01
5.86
0.00
3.94
5.00
0.83
1.93

3.70
2.93

3.31


* TROP. ST.
A ANN SEA

2.4 4.1
---- 10.3
5.9 10.4
7.9 13.7
3.1 4.8
17.5 26.3
11.0 16.8
0.0 0.0
7.0 11.1
10.7 16.0
1.8 2.9
4.4 6.5

7.3 11.8
5.9 9.2

6.6 10.5


TABLE 17


TROPICAL CYCLONE RAINFALL--LA BELLE


NO YRS
RECORD

0
0
2
5
5
5
5
5
5
5
5
5

17
30

47


ANNUAL
ME A0
RAIN



48.56
45.45
48.22
59.21
53.64
54.05
52.63
55.80
49.67
44.67

50.68"
51.74

51.36


SHURR.
* (JUNE
* MEAN



* 30.73
* 31.73
* 29.73
* 45.34
S41.30
* 31.99
* 34.35
* 41.09
* 30.91
* 30.75

*35.03
* 35.25

35.17


SEASON
- OCT)
4 ANN



63.3
69.3
61.7
76.6
77.9
59.2
66.4
73.6
62.2
68.3

69. 1
68.1

63.5


HURRICANE
MEAN 4 ANN

0.75 -
3.62 --
3.06 6.3
1.61 3.5
0.20 0.4
7.14 12.1
1.33 2.5
0.00 0.0
1.70 3.2
1.77 3.2
0.00 0.0
0.00 0.0

2.73 5.'4
0.30 1.5

1.77 3.4


RAIN
S SEA



10.0
5. 1
0.7
15.7
3.2
0.0
4.9
4. 3
0.0
0.0

7.8
2.3

5.0


TROP. STORM
MEAN ; ANN

0.00 ----
2.49
2.31 4.8
4.53 10.0
0.55 1.1
1.51 2.6
4.12 7.7
0.00 0.0
1.97 3.3
1.70 3.0
0.69 1.4
2.47 5.5

1.90 3.7
1.82 3.5

1.86 3.6


RAIN *
S SEA *



7.5
14.3 *
1.9
3.3 *
9.8
0.0
5.6
4. 1
2.2
8.0

5.4
5.2

5.3 *


HURR
MEAN

0.75
6.10
5.37
6.14
0.75
8.65
5.44
0.00
3.68
3.47
0.69
2.47

4.63
2.62

3.63


+ TROP. ST. *
O ANN 6 SEA *



11.1 17.5 *
13.5 19.4 *
1.6 2.5 *
14.6 19.1 *
10.1 13.0
0.0 0.0 *
7.0 10.5 .
6.2 8.4 *
1.4 2.2
5.5 8.0 *

9.1 13.2 *
5.1 7.4 *

7.1 10.3 *


TABLE 18


TROPICAL CYCLONE RAINFALL--MIAMI


ANNUAL
NO YRS MEAN
DATES RECORD RAIN

1919 23 5 52.29
1924 28 5 58.23
1925 33 5 72.94
1934 38 5 59.05
1939 43 5 56.40
1944 48 5 45.69
1949 53 5 52.37
1954 58 5 56.68
1959 63 5 57.93
1964 68 5 70.05
1969 73 5 56.66
1974 7S 5 50.96

1919 48 30 57.43
1949 78 30 57.52

1919 78 60 57.48


* HURR.
* (JUiNE
* MEAN

* 30.66
* 36.22
* 47.01
* 37.96
33.40
* 30.10
S37.42
* 32.93
* 38.49
* 50.17
* 36.62
30. 11

S35.89
37.62

36.76


SEASON
- OCT)
i ANN

58.6
62.2
64.5
64.3
59.2
65.9
70.8
53. I
66.4
71.6
64.6
59. 1

62.5
65.4

64.0


HURRICANE
MEAN 4 ANN

0.35 0.7
3.84 6.6
4.72 6.5
1.39 3.4
0.11 0.2
4.45 9.7
1.77 3.4
0.00 0.0
2.31 4.0
5.96 8.5
0.00 0.0
0.00 0.0

2.58 4.5
1.67 2.9

2.13 3.7


RAIN *
4 SEA *
I. o
10.6 *
10.0 *
5.2
0.3 *
14.8 *
4.7 *
0.0
6.0 *
11.9
0.0 a
0.n,

7.2
4.4

5.8 *


TROP. STORM
ItEA'I ANN

0.00 0.0
3.33 6.7
2.41 3.3
3.11 5.3
0.32 0.6
1.46 3.2
3.05 5.8
0.01 0.0
3.99 6.9
3.10 4.4
2.03 3.7
1.36 2.7

1.86 3.2
2.26 3.3

2.0r, 3.6


RAIN *
; SEA

0.0 *
10.7 *
5. 1
8.2 *
1.0 *
4.9
8.1 *
0.0 *
10.4
6.2 *
5.7
4.5

5.2 *
6.0

5.6 *


HURR
MEAN

0.35
7.72
7. 13
5. 10
0.43
5.91
4.82
0.00
6.30
9.06
2.03
1. 36

4.44
3.94

4.19


+ TROP. ST. *
O ANN 4 SEA *

0.7 1.1 *
13.3 21.3 *
9.8 15.2 *
8.6 13.4 *
0.8 1.3 *
12.9 19.6 *
9.1 12.9 *
0.0 0.0 *
10.9 16.4
12.9 1I I
3.7 5.7 *
2.7 4.5

7.7 12.4 a
6.8 10.5

7.3 11.4


DATES

1919 23
1924 23
1929 33
1934 38
1939 43
1944 46
1949 53
1954 58
1959 63
1964 68
1969 73
1974 78

1919 48
1949 78

1919 78


DATES

1919 -
1924 -
1925 -
1934 -
1939 -
1944 -
1949 -
1554 -
1959 I
1964 I
1969 i
1974 -

1919 '
1949 -

1919 7




















TABLE 19


TROPICAL CYCLONE RAINFALL--MOORE HAVEN


TROP. STORM RAIN


' ANN

0.0
3.9
3. 1
5.4
2.0
3.8
7.4
0.0
3.6
3.6
2.4
4.1

3.0
3.5

3.3


4 SEA

0.0
5.3
4.7
8.4
3. 1
5.2
10. 1
0.0
5.6
5. 1
3.6
6.0

4.4
5.2

4.8


HURR
MEAt4

0.64
4.73
3.78
3.65
1. 39
8.46
5.97
0.00
3.89
3.78
1.23
1.94

3.78
2.80

3.29


* TROP. ST. *
SAiNN 4 SEA

1.2 1.3 *
9.3 12.6
7.3 1.1 *
7.6 11.8 *
2.7 4.3 *
16.9 23.3 *
11.6 15.7 7
0.0 0.0 *
7.7 11.3 *
8.2 11.5 *
2.4 3.6 *
4.1 6.0 *

7.5 11.0
5.7 8.4 *

6.6 9.7


TABLE 20


TROPICAL CYCLONE RAINFALL--OKEECHOBEE


ANNUAL HIURR.
MEAN *(JUNE
RAIN MEAN

46.25 26.72
----- 31.36
49.19 33.71
50.37 31.50
49.09 25.51
43.09 23.93
46.58 33.13
49.96 30.45
46.21 31.04
44.57 32.21
48.95 30.37
35.26 21.54

48.96 30.29
45.60 30.07

46.97 3 30.18


SEASO:I
- OCT)
: ANN

57.3

68.5
62.9
58.1
60.2
71.1
61.0
67.2
72.3
62.0
61.1

61.9
66.0

64.2


HURRICANE
MEAN A ANN

0.40 0.9
4.11
4.10 8.3
0.97 1 .9
0.74 1.5
5.73 11.9
2.92 6.3
0.00 0.0
0.61 1.3
2.73 6.1
0.00 0.0
0.00 0.0

2.68 5.5
1.04 2.3

1.86 4.0


RAIN
4 SEA

1.5
13. 1
12.2
3.1
2.6
19.8
8.8
0.0
2.0
8.5
0.0
0.0

8.8
3.5

6.2


TROP. STORM
MEA:I AINN

0.00 0.0
1.19 ----
1.44 2.9
2.99 6.0
1.31 2.7
0.90 1.9
4.09 8.8
0.00 0.0
3.03 6.6
1.52 3.4
1.13 2.3
1.28 3.6

1.31 2.7
1.84 4.0

1.57 3.4


RA I
, SEA

0.0
3.8
4.3
9.5
4.6
3. 1
12.3
0.0
9.8
4.7
3.7
5.9

4.3
6. 1

5.2


HURR + TROP. ST.
MEAN % ANN % SEA

0.40 0.9 1.5
5.31 ---- 16.9
5.54 11.3 16.4
3.96 7.9 12.6
2.05 4.2 7.2
6.63 13.8 22.9
7.01 15.1 21.2
0.00 0.0 0.0
3.64 7.9 11.7
4.26 9.6 13.2
1.13 2.3 3.7
1.28 3.6 5.9

3.98 8.1 13.1
2.89 6.3 9.6

3.43 7.3 11.4


TABLE 21


TROPICAL CYCLONE RAINFALL--ORLANDO


ANNUAL
NO YRS MEAN
DATES RECORD RAIN;

1919 23 5 53.56
192'4 28 5 52.45
1329 33 5 51.64
1934 33 5 49.14
1939 43 5 51.36
1944 48 5 55.00
1949 53 5 53.10
1554 58 5 47.65
1959 63 5 53.93
1964 68 5 50.04
1969 73 5 49.19
1974 78 5 45.'43

1913 48 30 52.22
1949 76 30 49.90

1913 76 6 51i.06


" HURR.
* (JUrIE
* MEAN

* 32.65
* 33.39
* 31.35
* 30.43
* 32.56
* 39.36
* 34.58
* 30.99
* 34.48
* 32.42
* 23.14
*30. Il

S33.38
* 312.6

- 32.67


SEASON
- OCT)


61.0
63.4
60. 7
62.0
63.4
72.5
65. 1
65.0
63.3
64.8
59.2
66.3

63.9
64.3

64.0


HURRICANE
MEAN ANN

2.29 4.3
2.10 4.0
2.79 5.4
0.41 0.3
0.27 0.5
6.39 15.3
5.24 9.9
o.oo o.o
0.31 1.5
2.63 5.3
0.00 0.3
0.00 0.0

