Man-made alterations in the original ecosystem of
west-central Collier County have been massive and of long
duration. The changes we have been able to perceive are
listed below. It will be noted that much had been done
before the Golden Gate tract came under development.
1. Cutting of minor drainage canal systems
for agricultural purposes during the years 1940-1950.
2. Clearing of an estimated 13,440 acres of
pine, scrub cypress and grassland within the present bounds
of the Golden Gate for farming which included creation of
an estimated 190 acres of perimeter farm drainage ditches.
3. Clearing of approximately 425 acres of logging
tramways within the boundaries of the Golden Gate tract in
4. Cutting of the major cypress and pine resources
during the period 1943-1957 with attendant loss of canopy and
increase in fire hazard, but area still mainly undrained.
5. Digging of Golden Gate canal system, said to
be approximately 183 miles long and averaging 100 feet in
width, created approximately 2,200 acres of permanent water
where perhaps less than 100 acres existed before.
6. Clearing right-of-way for the Golden Gate canal
system created about 4,400 acres of "upland" berm and spoil
7. Clearing 813 miles of road right-of-way for
the Golden Gate road network to an average right-of-way
width of 120 feet, created an estimated 11,800 acres of road,
grassy swale and spoil pile habitat through the original
8. Drainage in the past decade has lowered the
water table over the 173.5 square mile (= 111,000 acres)
Golden Gate tract an estimated average of 2.5 feet.
9. Clearing and elevation of land for roadways
and canal berms has resulted in rapid colonization of these
drier sites by grasses such as broomsedges, panicum species
and weeds which pose special fire hazard each winter.
10. Fires have burned virtually every acre within
the Golden Gate tract, sometimes repeatedly, during the last
11. Fires, oxidation, and compaction have virtually
destroyed the peaty muck resources of the former wet strands
as well as the tree stands growing therein.
12. Opening of the tree canopy has had the following
a. Decreased the humidity levels so that
most moisture-loving epiphytic plants
are in final stages of dessication.
b. Destroyed the "greenhouse effect" which
protected delicate vegetation from cold
by allowing wind penetration into the
centers of remaining forest blocks.
c. Differential heating of roadways and
adjacent forest blocks creates locally
intense winds which further aggravate
drying effect on the drained forest.
d. Created nearly 2,000 miles of artificial
"edge" between forest and grassland which,
with drainage, has permitted rapid expan-
sion into old wetlands by upland birds,
mammals and insects.
13. Drainage has shortened the hydroperiod from
/ 5 months in dry years or 7 months in wet years originally
_to between 2.0 and 2.5 monthat present. ---
/--. Has "set the stage" for invasion by exotic--
species especially cajeput, Melaleuca quinque'nervia, and
Brazilian pepper, Schinus terebinthifolius.
15. Overdrainage, particularly of higher lands,
has lowered the water table to a position below the caprock.
We believe that this destroys capillary connection between
the groundwater and the sands lying on top of the caprock,
with a resultant severe water shortage in the plant root
zone. This is leading to a rapid conversion from cypress
to pine forests which is fostered by repeated burning.
As is usually the case, not all these impacts are
completely negative. Creation of permanent water in the
canal system has undoubtedly provided far more secure dry-
season refuge for aquatic and semi-aquatic animals than
originally existed. Furthermore the access, now made avail-
able to permanent water of the canals, creates better
conditions for edge feeding mammals like raccoons and otters
and for drinking by a number of other species. The canals
also support a much larger population of bass, bream, catfish,
gar, etc. than was possible in pre-drainage time and this,
in turn, has led to use of the area by ospreys and an
occasional bald eagle.
In the discussion on the fauna it was also indicated
that drying due to drainage had led to invasion of former
swamp forest areas by upland animals and the resultant popu-
lations attract predatory birds. The additional roadside-
forest edge habitat made available, particularly in the wetter
area south of S.R. 84, now may provide food and shelter in
greater measure than before clearing.
Finally, flooding of fallow farmlands produces large
numbers of small aquatic food organisms (see section on the
fauna) which are of undoubted importance (Browder, 1974) to
wading birds for maintenance feeding as well as rearing young.
During the six-month period of this project we made
numerous notes on the fauna of Golden Gate which are presented
in Table 6, as well as interviewing interested hunters,
loggers and private citizens regarding areas of occurrence of
the more noticeable animals. We also surveyed the literature
but found very little that pertained to the Golden Gate area.
The reader is referred to Layne (1974), Leopold, et al. (1969),
Loveless (1959), Loveless and Ligas (1959), and Schemnitz
(1972) for description of the general condition of birds and
mammals of the Big Cypress. Part of the literature survey
involved compiling brief life history descriptions for the
more common birds and mammals. In doing this we drew heavily
from Palmer (1949) and Schwartz and Schwartz (1959) as well as
adding data from our own files where useful. We would also
recommend the fine work by Kimball (1965) on butterflies and
moths of Florida, by Woodruff (1973) on scarab beetles, by
Muma (1967) on scorpions, whip scorpions and wind scorpions,
and by Needham and Westfall (1954) on dragonflies to anyone
wishing to study these larger insects. Some of their records
are from Collier County locations.
Although we believed the above kinds of information
would be appreciated, they actually were not expected to give
information which would be instructive in the context of
environmental conditions existing in the Golden Gates and
we began looking about for some method of assessment. The
search for some inferential methodology of ascertaining areas
of greatest animal abundance was rewarded, very early in
October, by our notation that there were extraordinary
numbers of hawks in the mixed forest area of southern Golden
Gate and these seemed to be taking up winter territories.
We reasoned that, since such birds are predators, their
Table 6. Fauna observed by the writers in the Golden Gate
Tract during the period October 1975 through
April 1976. Bird list contains many migrants
which are most common during the periods September-
December and March-May.
Mammals (Layne, 1974)
Didelphis virginiana Kerr
Sylvilagus floridanus J. A. Allen
Sylvilagus palustris Bachman
Sciurus carolinensis Gmelin
Sciurus niger avicennia Howell
Odocoileus virginianus Zimmerman
Procyon lotor Linnaeus
Lynx rufus floridanus Rafinesque
Ursus americanus floridanus Merriam
Dasyus novemcinctus Linnaeus
Reptiles (Conant and Conant, 1958)
Striped mud turtle
Florida box turtle
Florida green water snake
Florida water snake
Eastern garter snake
Southern ribbon snake
Southern ringneck snake
Florida black snake
Rough green snake
Smooth green snake
Eastern indigo snake
Yellow rat snake
Eastern coral snake
Dusky pigmy rattlesnake
Terrapene carolina bauri
Pseudemys floridanus peninsularis
Anolis carolinensis carolinensis
Natrix cyclopion florjdana
Natrix sipedon pictiventris
Thamnophis sfrtaldsq sirtalis
Thamnophis sauritus sqeckeni
Diadophis punctatus punctatus
Coluber ons trit or paldicola
Coluber constrictor ,prapus
Drymarchon corals couperi
Elephae obsoleta quadrivittata
Agkistrodon piscivorous piscivorous
Sisturus miliarius barbour
Florida cricket frog
Florida chorus frog
Southern leopard frog
Acris gryllus dorsalis
seudacris nigrita verrucosa
Rana pipiens sphenocephala
Fishes (Bailey et al., 1970)
Lepisosteus platyrhincus DeKay
Megalops atlantica Valenciennes
Ictalurus notalis (Lesueur)
Ictalurus melas (Rafinesque)
Clarias batrachus (Linnaeus)ll
Floridichthys carpio (Gunther)
Fundulus chrysotus (Gunther)
Jordanella floridae Goode and Bean
Gambusia affinis (Baird and Girard)
Poecilia latipinna (Lesueur)
Centropomus undecimalis (Bloch)
Lepomis macrochirus Rafinesque
Lepomis megalotis (Rafinesque)
Lepomis punctatus (Valenciennes)
Micropterus salmoides (Lacepede)
Eucinostomus gula (Quoy and Gainard)
Eucinostomus argenteus Baird and Girard
Archosargus probalocephalus (Walbaum)
Mugil cephalus Linnaeus
Birds (Robbins, Bruun and Zim, 1966)
Cooper's hawk -
/Introduced species probably in Golden Gate canal system as
cold-stunned specimen was found in Tamiami Trail canal a mile
west of Ochopee.
