Title: Some Hydrologics & Biologic Aspects of the Big Cypress Swamp, Drainage Area, Southern Florida
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Title: Some Hydrologics & Biologic Aspects of the Big Cypress Swamp, Drainage Area, Southern Florida
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Language: English
Publisher: U. S. Geological Survey
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Spatial Coverage: North America -- United States of America -- Florida
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Abstract: Jake Varn Collection - Some Hydrologics & Biologic Aspects of the Big Cypress Swamp, Drainage Area, Southern Florida (JDV Box 39)
General Note: Box 30, Folder 5 ( Some Hydrologics & Biologic Aspects of the Big Cypress Swamp, Drainage Area, Southern Florida - 1970 ), Item 1
Funding: Digitized by the Legal Technology Institute in the Levin College of Law at the University of Florida.
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Full Text

SOME HYDROLOGIC & BIOLOGIC


ASPECTS OF

CYPRESS


= THE
fSWA, ield, W4M i PmaBuUm ,%i
SWAMP


DRAINAGE AREA, SOUTHERN
1970


FLORIDA


UNITED STATES DEPARTMENT OP THE INTERIOR
GEOLOGICAL SURVEY
WATER RESOURCES DIVISION


BIG







UNITED STATES DEPARTMENT OF THE INTERIOR

GEOLOGICAL SURVEY

WATER RESOURCES DIVISION


















SOME HYDROLOGIC AND BIOLOGIC ASPECTS OF THE BIG CYPRESS SWAMP

DRAINAGE AREA, SOUTHERN FLORIDA

BY

H. Klein, W. J. Schneider, B. F. McPherson
and T. J. Buchanan


OPEN-FILE REPORT

70003



Prepared by the

UNITED STATES GEOLOGICAL SURVEY



Tallahassee, Florida

May 1970







FRONTISPIECE

DEPARTMENT of the INTERIOR

news release

OFFICE OF THE SECRETARY
Winge (202) 343-6843
For release Friday, November 7. 1969

SECRETARY HICKEL ORDERS WATER RESOURCE
STUDY OF BIG CYPRESS SWAMP IN FLORIDA

Secretary of the Interior Walter J. Hickel today directed the U. S. Geological
Survey to make a study of water resources in the Big Cypress Swamp watershed, site
of the proposed jetport facility near Everglades National Park, Fla.

The Secretary also directed three other Interior agencies--the Bureau of
Outdoor Recreation, National Park Service and Bureau of Sport Fisheries and Wild-
life--to work with state and local agencies on how to best utilize the Big Cypress
Swamp for fish, wildlife and recreation.

"Since the Big Cypress Swamp provides nearly 40 per cent of the water required
to maintain the ecology of Everglades National Park," Secretary Hickel said, "it
is essential that we know how much of the Swamp must be preserved to insure an
adequate water supply for the Park."

"This will be a primary purpose of the Geological Survey effort," he added.
"But another important benefit of the study will be to determine how much of the
Big Cypress must be preserved to maintain an adequate supply of water to those
communities on Florida's West Coast that depend upon the area for their domestic
water needs."

The survey also will determine what is needed to maintain the adjacent
estuaries which serve as a "nursery" for the State's important commercial fisheries
industry.

Two recent studies of the impact of the proposed jetport on the ecology of
south F4orida--the Department of the Interior's "Leopold Report" and a report
prepared under the auspices of the National Academy of Sciences--stressed the
critical importance of the Big Cypress Swamp watershed, he pointed out. While
both reports emphasized the importance of the Big Cypress, the question of precise
boundaries was left open.

"The Geological Survey scientists will examine the hydrology of the Swamp in
detail so that we can define the area to be protected'' Secretary Hickel said.

The study will get underway immediately, with a preliminary report expected
in 180 days,

x x x











TABLE OF CONTENTS


Bage

Frontispiece --------------- ------------------------- 1

Purpose and scope -------------------------------------------- 6

Summary and Conclusions ----------------------------------- 8

Physical characteristics of the Big Cypress ---------------- 15
Boundaries and drainage patterns ------------------------ 15
Ecology ----------------------------------------------- 22
Iand development ---------------------------------------- 24

Hydrologic characteristics of the Big Cypress ------------- 27
Storage and movement of water --------------------------- 27
Aquifers ---------------------------------------------- 40
Salt-water intrusion ------------------------------------ 44
Water quality ------------------------------------------- 46
Hydrobiologic relations --------------------------------- 55

The Big Cypress as a water source for Everglades National
Park -------------------- 64
Contributing area --------------------------------------- 64
Quantity of water --------------------------------------- 66

Water-control works in the Big Cypress ----------------------- 70
Golden Gate Estates system ------------------------------ 70
Barron River and Turner River Canals -------------------- 74

Probable effects of continued urban growth on water
resources and biota --------------------------------------- 77
Expected pattern of urban expansion --------------------- 77
Effects on water resources ------------------------------ 79
Effects on biota ---------------------------------------- 83
Effects on Everglades National Bark --------------------- 89

Acknowledgments ---------------------------------------------- 91

References --------------------------------------------------- 93










TABLES


Page


Table 1 --



Table 2 --







Table 3 --













Table 4 --


Normal monthly rainfall for the Everglades

and Southwest Coast Division, Florida

Nutrients, in mg/1, in water in the Big

Cypress, April 1969 March 1970, and in

water from canals in Broward County,

December 1968 June 1969.

Concentrations of the DDT family in water

(jg/l) and sediment and biota (Jg/kg) from

the Big Cypress, April 1969 March 1970,

and from canals in Broward County,

December 1966 June 1969; concentrations

of the DDT family (pg/1) in rainfall in

southern Florida, 1968-1970.

Average flow to Everglades National Park,

for periods 1941-62, 1963-69.








ILLUSTRATIONS


Page

Figure ].--Map of the Big Cypress showing the delineations of the
drainage area and the subareas. 17

Figure 2.--Map of the Big Cypress showing the major sloughs and
strands. 19

Figure 3.--Map of the Big Cypress showing flow directions in
December 1969. 21

Figure 4.--Map of the Big Cypress showing the areas platted for
development. 26

Figure 5.--Hydrographs of water level at bridge 105, well 54, and
well 382 for 1967 and 1968. 30

Figure 6.--Stage-duration curve for the Tamiami Canal at bridge
105 for the period 1952-69. 34

Figure 7.--Hydrograph of monthly mean discharge of the Tamiami
Canal outlets, 40-mile bend to Monroe. 36

Figure 8.--Graph of annual mean discharge for the Tamiami Canal
outlets, 40-mile bend to Monroe, for the 1941-69
water years. 38a

Figure 9.--Graphs of maximum, mean, and minimum monthly discharge
for the Tamiami Canal outlets, 40-mile bend to
Monroe, 1941-69. 38b

Figure O1.--Map of the Big Cypress showing the distribution of
flows during November 18-20, 1969. 38c

Figure 11.--Vegetal transect in the Big Cypress showing pine-palm-
palmetto forest through a cypress-tree community. 57a

Figure 12.--Vegetal transect in the Big Cypress showing wet prairie
into a hardwood hammock. 57b

Figure 13.--Vegetal transect in the Big Cypress showing wet prairie
into a cypress strand. 57c

Figure 14.--Vegetal transect in the Big Cypress showing wet prairie,
hammock, swamp forest, and lake in the Fakahatchee
Strand. 57d






Figure 15.--Graph showing the number and wet weight of fresh-water
prawns collected per trapping in a cypress strand in
the Big Cypress. 61

Figure 16.--Graph showing selected correlations of mean annual
discharges used for extending streamflow records to
the 22-year period, October 1940 to September 1962. 69a

Figure 17.--Maps showing location of the Tamiami Canal outlets. 69b

Figure 18.--Hydrograph of discharge for the Golden Gate Canal for
the 1966 and 1968 water years. 73

Figure 19.--Hydrograph of discharges for the Tamiami Canal outlets,
40-mile bend to Monroe and the Barron River Canal
for the 1966 water year. 75









PURPOSE AND SCOPE


The prime purpose of the study of the hydrology of the Big

Cypress, as expressed by the Secretary of the Interior in his news

release of November 7, 1969, was to determine the importance of the

Big Cypress in maintaining an adequate water supply for (1) the

Everglades National Park, for (2) the expanding population of

southwest Florida, and for (3) the adjacent estuaries, which consti-

tute nurseries for fish, some of which are commercially important.

This preliminary report and the reconnaissance on which it is

based were designed to provide the most essential available water

and ecologic facts needed by the public and public officials in

deciding upon the best utilization of the Big Cypress compatible

with the broadening and somewhat conflicting needs of the people.








To define the role of the Big Cypress in the hydrology of south

Florida, the following had to be determined, described, or delineated:

1. Boundaries of the Big Cypress drainage area;

2. Drainage features, flow patterns, and directions of flow;

3. Magnitude of water storage in and movement of water from

the Big Cypress;

4. Quality of the water and the relation of quality to the

biosystem;

5. Changes in water movement and quality caused by land develop-

ment to date;

6. Possible effects of further land development on the water

supply of the Big Cypress, the Everglades National Park,

the nearby west-coast cities, and the adjacent estuaries.









SUMMARY AND CONCLUSIONS


The Big Cypress is a hydrologic unit of 2,450 square miles of

flat, swampy area that merges into a coastal-marsh and estuarine

environment. The ecology is water dependent and is rich in biota.

Land is being developed in the western part of the drainage area as

the city of Naples expands eastward.

Water, a principal resource of the Big Cypress, governs the

ecology and influences the patterns of land development. Abundant

but seasonal rainfall and slow natural drainage allow water to

collect in ponds each year over as much as 90 percent of the

undeveloped area for as long as 4 months. During the dry season,

water in ponds and sloughs covers about 10 percent of the land.

A shallow aquifer presently supplies most water for municipal use

and irrigation. It extends from the land surface to a depth of

about 130 feet in Naples, to about 60 feet near Sunniland, and

wedges out near the east edge of the Big Cypress.