2.71 5.2
1.45 2.9

2.03 4.1


RAI N
3 SEA

7.0
6.3
3.9
1.3
0.8
21.0
15. 1
0.0
2.3
8.1
0.0
0.0

C. 1
6.5

6.4


TROP. STOPR RAINi
MEAN ANN 11 SEA

0.00 0.0 0.0
2.3. 4.5 7.1
0.12 0.2 0.4
3.57 7.3 11.7
1.27 2.5 3.9
0.8 1.8 2.5
1.74 3.3 5.0
0.00 o.0 0.0
1.69 3.1 4.9
3.74 7.5 11.5
0.31 1.6 2.8
2.33 5.1 7.7

1.39 2.7 4.2
1.72 3.4 5.4

1.55 3.0 4.8


DATES

1919 23
1924 28
1929 33
1934 38
1939 43
1944 48
1949 53
1954 58
1959 63
1964 68
1969 73
1974 78

1919 48
1949 78

1919 78


NO YRS
RECORD

4
4
5
5
5
5
5
5
5
5
S
5
5

28
30

58


ANNUAL
MEAN
RAIN

52.67
51.03
51.46
48. 10
50.33
50.11
51 .33
49.96
50.83
46.12
50.80
47.75

50.62
49.47

50.02


; HURRY.
* (JUINE
* ME AN

* 35.31
* 37.44
* 34.09
* 30.94
* 32.61
* 36.45
* 37.92
S30.18
32.83
S32.83
* 34.42
32. 14

* 34.41
33.39

* 33.38


SEASON
- OCT)
, ANN

68.0
73.4
66.2
64. 3
64. I
72.7
73.9
60.4
64.6
71.2
67.3
67.3

68.0
67.5

67.7


HURRI CANE
MEAN 4; ANN

0.64 1.2
2.75 5.4
2.19 4.2
1.04 2.2
0.40 0.8
6.59 13.2
2.15 4.2
0.00 0.0
2.04 4.0
2.11 4.6
0.00 0.0
0.00 0.0

2.27 4.5
1.05 2.1

1.66 3.3


RA I!
SEA

1.3
7.3
6.4
3.4
1.2
18. 1
5.7
0.0
6.2
6.4
0.0
0.0

6.6
3.1

4.9


DATES

1919 -
1924 -
1929 -
1934 -
1939 -
1944 -
1949 -
1954 -
1959 -
1964 i
1969 -
1974 ;

1919 4
1949 -

1919 -


NO YRS
RECORD

1
0
4
5
5
5
5
5
5
5
5
4

20
29

49


HURR
MEAN

2.29
4.48
2.92
3.98
1 .54
9.37
6.9d
0.00
2.50
6.38
0.81
2.33

4.10
3.17

3.63


+ TROP. ST.
% ANN t SEA

4.3 7.0
8.5 13.4
5.7 9.3
8.1 13.1
3.0 4.7
17.0 23.5
13.1 20.2
0.0 0.0
4.6 7.2
12.7 19.7
1.6 2.8
5.1 7.7

7.8 12.3
6.3 9.9

7.1 1.11











57










TABLE 22


TROPICAL CYCLONE RAINFALL--PUNTA GORDA

AIINUAL IIURR. SEASON
110 YRS MEAN (JUIE OCT) IIURrICAIIE RAI: TROP. STORM RAI HURR + TROP. ST.
DATES RECORD RAIN MEAlI ANN EA; AIIll SEA rEAN % AmN SEA MEAN S ANN S SEA *
1519 23 3 52.58 36.72 63.8 1.21 2.3 3.3 0.00 0.0 0.0 1.21 2.3 3.3
1924 28 4 53.55 *37.93 70.9 0.63 1.3 1.8 3.76 7.0 9.9 4.44 8.3 11.7 *
1929 33 5 50.41 32.92 65.3 2.15 4.3 6.5 1.46 2.9 4.4 3.60 7.1 10.9 *
1934 38 5 50.15 34.17 66.1 3.11 6.2 9.1 2.53 5.0 7.4 5.64 11.2 16.5
1939 43 5 51.48 34.23 .6.5 0.35 0.7 1.0 1.26 2.5 3.7 1.61 3.1 4.7
1944 48 5 57.66 42.14 73.1 6.11 10.6 14.5 1.05 1.8 2.5 7.17 12.4 17.0
1549 53 5 49.56 36.68 76.1 *. 2.75 5.5 7.1 4.03 8.1 10.4 6.78 13.7 17.5
1954 58 5 49.40 31.27 63.3 0.00 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0
1959 63 5 57.37 38.36 66.9 2.36 4.1 6.2 2.41 4.2 6.3 4.77 8.3 12.4
1964 68 4 45.75 33.71 73.7 1.46 3.2 4.3 2.12 4.6 6.3 3.58 7.8 10.6
1569 73 5 49.31 31.40 63.7 0.00 0.0 0.0 0.97 2.0 3.1 0.97 2.0 3.1
1974 78 5 45.37 32.63 71.9 0.00 0.0 0.0 2.64 5.8 8.1 2.64 5.8 8.1
1919 48 27 52.61 36.33 69.1 2.27 4.3 6.2 1.68 3.2 4.6 3.95 7.5 10.9 *
1949 78 29 49.59 34.36 69.3 1.09 2.2 3.2 2.03 4.1 5.9 3.12 6.3 9.1

1919 78 56 51.05 35.33 69.2 1.68 3.3 4.8 1.35 3.6 5.2 3.53 6.9 10.0




TABLE 23


TROPICAL CYCLONE RAINFALL--WEST PALM BEACH

ANNUAL IIURR. SEASON *
NO YRS MEAN (JUE OCT) HURRICANE RAIN TROP. STORM RAIN HURR + TROP. ST.
DATES RECORD RAIN MEAN 6 ANII MEAN ANN ; SEA -* EAN ANN Z SEA MEAN ANN % SEA *
*
1919 23 5 56.87 34.81 61.2 1.18 2.1 3.4 0.00 0.0 0.0 1.18 2.1 3.4
1924 28 .2 67.83 33.39 50.0 5.33 7.9 15.7 1.76 2.6 5.2 7.09 10.5 20.9 *
1929 33 5 66.55 40.53 60.3 7.72 11.6 19.0 1.49 2.2 3.7 9.21 13.8 22.7
1934 38 5 58.33 32.13 55.1 0.70 1.2 2.2 3.04 5.2 9.4 3.74 6.4 11.6 *
1939 43 5 64.&0 37.05 57.2 0.51 0.6 1.4 1.07 1.7 2.9 1.58 2.4 4.3
1944 48 S 70.98 47.59 67.0 8.66 12.2 1 .2 2.51 3.5 5.3 11.17 15.7 23.5
1949 53 5 56.31 39.56 70.3 3.27 5.8 6.3 3.16 5.6 8.0 6.43 11.4 16.2
1954 58 5 55.41 29.92 54.0 0.00 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0
155 63 5 55.01 36.58 66.5 0.94 1.7 2.6 3.61 6.6 9.9 4.55 8.3 12.4
1964 68 5 69.25 46.66 70.3 3.51 5.1 7.2 3.17 4.6 6.5 6.68 9.6 13.7
1969 73 5 63.25 36.92 58.4 0.00 0.0 0.0 1.04 1.6 2.8 1.04 1.6 2.8
1974 78 5 56.93 3 31.10 54.6 0.00 0.0 0.0 1.86 3.3 6.0 1.86 3.3 6.0
1519 48 27 63.83 37.80 59.2 4.02 6.3 10.6 1.65 2.6 4.4 5.66 8.9 15.0
1949 78 30 59.36 37.12 62.5 1.29 2.2 3.5 2.14 3.6 5.8 3.43 5.8 9.2 *
1919 78 57 61.48 37.45 60.9 2.65 4.3 7.1 1.89 3.1 5.1 4.54 7.4 12.1



















TABLE 24



JUNE RAINFALL--ALL STATIONS


AIIN UAL *
NO YRS MEAN
DATES RECORD RAIZI

1919 23 5 52.97
1924 28 5 56.26
1929 33 5 57.47 *
1934 38 5 53.40
1939 43 5 54.75
1944 48 5 57.42
1949 53 5 53.63
1954 58 5 53.19
1959 63 5 56.48
1964 68 5 53.66
1969 73 5 53.23
1974 78 5 48.65

1919 48 30 55.38
1949 78 30 53.14 *

1919 78 60 54.26


TOTAL
MEAN ANN

6.8 12.9 *
7.0 12.4 *
8.2 14.3 *
9.0 16.9 *
9.0 16.5 *
8.1 14.1 *
6.6 12.3
7.0 13.1
9.1 16.2 *
10.8 20.2 *
3.1 15.3 *
8.2 16.9 *

8.0 14.5 *
8.3 15.6 *

8.2 15.1 *


HURRICANE TROP STORM *
MEAN : MO MEAN MO *H

0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
0.0 0.0 a 0.0 0.0
0.0 0.0 1.2 12.9 *
0.0 0.0 0.0 0.0 *
1.3 16.1 0.0 0.0
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
0.0 0.0 1.6 17.2
0.8 6.9 2.1 19.0 *
0.0 0.0 0.0 0.0 *
0.0 0.0 1.3 16.4

0.2 2.7 0.2 2.4 *
0.1 1.5 0.8 10.0

0.2 2.1 0.5 6.3 *


TABLE 25


JULY RAINFALL--ALL STATIONS


ANNUAL *
NO YRS MEAN
DATES RECORD RAIN *

1919 23 5 52.97 *
1924 28 5 56.26 *
1929 33 5 57.47 *
1934 38 5 53.40 *
1939 43 5 54.75 *
1944 48 5 57.42 *
1949 53 5 53.63 *
1954 58 5 53.19 *
1959 63 5 56.48 *
1964 68 5 53.66 *
1969 73 5 53.23
1974 78 5 48.65