Great blue heron
Little blue heron
Great horned owl
Rall us limicola
Columbigallina pas serina
Black-throated blue warbler
Dumatella caro inensis
S inus tristis
Common Butterflies (Klots, 1951)
Ruddy dagger wing
Large orange sulphur
Euptychia hermes sosybia
Danaus gilippus berenice
Heliconius charitonius tuckeri
Dryas Julia cillene
Araulis vanilla nigrior
Pap lio cresphontes
Pap lio marcellus
Moths (Kimball, 1965)
Actias luna mariae-/
Cocytius antaeus medor (larva only)
Isoparce cupressiTlarva only)
Scarab beetles (Woodruff, 1973)
Rhino dung beetle
Deltachilum gibbosuum gibosuum
Phanaeus igneus floridanuslT "
Scorpions (Muma, 1967)
Hentz's striped scorpion
Slender brown scorpion-
Giant whip scorpion
Spotted tail-less whip
Tarantula marginemaculata (common)
Crustaceans (Hobbs, 1942; Pennak, 1953)
Procambarus alleni (Faxon)
Molluscs (Burch, 1973; Bartsch, 1937)
Fresh water clam
Apple snail ..
- Little attention was paid to moths, but the discovery of a
cacoon of this species on willow, Salix caroliniana, bordering
a farm drainage ditch 1/4-mile: easg ot the eastern terminus of
Golden Gate Boulevard seemed noteworthy since Kimball's southern-
most record was ClwisTOti and Kis'immee.
- Found in hole left during removal of cabbage palm by nurserymen
at S.R. 84 and Desoto Boulevard.
-Found on bobcat spoor at Patterson and S.E. 90th Street.
position, over winter, might be used to locate maximal
populations of prey species which could, in turn, be related
to habitat conditions.
The hawks of interest were red-shouldered hawks
and red-tailed hawks. On the basis of about 6 years of
intensive banding of such hawks in South Florida we suspected
that most, if not all, the red-shouldered hawks were local
nesting resident birds. Examination of the plumage color
and marking of the red-tails, on the other hand, showed
most to be migrants from the north. Careful counts of these
birds during a single short time period, with notation of
their position within the discrete blocks of land bounded
by roads (Figure 18), over time should show where prey
density was greatest.
Prey of the red-shouldered hawks in South Florida
is overwhelmingly made up of frogs, lizards, small snakes,
small turtles and crayfish. They will also eat mice and
other small mammals, but our experience suggests these are
swamp birds most dependent on aquatic and semi-aquatic
animals of the above types. Red-tailed hawks, on the other
hand, consume mice, squirrels and rats as well as some birds
and larger snakes.
It quickly became apparent that there was a dense
concentration of both species in the mixed forest area south
of S.R. 84 (Alligator Alley). This remained constant through
the winter and into early March. At that time the red-tails
returned north while the red-shoulders became much more
secretive as their nesting season commenced.
An actual census conducted during the period
December 6 through December 18, 1975 produced a count of 100
birds in the Golden Gate tract south of S.R. 84. Of this
total, 78 were found south of Berson Boulevard and west of
Desoto. An additional 16 hawks were scattered over the
burned-out cypress and mixed forest in the area bounded by
Distribution of red-shouldered and
red-tailed hawks in Golden Gate -
October 1975 March 1976.
Hatched area average of 1 hawk
per square mile. Solid area
average of 2 to 8 hawks per square
0 1 ? I4 I _
i f r-i T
-- -- -- -- I- 't-- I-
II I i
I I I-
Stewart Boulevard in the north, Lynch Boulevard on the south,
Desoto on the east and Miller on the west. Four additional
hawks were observed along stub-roads west of Miller Drive.
During that same time only two hawks were found north of
68th Avenue, S.W., in the cypress-pine-grassland habitat.
On the basis of these counts we believe that a
clear case can be made for assuming that the winter season
density of all small prey species was greatest in the
lightly burned mixed swamp forest, less dense in heavily
burned mixed swamp forest interspersed with pine-cabbage palm
strands, and least dense or virtually absent in dwarf cypress,
upland pine, and upland grasslands. Key factors appear to be
water, or at least moist conditions, which attract the prey
species, and dense foliage of the mixed forest which provides
mid-day shelter for the hawks.
It was noted that the hawks frequented perches near
roadsides along the undisturbed edges of the mixed forest
blocks. Red-tails appeared to hunt the spoil piles along
these edges. These spoil piles are composed of soil, rocks
and tree debris, overgrown by dense mats of vines, especially
milkweed vine, Funastrum clausum, broom sedge grass,
Andropogon spp, and weeds. Rats, snakes and mice are abundant
in these piles.
Finally, it was noted that the population of
red-shouldered hawks in the Jane's Scenic Drive was very
high at the same time period.
The winter distribution of deer, bear, turkeys and
the larger wading birds seems to conform very closely to
that shown by the hawks. The major deer hunting in the
Golden Gate appeared to be localized in an area east of
Desoto along the entire north-south sector of the Golden
Gate and then south of S.R. 84, to include-miost of the
mixed forest region as far west as Miller Drive. Hunting
activity was especially noticeable south of Stewart.
A sow bear with two cubs and a single yearling black
bear were reported to us as crossing Patterson a few blocks
north of Stewart. Turkey sightings were made on several
occasions east of the main "out-parcel" north of Stewart.
Eight gobblers were observed at one time at close range in
the early morning hours of December 18. Bobwhite quail were
most commonly seen in the grasslands dominated by pines but
also were fairly common along the weedy roadsides both north
and south of Stewart.
Wading birds were very abundant in abandoned farm
lands north and east of S.R. 84 in late November as they
fished-out the drying canals and ditches. They also occurred
in large numbers in flooded areas south of Stewart as the
water level fell during October, November and December.
Substantial numbers of white ibis (= "curlew") heads, wings
and legs were found, indicating a substantial number of these
birds are still harvested as food during the hunting season.