The Big Cypress is herein divided into three subareas, each

having reasonably distinct internal drainage. Delineation of

drainage boundaries and flow patterns were determined from aerial

photographs and from hydrologic data obtained in November and

December 1969. Subarea A, about 450 square miles in the north-

eastern part of the Big Cypress, drains southeastward into

Conservation Area 3 of the Central and Southern Florida Flood

Control District and contributes part of the water that enters the

Everglades National Park from Conservation Area 3. Subarea B, about

550 square miles in the western part, is characterized by an exten-

sive system of canals that drains southward and westward into the

Gulf of Mexico. Subarea C occupies the central part of the Big

Cypress and drains southward toward the western part of the Ever-

glades National Park. Its 1,450-square-mile area constitutes about

three-fifths of the Big Cypress. It drains naturally except for

two canals in the western part, the Barron River and the Turner

River Canals.

Construction of the Golden Gate water-control system began in

the early 1960's and has continued intermittently into 1970, thereby

establishing a pattern for urbanization in subarea B. As a result

of urbanization, runoff has accelerated, and water levels have

lowered 2 to 4 feet in a 54 square-mile area east of Naples. Flow

over the coastal weir in the Golden Gate Canal, the primary canal

of the Golden Gate Estates, ranged from 2,390 cfs (cubic feet per

second) on July 1, 1966, to 28 cfs on May 27, 1967. The average

flow over the weir was 350 cfs during 1965-68.









Water is presently withdrawn from the shallow aquifer by the

Naples municipal well field about 1 mile inland from the Gulf.

Average pumpage from the field is 6 mgd (million gallons per day);

the peak is 14 mgd. The lower water levels caused by pumping extend

as far as 1 mile westward and eastward from the well field. The

city is exploring 12 to 15 miles inland from the Gulf for its

ultimate supply. The total water potential is not now known, but

the average flow of 350 cfs from the Golden Gate Canal indicates

that at least 10 times the present peak pumping might be available

from the inland area without appreciable lowering of water levels.

The Everglades National Park annually receives an average of

541,500 acre-feet of water from subarea C, 56 percent of the total

received by the park from outside sources. Water from subarea C,

however, reaches 16 percent of the park area.








Long-term hydrologic records from stations on the periphery

of the Big Cypress reflect the cyclical rise in water levels during

the rainy season and the decline during the dry season. The annual

mean discharge through the Tamiami Canal outlets between 40-mile

bend and Monroe during 1941-69 ranged from 75 cfs in 1956 to 620 cfs

in 1960. Variations in monthly flow are wide; for example, the

discharge through the same outlets during October, the wettest

month, ranged from 2,700 cfs to less than 50 cfs. Long periods of

no flow were recorded as follows: 9 consecutive months beginning

December 1942; 8 beginning January 1944; 8 beginning January 1950;

and 8 beginning November 1961.

The quality of the water flowing toward the Everglades National

Park, in general, reflects natural conditions. The water has not

been seriously altered or greatly contaminated by pesticides and

nutrients. Concentrations of pesticides in sediments and biota and

of nutrients in water were significantly lower than those from nearby

urbanized areas but were comparable with those from other undeveloped

areas of Florida.










The biota of the Big Cypress is in delicate balance with the

seasonal fluctuations in water level. These fluctuations control

the growth and concentration of organisms in the fresh-water environ-

ment and determine the brackishness of the estuaries, which, in

turn, controls the estuarine ecosystem, a vital nursery and feeding

area for many marine animals. The Fakahatchee Strand, in particular,

is a unique water-dependent area rich in semitropical plants and

in wildlife. The biota of the Big Cypress is interrelated with that

of the Everglades National Park; many species migrate between the

two areas.

Until the present time, land development in subarea C has been

of little consequence and, therefore, has had no discernable effect

on the quantity and pattern of water movement to the Everglades

National Park. Significant land development involving flood-control

and water-management practices would result in a change in the

pattern of runoff and the period of inundation and would cause changes

in the ecosystem of subarea C and the northwestern part of the park.








Continued canal construction farther eastward will lower water

levels in progressively larger areas of subarea B. Water levels

in subarea B during the dry season are partly regulated by a series

of weirs, which controls canal flow and steps-up water levels from

low elevations near the coast to higher elevations in the interior.

The Barron River and Turner River Canals, constructed originally

as borrow canals for highway construction, are not as effective in

draining flood water as the canals to the west. They form a rudi-

mentary drainage network that intercepts only shallow flow.

Current pressures for land development center in three general

areas, the vicinity of Naples and eastward in subarea B; the southern

coastal strip; and Gum Slough. The recent agreement between the

Departments of the Interior and Transportation, the State of Florida,

and Dade and Collier Counties regarding the proposed commercial

jetport site has apparently reduced pressures for further land

development in the eastern part of subarea C, at least temporarily.









Urban expansion along existing patterns would alter ecosystems

in parts of the Big Cypress. The acceleration of runoff by canals

would reduce the period of inundation in a large part of subarea B,

which would bring about changes in biologic communities there; but

efficient management of the water resources could moderate the change.

Sufficient data are not available to predict the effect that specific

water-management practices might have on changes in the fresh-water

and estuarine environments.

A continuing program of hydrologic and biologic investigations

in the fresh-water and estuarine environments in subarea B would

furnish valuable information for determining the effects of drainage

on water quality, water levels, and biota. This information would

have transfer value in predicting changes in other parts of the

Big Cypress if they are opened to further land development. Further

investigations in subarea C would furnish benchmark information for

monitoring changes brought about by future changes in hydrologic

conditions.










PHYSICAL CHARACTERISTICS OF
THE BIG CYPRESS



Boundaries and Drainage Patterns


The Big Cypress Swamp is a loosely defined but recognized physio-

graphic province (Davis, 1943, fig. 1) southwest of lake Okeechobee.

Some generalized flow patterns through the area were shown by Parker

(1955, plate 11). Neither the physiographic boundaries nor the

generalized flow patterns, however, are sufficient for the hydrologic

interpretations required for this report.

Consequently, aerial photographs were taken specifically for the

delineation of drainage boundaries and patterns of flow for use in

this report. More than 580 aerial photographs of the general area,

at a scale of 1:30,000, were taken in December 1969. A mosaic was

made from the photographs; roads and cultural features were used

for control. The resulting semicontrolled mosaic was used to delineate

drainage boundaries and flow patterns. Where drainage boundaries and

flow patterns were less distinct, the photographs were examined

stereoscopically. Field observations at all culverts aided in the

detail of flow patterns. These observations were made in November and

December 1969, when water levels were high.










The drainage boundary is shown in figure 1. It encompasses a


2,450-square-mile area in which water flows generally southward in,

through, and from the physiographic province of the Big Cypress Swamp.

It defines the Big Cypress Swamp drainage area, hereinafter referred

to in this report as the Big Cypress.

For this report, the Big Cypress has been divided into three

subareas, as shown in figure 1. These have reasonably distinct

internal drainage determined largely by topographic configuration and

man-made drainage. Subarea A lies northeast of a low ridge and drains

southeastward into Conservation Area 3 of the Central and Southern

Florida Flood Control District. This 450-square-mile subarea is

roughly one-fifth the total area of the Big Cypress and contributes

part of the water that enters the Everglades National Park (hereinafter

called the Park) from Conservation Area 3.

Subarea B includes 550 square miles at the west edge of the Big

Cypress. It is characterized by an extensive system of canals, which

drain southward and westward into the Gulf Coast estuaries.

Subarea C occupies the central part of the Big Cypress and drains

toward the Park. It constitutes about three-fifths of the Big Cypress-

1,450 square miles. At present, subarea C is drained naturally except

for two canals in the western part, the Barron River and Turner River

Canals.



















































Figure 1.--Map of the Big Cypress showing the delineations of
the drainage area and the subareas.




17









Because of the flat topography and slow natural drainage, there

is no well-defined stream system in the Big Cypress except in the

estuarine environment along the Gulf Coast, where drainage tends

toward tidal channels. In the fresh-water environment, all drainage

is through sloughs and strands and by canals, as shown in figure 2.

























30' 15'


30












15'












2600












45'


ROAD

CANAL

LEVEE

COUNTY BOUNDARY

PARK BOUNDARY

A
VEGETAL TRANSECT


\ {~


G7 [SLOUGH
-.

i'U 1
O/


EVERGLADES

NATIONAL

PARK


Figure 2.--Map of the Big Cypress showing the major sloughs
and strands.


81o00


EXPLANATION


2530'


I








There are three generalized patterns of drainage in the Big Cypress.

In the northeast, drainage is diverted eastward by a low, nearly

imperceptible ridge extending from the Hendry-Collier County line in a

broad eastward-bending arc to the Collier-Broward County line, north

of the proposed jetport site. In the west, flow is through a system

of canals that diverts water both westward to the Gulf and southward

to the bays of the Ten Thousand Islands. Throughout the rest of the

Big Cypress, drainage is generally southward and tends to concentrate

in the Okaloacoochee Slough, the Barron River and Turner River Canals,

and the Fakahatchee Strand (fig. 2). Details of the flow patterns

are shown in figure 3.






The delineation of the Big Cypress is based on the unseasonably

high water levels of December 1969. At still higher levels, some

water would probably spill over the low dividing ridge from subarea A

to subarea C; some water would enter the Big Cypress from Lake Trafford

through the Camp Keasis Strand (fig. 2); and water from Bird Rookery

Strand would enter through culverts under Road 846 just east of its

junction with Road 858. Because of the flat terrain, boundaries are

indefinite along the north edge of the Big Cypress, particularly east

of Immokalee.



























W;B


I-W



^ ^-21.n 0tv



S'^ MONRo E COUNTY
\ i -- -


















December 1969.




21
^ ,,.i. ..- \ .





\ .'. 'f ".- -- ,.i




\ (' PARK
l----------------I- ---------------- -------










December 1969.


"-


/










Ecology


The ecology of the Big Cypress is water dominated. During the

wet season, as much as 90 percent of the undrained area is inundated;

during the dry season, as little as 10 percent is inundated, mostly in

shallow ponds and sloughs. Plants and animals are basically aquatic

and have adapted to fluctuating seasonal water levels.