1919 48 30 55.38 *
1949 78 30 53.14

1319 78 60 54.26 *


TOTAL
MEAI A ; ANN

7.6 14.3 *
8.4 14.9 *
6.4 11.1 *
7.1 13.4 *
7.8 14.3 *
9.0 15.7
7.5 14.0
6.9 13.0 *
6.9 12.1
7.5 14.0
7.0 13.2
8.0 16.4

7.7 13.9
7.3 13.8

7.5 13.9


HURRICANE TROP STORM *
MEAN 11t0 MEA; MO

0.0 0.0 0.0 0.0
0.4 4.3 0.0 0.0 *
0.6 9.1 0.0 0.0 *
0.2 3.0 0.4 6.0 *
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0 *
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0 *
0.0 0.0 0.0 0.0
0.0 .0 0.0 0.0
0.0 0.0 0.0 0.0

0.2 2.5 0.1 0.9
0.0 0.0 0.0 0.0

0.1 1.3 0.0 0.5


TABLE 26



AUGUST RAINFALL--ALL STATIONS


ANflUAL
NO YRS MEAN
DATES RECORD RAIN

1919 23 5 52.97
1924 28 5 56.26
1929 33 5 57.47
1334 38 5 53.40 *
1939 43 5 54.75
1944 48 5 57.42
1949 53 5 53..63
1 54 58 5 53.19
1559 63 5 56.48
1364 68 5 53.66
1969 73 5 53.23
1974 78 5 48.65

1919 48 30 55.38
1949 78 30 53.14

1919 78 60 54.26


TOTAL HURRICANE *
MEAN t ANN HEAN L MO

6.1 11.6 0.0 0.0
8.6 15.3 0.9 10.9 *
7.3 12.6 0.1 1.9 *
5.8 10.8 0.0 0.0
7.0 12.7 0.4 5.0 a
7.3 12.6 0.0 0.0 *
8.5 15.9 0.9 10.6 *
6.4 12.1 0.0 0.0
6.9 12.2 0.0 0.0 *
7.2 13.3 0.5 6.4 *
7.5 14.1 0.0 0.0
6.5 13.3 0.0 0.0

7.0 12.6 0.2 3.4 *
7.2 13.5 0.2 3.2

7.1 13.1 0.2 3.3


TROP STORM HURR C TS
MEAN I MO MEAN S MO

0.0 0.0 0.0 0.0 *
0.6 7.3 1.6 18.2 *
0.7 10.3 0.9 12.2 *
0.5 C.4 0.5 8.4 *
0.3 3.9 0.6 8.9
0.2 3.0 0.2 3.0 *
0.7 8.6 1.6 19.3
0.0 0.0 0.0 0.0 *
0.2 2.7 0.2 2.7 *
0.2 2.6 0.6 9.0 *
0.2 2.5 0.2 2.5 *
0.5 7.2 0.5 7.2 *

0.4 5.6 0.6 9.0
0.3 4.1 0.5 7.3
0.3 4.8 .6 8.
0.3 4.8 0.6 8.1


HURR & TS *
MEAN t MO *

0.0 0.0 *
0.0 0.0 *
0.0 0.0 *
1.2 12.9 *
0.0 0.0
1.3 16.1
0.0 0.0 *
0.0 0.0 *
1.6 17.2 *
2.8 25.9 *
0.0 0.0 *
1.3 16.4 *

0.4 5.1 *
1.0 11.5

0.7 8.4 *


HURR & TS *
MEAN X MO *

0.0 0.0 *
0.4 4.3 *
0.6 9.1 *
0.6 9.0 *
0.0 0.0 *
0.0 0.0 *
0.0 0.0 *
0.0 0.0 *
0.0 0.0 *
0.0 0.0 *
0.0 0.0 *
0.0 0.0 *

0.3 3.4 *
0.0 0.0 *

0.1 1.8 *






















TABLE 27


SEPTEMBER RAINFALL--ALL STATIONS


ANNUAL *
NO YRS MEAN
DATES RECORD RAIN

1919 23 5 52.97
1924 23 5 56.26
1929 33 5 57.47
1934 38 5 53.40
1939 43 5 54.75
1944 48 5 57.42 *
1949 53 5 53.63
1954 58 5 53.19
1959 63 5 56.48 *
1964 68 5 53.66
1969 73 5 53.23
1974 78 5 48.65

1919 48 30 55.38
1949 78 30 53.14 *

1919 78 60 54.26


TOTAL HURRICANE
MEAN A; ANN MEATL MO *

6.7 12.6 0.5 7.8 *
7.3 13.9 0.7 8.9 *
9.1 15.8 2.1 23.1
7.7 14.4 1.2 15.0
7.5 13.7 o.o 0.0 *
10.5 18.2 3.3 31.8 *
8.1 15.1 0.8 9.5 *
7.0 13.2 0.0 0.0
9.9 17.5 1.0 10.4 *
6.8 12.6 0.6 9.5 *
6.3 11.8 0.0 0.0 *
6.7 13.8 0.0 0.0

8.2 14.8 1.3 15.S
7.5 14.0 0.4 5.5
7.* 0.9 .
7.8 14.4 0.9 10.9


TABLE 28


OCTOBER RAINFALL--ALL STATIONS


ANNUAL *
NO YRS MEAN
DATES RECORD RAIN

1919 23 5 52.97
1924 28 5 56.26
1929 33 5 57.47
1934 38 5 53.40
1939 43 5 54.75
1944 48 5 57.42
1949 53 5 53.63
1954 58 5 53.19
1959 63 5 56.48
1964 68 5 53.66
1969 73 5 53.23
1974 78 5 48.65

1919 48 30 55.38
1949 78 30 53.14 *

1919 78 60 54.26


TOTAL HURRICANE *
HEAN i ANN MEAN % MO *

6.4 12.1 0.6 8.9 *
5.6 10.0 a 1.5 27.3
5.3 9.3 0.5 9.6 *
4.7 8.9 0.0 0.0
3.5 6.4 0.1 3.0 *
5.7 10.0 2.6 45.3
7.7 14.3 1.1 14.9
4.7 8.8 0.0 0.0 *
4.4 7.8. 0.7 15.6 *
5.7 10.6 1.1 18.6 *
4.7 8.8 0.0 0.0
2.8 5.7 0.0 0.0

5.2 9.4 0.9 17.0 *
5.0 9.4 0.5 9.7

5.1 9.4 0.7 13.4


TROP STORM
MEAN MO *

0.0 0.0 *
1.3 16.7
0.5 5.7 *
0.0 0.0 *
0.3 4.6 *
1.0 9.7 *
0.0 0.0 a
0.0 0.0 *
0.8 6.5 *
0.1 1.1 1
0.5 8.0 *
0.0 0.0 *

0.5 6.5 *
0.2 3.2 *

0.4 4.9 *


HUIRR c TS *
MEAN MO *

0.5 7.8
2.0 25.7
2.6 28.8 *
1.2 15.0 *
0.3 4.6 *
4.3 41.5 *
0.8 9.5 *
0.0 0.0 *
1.9 18.9 *
0.7 10.6 *
0.5 8.0 *
0.0 0.0 *

1.8 22.3
0.6 8.6 *

1.2 15.8 *


TROP STORM *
MEAN % MO *

0.0 0.0 *
0.0 0.0 *
0.0 0.0 *
0.6 12.7 *
0.5 13.7 *
0.2 3.4 *
2.0 25.7 *
0.0 0.0 *
0.0 0.0 *
0.0 0.0 *
0.5 9.9 *
0.1 5.4

0.2 4.1 *
0.4 8.7 *

0.3 6.3


HURR G TS *
MEAN % MO

0.6 8.9 *
1.5 27.3 *
0.5 9.6 *
0.6 12.7 *
0.6 16.7 *
2.8 48.7 *
3.1 40.6 *
0.0 0.0 *
0.7 15.6 *
1.1 18.6 *
0.5 9.9 *
0.1 5.4 *

1.1 21.1 *
0.9 18.3 *

1.0 19.7












TABLE 29


NUMBER OF HURRICANES AND TROPICAL STORMS PER

JUNE I JULY AUC. SEPT. OCT. OTHER TOTAL
YEAR H TS H TS H TS H TS II TS I; TS II TS ALL


I* I 1 1


1919
1920
1921
1922
1923

1924
1925
1526
1927
1928

1929
1930
1931
1932
1933

1934
1935
1936
1937
1938

1939
1940
1941
1942
1943

1944
1945
1946
1947
1948

1949
1950
1951
1952
1953

1954
1955
1956
1957
1958

1959
1560
1961
1362
1963

1964
1965
1966
1967
1663

1969
1970
1971
1972
1973

1974
1975
1976
1977
1978


I


YEAR


2 6 9 6 11 5 1 2 27 22 49
3 5 4 6 5 5 1 1 14 23 37
5 11 13 12 16 10 2 3 41 45 86


1


2









1




1 1

1 I
1


1











1 1




2


1919-4a
1949-76
1919-78


Nov 1










May 1
1 Nov


















1 May
Feb 1


































D
e


.9*tt*


MEAN RAINFALL 1919-1978
IN INCHES


THE SOUTH FLORIDA


WATER


MANAGEMENT DISTRICT


FIGURE 5

MEAN RAINFALL 1919-1978
HURRICANES AND TROPICAL STORMS


































aI
e


HURRICANES 8
TROPICAL STORMS


MEAN RAINFALL 1919-1978
IN INCHES


THE SOUTH FLORIDA


WATER MANAGEMENT DISTRICT


FIGURE 6

MEAN RAINFALL 1919-1978
HURRICANES & TROPICAL STORMS AND


lO


ANNUAL








inches or 15.8 percent for September and 1.0 inch or 19.7

percent for October.

The above figures correspond closely to the findings of

Cry (1967) for this region for 1931 through 1960. The

present study, however, provides more detail regarding South

Florida. Cry treated the entire eastern and southern coasts

of the United States and used data from only four stations

in South Florida: Bartow, Belle Glade, Homestead, and Key

West.