The conclusion reached is that the faunal distribution
is regulated, at least in winter, by the presence of water,
and that there is probably an annual migration up and then
back down the gradients in response to spread of surface
water in summer and recession of that water in winter.
Aquatic Food Production in Farm Fields
Farm fields, especially those that have lain fallow
for several years, seem to be especially productive breeding
or feeding areas for birds and numerous fish, crustaceans,
reptiles and amphibians. On several occasions we observed
groups of up to 300 cattle egrets, snowy egrets and assorted
herons feeding in such fields east of Desoto Boulevard. Their
temporary roosts occur at many locations in the cypress strands
east of these fields and such feeding concentrations occur
for at least three months (October-December) during the fall
On November 24 a sampling trip was made into a large
field complex lying immediately east of the eastern dead-end
of Golden Gate Boulevard. This one field complex, containing
about 3.5 square miles of ditched land, had apparently been
unplowed for about two years, as it was covered with heavy
growth, nearly six feet tall, of willow, primrose willow,
grasses and weeds. At the time of the visit all the shallow
interior ditches were dry except at the ends nearest to the
main perimeter drainage ditches which are a foot or more
deeper than the interior ditches.
Our sampling area was confined to the northwest
quarter section of this field tract nearest to the Golden
Gate terminus. Upon arrival we counted 250 cattle egrets,
20 white ibis, 5 great blue herons, 10 little blue herons
and 5 green herons feeding in one quarter-mile sector of the
main perimeter ditch. The levees alongside the perimeter
ditches were littered with the carapace sections of crayfish,
and leopard frogs were extremely abundant. Cattle egrets
were observed walking along the road and a number were
carrying leopard frogs in their bills, indicating satiation
Crayfish burrows were extremely abundant in the
damp sand of the ditch bottoms. Two sampling stations
were set up in isolated pools and all animals killed with
Pro-Nox-Fish. One station, typical of the many small pools
left at the lowest point in the interior field drains,
covered an area of 10 square meters and was 10 cm (4 in.7
deep. The second was located in the perimeter canal. This
covered 3 5square -meters and averaged 20 -m--in-.--in depttr
There was a surprising difference in faunal composi-
tion in the two pools with the smallest containing giant
diving beetles, water scorpions, predaceous diving bugs,
ostracods, crayfish, leopard frogs, green water snake,
banded water snake, cotton mouth moccasin, mosquito fish,
flagfish, redeared sunfish, longeared sunfish, and yellow
and black bullheads. All the sunfish and catfish were
The perimeter canal pool which was larger and
deeper, contained crayfish and very large numbers of
mosquitofish, flagfish, sailfin mollies and goldspotted
killifish, most of which were adults. No sunfish, catfish,
or aquatic insects were collected there.
Sampling in the larger pool produced 4 "dry" gallons
of these small fishes which weighed 11 pounds per gallon,
i.e. 44 pounds total fish. An estimated 10 pounds of large
crayfish were also taken. There were about 7,800 fish in
each gallon sample or a total of(j1, I2 fish in thiIs one
pool. On this basis we estimated a perimeter canal popula-
tion of such fishes as 3.2 million fish per surface acre of
ditch on November 24, a full month after predation by birds
was seen to commence.
Mosquitofish, Gambusia affinis, made up 60.3% of
the sampled population of the large pool. Flagfish, Jordanella
floridae, made up 36.3%; mollies about 3.3% and goldspotted
killifish, Fundulus chrysotus, made up about 0.1%.
Assuming a daily intake of 4 ounces of such fish as
being a reasonable daily consumption for the smaller herons
and egrets, we estimated that this one pool contained enough
Food for 176 herons for a day. Carrying the extrapolation even
further we calculated that there were about 22 acres of such
rim ditch in this field alone, which might contain, at maximum,
at least 70 million fish each year. We say each year because
all four species are annual fishes. That is, they can grow
from fry to adult in a single season and some, such as Gambusia,
can produce several broods in a summer. All these fishes, as
well as vast numbers of crayfish, frogs and aquatic insects
would have been produced in this one farm field complex
covering about 2,240 acres. The total acreage of abandoned
farm fields in the Golden Gate Tract alone comes to 19,526
which appears to have a potential for more than 560 million
small fishes weighing approximately 789,000 pounds each year
of normal rainfall. This is about 30 percent of the food
required (Kahl, 1962; 1964) by 6,000 pairs of wood storks
to produce their young in a single year.
Life History Data on Common Land Mammals
of Golden Gate Tract
Didelphis virginiana Kerr
Length to 36 in., with 15 in. rat-like prehensile
tail. Weight 4 to 15 lbs. Males smallest. Females
have brood pouch containing 13 teats, 12 in a semi-
circle and 1 in center. Up to 20 young born 1-1/2
to 13 days after mating; each smaller than a honey-
bee, weight 1/270 oz.; make their way to brood pouch
and attach to 1 of the 13 teats. Those that are
unsuccessful in finding a teat will die. Young
nurse for 2 months; leave brood pouch briefly at
5 weeks; shift for themselves by 8 weeks. Breed
at 1 year with 1 to 2 litters annually. Life span
8 years but usually not more than 2 years in wild.
Habitat wooded areas near streams; densely forested
areas not inhabited as much as farmed areas inter-
spersed with wooded tracts and waterways.
Food mainly animal matter such as grasshoppers,
stink bugs, beetles and ants but may include bird
eggs, carrion and wild fruit in season. Great
numbers of opossums killed on highways where they
come at night to feed on other animals killed by
autos. This is the only American marsupial.
Adaptable to man.
Said to occupy every habitat type in South Florida
with more being recorded from the Big Cypress region
than from the Everglades.
Future status: Probable slow increase during
Eastern cottontail rabbit, Sylvilagus floridanus J. A. Allen.
Length to 19 in., tail white. Weight 2-1/2 to 3 Ibs.
Breeds several times a year, perhaps as many as 4
times in warm, dry seasons. Growth affected by soil
fertility so that poor soils of South Florida
produce smaller cottontails.
Habitat open, brush, dry ground which, in Collier
County, is dominated by pine and saw palmetto. In
very good range the home territory may cover from
1 to 5 acres but in poor range may cover up to 15
acres. Scent glands on either side of the anus of
both sexes give off a musky odor which is left on
the ground where the rabbit sits, thus identifying
Gestation period 26 to 30 days; litter size varies
from 1 to 9 young with 4 to 5 being most common.
Most young breed for the first time in the spring
following their birth. Young are often killed by
flooding of the "form" or nest.
Fairly adaptable to man. Food includes a variety
of grasses, herbs and bark of shrubs.
Future status: Slow increase in drained and sparsely
developed areas followed by severe decline in numbers
at full development.
Marsh rabbit, Sylvilagus palustris Bachman.
Somewhat smaller than cottontail and darker in color;
some individuals appearing black in dim light.
Occupies virtually every habitat type in South Florida,
adopting a semi-aquatic mode of life in wet periods.
Ears shorter than cottontail and tail dark, versus
white "puff" of cottontail. Food much the same as
cottontail but often includes wetland and hammock
vegetation not found in drier situations where cotton-
No information available to us on reproduction.
Future status: In-as-much as marsh areas can be
maintained, population may remain relatively high
there but will decline in all developed areas.