The major plant communities can be divided into the following:

(1) pine-palm-palmetto forest, (2) wet prairie and marsh, (3) fresh-

water swamp, (4) hammock forest, (5) cypress forest, (6) tidal

marsh, and (7) mangrove swamp. In general, the hammock and pine-

palm-palmetto forests grow on land only several inches to several

feet higher than the surrounding wet prairies and cypress forests.

The surface under pine-palm-palmetto forests is often inundated

briefly after heavy rain and for perhaps several months during the wet

season. The wet prairies and marshes are treeless areas of emergent

vegetation that are seasonally inundated. Wet prairies are covered

with several inches of water during the wet season and are usually

dry during the dry season. Marshes have deeper water, but they may

also become dry at times.









The fresh-water swamps are areas of forest with hardwoods and

palms, epiphytic ferns, air plants, and orchids. These are inundated

most of the year. The Fakahatchee Strand is the largest, although

it contains some prairies, marshes, and hammocks. The plant life

within the Fakahatchee Strand is abundant and varied. Thirty eight

species of orchids alone grow there, seven of which are unique to

the area (Luer, 1964). The cypress forests also are inundated most

of the year. They are distinguished from fresh-water swamps in

that the principal tree is cypress.

The fresh-water prairies and marshes gradually change to tidal

marshes near the coast. These tidal marshes form a narrow band of

salt-tolerant grasses and sedges between the fresh-water and

estuarine environments. The mangrove swamps constitute a well-

defined zone bordering the tidal creeks, ponds, and bays along the

coast.

Animal life in the Big Cypress is both diverse and abundant.

Many species are aquatic. In the fresh-water environment, they

include prawns, mosquitofish, killifish, bass, and gar. Crabs,

shrimps, mollusks, and fish inhabit the estuaries; redfish, tarpon,

and snook invade the estuaries to reproduce and feed. The wildlife

consists of numerous species of amphibians, reptiles, birds, and mammals.

Seventeen of these are classified by the U.S. Fish and Wildlife Service

as rare or endangered. The better known of these 17 include the

American alligator, wood ibis, Florida everglade kite, Southern bald

eagle, and Florida panther.










land Development


In southern Florida, land development usually begins with the

construction of canals to drain swampy lands and to assure protec-

tion from high water during the rainy seasons. Significant develop-

ment affecting the Big Cypress began in the early 1920's, when two

major roads were built--the north-south road from Everglades City to

Immokalee, completed in 1926, and the Tamiami Trail, completed in 1928.

Both were constructed of borrow material from continuous pits adjacent

to the roads; the borrow pits became canals.

The north-south Barron River Canal, which furnished the fill

needed for the Everglades-Immokalee road (Road 29), was the first

major drainage canal in the Big Cypress. The Tamiami Canal, the

east-west borrow pit along the north side of the Tamiami Trail,

briefly intercepts water flowing southward and distributes the flow

to many bridges along the Tamiami Trail. A total of 49 bridges along

the 37-mile reach of canal between 40-mile bend and Road 29 distribute

flow to the western part of the Park. Culverts and bridges along

Road 94 similarly distribute flow.

Drainage was further modified in the late 1950's by construction

of the major Turner River Canal. This canal was the source of fill

for Road 840 A and extends from 1 mile south of the Tamiami Trail

northward for 20 miles.









Water was further controlled in 1963 with the completion of

Levee 28, the western boundary of Conservation Area 3A. The L-28

tieback levee and canal completed in 1965 assures the continued

southeastward flow of water through the 7.1-mile gap in Levee 28;

the Levee 28 interceptor canal, completed in 1967 (fig. 1), expedites

flow southeastward into Conservation Area 3 of the Central and

Southern Florida Flood Control Project.

The Everglades Parkway, commonly called Alligator Alley, was

completed in 1967. It extends eastward from Naples to the Fort

Lauderdale area and crosses the Big Cypress and Conservation Area 3.

Numerous bridges along the parkway permit southward flow of water.

Land development for housing in subarea B began in the 1960's

in the 188-square-mile Golden Gate Estates area in western Collier

County (fig. 4). Drainage canals, notably the Golden Gate Canal






and the Cocahatchee River Canal, have been dug to drain the western

part of the estates. In November 1969, the Fahka Union Canal was

completed to drain the southern part.

In 1966, the developers of Golden Gate Estates, acquired 105

square miles of land immediately west of Road 29 and south of the

Everglades Parkway. This tract, which includes all the Fakahatchee

Strand, has not been developed.

Areas currently under development or presumed to be planned

for development are shown on figure 4.


















30' 15'


I LIU -h' *. :
d, )1 ,.-- I
ooI
1, 28 .-h-k I- 4






COLCOUT COUNTY

-t
45' ROAD 45
CANAL


COUNTY BOUNDARY \ _' I
-\, EVERGLADES
PARK BOUNDARY r
\. NariONAL
PLATTED FOR DEVELOPMENT R\ r 2 0K'
i' 0 IDMLES I 25o
45' 30 1 5


Figure 4.--Map of the Big Cypress showing the areas platted
for development.


s810o









HYDROLOGIC CHARACTERISTICS OF THE BIG CYPRESS


Storage and Movement of Water


The undeveloped parts of the Big Cypress are largely inundated

during the rainy season, generally May through October. Normal

monthly rainfall for the Everglades and southwest Florida areas are

given in table 1. Nearly 80 percent of the rain normally falls

during the 6-month rainy season. Rainfall averages 53 inches per

year, but it has ranged from 35 inches to 80 inches per year. Summer

rains are usually short, intense, and frequent. Winter rains usually

result from frontal systems and are of longer duration and of less

intensity. Hurricanes occur most frequently in September and

October and usually bring torrential rainfall.

During the rainy season, shallow depressions fill with water,

and, because of the poor drainage, water stands on the land until

it evaporates or slowly drains off. Thus, as much as 90 percent of

the undrained part of the Big Cypress is inundated to depths rang-

ing from a few inches to more than 3 feet at the height of the rainy

season. As the dry season begins, the water level starts to recede.

The recession normally continues into May, when perhaps 10 percent

of the undrained area is covered by water in ponds and sloughs.









Table l.--Normal monthly rainfall for the Everglades and
Southwest Coast Division, Florida.


[Data composite from 12 stations of the U.S. Weather
Bureau on the periphery of the Big Cypress.]



Month Precipitation
(inches)

Jan. 1.63

Feb. 1.91

Mar. 2.65

Apr. 2.98

May 4.32

June 8.29

July 8.18

Aug. 7.47

Sept. 8.47

Oct. 4.39

Nov. 1.53

Dec. 1.42


53.24 (Total


Year









Records of water-level fluctuations are available from a few

sites, mostly near the outer edges of the Big Cypress. Water-level

fluctuations for the Tamiami Canal at bridge 105, 12 miles west of

40-mile bend, are probably representative of the water conditions

within subarea C; fluctuations in well 54, along the Everglades

Parkway at the eastern Collier County line, are probably representa-

tive of conditions in part of subarea C; and records of fluctuations

in well 382, a few miles east of Naples, are probably typical of

well-drained conditions in the western part of subarea B. Hydro-

graphs of the three stations for 1967 and 1968 are shown in figure 5.























BRIDGE 105


1967 1968


1967 1965
WELL 382
12D FCE -

,1- --_
L,-------- --------







SUBAREAF B
J F N 0 N D J I AF I M IAIM I JI J IA 0 N D


1967


1948


Figure 5.--Hydrographs of bridge 105, well 54, and well 382
for 1967 and 1968.








The three hydrographs in figure 5 reflect the cyclical rise

in water levels during the rainy season and the decline in levels

during the dry season. The graph for the Tamiami Canal at bridge

105 shows that inundation persisted for about 7 months in 1967 and

for nearly the same period in 1968. Water levels there are unaffected

by upgradient drainage and water-control works. The rate at which

water levels recede after the rainy season is a rough measure of the

runoff characteristics of the Big Cypress. The recession rates in

the channel at bridge 105 were 0.02 to 0.03 foot per day when the

area was inundated and 0.06 to 0.08 foot per day when levels were

generally below the land surface. These rates confirm general

observations that runoff from the Big Cypress is slow and that

water is stored within subarea C for extended periods. Water-level

fluctuations at bridge 105 reflect hydrologic events in the upgradient

areas of subarea C as well as events in the immediate vicinity.

The hydrograph for well 54 shows hydrologic conditions at the

eastern periphery of subarea A, where water levels are affected by

water-management practices in the Levee 28 Interceptor Canal. The

water levels remained a few feet below or slightly above the land

surface throughout 1967-68.










The frequent showers and the consequent rapid drainage to the

adjacent interceptor canal causes the sawtooth effect on the hydro-

graph during the rainy season. The lowest water level of record

in the vicinity of well 54 was about 5 feet below the land surface

at the end of the prolonged drought of 1962.

The hydrograph for well 382, a few miles east of Naples and

0.7 mile from the Golden Gate Canal, shows the contrast in pattern

and magnitude of fluctuations where drainage has been established.

The water level approached the land surface during the rainy seasons

of 1967 and 1968. The rapid rate of recession of water levels

demonstrates the efficacy of the drainage system.










The stage-duration curve'for the Tamiami Canal observation

station at bridge 105 (fig. 6) indicates the percentage of time






that a selected water level is equalled or exceeded at that site.

Note that the curve represents water level and not water depth.

The total range of water level during 1952-69 is 6.2 feet and

represents the difference between extremes of flood and drought.

During November 1969 to February 1970, the water level ranged from

8.0 to 8.9 feet above sea level, indicating that conditions in the

interior of the Big Cypress were wetter than average and that

inundation was widespread. At a level of about 7.5 feet the area

of inundation is greatly diminished, and the stage-duration curve

reflects the duration of ponded levels and ground-water levels in

the general area. At a level of about 7.0 feet, inundated areas

decrease to isolated ponds and the major sloughs; levels below

7.0 feet represent declines below the land surface.




































w

-j
J

( 8--
z L.ND SUL/FACE,, -1952- 69




m
<
'- 5 ---- -- -- -- -- -- --_- -
Id \
w
z

z \
0

3
--
21

OJ Q5 2 10 30 50 70 90 98 99.5 99.9
PERCENTAGE OF TIME DISCHARGE
EQUALED OR EXCEEDED THAT SHOWN


Figure 6.--Stage-duration curve for the Tamiami Canal at bridge 105 for
the period 1952-69.