Although data for individual storms may at times reveal

quite high amounts of rainfall, such as 12.50 inches on June

14, 1936, at Everglades City and 18.75 inches for June 14

and 15 combined at the same station, incidences of very high

rainfall associated with tropical cyclones are in fact

relatively rare. In most years little or no rainfall

attributable to tropical cyclones falls at any given

station. When years of low tropical cyclone rainfall are

averaged with the years of very high rainfall, the resulting

mean is far lower than the few high values would seem to

indicate. The rainfall which resulted from the hurricane of

June 14 and 15, 1936, equaled 34.9 percent of the sixty-year

annual mean for that station and 28.6 percent of the total

65.52 inches which fell in that year. Both of these

percentages are much higher than the 7.7 percent per year

long term mean for combined hurricane and tropical storm

rainfall at that location.









Possible Indications of Climatic Change

Examining the temporal frequency of tropical cyclones

(Table 29) and the amount of rain which they have brought

during each of the sixty years under study (Table 30 and

Figure 7) discloses that no rain from hurricanes fell during

the last ten years of the study period. A similarly long

time without hurricanes occurred in the mid-1950s, including

a five-year interval from 1954 through 1958 in which neither

hurricanes nor tropical storms influenced the area. Another

interval of low hurricane activity is found from 1937

through 1943, and a time of no tropical storms is found

during the first six years of the study period.

Although temporal patterns may not be apparent to the

eye, a time series analysis of rainfall, carried out by

Isaacs (1980) for eight Florida cities, including three

stations used in the present study, found that rainfall

cycles could be identified and that peak rainfall years were

closely associated with tropical weather systems. Isaacs

observed cyclical periodicities for rainfall of 7.5 years

for Fort Myers, 5.0 years for Fort Lauderdale, and 5.0 to

5.5 years for Orlando.

Correlations of seasonal and annual rainfall with

tropical cyclone rainfall, and with number of tropical

cyclones per year (Table 31) demonstrate that significant

relationships can be found between the occurrence of

tropical cyclones and the amount of rain which falls in a

given year. Thus, if a tendency for fewer tropical systems









to strike the region can be verified, there should be a

concomitant decrease in overall rainfall.

Evidence for climatic variation is found in the

differences observed in mean rainfall for the first thirty

years compared to the last thirty years. A t-test (Table

32) has been applied to the pairs of thirty-year samples in

order to determine if the observed differences were the

result of random chance. Total annual rainfall, rain from

hurricanes and combined rain from hurricanes and tropical

storms are all found to be significantly lower during the

second thirty-year interval.

The differences between these means and the

aforementioned close association between total rainfall and

the occurrence of tropical systems strongly suggest that

there was a tendency for less rain to fall in South Florida

during the last thirty years and that the decrease is

closely related to a decline in hurricane activity. The

difference between the annual means for the two intervals is

2.24 inches and the difference between the hurricane season

means is .96 inches. The 1.60 inch drop in rainfall from

hurricanes during this period accounts for more than the

amount by which seasonal rainfall declined and most of the

decline in annual rainfall. The decline in hurricane

rainfall was so much greater than the slight increase in

tropical storm rainfall that it makes a significant decline

in combined hurricanes znd tropical storm rainfall. A

similar pattern is found for mean rain per storm (Table 33).










66







TABLE 30


TROPICAL CYCLONE RAINFALL BY YEAR--ALL STATIONS

ANIIUAL HURR. SEASOII
t (JUliE OCT) *
NO YRS TOTAL HURRICANE RAIN TROP. STORII RAIN HURR + TROP. ST.
DATES RECORD RAIN TOTAL ANN TOTAL I ANN SEA TOTAL ; AIJNN SEA TOTAL AMHN % SEA

1919 1 55.02 28.49 51.b 0.92 1.7 3.2 0.00 0.0 0.0 0.92 1.7 3.2
1920 54.49 32.72 60.0 1.67 3.1 5.1 0.00 0.0 0.0 1.67 3.1 5.1 *
1921 47.13 29.39 63.4 2.66 6.1 9.6 0.00 0.0 0.0 2.86 6.1 9.6
1922 56.81 44.10 75.0 .0 0.00 0.0 0.0 0.00 0.0 0.00 0.0 0.0 *
1923 1 49.41 32.90 66.6 0.00 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0
1924 1 63.64 43.69 68.7 6.24 9.8 14.3 0.00 0.0 0.0 6.24 9.8 14.3 *
1925 58.36 28.33 48.5 0.00 0.0 0.0 3.56 6.1 12.6 3.56 6.1 12.6
1926 61.90 40.99 66.2 3.29 5.3 8.0 6.53 10.6 15.9 9.8 15.9 24.0 *
1927 39.64 30.44 76.8 0.00 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0
1928 57.78 43.71 75.6 8.18 14.2 18.7 3.16 5.5 7.2 11.34 19.6 25.9 *
1929 59.59 43.40 72.8 4.33 7.3 10.0 0.00 0.0 0.0 4.33 7.3 10.0
1930 66.84 38.06 56.9 0.00 0.0 0.0 2.61 3.9 6.9 2.61 3.9 6.9
1931 4S.04 25.32 52.7 0.00 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0
1932 1 53.16 33.54 63.1 0.00 0.0 0.0 3.72 7.0 11.1 3.72 7.0 11.1
1533 59.72 41.26 69.1 12.34 20.7 29.9 0.00 0.0 0.0 12.34 20.7 29,9 *
1934 54.81 32.31 58.9 0.00 0.0 0.0 2.74 5.0 8.5 2.74 5.0 .5 *
1935 1 51.57 37.11 72.0 a 6.53 12.7 17.6 0.00 0.0 0.0 6.53 12.7 17.6
1936 63.27 3C.27 60.5 1.07 1.7 2.8 6.76 10.7 17.7 7.83 12.4 20.5
1937 1 56.53 35.08 62.1 0.00 0.0 0.0 2.68 4.7 7.6 2.68 4.7 7.6
1938 40.32 29.28 71.7 0.00 0.0 0.0 3.02 7.4 10.3 3.02 7.4 10.3
1939 54.14 39.94 73.8 1.75 3.2 4.4 0.00 0.0 0.0 1.75 3.2 4.4
1940 58.01 36.27 62.5 0.00 0.0 0.0 1.34 2.3 3.7 1.34 2.3 3.7
1941 1 60.24 34.60 57.4 0.53 0.9 1.5 4.12 6.8 11.9 4.65 7.7 13.4
1942 5 2.32 29.48 56.3 0.00 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0
1943 49.06 33.89 69.1 0.00 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0
1944 45.73 33.15 72.5 5.35 11.7 16.1 0.00 0.0 0.0 5.35 11.7 16.1
1945 53.65 42.74 79.7 11.00 20.5 25.7 2.56 4.8 6.0 13.56 25.3 31.7
1946 1 51.13 33.58 65.7 1.48 2.9 4.4 1.57 3.1 4.7 3.06 6.0 9.1 *
1947 1 78.10 52.78 67.6 8.2; 1 .5 17.6 4.58 5.9 8.7 12.61 16.4 24.3 *
1,486 58.46 40.60 65.4 10.03 17.2 24.7 0.0 0 0.0 .0 10.03 17.2 24.7 *
1549 1 53. 1 41.08 76.3 4.53 .4 11.0 0.00 0.0 .0 0. 4.53 8.4 11.0
1950 1 45.88 33.31 73.7 9.55 20.8 29.3 0.00 0.0 0.0 9.56 20.8 28.3
1951 50.09 35.06 70.0 0.19 0.4 0.5 4.72 9.4 13.5 4.91 5.8 14.0
1952 1 52.82 35.91 63.0 0 .00 0.0 0.0 1.57 3.0 4.4 1.57 3.0 4.4 *
t1;3 1 C;.32 t 4.12 70.5 0.00 0.: ;.0 2. t1 1;.4 il.1 .1 13.4 19.1
1954 1 57.22 34.90 61.0 a 0.00 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0
1955 42.99 29.94 69.6 0.00 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0
1956 42.68 31.44 73.7 0.00 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0
1557 1 62.76 35.41 56.4 0.00 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0 *
1958 60.28 28.50 47.3 0.00 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0 *
1959 73.45 48.01 65.4 3.44 4.7 7.2 7.86 10.7 16.4 11.30 15.4 23.5 *
1960 65.60 46.07 70.2 5.14 7.8 11.2 4.20 6.4 9.1 9.34 14.2 20.3 *
1961 39.44 24.00 60.8 0.00 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0 *
1962 51.66 3 33.09 73.7 0.00 0.0 0.0 0.92 1.8 2.4 0.92 1.8 2.4 *
1963 52.23 29.70 56.9 0.00 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0 *
1964 1 50.12 32.00 63.9 5.03 10.0 15.7 1.96 3.9 6.1 6.99 13.9 21.8 *
1965 1 50.04 37.48 74.9 t 1.77 3.5 4.7 0.00 0.0 0.0 1.77 3.5 4.7 *
1966 1 60.49 39.78 65.8 4.65 7.7 11.7 0.00 0.0 0.0 4.65 7.7 11.7 *
1967 46.61 36.50 78.3 0.00 0.0 0.0 0.36 0.8 1.0 0.J6 0.8 1.0 *
1968 61.03 44.22 72.5 3.10 5.1 7.0 .26 15.2 20.9 12.35 20.2 27.9 *
1969 1 65.18 42.78 65.6 0.00 0.0 0.0 2.92 4.5 6.8 2.92 4.5 6.8 *
1970 1 50.37 28.25 56.1 0.00 0.0 0.0 1.60 3.2 5.7 1.60 3.2 5.7 *
1971 1 46.21 34.08 73.7 0.00 0.0 0.0 0.96 2.1 2.8 0.96 2.1 2.8
1972 52.18 29.02 55.6 0.00 0.0 0.0 0.33 0.6 1.1 0.33 0.6 1.1
1973 1 52.22 34.29 65.7 0.00 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0 *
1974 1 49.62 37.75 76.1 0.00 0.0 0.0 6.94 14.0 18.4 6.34 14.0 18.4
1975 45.37 33.22 73.2 0.00 0.0 0.0 0.53 1.2 1.6 0.53 1.2 1.6 *
1976 1 47.25 28.68 60.7 0.00 0.0 0.0 2.34 5.0 8.2 2.34 5.0 8.2
1977 48.48 30.00 61.9 0.00 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0
1978 1 52.55 31.00 59.0 0.00 0.0 0.0 0.00 0.0 0.0 0.30 0.0 0.0







































