Gray squirrel, Sciurus carolinensis Gmelin
Length 14 to 21 inches; weight 3/4 to 1-1/2 lbs.
May live 6 to 10 years in the wild and 15 years in
Mating chases typical of this species have been
observed in late February and early March in South
Florida. Gestation 44 to 45 days with 1 to 6 young
in a litter. Young weigh about 1/2 oz. at birth;
the young are half-grown at 8 weeks at which time
they are weaned. Most nests found in Golden Gate
were in hollow cypress. Habitat dense hardwood
or mixed hardwood, pine and cypress forest with
lesser numbers in stunted cypress and pine.
Usually remain within 200 yards of nest tree but
may travel much farther if nearby food plants fail.
Food consists mainly of seeds, buds, nuts and small,
soft fruits. Large wetland stands of maple or willow
_._ __i.i_ ______ ~__~ _I 1_ _ _I___~_~ r ____ ___
are said not to be good habitat for gray squirrels.
Cypress cones and pine seeds important part of diet
in Collier County. Bird eggs and insects form a
small portion of the diet.
Future status: Probable increase throughout with
Fox squirrel, Sciurus niger avicennia Howell
Length to 29 inches, usually less. Weight 1 to 3
lbs. This must be considered as a rare and endangered
species in South Florida. It has been seen by us in
Everglades City, on the "Wilderness Golf Course" in
Naples, in cypress along the extreme west edge of
Golden Gate at Golden Gate Boulevard, on the Loop
Road south of the Tamiami Trail in the Big Cypress,
crossing the Tamiami Trail near 40-Mile Bend on the
Tamiami Trail, and in the Corkscrew Swamp Sanctuary
Reported declines in populations have apparently been
caused by hurricanes, logging, hunting, fires and
land development. Fire loss of nest trees now a major
factor. Females have 4 pairs of teats; litters contain
1-6 young. May live 4 to 7-1/2 years in wild and up to
9 years in captivity.
Habitat variable but most often occurs in cypress and
pine habitat along edges of larger strands of Collier
County. May be variously marked with black, red,
orange and white in southwest Florida.
Future status: Probable extirpation.
White-tail deer, Odocoileus virginianus Zimmerman
Length to 8 feet, usually less with tail to 11 inches.
Height to shoulder to 4 feet. May attain weight of
up to 300 pounds but South Florida individuals usually
Habitat open, marshy sloughs near dense cover of mixed
hardwood, pine and cypress. Breed in fall with young
born 6-1/2 to 9 months later. Young weigh about 3
pounds at birth. Major concentrations of deer occur
in the Big Cypress where the 1969 population was esti-
mated by U. S. Department of Interior as 1 deer per
36 acres. Loveless (1959) estimated that the population
of the 2,000 square mile Everglades area varied from
about 1 deer per 233 to 1 deer per 150 acres.
Schemnitz (1972) estimated average pre-hunting density
in the combined area of the Big Cypress; Conservation
Areas 1, 2, and 3, and Everglades National Park as
1 deer per 236 acres. Loveless and Ligas (1959) found
that the Everglades deer consumed 51 species of plants
but depended heavily on 10 species as follows:
White water lily, Nymphea odorata
String lily, Crinum americanus
Coastal-plain willow, Salix amphibia carolinianana)
Green briars, Smilax sp.
Primrose willow, Jussiaea peruviana
Elderberry, Sambucus simpsoni
Rougeplant, Rivinia humilis
Groundsel tree, Baccharis glomeruliflora
Royal fern, Osmunda regalis
From the above it was concluded that sloughs provide
the most essential food plants while higher, densely
forested hammocks were more important for shelter
from natural predators, from bothersome insects and,
of course, from hunters. The common practice by hunters
of using dogs to "flush" deer from such cover attests
-~- ----- rr
to the importance of mixed forest to the deer popu-
lation. Cypress and pine have much less value to
deer as shelter and, in the virtual absence of water
through drainage may be virtually useless.
Future status: Increased human use guarantees drastic
decline in Golden Gate Tract.
Raccoon, Procyon lotor Linnaeus
Total length said by Palmer (1949) to range between
26 and 38 inches, with tail length between 7-7/8 and
12 inches. South Florida specimens smaller; three
road kills in the Big Cypress ranged between 24 and
32 inches and weighed 10, 13 and 14-1/2 pounds.
Occur throughout the Golden Gate Tract but sightings
are most common along canals, around farm field ditches
and, especially, in the vicinity of mixed forest of
large cypress, maple, willow, pond apple and in flag
ponds. Raccoons are essentially omnivorous eating
fruit, grasses, sedges, nuts, aquatic animals such
as crayfish, leopard frogs, small fish, some fresh-
water molluscs, insects, small birds and bird eggs
and small mammals. Fruits of the exotic Brazilian
pepper, Schinus terebinthifolius, heavily utilized
Gestation period is 63 days. Litters said to contain
1 to 7 young with an average of 3 or 4. Sightings in
Golden Gate and Big Cypress generally suggest that
average number of young which survive the first year
is close to 2, although some females have been seen
with up to 4 nearly-grown young.
Future status: Probably will increase slightly to
full build out of Golden Gate followed by decline to
lower levels as traffic takes its usual toll.
Bobcat, Lynx rufus floridanus Rafinesque
Length 22-1/2 to 50 inches, weight 10 to 40 pounds;
South Florida specimens seem to tend to lighter
weights than northern populations. Males said by
Schwartz and Schwartz (1959) to be smaller than
females. Live 10 to 12 years in the wild state and
to 25 years in captivity.
Habitat beach strands, mangrove forests, mixed
hardwood hammocks, grass prairies, cypress and
high pineland. Gestation period 50 to 70 days.
Litter size between 1 and 5 but usually 2 or 3
A study of food habits of 41 bobcats in Missouri
produced the following types and percentages by
Rabbits 67.0; mice, rats and shrews 0.7;
squirrels 9.9; deer 8.6 (some of which was
probably carrion); opossums 1.9; domestic
cats 1.7; wild turkeys 7.9; quail 1.7;
undetermined meat 0.5; and grasses 0.1
Home territory marked by clawing of tree bark and
urine scent posts. Usual home territory about 5
square miles but this range may be extended to as
much as 40 square miles in times of food shortage
and during mating season. Big Cypress population
has been reported at 1 per 2 square miles (Layne,
Future status: Drastic decline with increased
human use and destruction of home territories.
Black bear, Ursus americanus floridanus Merriam
Length 50 to 78 in.; tail 4 to 5 in.; hind foot
7 to 14 in.; skull length 10 to 13 in.; skull
width 6 to 8 in.; weight 200 to 600 pounds, although
South Florida specimens usually lighter than the
stated (Schwartz and Schwartz, 1959) maximum. Lives
12 to 15 years in the wild and have lived more than
25 years in captivity.
Habitat heavily wooded areas such as mixed forest
of the Fahkahatchee and Picayune Strands and coastal
mangroves close to dense hardwood and pine upland
forest. Females usually range in an area with a
10-mile radius but males may go somewhat farther.