The long-term record of flow through the Tamiami Canal outlets

within the reach represented by flow at bridge 105 (40-mile bend

westward to Monroe) is shown in figure 7. The hydrograph shows






the annual cycle of increased discharge during the rainy seasons

and reduced discharge during dry seasons. It shows also the wide

variation from year to year. Because changes by man within this

subarea (C) have not been significant, the fluctuations in discharge

reflect only the differences in the patterns of occurrence and the

total annual rainfalls. The discharge during 1940-69 ranged from

zero during droughts to more than 3,000 cfs after Hurricane Donna

in 1960. The discharge is distributed through 29 bridges within

about 20 miles. The longest periods of no flow were: 9 consecu-

tive months beginning December 1942; 8 beginning January 1944;

8 beginning January 1950; 8 beginning November 1955; and 8 beginning

November 1961.


































TAMIAMI CANAL OUTLETS, 40-MILE BEND TO MONROE
3500
3000-


I A A 4i


iIAAANi AMUd


- - 9 4 ~- P -- -' i 9 ~ 4 -4-' P -- I" 9 '- -


1940


1968


Figure 7.--Hydrograph of monthly mean discharge of the Tamiami Canal
outlets, 40-mile bend to Monroe.


o
,
U)
oi
a h


4 1000
u
S fi


~ ~~ _-L I I i i i PH i n iii


I m T n I"-










The annual mean discharge southward through the Tamiami Canal

outlets from 40-mile bend to Monroe for the total period of.record,

1941-69, ranged from about 75 cfs in 1956 to 620 cfs in 1960. The

graph in figure 8 shows the wide variation in discharge possible






from year to year. Equally wide variations in discharge occur from

month to month, as shown in figure 9. For example, the discharge






through these outlets for October, the wettest month, ranges from

2,700 cfs to 50 cfs, or perhaps less. Water levels at bridge 105

can change from 3.5 feet below the land surface to 1 foot above the

land surface within a 2-week period.

Additional data on the distribution of flows were obtained for

this report. Discharge was determined at 253 sites in November 1969.

These discharge data and data from the Tamiami Canal outlets were

used to determine the regional distribution of surface flows within

Big Cypress. Figure 10 shows the distribution of flows measured






during November 18-20, 1969.































a--
z
O
w
(n 600



I-
IJ
CL




U

300 -



U
(U


-I 100

z
z

1941 1945 1950 1955 1960 1965 1969




Figure 8.--Graph of annual mean discharge for the Tamiami Canal
outlets, 40-mile bend to Monroe, for the 1941-69
water years.






























Z8400 --|-I--|----|--|---
O
0
Z 2400 -
0
U
L&J
C,
I 2000 -
w
a-
I--
1600-
tiL MAXIMUM
U
& 1200 -
Boo-


MEAN ,' \
4 / \
"'400 -4

MINIMUM '

O I I I I I I I I
J F M A M J J A S 0 N D



Figure 9.--Graphs of maximum, mean, and minimum monthly discharge for
the Tamiami Canal outlets, 40-mile bend to Monroe,
1941-69.


38b



























3d











15'











2600











45


L-28 Twrek Lwr


COUNTY
v -.


Figure 10.--Map of the Big Cypress showing the distribution of
flows during November 18-20, 1969.


38c


EXPLANATION

ROAD

CANAL

LEVEE

COUNTY BOUNDARY

PARK BOUNDARY
350


2530'










The flow generally increases from north to south; however, flow

in the Barron River Canal decreased between the Everglades Parkway

and the Tamiami Canal because water spilled over its banks into

adjacent sloughs. North of the Everglades Parkway, the Barron River

Canal picks up flow from the Okaloacoochee Slough (fig. 2). Inter-

mittent records indicate a flow increase of about 150 cfs in that

reach during the recent high-water season. Large volumes were also

carried by drainageways in the Fakahatchee Strand.

Flow from the drainage system of the Golden Gate Estates was

about 660 cfs (637 + 19) to the south and about 400 cfs (366 + 55)

to the west. The Levee 28 Interceptor Canal, in subarea A, carried

400 cfs. Long-term discharge records of the Tamiami Canal outlets

show that large volumes of fresh water are contributed by the Big

Cypress to the Park. The November 1969 discharge measurements show

that substantial volumes of water are contributed to estuarine areas

along the Gulf Coast west of the Park.









Aquifers


The shallow aquifer presently supplies all water for municipal

use and irrigation in Naples and adjacent areas. The aquifer is

composed of the upper limestone of the Tamiami Formation, of Miocene

age, and the Pamlico Sand and the Anastasia Formation, of Pleistocene

age. Fine sand, clay, and marl in the lower part of the Tamiami

Formation and the upper part of the underlying Hawthorn Formation are

relatively impermeable and serve as a base for the shallow aquifer

and as a confining unit for the deeper Floridan aquifer (McCoy, 1962,

p. 24).

As indicated by McCoy (1962, p. 12), the Tamiami Formation

underlies nearly all of Collier County, and in the southern and

eastern parts of the county it lies at the surface or is covered by a

veneer of younger deposits. The upper part of the formation in

Collier County is composed of thin but highly permeable limestone.

This limestone apparently wedges out a few miles west, south, and east

of Immokalee. According to Schroeder and Klein (1954, p. 4), it does

not occur near the Dade-Broward County boundary. In a test well due

east of Immokalee at the Hendry County boundary, limestone of the

Tamiami Formation was penetrated at a depth of 22 feet; it was more

than 32 feet thick. The shallow depth of irrigation wells immediately

east of Immokalee suggests a thinning of the limestone to the west.










In the vicinity of Naples, the top of the limestone of the

Tamiami Formation ranges from about 25 to 55 feet below the land

surface. In the southern and southeastern parts of Collier County

it is at or near the surface. It is exposed in canals and ditches

and is quarried extensively along U. S. Highway 41 and along Road 29,

principally near Sunniland (McCoy, 1962, p. 13).

Limestone of the Tamiami Formation forms the principal part of

the shallow aquifer in Collier County. Its high permeability and

widespread occurrence are of extreme importance to the water resources

of the Big Cypress.

The Anastasia Formation is exposed along the canal banks on the

north side of Road 846. Two miles east of the intersection of Road 846

and U. S. Highway 41, a hard dense limestone layer in the formation

occurs near the land surface. This layer dips toward the Gulf of

Mexico.

McCoy (1962, p. 14) indicated that limestone of the Anastasia

Formation is generally permeable, and, where the formation thickens,

as in Naples, it forms an important part of the shallow aquifer.










In Collier County the Pamlico Sand is composed of fine to medium

quartz grains. The bottom of the sand is 10 to 15 feet below sea level

in Naples, where it overlies the Anastasia Formation. In the interior,

the Pamlico Sand forms a thin blanket over the Tamiami Formation or the

hard limestone layer of the Anastasia Formation. The permeable sand

permits rapid infiltration of rainfall.

The shallow aquifer has a maximum thickness of about 130 feet in

western Collier County, where limestone of the Tamiami Formation, the

Anastasia Formation, and the Pamlico Sand are hydraulically inter-

connected. The aquifer thins eastward to about 60 feet near Sunniland

and wedges out near Dade County. In southern Collier County it is

composed of highly permeable limestone of the Tamiami Formation, which

extends to a depth of at least 90 feet (McCoy, 1962, p. 24).

At present, water is withdrawn from the shallow aquifer for the

city of Naples from its municipal well field about 1 mile inland from

the Gulf of Mexico. Average pumpage from the well field is about 6 mgd

(million gallons per day), and the peak is about 14 mgd, when lawns are

irrigated heavily. Lower water levels caused by pumping in the well

field extend westward and eastward for about 1 mile from the well field.

The community of Golden Gate, just east of Naples also pumps about 1 mgd

from the shallow aquifer.











Withdrawals from the shallow aquifer for municipal supplies

and irrigation are small compared with natural discharge.

The water is a hard calcium bicarbonate type containing low

concentrations of chloride, with the exception of coastal areas of

salt-water contamination. McCoy (1962, table 3) states that shallow

ground water in the interior is of excellent quality.

The Floridan aquifer at depths greater than 400 feet is capable

of yielding large quantities of mineralized water (3,000 to 5,000 mg/l

dissolved solids) to flowing wells. The aquifer is a potential source

of supplemental water supplies for municipalities through desalination.









Salt-water intrusion


The known areas of salt-water intrusion in the shallow aquifer

are within a few hundred feet of the Gulf of Mexico and Naples Bay

and under the southern part of the city of Naples (McCoy, 1962,

p. 53-57). Salt-water contamination occurs at a depth of 40 to 60

feet below sea level in the area extending from Naples eastward at

least to Road 858. At depths less than 40 feet, the water contains less

than 250 mg/1 chloride, but the chloride content increases with depth.

Other areas of salt-water intrusion are the low coastal marshes seaward

of U. S. Highway 41 from Road 92 to Road 29 and possibly to Road 840A.

The increase in municipal pumping in Naples has caused no noticeable

inland migration of salt water in the shallow aquifer.

There are three possible sources of salt-water contamination in

Collier County: (1) inland movement of sea water along tidal reaches

of streams and canals, with resultant intrusion into the shallow aquifer

when fresh-water levels are low; (2) residual sea water left in the

sediments at the time of deposition or during past invasions of the

sea; and (3) upward movement of mineralized water under pressure from

the deep artesian aquifer. Critical sources of salt-water intrusion

are uncontrolled reaches of streams and canals, which permit inland

penetration of sea water in the flat coastal areas. Although mineralized

water may move upward naturally, where the aquiclude is thin and

moderately permeable, significant sources of contamination may be

upward leakage from deep artesian wells through corroded well casings

or through open well bores.