I I


I I


I-

a:


0
A
m a)








w
z
2

M AA A
. i L k ?.,,
Lio iZ | T L nii ni 1K m i


0 0 01 0 w
C) O Yf u r-


YEARS

FIGURE 7
RAINFALL BY YEAR


2
w
Zc


m m
0* N
- *0


r I I r I I









68







TABLE 31

CORRELATION COEFFICIENTS
60 YEARS, 19 STATIONS

PAIR R R2

ANNUAL RAIN VS. SEASON RAIN 0.73* 0.54
ANNUAL RAIN VS. HURRICANE RAIN 0.28 0.08
ANNUAL RAIN VS. TROPICAL STORM RAIN 0.48* 0.23
ANNUAL RAIN VS. HURRICANE + TROP. STORM RAIN 0.52* 0.27
SEASON RAIN VS. HURRICANE RAIN 0.52* 0.27
SEASON RAIN VS. TROPICAL STORM RAIN 0.46* 0.22
SEASON RAIN VS. HURRICANE + TROP. STORM RAIN 0.69* 0.48
ANNUAL RAIN VS. NUMBER OF HURRICANES 0.25 0.06
SEASON RAIN VS. NUMBER OF HURRICAIIES 0.39* 0.16
ANNUAL RAIN VS. NUMBER OF TROP. STORMS 0.37* 0.14
SEASON RAIN VS. NUMBER OF TROP. STORMS 0.34* 0.12
ANNUAL RAIN VS. NUMB. OF HURR. + TROP. STORMS 0.45* 0.29
SEASON RAIN VS. NUMB. OF HURR. + TROP. STORMS 0.54* 0.29

CRITICAL VALUE OF R:
at 0.05 Confidence Level = .25
at 0.01 Confidence Level = .33

= Sig. at 0.01 Level
All are significant at 0.05 Level



TABLE 32

t-TESTS OF RAINFALL DATA--ALL STATIONS
1919 48 1949 78
MEAN S.D. MEAN S.D. t

ANNUAL 55.3d 7.72 53.14 8.00 3.07*
SEASONAL 36.20 6.19 35.24 6.03 1.51
HURRICANE 2.uo 3.81 1.25 2.37 4.06*
TROP. ST. 1.63 2.07 1.84 2.86 -0.48
HURR. + T.S. 4.49 4.22 3.09 3.89 2.76*
CRITICAL VALUES OF t:
0.05 Confidence Level = 2.04
0.01 Confidence Level = 2.75

= Significant at .01 Level


TABLE 33

INCHES OF RAINFALL PER TROPICAL CYCLONE
1919-48 1949-78 1919-78

HURR. RAIN / NO. OF STORMS 3.18 2.55 3.00
TR. ST. RAIN / NO. OF STORMS 2.33 2.40 2.37
HURR. + T.S. / NO. OF STORMS 2.61 2.51 2.63









Rainfall per hurricane has declined while rainfall per

tropical storm has risen but by a lesser amount.

Hebert (1980) has observed that in the absence of

tropical weather systems, other atmospheric conditions, such

as a shift in upper air currents, may produce periods of

rainfall greater than that which occurs during years of

tropical cyclones. This research has shown Hebert's

statement to be correct although it is also valid to state

that years in which tropical cyclones strike generally tend

to be wetter than years when the great storms do not

influence the region.

Paradoxically, although years of tropical cyclone

activity tend to be wetter than years without the great

storms, the principal difference in rainfall seems to be

during the non-hurricane season months. In spite of

statistically significant drops in hurricane rainfall and

combined hurricane and tropical storm rainfall during the

second half of the study period, hurricane season rainfall

did not decline significantly. Thus, Hebert's observation

of other causes taking the place of tropical cyclone

rainfall may be true during hurricane season but perhaps not

acceptable for the entire year. This finding may be a clue

to evidence which could link the occurrence of tropical

cyclone activity with other features of the atmosphere which

may be associated with rainfall during the months of

November through May. The observation of such complexities

in the mechanisms which influence weather is another example







70
of why it is important to know in advance what effects

weather modification may have and how difficult it is to

ascertain those effects.
















CHAPTER 6

WATER FROM TROPICAL CYCLONE RAINFALL



Only part of the water that falls as rain can be

saved for later use. Some -rainfall infiltrates the ground

immediately while the remainder may be ponded for several

days before soaking in or stay on the surface until it flows

out of the area or evaporates. Some water that soaks into

the ground will return to the surface as seepage into lakes

and streams or may pass directly to the atmosphere by

evapotranspiration.

Estimates of the amount of water available from

tropical cyclones are obtained by multiplying the depth of

rainfall from these storms by the areas of polygons which

have been defined around each weather station, and

calculating how much of the total water could have entered

the ground or remained in surface storage in each polygon.

An estimated quantity of water that would be lost to

evapotranspiration is then deducted from the sum of ground

and surface water storage in order to obtain the net amount

of new water available from hurricanes and tropical storms

for a year of average rainfall.










Methodology for Estimating Infiltration



Many factors affect the rate and volume of

infiltration. Some of the more important considerations are

topography, ground cover, porosity, permeability, and the

amount of water already occupying potential storage space.

Numerical models have been designed to estimate the amount

of runoff that occurs in specific watersheds, including some

parts of the South Florida Water Management District

(Shahane, Berger, & Hamrick, 1977), (Shahane & Hamrick,

1974), (Shih, 1976). No comprehensive model of infiltration

is available, however, for the Water Management District,

therefore, empirical data are used to obtain direct

estimates of the amount of increased groundwater storage

resulting from tropical cyclone rainfall.

The procedure for estimating the amount of infiltration

from tropical cyclones is that of determining soakage rates

based upon the relationships between sets of paired data for

rainfall and rise of water level in observation wells, and

applying those rates to historical rainfall data per storm.

Mean depth of the water table is used as a maximum limit to

the amount of groundwater rise allowable for the rainfall

from each storm and perennial wetlands are assumed to

accommodate no increased groundwater storage.

For the purpose of estimating the areas over which

given depths of water were spread, the South Florida Water

Management District was divided into nineteen regions










(Figure 3, Table 34) based upon the weather stations used in

the earlier part of this study. Each region is a polygon

that is drawn so that any point within it is closer to the

weather station in its area than to any other station

(Theissen, 1911). Rainfall from hurricanes and tropical

storms is assumed to extend uniformly across the area and a

mean soakage rate is calculated for each polygon.

Water level data from 55 wells (USGS, 1976-1978)

(SFWMD, 1931) are used (Figure 3, Table 35). Data from some

wells located near polygon boundaries are used to calculate

infiltration for two or three polygons. No satisfactory

well data could be obtained for two polygons with very small

dry areas along the edge of the Water Management District.

Infiltration estimates for these areas, in the vicinities of

Bartow and Punta Gorda, use the mean soakage function for

two other nearby polygons.

Initial plans called for subdividing the polygons into

smaller areas around each well site based upon differences

in ground porosity. This was not possible because no

porosity data were available. According to Kreitman (1901),

Director of Groundwater Division, SFWMD, the porosity of

these wells has not been studied. Kreitman also commented

that if such data were available they would yield misleading

results because the antecedent moisture conditions above the

water table before each storm would not be known. He stated

that the South Florida Water Management District and the

United States Army Corps of Engineers have found that one

































* WEATHER STATIONS
* WELLS, SEE TABLE 35


POLYGONS


AND
OBSERVATION WELLS


FIGURE 8


POLYGONS AND OBSERVATION WELLS






































TABLE 34


POLYGON SPECIFICATIONS


POLYGON TOTAL DRY *


NAME *


ARCADIA
AVOil PARK t
BARTOW
BELLE GLADE *
EVERCLADES CITY
FELLSI'ERE *
FORT LAUDERDALE *
FORT IIYE5S f
FORT PIERCE
HOIESTEAO *
ISLEII ORTII
ILISSIIIHEE
LA CELLE
;11Alll
HCCEE 1AVEI
Or.ECCIIOCEE
ORLA:IDO *
PUL;T. 5GOfDA
ICST PALI EACH f


AREA AREA
SQ M111 SQ HI

116 2
C43 597
38 32
1735 732
1616 79
309 138
924 433
034 357
563 311
1251 t 281
171 125
321 546C
1331 27
756 26
1OL1 2:)
1335 561
1593 124
97 15
76; 374


IHPOUND- *
ABLE *
SQ. 11t

1 16.0 *
843.0 *
33.0 *
147'4. *
0.0 *
231.8
462.0
0.0
0.0
125.1
171.0
"21.0
1L6.3 *
31'7.

9;4.5 *
159.3.
0.0
93.C *


DEPTH
TO AFTERR
FEET

3.840
3.622
3.622
3. 494
3.173
6. 176
5.613
11 .52a
8.543
5.515
21 73
21. ;136
4.0357

3 .n

41.915
3.001
5.156


MAX. IIICR.
STORnGE *
FEET *

0.641 Y -
0.605 Y -
0.605 Y -
0.563 -
0.530 Y -
1.031 Y -
0.937 Y -
3.2(1 Y -
1.427 Y
0.921 Y*
3.620 Y -
3.620 Y
0.i77 Y
0.513 Y -
0.267 Y -
1.063 Y -
7.000 Y -
0.501 Y -
0.1 Y -


STORAGE *
FUNCTION *


-.008 + .488 X *
-.013 + .756 x
-.008 + .637 X *
.049 + .137 X *
.035 + .336 x
-.002 + .441 X *
.038 + .421 X f
-.045 + .864 X
.042 + .266 X f
.022 + .351 X
-.004 + .639 X *
.086 + .203 X
-.016 + .425 X t
.020 + .235 X *
.003 + .623 X
.076 + .334 x
.004 .651 X *
-.312 + .456 X
.027 + .349 X *


EVAPO-*
TRANS *
9. *

96.2 *
94.0 *
89.4 *
89.1
100.0
85.7 *
82.5 *
100.0 *
92.8 f
86.8 *
93.0 *
96.1
93.2 *
50.4 *
38.0 *
ICO.O
-3.9 *
100.0 O
21.3 *





















No.