Layne (1974) said that the present center of
abundance in Florida is the Big Cypress where 80 to
100 were estimated to be present in 1969 (U. S. Dept.
of Interior, 1969). Bernie Yokel reported (personal
communication) sighting of a sow with one cub on the
Rookery Bay access road in 1973 and another sighting
at the Rookery Bay Research Station "in the fall" of
1974. Spoor found on the Rookery Bay Road contained
pond apple, Annona glabra, seeds. During this study
a "sow and two cubs" and a single adult were reported
by hunters as having been seen crossing Patterson
Boulevard in the vicinity of Stewart Boulevard.
Schemnitz (1972) in Layne (1974) estimated 146 bears
in Collier County.
Food varied, including grasses, berries, seeds, nuts,
inner bark of certain trees, roots, ants, bees and
honey, grasshoppers, frogs, fish, small mammals, bird's
eggs, carrion and garbage. Black bears are said
(Morton, 1964) to cause considerable damage to
commercial bee yards or apiaries in Collier County.
Females have their first offspring, usually a single
cub, at about 3 years of age and subsequent litters
consisting of 2 or 3, rarely 4 cubs, on alternate
years thereafter (Schwartz and Schwartz, 1959).
Future Status: Decline in population due to
increased human population density and hunting
Nine-banded armadillo, Dasypus novemcinctus Linnaeus
Introduced species. Palmer (1949) had the following:
Length to 28 inches, plus tail about 1 foot. Weight
to 15 pounds. Young born in litters of four, all one
sex and "identical" from first of February to April.
Food almost exclusively insects (85%) such as ants
and beetles mixed with earth; 13% vegetable. Dung
like small clay marbles. Body temperature may
undergo 6 to 80F drop in 4 hours.
Has become exceedingly abundant in higher, dry sand
areas throughout the Golden Gate Tract; less abundant
but common in mixed hardwood-cypress of main cypress
and mixed forest strands. Considerable numbers of
dead armadillos in drier regions which have been
burned repeatedly suggests that fire or drought may
cause significant mortality. Layne (1974) summarizes
state of knowledge about this species in South
Future status: Near-term increase followed by decline
in numbers with build-out of higher land.
Life History Data on Game Birds
of Golden Gate Tract
Wild turkey, Meleagris gallopavo
Length to 50 inches of which about 18 inches is tail.
Differs from "barnyard" or domestic turkey in having
chestnut instead of white tips to tail feathers and
upper tail coverts. Normally wild turkeys weigh
about 20 pounds for gobbler and 10 pounds for hen.
Male maintains harem of up to 15 hens. Nest on
ground, eggs incubated by hens; eggs 10-15 which
incubate in 28 days at a temperature of 1090F.
Habitat deep woods of mixed forest where seeds,
acorns, fruits and insects can be found near the
roosting area. Center of abundance in Golden Gate
appears to be in mixed forest between Lynch
Boulevard and S.R. 84 where they may be seen on
roadways or heard gobbling in woods at daybreak.
Groups of up to 8 bachelor gobblers have been
seen in the area. Walk in single file with a
peculiar, long-legged stride. Golden Gate birds
are taller and much more "streamlined" than
barnyard birds and old gobblers have proportionately
Future status: Uncertain because of intense hunting
pressure. We predict extirpation in the Golden
quail, Colinus virginianus
Length of northern birds up to 11 inches but
length of few specimens seen South Florida nearer
8 to 9 inches. Weight about 6 to 7 ounces.
Color darker than in more northerly populations.
May keep mates more than 1 year though there is
competition for hens at start of each breeding
season. Cock builds nest on ground in fine grass
where 7-28 eggs are deposited. Several pairs may
use same nest. Eggs hatch in 23 to 24 days
following incubation by both cock and hen.
Food mainly insects and small weed seeds. Wide-
spread in Golden Gate from dwarf pine-cypress
stands to pine-cabbage palm strands of the southern
mixed forest plant association. One species whose
range probably has expanded with drainage. They I
are said to be non-migratory. Nesting begins in
April and lasts till June with occasional second j
nesting in August. Fire may be a limiting factor
during the April-May dry nesting season and severe
mortality can occur when nests are flooded out by
heavy rains. I
Future status: Good as fire further reduces timber
cover and conversion from wetland to dryland con-
ditions, but poor for the long-term as building
reduces available territory. I
The general absence of vertical relief and the
very gradual seaward slope of lands within the Golden Gate
drainage basin has prevented the formation of well-defined
water courses. As a result, once soil saturation levels were
reached, rain water tended to pool in shallow basins before
moving down-grade through naturally lower areas. Once these
flow-ways were filled to capacity, any further rainfall
probably caused a sheet-flow of fresh water.
As can be seen from Figure 19 the general pattern
of low flows was roughly southeasterly in the northern part
of the system, turning southward below the line of the ten
foot contour close to the present route of S. R. 84. In
addition to drainage from lands within the Golden Gate Estates,
the system received runoff from thp .ntllthbpn p.nd of the Corkscrew
marsh and from the western portions of the Fahkahatchee Strand.
Corkscrew Swamp probably drained primarily into
the Cocohatchee basin, and only at high water levels would
any flow move southward toward the Picayune Strand. The
connection between the Fahkahatchee and the upper end of
the Picayune Strand was apparently well-defined, and water
probably moved from one to the other depending upon the
relative flood stages of the two strands. In all probability
the Picayune system acted as an overflow area when heavy
rains north of the Okaloacoochee Slough caused high water
levels in the Fahkahatchee.
Although much of the slough system is no longer
"active" its remnants are still recognizable, and its former
course can be traced by careful analysis of aerial photographs
and by field inspection. North of Golden Gate Boulevard the
major flow-way, or slough, is composed of two separate "arms";
Figure 19. Distribution of historic flow-ways.
S SO 846
... ,I l------
"E- -- _-._..
-- ;|\. 51 4
I S 846
43 SR 858
*__ I 's W Ia
I' I -si
F -. I =F
S- --- 84 8 --
S-4- i Is
\1 951 i ---,-4 --d3
--!-- --- .
---- E "
S "*- -- ~= -
I I LW-
11ll- I _
I II l
NI > I f1 r;- IL
1 I lH I
S I I IIi. n
the westerly one from the Corkscrew Marsh, the easterly
draining the pineland areas to the north. It is charac-
terized by larger cypress than those occurring in surrounding
areas, although drainage in recent years has allowed pines
to invade in the vicinity of North Golden Gate. Slightly
north of Golden Gate Boulevard the western slough produces
two shallow offshoots which meander into the north end of
the Belle Meade basin until they reach a series of pineland
ridges giving rise to shallow perched freshwater impoundments.
The two arms converge in the vicinity of Golden
Gate Boulevard, at which point the flow-way is almost one
mile wide and its surface is between 8" and 1' deeper than
adjacent dwarf cypress areas. Approximately 2 miles to
the south it becomes constricted to a width of roughly 1/4
mile before widening once more into what was formerly large
cypress and is now a mixed swamp forest.
In the vicinity of S. R. 84 the flow-way is joined
from the east by the "cross-over" from the Fahkahatchee by
way of a deep, narrow slough heading south adjacent to Frances
Boulevard, and a wider, shallower slough slightly to the north.