In 1968, the Collier County Commission established a "Salt

Barrier Line" beyond which uncontrolled drainage canals may not

be excavated. All new canals extending inland from this line are

required to have an adequate control structure at this line to prevent

further inland penetration of sea water. Although these structures

are primarily intended as.salinity barriers to prevent salt water from

moving inland along canal channels, they serve a secondary purpose in

regulating drainage of inland areas and in maintaining relatively high

ground-water levels in coastal areas.









Water Quality


The water of the Big Cypress is relatively unpolluted. This

conclusion is based on analysis of water from 15 sites (November

1969-March 1970), on some sparse data previously collected in

April and July 1969, and on comparisons of these data with those

from other areas in Florida. Generally, in the Big Cypress, con-

centrations of nitrogen, phosphorus, total organic carbon, and

persistent pesticides, which often serve as indicators of pollution,

are similar to concentrations in nearby, relatively uninhabited

areas but are considerably less than those of nearby urbanized areas.








Nitrogen and phosphorus are the two principal nutrients of

aquatic systems. In the Big Cypress, concentrations of total

nitrogen ranged from-0.19 to 1.85 mg/l (milligrams per liter) and

averaged 0.82 mg/l. About 81 percent of the total nitrogen was

organic, indicative of a natural environment. Concentrations of

total phosphorus (as P04) ranged from 0 to 0.33 mg/l and averaged

0.07 mg/1. For comparison, in 1969, concentrations of total nitrogen

in the upper St. Johns River in east-central Florida ranged from

0.55 to 1.4 mg/1 and averaged 1.06 mg/l. Concentrations of total

phosphorus (as PO4) in the upper St. Johns River basin ranged from

0.11 to 0.47 mg/l and averaged 0.26 mg/1 (D. Goolsby, oral communica-

tion, April 1970). In comparison with the more heavily populated

area of nearby Broward County, both the upper St. Johns River basin

and the Big Cypress have significantly lower concentrations of

nitrogen and phosphorus. Average concentrations of total nitrogen

and phosphorus (as PO4) in the canals of Broward County were 1.67

and 1.19 mg/l, respectively (table 2).











Table 2.--Nutrients, in mg/l, in water in the Big Cypress,
April 1969-March 1970, and in water from canals
in Broward County, Fla., December 1968-June 1969.


The Big Cypress


Broward County Canals


Constituent Range Mean No. of Range Mean No. of
samples samples


Nitrate
NO3

Nitrite
NO2

Ammonia
NH4

Organic Nitrogen
N

Total Nitrogen
N

Total Phosphorus
P04

Total Organic
Carbon


0.00-2.8 0.28


0.00-0.03


0.00-0.56


0.01


0.08


0.15-1.0 0.67


0.19-1.85


0.00-0.33


0.82


0.07


4 -27 11


0.00-12.0


0.oo- 0.67


0.oo- 3.5


0.00- 2.0


0.44- 2.8


0.01-24.0


1.26


0.08


0.62


0.86


1.67


1.19









Total organic carbon, which is a measure of the level of decay

of vegetal matter and other wastes, ranged in concentration in the

Big Cypress from 4 to 27 mg/1 and averaged 11 mg/1 (table 2).

Similar concentrations (12 to 23 mg/l) are reported from sparse

data from the Oklawaha and Withlacoochee Rivers in 1968 and 1969

(M. Kaufman, written communication, 1970). In Florida, vegetation

is abundant, and its decomposition and oxidation probably result

in this background concentration. Sparse data obtained during

1968-70 in southern Florida indicate that the concentration of

organic carbon in rain is low, averaging 3 mg/1 in 10 samples.

Organic carbon also occurs in many types of waste, including sewage

effluent. Total organic carbon concentrations as high as 420 mg/1

have been measured in canals in Dade County. Concentrations of this

magnitude are indicative of pollution.









Much of the abundant vegetation eventually becomes incorporated

into the sediment, where it represents a large potential reservoir

of organic carbon, nitrogen, and phosphorus.

In four ponds sampled in the Big Cypress, the sediment (dry

weight) had concentrations that ranged from 33.1 to 46.0 percent

total organic carbon and from 2.51 to 3.0 percent total nitrogen.

Sparse data from the upper St. Johns River basin indicate that

total organic carbon and total nitrogen in sediment are similarly

high in places. Sediment from a fifth pond in the Big Cypress had

a low concentration of total organic carbon (7.9 percent) and total

nitrogen (0.63 percent). The bottom of this pond was covered with

fine silt, which presumably originated from construction of the

adjacent highway, the Everglades Parkway. The sample contained

much of this silt; consequently, it contained relatively less

organic carbon and nitrogen.

Many trace elements and heavy metals are also essential for

life. In excess, however, the same materials kill many organisms

and pollute water. Concentrations of trace elements and heavy

metals in the waters of the Big Cypress are generally below levels

that are listed as the recommended upper limit for fish and wild-

life (McKee and Wolf, 1963).









Although organophosphate compounds, such as parathion and

malathion, are the most commonly used pesticides in Florida,

persistent chlorinated hydrocarbons, such as DDT, dieldrin, and

toxaphene, are also used and are found in the water, sediments, and

biota. The use of persistent pesticides results in biologic

magnification, a phenomenon in which toxins are increasingly con-

centrated in organisms up the food chain. As a result, large

predators at the top of the food chain may have concentrations that

interfere with reproductive processes or that result in chronic

diseases. Components of the DDT family (DDT, DDD, DDE) are the

most commonly detected pesticides in the Big Cypress ecosystem.

The concentration of the DDT family in the sediments of the

Big Cypress is significantly lower than that in the sediments of

canals in nearby Broward County (table 3). The average concentra-

tion was 5.09 pg/kg (micrograms per kilogram) in the Big Cypress

and 62.91 pg/kg in the Broward Canals. The average concentration

in the water, however, was higher in the Big Cypress, 0.07 pg/1

(micrograms per liter), than in Broward, 0.02 pg/1. The high

average in the Big Cypress is a result of three individually high

analyses of water samples collected near areas of human habitation

or activity. Sediment concentration is a better indicator of

pesticide contamination than water concentration because sediment

samples become more nearly integrated over a period of time. The

concentration in a water sample, on the other hand, may reflect

only temporary and local contamination.







Table 3.--Concentrations of the DDT family in water (pg/l) and sediment and
biota (pg/kg) from Big Cypress, April 1969 to March 1970, and from
canals in Broward County, December 1966 to June 1969. Concentrations
of the DDT family (pg/l) in rainfall in southern Florida, 1968 to
1970.


Water


Big Cypress


Broward County


Range Mean No. of samples Range Mean No. of samples

0.00-0.69 0.07 21 0.00-0.10 0.02 53

Sediment

0.00-16.39 5.09 20 0.00-1,172.0 62.91 35

Aquatic plants .

0.0-158 9 No data

Fish l

0.0-7,430 18 No data

Rainfall

Southern Florida

Range Mean No. of samples

0-4.75 0.65 29


I/ Mean values not given because different species were sampled.


52









Aquatic animals and plants from the Big Cypress tended to

contain higher concentrations of persistent pesticides than sedi-

ments (table 3). Aquatic plants had concentrations of these toxins

as high as 158 pg/kg, and fish had concentrations as high as

7,430 tg/kg. Plants and fish from the Golden Gate Canal near Naples,

had the highest concentration. Four fish (sunfish, large mouth bass,

and Florida Spotted gar) collected in the canal had concentrations

of the DDT family that ranged from 290 pg/kg to 7,430 Pg/kg.

Water quality changes seasonally and diurnally in the Big

Cypress. The changes are related to the natural hydrologic and

biologic regimes. The seasonal recession of water levels triggers

physical, chemical, and biological changes in water quality. During

low water, diurnal fluctuations in dissolved oxygen are greatest

as a result of the high concentration of organisms in the remaining

water. During the day, plants produce excess oxygen by photo-

synthesis. Dissolved oxygen as high as 150 percent saturation was

measured in one cypress pond in late afternoon. At night, dissolved

oxygen decreases as photosynthesis ceases and respiration demands

are met. Concentrations of dissolved oxygen may fall below 20

percent saturation (2 mg/l) before dawn. Fish-kills sometimes occur

at this time. Dr. Burton Hunt has observed, during several years,

spring fish-kills in the Tamiami Canal that usually began about

10 miles west of 40-mile bend, U.S. Highway 41, and often spread

both east and west for several miles (oral communication, 1969).

These kills occurred during periods of low dissolved oxygen.








The meager available data indicate that nutrient concentration

in water changes seasonally in the Big Cypress. The average con-

centration of total nitrogen from six stations decreased from

0.96 mg/1 in the dry period of April 1969 to 0.55 mg/1 in the wet

period of July 1969. Similarly, the average concentration of total

phosphorous decreased from 0.16 mg/1 in April 1969 to 0.01 mg/1 in

July 1969.









Hydrobiologic relations


The distributionand composition of the ecologic communities

in the Big Cypress reflect the seasonal availability of water.

Because of the seasonal fluctuation in water levels, the area is

rich in aquatic and water-tolerant flora and fauna. They constitute

a part of an ecologic system compatible with cyclic fluctuations in

water levels and adaptable to the natural catastrophes of fire,

flood, hurricane, and drought.

Because of the seasonal fluctuations in water levels, land

elevation is a controlling factor in the type of ecologic community

in a given location. Differences in elevation of 1 or 2 feet

distinguish hammock forest from wet prairies and fresh-water swamps.

These small differences, therefore, affect the ecology significantly.









Vegetal transects within the Big Cypress clearly show the close

relations between water levels, land elevation, and vegetation. The

transects are shown in figures ll-14; their locations are shown in

figure 2. The water levels shown on transects of the pine-palm-






palmetto forest (fig. 11) and the hardwood hammocks (fig. 12) repre-






sent a maximum (September 12, 1960), a minimum (May 30, 1962), and

that at the time of field investigation, November-December 1969.