TABLE 35


OBSERVATION WELL INDEX


LATITUDE
deg min sec


LOIIT ITUDE
deg min sec


PCLY GON
(north to south)

Isleworth

Orlando
Is
Ki ss niee
Fel 1 smere
Avon Park
1.

Is


Okeechobee

Is

Fort Pierce
11

West Palm Beach
Is

Bel l Glade


I I



11
Moore Hlaven


La Belle
I.



Fort Myers
I.


Everglades

Fort Lauderdale
"I


Miami

11
Homestead
1.


COMBINATION WELL AND RAIN GUAGE INSTALLATIOIIS

28 25 81 22 Taft
28 19 81 09 Lake Myr
28 17 81 28 Kissimme
27 37 81 15 Lake Lot
27 35 81 22 Avon Par
27 23 81 02 Basinger
Beach 26 39 80 05 West Pall


tle
e
ella
k

m Beach


NEARBY TOWN OR FEATURE


Lake Buena Vista
Windermere
Bee Line Expressway
Pine Grove
St. Cloud
Kenansville
State Road 60
State Roads 60 & 630
Highlands & Polk Co. line
Lake Placid
U. S. Highway 98
Basinger
State Road 68
State Road 710
Indian Town
Fort Pierce
Fort Pierce
Palm Harbor
Juno
West Palm Beach
Boynton Beach
U. S. Highways ;S & 441
Canal Point
Lake Harbor
Big Cypress Indian Res.
Alligator Alley
Clewiston
Moore Haven
Pain Dale
La Belle
Felda
Immokalee
Lehinh Acres
North Fort Myers
Fort flyers
Bonita Springs
County Road 846
Alligator Alley
Ochopee
Pompano Beach
Fort Lauderdale
U. S. Highway 27
Pennsuco
Kendall
U. S. Highway 41
South Miami Heights
Florida City
Everglades Nat. Park


Orlando
I
Kissimmee
Avon Park
II
Okeechobee
West Palm








77
inch of water will occupy about six inches in the ground.

This one-to-six ratio indicates that newly infiltrated water

occupies only about seventeen percent of the ground volume

in a region that Kreitman estimates to have an average

porosity between twenty and thirty percent.

Initial research design also specified that tropical

cyclone rainfall data compiled earlier would be used to

compute infiltration rates. Very little of those data are

useful for this operation, however, because records for most

observation wells begin in the early to mid-1970's, allowing

little overlap between the times of tropical cyclone

rainfall in South Florida and the time for which well data

are available.

The rainfall data used to compute infiltration rates

are of two types. First, times of widespread heavy rainfall

emanating from large weather systems are used. Because of

the distances between many wells and the nearest rainfall

gauge, only storms which dropped rain over large contiguous

areas can be used and isolated thunder showers are avoided.

This information is supplemented by data from combination

well and rain gauge installations where well level and

rainfall are recorded continuously on the same roll of

paper. Data of this type, however, are available for only a

small part of the Water Management District.

An S-shaped soakage function was expected because small

amounts of rain would be insufficient to penetrate to the

water table and very large amounts of rain would saturate








the ground so that no additional water could be stored.

The data, however, do not indicate an S-shaped curve.

Scattergrams of paired rainfall and well data for all

polygons and for combination sites indicate a linear

increase in the amount of soakage associated with increased

rainfall: therefore, linear regression is used to calculate

infiltration rates.



Methodology for Estimating Impoundable Surface Water



Certain parts of the South Florida Water Management

District contain dikes which enclose reservoirs that are

used to store surface water. These consist primarily of

Lake Okeechobee and three Conservation Areas southeast of

the lake (Storch, 1973). Any rain which falls on to one of

these reservoirs or their watersheds could potentially be

caught and stored in these or other closed depressions at

upstream locations, if the available storage capacity is not

already full. Outside of these areas, most rain falls in

places where it is not feasible to retain large quantities

of water for later use or in locations from which it cannot

be transported to areas where it may be needed.

In order to estimate the amount of impoundable surface

water, the area of the reservoirs and their contributing

watersheds is measured for each polygon and the resulting

figure is multiplied by the depth of rainwater per storm

which fell at the central weather station for that polygon.










Infiltration which would have occurred in the dry parts of

the watersheds is then deducted, so that only runoff and

ponded water are included in the net impoundable surface

water total. It is assumed that adequate storage capacity

will be available to retain all of this water, but there may

be times during very wet seasons when all reservoirs will be

full and any new increment of rainfall will have to be

allowed to flow freely to the sea.



Methodology for Estimating Evapotranspiration



Rates of evapotranspiration vary greatly, depending on

numerous factors such as temperature, intensity of sunlight,

humidity, cloud cover, ground cover, windspeed, growth

cycles of vegetation, and the amount of moisture available

(Storch, 1972). It is not possible to account for all of

the variations which might occur in different parts of the

study area at any given time. Generalized estimates of

average evapotranspiration are therefore used. These

estimates are obtained by dividing potential annual

evapotranspiration (Visher & Hughes, 1969) by mean annual

rainfall to determine the percentage of moisture which would

be lost to this cause during an average year. It is assumed

that these rates apply equally to all rainwater that falls

during the year regardless of time or source.










Estimates of Water from Tropical Cyclone Rainfall



Analysis of various aspects of the amount of water

available from hurricane and tropical storm rainfall (Tables

36 and 37) show that after runoff and evapotranspiration are

considered, relatively little water remains for human

consumption. Some polygons have very small perennially dry

surface areas and much of the Water Management District has

only a few feet of storage space between the water table and

the ground surface. Water remaining in the ground and on

the surface after the storm has passed is subject to high

evapotranspiration rates and is depleted naturally with the

passing of time, without human consumption. Although under

ideal conditions, given the rainfall of 1919 through 1948,

it may be possible to save 428,590 acre feet of hurricane

rainfall per year in the ground and 774,100 acre feet in

surface reservoirs, if that water is not used in one year,

only 102,300 acre feet will remain. Using rainfall data

from 1943 through 1978, only 74,270 acre feet would remain

after one year.

Estimates of rainwater per polygon reveal that the

area distribution of water which is available for human use

after the passage of a hurricane or tropical storm, is not

the same as the distribution of storm rainfall. Some

polygons may receive very little infiltration, and several

which have no impoundable area are considered to have no

increase in surface storage, even though some may occur.
























TABLE 36



WATER FROM HURRICANE RAINFALL

(ACRE FEET f 1,000)


POLYCO *
NAIIE DATES

ARCADIA 1919 48
1949 78
1715 73

AVO PAR 1919 II 48
1949 72
1919 78

BARTO 1919 48
1949 78
1919 78 *

BELLE GLADE 1919 48
S1949 78
1919 78

EVERCLAOES CITY 1919 48
*1949 70
1919 78

FELLSEMIC 1919 42
*1949 78 *
1919 78

FORT LAUOERALE 1919 48
S1949 78
S1919 7

FORT TLERS 1919 48
S1949 78
1 t19 78

FORT PIERCE 1919 48
1949 78
1919 73

HOMESTEAD 1919 48
S1949 78
S1919 78

ISLEWORT 1919 48
1949 78
S1919 78

KISSIMEE 1919 48
S1949 78
1919 78

LA BELLE 1119 48
19 9 78
S1919 78

MIAMI 1919 48
S1949 78
1919 78

MOORE HAVEU 1919 43
1949 78
1919 78

OrEEC:IOEEE 1919 48
S1949 78
1919 78

ORLAONO 1919 48
S1949 78 3
1919 78

PUNTA ORDA 1919 48
S1949 78
1919 78

WEST PALM BEACH 1919 48
1949 78
S1919 78

TOTAL 919 48
S1949 78
1919 78


TOTAL
TOTAL ArlNUAL *


385.1
207.1
592.2

3551.4
1723.3
5274.7

159.0
67.6
226.6

8499.2
3954.9
12454.1

8505.8
2562.3
11063.1

1468.5
632.2
2100.7

5775. 1
2236.8


3988.6
1346.5
5335. 1

24E5.9
1221.2
3707.1

6593.9
2703.5
9297.4

637.6
421.7


1765.0
1053.3

3436.7

5181.7

5813.1
1704.4
7517.5

3132.1
2021.2
5153.3

3922.2
1-17.2
5737.4

5715.2
2230.0
7945.2

639. 1
368.0
1057.1

352. 1
169.8
521.9

4608.0
1560.2
6183.2

69698.5
2 733. 1
9E431.6


12.0
6.9
.9
110.4 *
57.4
87.9 2

5.3
2.3
3.8

283.3 1
131.3 *
207.6 1

283.5
65.4 *
184.5

49.0 *
21.1 1
35.0

192.5 1
74.6
133.5 2

133.0
44.9
38.93

82.9
40.7
61.8

219.8
90.1
155.0

21.3
14.1
17.7

113.9
58.8
86.4

193.8
56.3
125. 3

104.4
67 .
85.3

130.7
60.6
95.7

190.5
74.3
132.4

23.0
12.3
17.0

11 .7
5.7
8.7

153.6
52.7
103.1

2323.3 "1
957.8
1640.5 ,1


SIMPnOIDABLE *
ftIIILTRATInsl SURFACE ILAT R *
TOTAL A:NIJUAL TOTAL Ai;;JIAL

2.96 0.10 382.16 12.7 *
1.60 0.05 205.53 6.85
4.56 0.0. 507.69 9.79

765.08 53.24 1786.31 59.54
853.10 23.44 870.21 29.01
618.19 L3.64 265G.5Z 44.28

83.96 2.80 75.01 2.50
37.39 1.25 f 30.22 1.01
121.35 2.02 105.24 1.75 *

290.35 43.o0 5933.96 197.80
633.40 21.11 2728.2k 90.94
923.75 32.06 8662.21 144.37

187.49 6.25 O.00 0.00
66.06 2.23 0.00 0.00
254.36 4.24 0.00 0.00

284.46 9.48 1050.20 35.01 *
122.03 4.07 452.16 15.07
406.49 6.77 1502.36 25.04

423.63 47.46 2887.56 96.25
580 .72 19.62 111 .451 37.28 2
012.40 33.54 4705.37 64.77