Immediately south of S. R. 84, at the point where the flow-way
crosses the 10' contour, it divides around a higher pineland
area. The main slough continues on the eastern side of the
pineland and a minor western slough meanders southward,
apparently never really rejoining the main slough.
By way of a series of wet prairies and cypress
strands, the main slough heads almost due south, entering
the previously logged deeper portions of the Picayune Strand
about 2 miles north of Stewart Boulevard. From this point
to the southern end of the Golden Gate system (approximately
7 miles) the slough is between 1 and 1-1/2 miles wide and
varies between 12 and 18" deeper than adjacent lands.
Carter, et al. (1973) measured water quality para-
meters at 16 stations in the vicinity of the Fahkahatchee
Strand and in the Fahkahatchee River and Bay and Fahka-Union
Canal and Bay. They also measured trace metals and pesticides
of water, sediment and biota at 7 stations in the vicinity of
the Fahkahatchee Strand. Their results are summarized below
for the stations north of the Tamiami Trail. Temperature
varied seasonally from 20 to 35.50C. The pH varied between
7 and 8. Apparent color ranged from 30 to 100 APHA PT-Co
units, and had a median near 60 units. The mean conductivity
varied from .44-.81, mmho/cm north of the Trail and stations
8 and 9 on the Trail had means of 6-15 mmho/cm. The chlorides
are predominant in the conductivity and chlorides were
25-70 mg/l north of the Trail and 10 x 103 at the two Trail
stations. The mean turbidity at all stations was 2-3 JTU's.
The dissolved oxygen was low and the mean values
varied from 1.5-4 mg/l at all of the stations except number
10 at the weir at the Trail on the Fahka-Union Canal. Here
dissolved oxygen had a mean of 7.0 mg/l. The mean sulphate
concentration varied from 1-3.2 mg/l north of the Trail but
values of 44 mg/l were found at the Fahka-Union weir and
from 221-251 mg/l at the Trail sites (8 and 9). The mean
alkalinity varied between 155 and 250 mg/l at the 10 "fresh
water" stations. The mean "tannin and lignin-like substances"
varied from 0.5 to 1.9 mg/l at the 10 stations. The mean
nitrate and nitrite ranged from less than .01 to 0.08 mg/l
(N) while total Kjeldahl nitrogen ranged from 0.4 to 1.65
mg/l. Values of Kjeldahl nitrogen were generally higher
north of the Trail and lower in the bay systems to the south.
Total phosphates ranged from .02-.08 mg/l and were relatively
consistent in both fresh and salt water systems. Total
organic carbon varied from 10-26 mg/l and was generally more
abundant north of the Trail.
Trace metals and pesticides were examined at 5
stations north of the Trail and 2 in the bay systems to the
south. Both water and sediments were examined. In the water
no arsenic, mercury or pesticides were detected. Iron varied
from 100 to 5600 Vg/l as maximum values in the fresh waters
and from 460-540 Vg/l in the bays. Copper was absent north
of the Trail but 30-60 vg/l were found in the bays. Cadmium
was generally absent north of the Trail. Trail and bay
stations had 30-50 ug/l. Nickel was absent north of the
Trail but present (280-670 pg/l) on the Trail and in the bays.
Zinc maxima varied from 30-70 ug/l north of the Trail and
were 100 Vg/l in the bays. Lead occurred in maximum concen-
trations of 200-250 Vg/l in the fresh waters and 370-500 pg/l
in the bays. Manganese maxima varied from 60-80 pg/l in the
fresh water to 80-200 pg/l in the bays. In the sediments
concentrations of metals and pesticides were higher than in
water. Arsenic was spotty but the maximum observed was
11.5 ug/g, the maximum Cd concentration was 6 pg/g, and this
only occurred at a single station in one sample. Cr maxima
varied from 12-67 pg/g, Cu from 3-19 pg/g, Ni from 8-58 ug/g,
Zn from 6-101 Vg/g with most occurring in fresh water stations;
Pb from 9-1079 vg/g, with most in fresh water stations; Mn
from 17-152 pg/g and Hg from .2-1.42 vg/g, with more found
in the bay.
As mentioned above, no pesticides were found in
the waters and out of 24 pesticides only 6 were detected in
the sediments. DDT, DDD and DDE were found at all stations
with maxima between 0.22-3.2, 0.22-3.2 and 0.21-2.3 pg/kg
respectively, except for extraordinary high readings in April
at station 3 in the Barron River Canal at Copeland. Here
DDT and DDD were present at concentrations of 160 pg/kg and
DDE was recorded at 96 ug/kg. Methoxychlor was only found
at station 3 at a maximum value of 2.1 pg/kg. PCB's were
found at all stations except 6 in the Fahka-Union Bay.
Maximum values ranged from 2.6 to 130 pg/kg with generally
higher concentrations along the Alligator Alley and in the
vicinity of Copeland and Jane's Scenic Drive. Dieldrin was
found at C@peland (2.3 pg/kg) and in Fahka-Union Bay (13 pg/kg).
During the fall of 1975 and winter of 1976, we
examined water quality in the Golden Gate Canal system and in
the Tamiami Canal from Ochopee to Collier-Seminole State
Two sampling trips were made. One on 28 October
1975, attempted to obtain data during heavy runoff, and one
on 26 January 1976 was designed to obtain data during the dry
season when runoff is minimal.
Station locations are identified in Figure 3 and
Table 7 presents data on the physical and chemical water
quality parameters measured.
The time of sampling on both trips was similar
except at the Ochopee station which was visited late in
the October sampling and early in the January trip. As one
would expect, temperature in January was several degrees
cooler than in October, with the exception of the 10 ST/8 ST
sample taken from a farm ditch where ground water was being
pumped for irrigation purposes. Although conductivity and
NaCl equivalent and total dissolved solids (CaCO3 equivalent)
were only measured in January, the trend exhibited by salinity
would be reflected in these measurements. Salinity increased
at all stations with the most pronounced changes occurring
along the Tamiami Trail. Elsewhere salinity increased 1-4
ppt or in terms of NaC1 equivalents (mg/l) the interior
"fresh water" areas have chlorides of 240-470 ppm. These
values approach upper limits for some crops and may become
excessive for farming by the end of the normal dry period.