They were interpreted for the sites from records of nearby Geological

Survey gages. The transects for the cypress strand (fig. 13) and






the Fakahatchee Strand (fig. 14) show only the water level at the






time of field investigation, when water levels were somewhat above

average. Because these transects are remote from gaged sites, no

estimates could be made of maximum and minimum stages.










































S-J
z 7. ...o ,
"' .-- o. ,toii on, '^ ==


S" -ATER LE VEL MAY JO, 19 2 .Eo-... o

^0
64 i LIMESTONE .





2-
-w

0 100 200 300 400 500 600
FEET


Figure 1l.--Vegetal transect in the Big Cypress showing pine-palm-
palmetto forest through a cypress-tree comnnity.




































RUSH SAWGRASS WEED *
S10-

4 4.TA LLVEL EP 2, 9
8-
U 7-SDIMENT
6


j I.E E L ..... 0 96
i3
0 100 200 300 400 500 6C
FEET




Figure 12.--Vegetal transect in the Big Cypress showing vet prairie
into a hardwood hammock.


57b
















































FEET


Figure 13.--Veptal tnusect In
into a qpsrp


the Big qrpress showing vet prarle
strfAd.












































4LJ 00 *


S AT


0
-- -





100 FEET





Figure 14.--Vegetal transect in the Big Cypress showing wet prairie,
hammock, swamp forest, and lake in the Fakahatchee
Strand.


57d








As shown in figure 12, the hardwood hammock forest is established

on land above high water. These hammocks are seldom inundated, but

many have small, shallow depressions that contain water, at least

during the wet season. The hardwood hammock at this site is sur-

rounded by a wet-prairie and marsh environment that is covered with

several inches of water during the wet season but is dry during

the dry season.








Figure 11 depicts three distinct communities. The pine-palm-

palmetto forest, although inundated for at least part of the year,

occupies the higher elevations. A wet-prairie community grows

where ground elevation is only inches lower than that of the pine-

palm-palmetto forest. The cypress forest grows at the lowest

ground elevation, as much as 2 feet lower than the pine forest.

The cypress forests are inundated most of the year. They contain

two distinct types of cypress: a small variety that grows in the

shallow water and a large variety that grows in the deep water. In

profile the large cypress-tree community is bell shaped, with the

tallest trees in the center and successively shorter trees toward

the edges. Open ponds occur within some of the tree communities;

these are vital to survival of many plants and animals during

drought. A somewhat similar transect is shown in figure 13. Again,

the wet-prairie environment yields to scrub cypress and, at a

slightly lower elevation, to a tall cypress-tree community in the

form of a strand. Such strands, along with the ponds in the tree

communities, are the last areas to become dry during the dry season;

many contain water perennially except during extreme drought.

Figure 14 shows a transect into the Fakahatchee Strand. Although

the Fakahatchee Strand is considered basically to be a swamp-forest

environment, the presence of other communities is obvious. This

strand contains more open water than any other fresh-water area in

the Big Cypress. It is ecologically rich and is unique in its

composition of flora (Finn, 1966).







As shown in the four transects, local ground elevations generally

vary less than 3 feet. Although the extremes of variations in water

levels are about 6 feet, the normal range is about 3 feet. Thus, the

seasonal fluctuations in water levels result in extensive, almost

complete inundation during the wet season and in localized concentra-

tion of water in the sloughs and ponds in the dry season.

The availability of food in the Big Cypress is related to

seasonal water levels. During the seasonal high-water period,

abundant food is produced in the flooded areas. Periphyton mats,

growing as thick as 2 inches on submerged vegetation and on the

flooded land, provide an abundant source of food for fish and

invertebrates. During this period, these populations increase

significantly. During the unseasonably high-water period between

December 1969 and March 1970, fresh-water prawns, the dominant species

trapped in a cypress slough near Road 94, increased from 31 specimens

per trapping with a total wet weight of 3 grams to 123 specimens

per trapping with a total wet weight of 10 grams (fig. 15). This






corresponds to the patterns of increase that have been measured in the

Everglades during comparable wet periods. As water levels decline

during the dry season, aquatic populations are forced to concentrate

in the remaining water in the ponds and sloughs. Densities as high as

5,000 fish per cubic meter of water have been reported (Kahl, 1962).






























(31) NUMBER OF PRAWNS PER TRAPPING

z
a. (123)
~I (65)




m5
a(31)
(5 (31)
a:


--


DECEMBER
1969


JANUARY


FEBRUARY
1970


MARCH


Figure 15.--Graph showing the number and wet weight
collected per trapping in a cypress
Cypress.


of fresh-water prawns
strand in the Big








The biomass concentrated in the ponds and sloughs is a rich

source of food for larger animals, especially fish, snakes, alligators,

and predatory birds. Iarge flocks of wading birds depend mostly

upon this concentration of fish for their food. As many as 350 wading

birds have been observed feeding in one small cypress pond less

than 150 feet in diameter (Barry Michael, oral communication, 1969).

The estuarine environment is equally responsive to change in

the fresh-water outflow from the inland areas. This fresh-water

outflow mixes with the salt water in the estuaries to provide

brackish conditions required by many marine and estuarine species

during some or all phases of their development (Tabb, 1962; McPherson,

in preparation).










The major vegetal food source in the estuaries is detritus from

the red mangrove (Heald, 1969; Odum, 1970), which is decomposed by

various microorganisms. The mangrove leaves and stems decompose

more readily in brackish water than in fresh water or on land. Thus,

the detritus-consuming organisms in the brackish environment, in

turn, provide food for higher organisms. Because of the abundance

of food and other salutary influences, the estuaries that drain the

Big Cypress are habitats for several commercially important marine

animals. Data from the Bureau of Commercial Fisheries indicate that

more than two million pounds of marine animals with a value of more

than $300,000 were landed in the vicinity of the Ten Thousand

Islands in 1960. Sixteen commercial species in this area are

dependent upon the brackish water of the estuaries at some stage of

their life cycle (Tabb and Yokel, 1968).

Water levels in the Big Cypress are of major importance to the

ecosystem because of the fact that a relatively narrow range in

stage governs the complete range of plant communities in the fresh-

water environment and the salinity balance in the estuaries. At

any given location, the environment can range from fresh-water swamp

to hammock forest within a range of average annual water levels of

less than 3 feet. A dynamic but delicate adaptation of species to

water levels prevails, and any abrupt and permanent changes of even

a few inches in the water-level regimen would result in major changes

in the ecology.





63







THE BIG CYPRESS AS A WATER SOURCE
FOR EVERGIADES NATIONAL PARK


Contributing area


Nearly half the Big Cypress--l,160 square miles--contributes

drainage directly to the Park. This half consists of that part of

subarea C east of the Barron River Canal.

The Barron River Canal was delineated as the general western

boundary of the contributing area on the basis of recent aerial

photographs. Aerial photographs, field observation, and available

hydrologic data indicate that the Barron River intercepts much of

the flow of the Okaloacoochee Slough except during high water, when

some water spills into the Fakahatchee Strand. In early April 1970,

about 50 cfs of water was flowing across Road 29 from the Okaloa-

coochee Slough into the Fakahatchee Strand. Available hydrologic

data indicate that the Barron River Canal intercepts as much as

150 cfs of the westward flow of the Okaloacoochee Slough. Although,

at times, flow across Road 29 is eastward as a result of locally

heavy rains, the net flow, undoubtedly, is predominately westward

into the Fakahatchee Strand. Thus, the western boundary of the area

contributing water to the Park is somewhat indefinite.









As a major drainage course through the Big Cypress, the

Fakahatchee Strand carries a significant part of the runoff. The

strand, however, does not pass through the Park, but lies just to

the north and west of it. Nevertheless, the strand is hydraulically

connected with the Park during high water. Further, some strand

water probably enters the lower ends of the estuaries that extend

inland into the Park.








Quantity of Water


The amounts of water entering Everglades National Park from

the Big Cypress in relation to other surface supplies available to

the Park are given in Table 4. The table shows computations of

average discharge into the Park for two periods, one before

(1941-62) and the other after (1963-69) the control of releases of

water from the Everglades drainage system to the Park.

These flow values indicate that subarea C contributed between

55 and 60 percent of the surface inflow received by the Park during

the 22 years before control of Everglades water at the northern

boundary of the Park and also during the subsequent 7 years, when

the Conservation Area 3 controls were in operation.

The inflow from subarea C of the Big Cypress supplies about 16

percent of the Park, an area of about 350 square miles at the extreme

northwest end of the Park. Thus, 16 percent of the Park area

receives between 55 and 60 percent of the total surface inflow.










Table 4.--Average flow to Everglades National Park, for the
periods 1941-62 and 1963-69.


Location



From Everglades and East Coast
drainage systems:
Taylor Slough
near Homestead /

Tamiami Canal outlets,
levee 30 to levee 67A

Tamiami Canal outlets,
levee 67A to 40-mile bend
Subtotal

From Big Cypress (subarea C):
Tamiami Canal outlets
40-mile bend to Monroe /

Tamiami Canal outlets
Monroe to Carnestown 2/

Barron River Canal
near Everglades 2/
Subtotal


Records
Available


1961-69


1941-62
Average discharge
cfs acre-feet
per year


46 33,300


1939-69 343


1939-69 172
561


1939-69 272


1953-69 380


1953-69


96
748


248,300


124,500
406,100


1963-69
Average discharge
cfs acre-feet
per year


45 32,600


98 70,900


477,100
580,600


196,900 299


275,100 405


69,500
541,500


102
806


216,500


293,200


75,800
585,500


Total average southward flow to Park


1,309


Note.--Hydrologic rather than calendar years
For example, the 1941 hydrologic year


947,600 1,608 1,164,100



are used in above table.
begins October 1, 1940.


Yl Measured near Royal Palm Hammock but considered representative index of
flow entering the Everglades National Park from the northeast.

2/ Drainage from Big Cypress considered as index of flow but does not include
any flow originating in area between Tamiami Canal and the park boundary.








Shorter records were correlated with longer records from

nearby stations and extended. The correlations, examples of which

are shown on figure.16, are considered to be fairly good. The






locations of the various contributing segments of the drainage

(table 4) are shown on figure 17.