1114.11 37.14 0.00 0.00
325.39 10.6 0.00 0.00
140.000 24.00 0 O.00 0.00

590.99 19.70 0.00 0.00 *
296.47 9.08 0.00 0.00
887.46 14.79 0.00 0.00 *

626.70 20.C9 659.39 21.93
268.54 8.95 270.35 9.01
895.24 14.32 929.74 15.50 *

289.18 9.64 348.40 11.61 *
192.50 6.42 229.21 7.64
481.63 0.03 577.61 9.63

1291.01 43.03 2125.67 70.86
668.50 22.28 1096.,5 36.55 *
1959.50 32.66 3222.zl 53.70

42.65 I.42 809.*4 26.97
10.82 0.36 237.'2 7.91
53. 4 0.89 1046. 7 17.44

379.93 12.66 1440.75 48.02
232.56 7.75 929.17 30.99
612.49 10.21 2370.52 39.51

589.16 19.04 2:52.46 78.42
217.46 9.92 1065.47 35.52
366.62 14.7 3417.93 56.37

1553.30 51.94 2442.36 81.41
705.06 23.50 6 855.33 28.53
2263.36 37.72 32'! .29 54.97

350.42 11.95 330.67 11.02 *
131.29 6.33 176.74 5.89
549.71 9.16 07.41 6.46

21.72 0.72 0.00 0.00
10.36 0.35 0.00 0.00
32.08 0.53 .00 0.00

957.65 31.92 599.04 19.97
359.05 11.97 205.43 6.85
1316.70 21.94 804.47 13.41

2857.80 428.59 '23223.10 774.10
5661.62 195.39 10471.60 349.05
8719.40 311.99 33694.70 561.58


IIIFILTRATION *
SIMP SURfC
TOTAL A:NiuAL


385.12
207.13
592.25

3551.39
1723.32
5274.71

158.97
67.61
226.58

7224.31
3361.64
10586.00

187.49
66.86
254.36

1334.66
574.20
1908.86

4311.24
1707.13
6018.37

1114.11
325.89
1440.00

590.99
296.47
887.46

1286.10
538.89
1824.98

637.58
421.71
1059.29

3416.67
1765.04
5181 .71

851.79
248.25
1100.04

1820.67
1162.33
2933.00

2941.62
1362.92
4304.54

4000.66
1560.99
5561.65

689.08
368.03
1057.12

21.72
10.36
32.08

1556.69
564.48
2121.17

36080.90
16333.30
52414.10


12.84
6.90
9.87

118.38
57.44
87.91

5.30
2.25
3.78

240.81
112.05
176.43

6.25
2.23
4.24

44.49
19.14 *
31.81

143.71
56.90
100.31

37.14 *
10.16 *
24.00

19.70
9.88 *
14.79

42.87
17.96
30.42 *

21.25
14.06
17.65

113.89
58.83
86.36

28.39
8.27
18.33

60.69
38.74 *
49.72

93.05 *
45.43 *
71.74 *

133.36
52.03
92.69

22.97
12.27
17.62

0.72 f
0.35
0.53 *

51.89
18.82
35.35

1202.70
544.44 *
873.57


INFILT & SURFC
MIIIS VAP *
TOTAL AntIUAL
14.63 .49 f


14.63
7.87
22.51

340.93
165.44
506.37

16.85
7. 17
24.02

797.45
366.42
1153.87

0.00
0.00
0.00

190.86
82.11
272.97

754.47
238.75
1053.22

0.00
0.00
0.00

42.55
21.35
63.90

169.76
71.13
240.90

44.63
29.52
74.15

133.25
68.84
202.09

6.81
1.99
8.80

174.78
1I1 .58
286.37

58.03
27.26
86.09

0.00
0.00
0.00

42.03
22.45
64.48

0.00
0.00
0.00

291.10
105.56
396.66

3068.96
1387.43
4456.38


0.49 A
0.26 *
0.38 *

II.36
5.51 *
8.44 *

0.56
0.24
0.40

16.25
12.21 *
19.23
S0.00
0.00
0.00 *

6.36 *
2.74
4.55

25.15
9.96
17.55 *

0.00 *
0.00
0.00

1.42
0.71 *
1.06

5.66 t
2.37 *
4.01
1.49
0.98 *
1.24

4.44
2.29
3.37 *

0.23
0.07 *
0.15

5.83
3.72
4.77

1.96
0.91 *
1.43

0.00 *
a.0 *
0.00

1.40 f
0.75
1.07

0.00 *
0.00o
0.00
0.00*

9.70
3.52 *
6.61

102.30
46.25
74.27


See note following Table 37.























TABLE 37



WATER FROM TROPICAL STORM RAINFALL

(ACRE FEET x 1.000)


POLYGON A TOTAL
I1AME DATES TOTAL ANNUAL

ARCADIA 1919 48 211.9 7.1
1949 78 297.5 9.
1919 78 509.4 8.5

AVONI PARK 1919 43 1490.3 49.7
S1949 76 2296.6 76.6
1919 70 3737.4 63.1

BARTOv 1919 48 78.5 2.6
1919 78 65.8 2.2
1919 78 144.3 2.1

BELLE GLADE 1919 48 4517.5 150.6
1949 78 4912.6 163.8
19 73 9430.1 157.2

EVERGLAOES CITY 119 1 48 6169.2 205.6
1949 78 4063.7 1 5.5
1919 78 10232.9 170.5

FELLSMERE 1919 48 991.9 33.1
S1949 78 1163.5 38.8
1919 78 2155.4 35.9

FORT LAUDERDALE 199 48 2731.1 91.0
S1949 78 3047.0 101.6
1919 78 5778.1 96.3

FORT MYERS 1919 48 a 2822.2 94.1
1949 78 3351.7 111.7
1919 76 6173.9 102.9

FORT PIERCE A 1919 48 1747.3 56.2
A 1949 73 A 1702.5 56.6
S1919 78 A 3443.C 57.5

HOMESTEADO 191 48 A 3Z81.1 129.4
S17949 71 333 .0 111.0
S1919 78 7211.1 120.2
S A
ISLEVORTH 1919 48 305.8 10.2
A 1949 78 A 379.8 12.7
S 1919 7 78 625.6 11.4

RISSIMMEE 1919 43 1440.6 48.0
A 1949 76 2078.1 69.3
S1919 78 3518.7 53.6

LA BELLE 1919 48 4042.7 134.8
S1949 78 388'.4 129.5
S1919 78 7927.1 132.1

MIAMI 1919 48 2254.7 75.2
1949 78 2736.9 91.2
S1919 78 A 4991.6 83.2

MIOO.E HAVEN 1919 48 2617 .9 87.2
S1949 78 3027.4 100.9
A 1919 78 5641.3 94.1

OKEECHOBEE 1919 43 270'.9 93.0
1949 78 3935.i ) 131.2
S1919 78 6724.3 112.1

ORLAHDO 1919 48 352.9 11.8
1949 7E 437.5 14.6
S19S9 76 790.4 13.2

PUNTA GORDA 1919 68 A 260.3 8.7
e 1949 78 3714.8 10.5
1919 78 5 575.1 9.6

VEST PALM BEACH 1919 48 2021.8 67.1
S1949 78 A 2628.8 87.6
1919 78 650.6 77.5

TOTAL 1919 48 40726.1 1357.5
A 1949 78 A 43654.5 1455.1
S1919 78 84360.6 1406.3


SIMPOUHDASLF
S IIFILTRATIO: SURFACE WATER
TOTAL Al:IUAL TOTAL ANNUAL

A 1.58 0.05 210.32 7.01
S 2.27 0.03 295.25 9.84 *
3 .35 0.06 505.56 8.439

S 698.85 23.30 792.02 26.40
1101.57 36.72 1194.93 39.63 0
1 300.43 30.01 1937.00 33.12

A 42.77 1.43 3 95.68 1.19
S 34.36 1.16 30.95 1.03
A 77.63 1.29 66.63 1.1 1

A 815.52 27.18 3024.34 100.81
S 915.56 30.52 A 3260.15 108.67
A 1731.08 28.85 A 6284.46 104.74

A 135.21 4.51 0.00 0.00
S 107.45 3.58 A 0.00 0.00
4 242.66 4.04 0.00 0.00

S 191.33 6.39 709.42 23.65
S 225.09 7.50 832.10 27.74
A 416.92 6.95 7 1541.52 25.69

f 749.42 24.9C8 1365.55 45.52
S 843. 33 28.1 1 1523.49 50.78
1592.75 26.55 28 39.04 48.15

779.10 25.97 0.00 0.00
932.99 31.10 0.o0 0.00
A 1712.03 22.53 0.00 0.00

S 423.93 I.713 0.00 0.00
A 412.44 ;1.75 0.00 0.00
S06 .37 14.44 0.00 0.00

A 335.12 12.84 388.11 12.94
S 353.54 11.76 333.00 11.10
A 738.66 12.31 721.11 12.02

S 1 36.44 4.55 169.36 5.65
A 170.07 5.67 209.78 6.99
A 306.51 5.11 379.13 6.32

804.20 26.81 636.30 21.21
A 933.63 32.79 A 1094.49 36.48
S1787.B3 29.80 1730.87 28.85

A 29.32 0.98 562.75 13.76
S 27.13 0.90 540.83 18.n3
A 56.45 0.94 110).58 18.39

A 275.58 9.19 A 1037.16 34.57
S 329.CI 10.99 1258.98 41.97
A 605.3) 10.09 2296.14 38.27

S 429.07 14.30 1533.59 51.12
A 44 .20 14.6I 1826.33 60.8
6 73.27 14.55 3359.92 56.00

951.54 31.72 1000.69 33.36
1796.55 39.68 1553.61 51.95 ^
A 214 .09 35.30 2553.30 42.66

* IS5.53 6.18 167.40 5.53
S 229.'1 7.65 203.07 6.94
A 414.35 6.92 375.4. 6.26

16.05 0.53 0.00 0.00
S 19.55 0.65 A 0.00 0.00
S 35.60 0.59 0.00 0.00

A 472.6 7 15.76 A 262.83 8.76
S 595.42 19.35 341.75 1 .39
A 1068.29 17.30 604.58 10.08

A 7523.94 250.80 *11895.60 396.52
: 8954.66 294.50 1650s 8.a8 483.63
A16478.80 274.6S) 26404.40 440.07