Because the farm ditch 8 ST station had relatively low NaC1
equivalents it is believed that pumping does not cause
increased chlorides, but rather rapid dewatering via canals,
plus concentration during evapotranspiration probably is the
~ ~ __I~___ il~_______ _~_
Br'24 Br 24
Br 8 Br 8 Br 13 Br 19 Br 19 10 ST 8 ST
OCT JAN OCT JAN JAN OCT JAN OCT JAN
Dissolved Oxygen (mg/1)
Apparent Color (APHA Co)
Nitrite N (mg/1)
Nitrate N (mg/1)
Inorganic Phosphate (mg/1)
Organic Phosphate (mg/1)
Total Phosphate (mg/1)
Chromate (Cr +6)
NaCl (eq) (mg/1)
Total Dissolved Solids
as CaC03 (eq) (mg/1)
- ...--~--~----~--.. -
~.. ---- ----- -=--- -- ------------ -----~----.-- -- -- ---------- .--.. ------- -- -- --- -- -- ---- --- ------------- --------l-------~i~-T~ -- ~n
Ft ..,-rIBnr ~ uLu _J i~r ~ .~rur~ LUI dibL ~ ~ uu
W 21 W 21
Cope- Cope- Ochop- Ochop-
W 19 E Br E Br E JSD E JSD land land pee pee
JAN OCT JAN OCT JAN OCT JAN OCT JAN
Dissolved Oxygen (mg/l)
Apparent Color (APHA Co)
Nitrite N (mg/1)
Nitrate N (mg/1)
Inorganic Phosphate (mg/l)
Organic Phosphate (mg/1)
Total Phosphate (mg/l)
Chromate (Cr +6) (mg/l)
NaCl (eq) (mg/l)
Total Dissolved Solids
as CaCO3 (eq) (mg/1)
- 310 250 200
cause of increasing chloride levels. The effectiveness
of barriers or weirs is demonstrated at Ochopee where the
salinity above a small earthen dam was 2 ppt while seaward
of the barrier the salinity was 28 ppt. Dissolved oxygen
was generally higher in January than October which reflects
colder temperature and a higher saturation value. All of
the fresh water canals had relatively low 3-5 ppm dissolved
oxygen near mid-day when photosynthesis should be high
and this may imply dawn values of dissolved oxygen which
do not meet current state standards. The pH is generally
neutral to slightly basic in fresh waters. The station
at bridge #13 is anomalously basic. The Tamiami Trail
stations were more basic in January reflecting the influence
of buffering by sea water.
The apparent color (APHA Pt-Co standard) was
higher in October than January and this reflects the movement
of stained material from swamp and cypress areas during
the wet season. The effect is more pronounced in the fresh
waters of the northern areas than in the southern saline
areas. Turbidity also decreased in January compared to
October and this reflects lower velocities and less swamp
and upland drainage.
The nitrite nitrogen was generally low and was only
detectable (>0.01 mg/l) at a few scattered stations. This may
result from reduction of nitrate during analysis.
Nitrate nitrogen values were relatively high (about
0.7-0.8 mg/l) compared to values for Water Management District
7 (Cocohatchee), and extremely high compared to Carter et al.
(1973) and McPherson (1970). The nitrate-nitrogen appears
about double the world fresh water average, but is well within
the acceptable range for potable water. The presence of iron
can interfere with the cadmium reduction technique and give
improper high results. Since Fe was present in most samples
our NO3-N should only be taken as indicative of a potential
high concentration. Highest concentrations occurred in the
estuarine waters found near the Tamiami Trail.
", I I -, I I l l -
Orthophosphate concentration was uniformly low and
varied from 0.01 to 0.08 mg/l of phosphate. Metaphosphates
increased from October to January as did the supply of
organic phosphate. These increases are reflected in total
phosphates. The total phosphates agree closely with those
found by Carter et al. (1973).
Silica (Si02) concentration was high (4-7 mg/1) in
the fresh water and lower (2 mg/1) in the brackish waters
near the Trail.
Trace metals Mn, Co, Chromate +6 were rare and only
detected in a few samples. Iron was spotty and occasionally
occurred in relatively high concentrations (up to 1.1 mg/1)
but this is not unusual in the sandy soils of South Florida
where the activity of sulphur reducing bacteria in past eras
produced patchy distributions of "iron sands".
In summary, the general quality of the Golden Gate
water system is good. No evidence of unusual substances was
observed by us or Carter et al. (1973). The relatively high
nitrate nitrogen concentration found in our cursory survey
should be examined further because of the implications to
water management and weed control. The collection, preserva-
tion, and analysis techniques used in determining N03-N can
lead to order of magnitude errors and it is recommended that
further study of nutrients (both nitrogen and phosphorus)
be included in future phases.
OUTFLOW TO ESTUARINE AREAS
The adverse effects of the Golden Gate canal drainage
are not restricted to the freshwater systems, but are demon-
strable in the adjacent estuarine zones. This is true of Naples
Bay and is even more evident in the case of Fahka Union Bay,
into which the Fahka Union canal discharges. In a two-year
survey of Fahka Union and adjacent Fahkahatchee Bay, Carter
et al. (1973) concluded that the former had been negatively
affected by canal drainage inflow. The abundance and diversity
of fishes and invertebrates was lower in Fahka Union Bay,
and sedimentation rates were greater, as was the concentration
of metals in the sediments. Salinity variations were larger
and more rapid, placing intolerable stress on estuarine
organisms, and nutrient levels were also lower in Fahka Union
All these factors combine to produce a net reduction
in the numbers of fish and invertebrate species of economic
importance to man. Coastal bays are the prime habitat for
adults of sports fishery species such as snook, seatrout,
red fish and mangrove snapper. In addition they also serve
as nursery areas for these same species, and for other species
of commercial importance, such as pink shrimp.
The dependence of Fahkahatchee Bay on its surrounding
mangrove communities was also indicated by Carter et al. (1973).
They concluded that these mangroves constituted at least 57%
of the resource base of the Bay, and that their level of con-
tribution might actually be as high as 80%.
.The degree to which mangrove systems contribute to
the support of adjacent bays is dependent to a large extent
on tidal flushing and on the amount of freshwater which passes
through them during the rainy season. Heald et al. (1974)
have commented that the most vigorous mangrove stands, and
14rr----. ---i--^ -1:-- -I------ --i-r i -
those which contribute most to adjacent bays, are to be found
at the lower ends of major watersheds where they are subjected
to sheet flow of freshwater.
If this sheetflow pattern is "short-circuited" as in
the case of the Fahka Union system, several major changes occur:
(1) A pathway by which detritus and other aquatic food sources
are exported from the mangroves to the bay is lost. (2) The
vigor of the mangrove stands themselves declines. (3) The
filtering action of the mangroves is by-passed, and greater
quantities of heavy metals and silts reach the bay within
relatively short periods. (4) Salinity variations become
sufficiently rapid to exceed the tolerance limits of juvenile
and larval forms of many organisms, and a concomittant loss in
the populations of species of economic importance follows.
In order to mitigate these problems in Fahka Union
Bay, Carter et al. (1973) recommended that the U. S. 41 canal )
be utilized as a spreader waterway to re-establish sheetflow
through the mangroves and saline marshes bordering Fahka Union
Bay. Black, Crow and Eidsness (1974) proposed a similar
solution, adding further that this would aid in the prevention
of further saline intrusion. We can only add our similar
recommendation to these eminently sensible suggestions.
The most recent mapping of lands in Collier County
which have been cleared for farming was produced by the
University of Florida (1975). It clearly illustrates three
centers of "truck farming." The largest area, and probably
the oldest from the standpoint of use, lies in the region
bounded on the east by S. R. 29, on the south by Golden Gate
Boulevard and on the west and north by S. R. 846. A second,
much more recently developed center is located southeast of
Naples in the Belle Meade Basin and the third center lies in
the Cocohatchee River Basin. Much of the cleared land in
the northern sector of Golden Gate Estates is now lying
fallow, abandoned mainly because of difficulties with water
management. Most of the cleared lands in this higher site
are Immokalee fine sands, deep phase, said by Leighty, et al.