The flows contributed to the Park from the Big Cypress, as

calculated for this report, differ from those reported by Leopold

(1969). Those in the Leopold report are based on an index of water

needs in the Park, using the available data for the 10-year period

ending in 1962, before water control in the Everglades. Flows in

the Leopold report were modified to be comparable with the figure

260,000 acre-feet per year, widely used as the average annual water

needs for the Park from the Tamiami Canal outlets from Levee 30 to

40-mile bend. The computations in the present report are based on

historic flows during 1940-62, before control of water releases from

the Everglades southward across Tamiami Trail.

















z
0
WCz


cu 500
w
03


L) Z
-oz 00

1L4)



ow

yo 200 ----, -----
0



ARECORD 1961-69
a 100









e O RECORD 1961-69
50 100 500 1000

200
z
0










00

D <


(n RECORD 1953-69



DISCHARGE,CUBIC FEET PER SECOND
TAMIAMI CANAL OUTLETS, 40-MILE BEND TO MONROE

Figure 16.--Graph showing selected correlations of mean annual discharges
used for extending streamflow records to the 22-year
period, October 1940 to September 1962.









TAMIAMI CANAL OUTLETS


LOCATION


2-2888 MONROE TO CARNESTOWN


t-2889 40-MILE BEND TO MONROE


II EVERGLADES NATIONAL PARK I I I
2-2890.4 LEVEE 67-A TO 40-MILE BEND 2-2890.6 LEVEE 30 TO LEVEE 67-A


Figure 17.--Maps showing location of the Tamiami Canal outlets.


69b










WATER-CONTROL WORKS IN THE BIG CYPRESS


Golden Gate Estates System


Construction of the Golden Gate water-control system began

in the early 1960's and has continued intermittently into 1970.

The initial phase began with the excavation of the Golden Gate

Canal, the primary canal that discharges water to the Gulf of

Mexico at Naples (fig. 1). At about the same time, Road 846 from

Naples to Immokalee, Road 858 east of Naples, and Road 951 south-

east of Naples were nearing completion. The borrow canals adjacent

to those roads were connected with the Cocohatchee River Canal in

the north and with the Henderson Creek Canal in the south, thereby

furnishing the basic network of a drainage system. Although the

canals are shallow, they are moderately effective in draining water

from the Golden Gate Estates, a 6-mile-wide rectangular area of

about 54 square miles east and northeast of Naples. Before construc-

tion of the drainage network, the area inland from Naples was

inundated each year during the rainy season, much as other parts

of the Big Cypress are.









The Golden Gate Canal extends inland from the Gulf about

20 miles. The bottom of the canal is excavated to about 5 feet

below sea level near the coast and to 6 to 8 feet above sea level

in the interior. The shallow depth of the canal and the distribu-

tion of weirs in the canal network limit the drainage of water

from the shallow aquifer in inland areas. By limiting the drainage

from aquifer storage, regional water levels near the coast are not

lowered enough for salt-water intrusion. Salt-water intrusion

caused by uncontrolled drainage by canals in the early development

of southeastern Florida was described by Parker (1951, p. 826-827).

When water levels are high, ground water moves to the canals

and flows over the weirs. Soon after the rainy season, flow over

the interior weirs ceases but continues longer in downstream reaches.

Water has continued to flow over the primary weir near the outlet

of the Golden Gate Canal since it was completed, about 1964.









Flow over the primary weir of the Golden Gate Canal has ranged

from 2,390 cfs on July 1, 1966, to 28 cfs on May 27, 1967, with an

average of 350 cfs (228 million gallons per day) during 1965-68.

The pattern of daily flow over the weir for 1966 and 1968 is shown

in figure 18. During the 1965-68 period of record, little or no






known flooding occurred in the area drained by the canal. An indica-

tion of the effectiveness of the canal in lowering water levels in

adjacent areas is shown by the rapid rate of recession of water

levels in well 382. (See fig. 5 for hydrograph.) Since the

beginning of water control in the Golden Gate Estates area, water

levels have been lowered by an average of 2 to 4 feet.

In 1968, construction was started on the Fahka Union Canal,

17 miles east of Naples and 6 miles west of the Fakahatchee Strand.

When it is completed, this canal will extend northward nearly to

Lake Traffard. The southernmost weir in this canal is 300 feet

north of U.S. Highway 41. The crest elevation is 2 feet above sea

level. Weirs will be distributed throughout this canal system also

to limit the drainage of water from the shallow aquifer and to main-

tain water levels in conformance with the general slope of the land

surface. Canals will connect the Fahka Union system with the Golden

Gate system. The Fahka Union Canal system should be as effective as

The Golden Gate system in lowering annual peak water levels and in

reducing inundation in subarea B.




























0 500



S OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEPT

LJ 3000

W 2000 \ --~ ^ -^^
1 96000 1967 1 9y


C 500 I -




0 100- -- -__
OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEPT
WATER YEAR


Figure 18.--Hydrograph of discharge for the Golden Gate Canal for the
1966 and 1968 water years.











Barron River and Turner River Canals


The Barron River Canal excavated during the 1920's to obtain

fill material for Road 29, extends from Everglades City northward

to limokalee. Similarly, the Turner River Canal, 5 miles east of

the Barron River Canal, excavated during construction of Road 840A,

extends from the Tamiami Canal northward to the Everglades Parkway.

The two canals form the basis of a drainage system for the western

part of subarea C south of the Everglades Parkway. The effect of

the canals on lowering water levels has been relatively small.

Records of flow are available for 17 years for the Barron River

Canal, but only partial records of flow are available for the Turner

River Canal. The discharge of the Barron River Canal during the

1966 water year is shown on figure 19. The hydrograph shows the






typical high discharge for the rainy season and the general decline

in flow through the end of the dry season. The average discharge

for 17 years of record is 102 cfs, with a maximum average year's

discharge of 292 cfs and a minimum of zero.


























40 MILE BEND TO MONROE


S500oo
0
m 200






S OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP
U


u BARRON RIVER CANAL
10Oo----
__ ___16____________ r
x WATER YEAR

100-
50
20

0OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP1



Figure 19.--Hydrograph of discharges for the Tamiami Canal outlets,
40-mile bend to Monroe and the Barron Canal for the
1966 water year.











The flow of the Barron River Canal is controlled through a

series of stop-log controls at seven sites north of U.S. Highway 41.

In general, all boards are removed from the controls during the

rainy season, and, as water levels decline after the rains cease,

the boards are replaced to limit drainage from the shallow aquifer.

Flow exceeds 100 cfs for several months, (see fig. 19), suggesting

continuous contribution of water from the shallow aquifer. As the

dry season persists, the water table continues to decline because

of evapotranspiration and seepage to the canal. In the upper reaches,

the canal goes dry when the water table declines to levels below

the canal bottom. The Barron River and Turner River Canals receive

substantial quantities of water from the Okaloacoochee Slough.

Because the Barron River Canal is more than 40 years old, water

levels in the vicinity have stabilized.











PROBABLE EFFECTS OF CONTINUED URBAN GROWTH
ON WATER RESOURCES AND BIOTA


Expected Pattern of Urban Expansion


Existing water-control and drainage systems, the beginning of

rudimentary drainage works, and areas already proposed and platted

for housing suggest four general areas of urban growth in the near

future. The major area of urbanization is the Golden Gate Estates

complex, which is expanding east and southeast from Naples, as shown

in figure 4. The primary Fahka Union Canal, which will provide water

control for the inland phase of development, is nearing completion,

and housing construction immediately inland from Naples is underway.

As urbanization continues, secondary canals will be required for

protection against high water levels.

The second probable area of urbanization is the low coastal

zone from Naples southeastward to Ochopee. Development seaward of

U.S. Highway 41 will probably start soon. Canals are being excavated

from the highway to the coast to provide fill for home construction

and to furnish access to the Gulf for small boats. Coastal urbanization

of this type should accelerate because of the high desirability of

waterfront housing with access to the ocean. Some scattered industrial

growth may be expected adjacent to and immediately north of U.S. Highway

41, probably of the light-industry type associated with building

construction and services.












A third probable site for development is 200 square miles west

and east of the Barron River Canal between the Everglades Parkway and

U.S. Highway 41, which includes the Fakahatchee Strand. Development

plans here are not known, but the 100-square-mile area east of the

Barron River Canal is bounded on both sides by canals, which represent

the beginning of water control. This area, part of subarea C, contributes

water to the Park. In 1970 a few scattered dwellings had been built,

mainly along U.S. Highway 41; building will probably continue but at

a slow rate, unless additional protection from high water is provided.

Gum Slough and vicinity, a 50-square-mile area immediately north

of the Park, may be developed in the near future. A formal drainage

district was proposed in 1969, but, because of objections, no further

action has been taken.

The 39-square-mile area owned by the Dade County Port Authority,

intended to become a jetport, is rather inactive. At present, one

runway is operational for training under an agreement between the

Departments of Interior and Transportation, State of Florida, and Dade

and Collier Counties. Further development is precluded under the

present terms of the agreement.

The remainder of subarea C east of the Turner River Canal, ex-

cluding the jetport site, is undeveloped and is not at present subject

to pressures for development.











Effects on water resources


An area such as the Big Cypress cannot be urbanized until

drainage and water-control measures are begun. Once a drainage

system becomes operational, water supplies commensurate with pro-

jected water needs are required. Water control can be achieved by:

(1) raising the land surface by filling to elevations above high-

water levels; (2) excavating systems of controlled primary and

secondary drainage canals; and (3) combining land fill and canal

excavation. Each affects water levels differently. Excavation for

land-fill operations results in a slight lowering of water levels

because of increased space for ponding of water and increased

evaporation from the more persistent excavated open-water areas;

canal systems result in a significant lowering of water levels; the

combination of land fill and canal excavation results in an inter-

mediate lowering of water levels. Uncontrolled drainage, causing

massive water losses, would probably change the aquatic ecosystems

irreversibly. But areas of future urbanization will probably have

similar patterns and methods of water control and management as

those in the Golden Gate Estates, where controlled drainage is

designed to lower the overall water level evenly and to prevent

excessive draining of the shallow aquifer.