INFILTRATION
& IMP SUkRFC
TOTAL ANIIUAL

211.39 7.06 *
297.52 9.92
509.41 8.49

1490.87 49.70 A
2296.56 76.55 *
3767.43 63.12

78.45 2.62 *
65.81 2.19
144.26 2.40 *

3839.86 128.00 *
4175.71 139.19
8015.56 133.59

135.21 4.51
107.45 3.58 *
242.66 4.04 *

901.25 30.04 *
1057. 19 3 .24
1958.44 32.64 *

2114.97 70.50 A
2366.82 78.89 *
4481.79 74.70

779.10 25.97 *
932:99 31.10 *
1712.09 26.53 *

423.93 14.13
442.44 14.75 *
66 .37 14.44 *

773.23 25.77 *
686.54 22.88 *
1459.77 24.33 *

305.79 10.19 *
379.85 12.66 *
685.64 11.43

1440.58 48.02 *
2078.12 69.27 *
3518.70 58.64 *

592.07 19.74
567.96 18.93 *
1160.03 19.33 *

1312.74 43.76 *
1588.79 52.96 *
2901.53 48.836

1962.66 65.42 *
2270.53 75.68 a
4233.20 70.55 *

1952.23 65.07
2755.16 91.4 *8
4707.39 72.46 *

352.94 11.76 *
437.48 14.58 *
790.42 13.17

16.05 0.53 *
19.55 0.65 *
35.60 0.59

735.70 24.52
937.17 31.24
1672.87 27.88

19419.50 647.32
23463.60 782.12 *
42883.20 714.72 A


INFILT L SURFC A
MIN1US EVAP
TOTAL ANtIUAL

8.05 0.27
11.31 0.38 *
19.36 0.32

143.12 4.77 A
220.47 7.35 A
363.59 6.06 A

8.32 0.28 A
6.98 0.23 *
15.29 0.25 A

418.54 13.95 *
455.15 15.17 *
873.70 14.56 A

0.00 0.00
0.00 0.00
0.00 0.00

128.88 4.30 A
151.168 5.04 A
280.06 4.67 A

370.12 12.34 *
414.19 1 .81 *
714.31 13.07

0.00 0.00
0.00 0.00
0.00 0.00

30.52 1.02
31.o6 1.06
62.38 1.04

102.07 3.40 *
90.62 3.02 *
192.63 3.21 A

21.41 0.71
26.59 0.89 *
47.95 0.80

56.18 1.87
81.05 2.70 *
137.2S 2.29

4.74 0. 16
4.54 0.15
9.2A 0.15 *

126.02 4.20 *
152.52 5.08 *
278.55 4.64

39.25 1.31
45.41 1.51 A
34.66 1.41

0.03 0.00
0.03 0.00
0.00 0.00

21.53 0.72 *
26.69 0.89 *
48.22 0.80 *

0.00 0.00
0.00 0.00 A
0.00 0.00

137.58 4.59 *
175.25 5.84 *
312.83 5.21

1616.33 53.88 A
1893.80 63.13 1
3510.14 58.50 *


See note on following page.









Note Regarding Tables 36 and 37



"TOTAL" is the total amount of water from hurricane
rainfall. It is determined by converting the rainfall
depth from inches to feet and multiplying that quotient
by the area in acres.

"INFILTRATION" indicates the estimated amount of
water which entered the ground. It is calculated by
applying the soakage function to the rainfall depth and
multiplying that product by the area of dry land surface
in acres. This value is not allowed to exceed the maximum
storage possible within the space between the ground
surface and the mean water table. Dry areas were
identified by topographical maps, Landsat remote sensing
imagery and U-2 aerial photographs at the scale 1:250,000.

IMPOUNDABLEE SURFACE WATER" is an estimate of the
amount of runoff that could be Impounded in existing
reservoirs if other water was not already occupying the
necessary space. It is calculated by multiplying the
rainfall in feet by the area of Lake Okeechobee, the three
Conservation Areas, and all of the area which drains into
these reservoirs (Figure 9), and deleting infiltration
which would occur in the dry parts of these areas.

"INFILTRATION & IMP SURFC" is the sum of two
preceding columns. It is an estimate of the total water
that could be retained after initial runoff from storm.

"INFILT & SURFC MINUS EVAP" is the net water
remaining in the ground and on the surface after a year
of evapotranspiration. Evapotranspiration rates are
taken from Visher and Hughes (1969).










Using the procedures described above, all of the increase in

surface storage (Figure 9) and much of the added ground

water are found at inland locations in the central and

northern parts of the Water Management District, while

rainfall (Figures 5 and 6) is more evenly distributed, with

the greatest quantities falling along the southeastern

coast.

When the rainfall data are converted from

unidimensional depths (Tables 4 through 23) to volumetric

measurements (Tables 36 and 37), the close relationship

between rainfall and water supply becomes apparent. The

rainfall from hurricanes for the second half of the study

period was only 44 percent of that for the first half.

Although the total water from hurricanes declined by a

greater proportion, to 41 percent of the earlier total,

infiltration and impoundable runoff declined slightly less,

to 44 and 45 percent, because of changes in the area

distribution of rainfall between the two intervals.

The percentage of rainfall from all sources, which

would be available after infiltration, runoff, and

evapotranspiration are budgeted, would be very similar to

that of hurricane and tropical storm rainfall. Although

runoff may increase during heavy storms, the rainfall rates

which normally accompany a hurricane or tropical storm

rarely exceed those from other sources, and when extremely

high rainfall occurs it is usually limited to a relatively

small part of the Water Management District. Runoff from























































FIGURE 9


IMPOUNDABLE CATCHMENT AREAS








86

hurricanes and tropical storms may occasionally exceed

runoff from other rainfall sources, but lighter rains often

fail to provide significant soakage and may make no net

contribution to terrestrial moisture after a day of

evapotranspiration. Tropical cyclone rainfall is generally

enough to add significant quantities of water to ground and

surface storage.
















CHAPTER 7

WATER SUPPLIES
IN THE SOUTH FLORIDA WATER MANAGEMENT DISTRICT


The foregoing summaries and analyses of hurricane and

tropical storm rainfall data provide information regarding

the relative importance of rainfall from these sources as

part of the total rainfall of the South Florida Water

Management District and indicate the amount of usable water

which remains after runoff and evapotranspiration have taken

place. The use and management of water must also be

considered, however, if the full significance of tropical

cyclone rainfall to water supplies is to be understood. In

the remainder of this study, the effects of reduced rainfall

on water supplies are treated in relation to projected

demands for water and the impacts that possibly declining

supplies and increasing demands would have on water

management policies and practices in the SFWMD.



Origin of the SFWMD



Attempts to influence the water balance in South

Florida began in the 1850's, when the United States Congress

put all swamp and overflow lands into state ownership

through the Swamp Lands Act of 1850. Efforts to drain










wetlands were financed by the sale of land to private

interests, and in Florida, a board of internal improvements

was established in 1851 to negotiate these transactions.

Draining wetlands continued to be the primary form of water

management in the region until the 1930's. The U.S. Army

Corps of Engineers entered the region in 1899 and began to

construct numerous water control and diversion structures

which are still used by the Corps and the South Florida

Water Management District (Smith, 1980).

The hurricanes of 1926 and 1928 demonstrated that while

existing canals were capable of handling routine drainage,

they could not absorb the excess water from a severe storm

rapidly enough to prevent flooding, and flood control thus

became a new objective of water management in the region.

In 1948, Congress adopted the Central and Southern Florida

Flood Control Project and the following year, the Florida

Legislature created the Central and Southern Florida Flood

Control District. The Army Corps of Engineers assisted the

Flood Control District by constructing and operating water

control structures (Smith, 1930).

Extended drought between 1931 and 1945 brought the

problem of maintaining adequate water supplies to the

foreground. Groundwater levels became so low that saltwater

intruded into municipal wells of coastal cities. Land which

was normally underwater became dry and thousands of acres of

"muck" soil were lost to fires (Smith, ISSo)









Continued increases in water demand and worsening

problems concerning supply culminated in the Florida Water

Resources Act of 1972 which created the South Florida Water

Management District as part of a statewide system of water

management districts. Several modifications were made to

water management district boundaries in South Florida by

amendments in 1973 and 1976, leading to the present

configuration of districts. Duties and authority of the

water management districts were altered and clarified as

part of the Environmental Reorganization Act of 1975.

The Water Resources Act states that the water

management districts may be authorized to perform the

following functions: 1) Administer and enforce all

provisions of the Act, including the permitting of

consumptive uses, regulation of wells, and management and

storage of surface waters. 2) Cooperate with the federal

government in matters of flood control, reclamation, and

conservation. 3) Establish and control the level of water

in canals, lakes, rivers, channels, reservoirs, and streams,

and maintain those levels by means of dams, locks, flood

gates, dikes, and other structures. 4) Plan, construct,

operate, and maintain physical works.









Water Management Goals in the SFWMD





The South Florida Water Management District has

published the set of objectives listed below.



1. Water Supply. Ensuring fresh water
resources for all needs.

2. Water Conservation. To fully conserve and
control the water resources in the District so as
to realize their full beneficial use.

3. Prevention of Salt Water Intrusion. To
protect fresh water through regulation of water
use and by installing salinity control structures
to hold fresh water levels high near the coast.

4. Flood Control. To prevent damage and
control the discharge of water from floods in the
event of hurricanes or excessive rainfall.

5. Protection and Enhancement of Fish and
Wildlife. Conservation of our natural resources
to prevent exploitation, destruction, or neglect.

6. Maintenance of Desirable Groundwater
Levels. Providing canals, levees, dams,
reservoirs, holding basins, pumping stations, and
other works, for utilization and conservation of
surface and groundwater.

7. Navigation. To assist in maintaining the
navigability of rivers and harbors.

8. Public Recreation. To operate and maintain
quality water-based recreation facilities.

9. Preservation of Important Wilderness Areas
and their Ecosystems. To ensure water management
practices are sensitive to environmentally
fragile areas.

10. To Promote the Health, Safety, and General
Welfare of the People of the State. (SFWMD,
1980, p. 5)




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