The first effect of urbanization in the eastern part of subarea

B and the western part of subarea C would be to lower the annual

high-water levels and to accelerate runoff adjacent to improved

primary canals. Secondary canals would lower water levels in

progressively larger areas. Thus, fresh-water runoff would be

accelerated further. The net result of urbanization would be to lower

water levels in the western half of the Big Cypress and to reduce the

time the land is inundated.

The annual controlled discharge of the primary canals represents

not only water discharged for protection from high water levels but

also water potentially salvageable, through good water management,

for urban use.











The ultimate configuration of the water table under urbanization

would be similar to that of the present day but at a lower elevation.

The system of controls (weirs) in the canals, under good water

management, would permit discharge of flood water only and would step

the water levels up from lower elevations at the coast to high

elevations in the interior. The depth of canals below the water

table would have a significant effect on ground-water pickup along

canals, the seaward flow in canals, and the height of the regional

water table.

Maintaining water levels above sea level (2 feet or more) in

the coastal areas would be a major factor in preventing salt-water

intrusion. With this safety factor, municipal well fields could be

established near the coast to serve the expected coastal urban

growth. Preferred sites would be inland from coastal control

structures and adjacent to primary canals. Such sites would assure

nearly constant well-field replenishment by infiltration from canals,

thereby minimizing lowering of water levels.










The prime factors in the optimum development of water resources

are design and subsequent water management commensurate with hydrolo-

geologic conditions. Effective water management will have to include

control of water pollution, as population increases. If urban planning

and water management are haphazard, pollution could constrain the use

of the shallow aquifer for water supplies and the lakes and canals for

recreation. Pollutants in canals could readily move to adjacent well

fields. When canal systems are fully operational and demand for water

increases with population growth, flow in canals may decrease, resulting

in less dilution and flushing of any pollutants reaching the canals.

The control of pollutants reaching canals, therefore, may become of

critical importance.

No estimate is available of the total water-supply potential of

subarea B and the western part of subarea C. The present total water

use in those areas is insignificant compared with the quantity evap-

orated, transpired, and discharged through the canal systems. The

largest center of water use is the Naples area, where the peak daily

water needs are about equal to the minimum discharge of the Golden

Gate Canal (28 cfs, or 18 mgd), or to about 8 percent of the average

discharge of the canal. The western part of the Big Cypress, there-

fore, can yield at least 10 times the present Naples water use with-

out significantly lowering water levels. The Naples Water Department

is presently exploring 12 to 15 miles inland for future municipal

water supplies. No estimate is now available for the water potential

of the remainder of subarea B and the eastern part of subarea C.


82











Effects on biota


Uncontrolled drainage of the Big Cypress, especially in the

Fakahatchee Strand and other major slough areas, would undoubtedly

alter the local ecology and would influence that in surrounding

areas. The ecology of the Big Cypress would, of course, be changed,

and biota in estuaries and the adjacent Gulf of Mexico would be affected.

Plants and animals of the Big Cypress depend on the seasonal

fluctuation and movement of fresh surface water. In this environ-

ment, aquatic foods are produced seasonally. The widespread pro-

duction of aquatic foods when most of the land is inundated and the

subsequent concentration of this food in creeks, sloughs, and ponds

as water levels decline in the dry season are most significant in

maintaining the rich and varied biota.

Uncontrolled drainage of the Big Cypress would decrease the

extent and the duration of fresh-water inundation, thus decreasing

production of aquatic food and fish. Populations of the larger fish,

reptiles, birds, and mammals that depend upon concentration of fish

could be reduced or eliminated. Similarly, the estuarine environment

would be affected by changes in water-flow patterns, as fresh-water

inflow to the estuaries controls seasonal changes in salinity, a key

factor in estuarine ecology.










In general, estuarine species are adaptable to wider ranges of

environmental changes than marine or fresh-water organisms are, but

they are susceptible to excessive variations in salinity, temperature,

or turbidity (Hedgpeth, 1957), especially when the variations are

rapid. Such variations or changes in the seasonal cycles of the above

parameters would adversely affect the nursery function of the water.

Drainage of subarea C comparable with that of the western part of

subarea B would produce conditions that could not be tolerated by some

estuarine species. Increased silt and mud in the estuaries from

construction activities also would adversely affect benthic forms,

vital to the food chain, by covering them, reducing light penetration,

or covering hard substrata necessary for larval attachment.

Drainage and development of the Big Cypress undoubtedly would

result in some increase in pollution. Pesticides are now at

relatively low concentrations in the Big Cypress and are significantly

lower than in the surrounding developed areas (table 3). Land

development would probably increase pesticide levels in the water,

sediment, and biota, and higher levels of organochlorine pesticides

would be concentrated at the top of the food chain in the predatory

birds, mammals, and fish.











These organochlorine pesticides increase the production of

enzymes in birds. Excess enzymes break down steroid hormones essential

to production of calcium, resulting in eggs with thin shells and in

increased mortality of the young. The high level of these compounds

in the American eagle and several hawks, probably accounts for their

declining numbers in the United States in recent years (Hickey and

Anderson, 1968).

Increased pesticide buildup in the estuaries would endanger the

nursery function of the water, because young organisms are usually

more sensitive to toxins than adults (Moore, 1958). Crustaceans, which

constitute one of the larger estuarine groups, are intolerant of

chlorinated hydrocarbons. Aldrin and endrin concentrations as low as

0.6 part per billion kills pink shrimp, the most commercially important

crustacean in these waters (U.S. Department of the Interior, 1964).










Further drainage and development of the Big Cypress would

likely result in increased nutrients in the canals and estuaries, which

could lead to changes in species composition of both fresh- and

brackish-water organisms and to eutrophication. Recent studies by

Wood (oral communication, 1970) have shown that the species composi-

tion of periphyton in the Park has changed noticeably within the

last few years. Wood believes that these changes may have resulted

from increased nutrients.











The western part of the Big Cypress in subarea B is now being

drained. The lowering of water levels and change in runoff patterns

will result in biologic change. The change can be minimized only

through careful planning and proper resource management.

Drainage with consequent loss of habitat has reduced the number

of wood ibis in the Big Cypress from about 15,000 in the mid-1960's

to less than 6,000 in 1969 (William Robertson, written communciation,

1969). At least 60 percent of the wood ibis of the United States

nest in this area. To compensate for the loss of feeding area, as

a result of this drainage, artificial ponds are being constructed

near the Corkscrew Swamp to furnish adequate food for a major

colony of wood ibis.

Water hyacinths are now common in the Golden Gate Canal and

can be expected to spread. Extension of canals would facilitate

the dispersal of some undersirable aquatic plants, including water

hyacinth. This plant is common in most canals in south Florida and

can extend its range into the interior swamps. Such spreading has

been observed in some cypress ponds north of U.S. Highway 41, where

the water hyacinth has replaced water lettuce, considered to be a

more desirable plant. After this replacement, open-water areas in the

ponds were reduced, and ducks were no longer observed in the area

(Oscar Owre, oral communications, 1970).












Extensive drainage and development of the Big Cypress, particularly

subarea C, would result in extensive change in the environment of

downstream areas, including parts of the Park. The fresh-water

ecosystem would be depleted and replaced by a terrestrial ecosystem.

The present estuarine environment would be significantly altered.

Wildlife, including rare and endangered species dependent upon aquatic

environment or wilderness areas, would be further reduced in number

and might be destroyed.










Effects on Everglades National Park


Continued eastward urban expansion in the Big Cypress,

particularly into subarea C south of Everglades Parkway, would

affect water flow, water quality, and biota of the Park.

At present, an average of 541,500 acre-feet of water per year

moves toward the western part of the Park from subarea C. This

water is of good quality and does not have high concentrations of

undesirable contaminants. The annual wet and dry cycle, with its

attendant inundation and recession, is conducive to production and

concentration of aquatic foods, which support a wide variety of

birds and animals in the Big Cypress and in the Park. Drainage

and development would change the period and pattern of flow, would

increase contaminants in the water, and would reduce aquatic pro-

duction. These changes would adversely affect both the fresh-water

and estuarine biota of the Park.

Large wading birds, such as the wood ibis and the roseate

spoonbill, that congregate at times in the Park live in much larger

areas than the Park. These birds move back and forth between the

Park and the Big Cypress. Extensive drainage and development of

the Big Cypress, therefore, would eliminate their northern habitat.











A continuing program of hydrologic and biologic investigations

in the fresh-water and estuarine environments in subarea B would

furnish valuable information in determining the effects of drainage

on water quality, water levels, and biota. This information would

have transfer value in predicting changes in other parts of the

Big Cypress if they are opened to further land development. Further

investigations in subarea C would furnish benchmark information for

monitoring changes, both in the Big Cypress and in the Park, brought

about by future changes in hydrologic conditions.










ACKNOWLEDGMENTS


All the people who have kindly lent assistance and who have

freely given information vital to this report and the investigation

on which it is based are here most gratefully acknowledged. All

who aided would be too numerous to list, but they, as well as those

listed below, who helped directly, should know that their contribu-

tions are much appreciated by the authors.

The following people provided information or assistance in

the preparation of this report:

J. I. Garcia Bengochea Black Crow and Eidsness

R. A. Ghiotto Black Crow and Eidsness

B. T. Hunt University of Miami

J. A. Kushlan University of Miami

J. Kuperberg Collier County Conservancy

M. Morris National Park Service

F. Nix National Park Service

J. C. Ogden National Park Service

P. Owens National Audobon Society

0. T. Owre University of Miami

J. C. Raftery National Park Service

W. B. Robertson National Park Service

J. W. Rogers Collier County Sheriff's
Department












W. F. Savidge

J. B. Sitzler

Smally, Wellford and Nalven

W. V. Storch


R. L. Taylor


Turner

Vernon


E. C. Winte


City of Naples

Dade County Port Authority



Central & Southern Florida
Flood Control District

Central & Southern Florida
Flood Control District

Collier County

Florida Department of Natural
Resources

National Park Service




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