(1954) to have been covered by "slash pine, saw palmetto,
gallberry, running oak, broomsedge, wire and carpet grasses."
Under natural conditions this soil type was charac-
terized by a soft organic hardpan at depths averaging 30 inches
but varying between 24 and 40 inches below the surface. This
hardpan, also referred to as a "stained organic layer", seemed
to represent the approximate location of the pre-drainage
According to Mr. Don Lander, County Agricultural
Extension agent for Collier County, these fields could be
worked, beginning most years, in mid-August. Main crops
were green peppers, cucumbers and tomatoes. Leighty et al.
(1954) said that such fields were de-watered by digging a
network of open ditches at intervals of about 700 feet. The
fields were surrounded by low levees formed by digging of
peripheral main drainage canals and surplus water was simply
pumped over these containment levees to spread over adjoining
undisturbed land where some re-charge presumably was
accomplished. This practice is apparently still followed in
some areas. Management of water levels then, as now, attempted
to hold ground water at depths of about 24 inches. At that
level capillary ac "ini the~fTine, sandy soil insured suffi-
cient moisture in the 6 to 8 inch deep root zone.
ShaIl6w wells, 40 to 100 feet deep, have provided
water as needed during dry seasons. The draw on such wells
has increased markedly as major drainage activities lowered
the water table to depths greater than 24 inches.
We were initially led to believe that salt accumula-
tion had become a problem in recent years but agent Lander
explained that this was not true. The usual wells of 40 to
100 foot depths still produce water with chloride content of
400 to 800 (rarely to 1000) ppm, but farm crops can tolerate
chlorides up to about 1500 ppm without undue stress. He
further concluded that build-up of salts due to evaporative
processes was no problem since these were leached from the
soil each rainy season.
Why, then, if water in wells is still of good quality
and salt accumulation seems not to be a problem, has so much
land been abandoned? The answer apparently lies in the extent
to which ground water has been reduced by drainage. Over most
of this large northern area dry season ground water levels now
reside below the caprock under the Immokalee soils at depths
greater than 4 feet. This makes watering of the drained sands
extremely difficult since capillarity has been destroyed (a
natural watering system with low cost to manage) and must be
replaced by constant pumping (a costly artificial process).
It has been reported that ditch irrigation has failed in
recent dry seasons due to the inability of water to traverse
underground from ditch to ditch before being removed by
evapotranspiration or downward percolation. Apparently, the
cost was too high for many farmers who have since moved down
gradient into the Cocohatchee and Belle Meade Basins where the
water table is nearer the surface.
Another cost which came as a result of overdrainage
of the Immokalee highlands was the cost of chemical methods
of combating plant pests which formerly were controlled by
surface flooding during the non-growing seasons. The
effectiveness of such flooding in pest management was
summarized by Genung (1976) as follows:
"The concept and practice of flooding land
to reduce or eliminate certain pest problems
most probably developed from observations
on lands that were naturally inundated either
seasonally or sporadically. ... When such
flooding has occurred in the agricultural
area, it was observed that many subterranean
insects came to the soil surface with resul-
tant high mortality of cutworms, white grubs,
and other larvae. More resistant insects such
as wireworms, also surfaced enabling certain
natural control agents, particularly birds,
to predate more effectively. Certain other
normally less spectacular natural enemies such
as carabids, however, were observed to be
reduced as drastically as their pest hosts
In the move from place to place farming interests have
gone from the most desirable soil (Immokalee fine sand deep
phase) of the highlands to Pompano, Arzell and Charlotte sands
of the Cocohatchee Basin and are now in the process of clearing
and farming the Immokalee fine sand, shallow phase and associated
Broward and Ochopee soils of the Belle Meade Basin.
Examination of the soil texture and moisture analyses
of Leighty et al. (1954) and Stewart, Pomell and Hammond (1963)
show that an entirely new set of problems face farmers in those
areas. These range from low organic content, drought over-
drained texture, rock too near the surface or, where marls occur,
difficulty in drainage.
The picture presented by the above brief analysis
shows farming interests fleeing before "progress" in the form
of land drainage and potential urbanization. If the pattern
continues where will this important aspect of the economy
move next? Looking at the soils map and patterns of wilderness
acquisition and urban development in Collier County generally
we can see no future for agriculture there unless a deliberate
effort is made in planning to accommodate this activity within
the zones already found to be most productive and then to
restore the conditions which make such farming least costly
in terms of environmental impact. We believe that restoration
of high groundwater levels will make a major contribution.
When farming activity and natural ecosystems are
discussed together there is a tendency to indict farming as
being universally unacceptable because of the uses of chemicals
and fertilizers and the oft-assumed harm done by this use.
In the foregoing paragraphs we have discussed how loss of
water supply through overdrainage has forced farmers to
abandon the control of pests by flooding and adopt pesticides
instead. If, therefore, water is made available again by
manipulation of drainage controls there should be fewer
damaging chemicals used and the words of George Cornwell
(1976) should then become appropriate in the Golden Gate and
"Clearly agricultural production and wilder-
ness preservation are incompatible uses of the
same space at the same time. But there is no
logical reason why they cannot be harmonious,
even synergistic neighbors. Indeed, they must
learn to become so throughout the world, for
almost every wilderness has, on or within its
borders, an increasingly intensive agricultural
system. Preservers of wilderness must recog-
nize the human values, the necessity and
desirability of the farms and fields on their
doorsteps. Also, farmers whose lands buffer
wilderness systems must acknowledge the need
to implement extraordinary measures to avoid
damaging adjacent wildlands."
We see considerable wisdom in Dr. Cornwell's state-
ment and believe care should be used by decision makers in
making adjustments in land and water use which will permit agri-
culture to exist in the synergistic ways that Dr. Cornwell
In attempting to assess the general applicability
of land parcels for various potential uses we were primarily
guided by the results of our natural resource assessment,
and by the Leighty soils maps. We should caution that our
"categories" do not always indicate the most logical uses
of these lands if they were in a relatively undisturbed
condition. They reflect, in some instances, the fact that
specific areas are so severely impacted that attempted resto-
ration and maintenance would not be justified.
We believe that, within certain limits, the Golden
Gate Estates can accommodate urban development, agricultural
operations and recreational activities. At the same time,
restoration and maintenance of natural flow-ways, recharge
and overflow storage areas is feasible, and can be achieved
within a relatively short space of time.
The following observations contributed heavily
to our assessment of land suitability:
1. Within the Golden Gate system the most signi-
ficant recharge areas, water storage areas, wildlife habitats,
and the forest areas most worthy of restoration efforts lie
south of S. R. 84 (Alligator Alley).
2. The most important historic flow-way was oriented
approximately southeast from the south end of Corkscrew Marsh
to S. R. 84, before heading almost due south to Fahka-Union Bay
via the Picayune Strand (Figure 19).
3. The impact of severe recurrent fires has been
greatest to the south of S. R. 84, where the larger, more
densely spaced trees produce a greater fuel load.
4. In spite of the canal network which produces
the observed negative effects of seasonal overdrainage, the
10 year storm would cause flooding of u- t'9.2 fet f9om1 the
City of Golden Gate eastward to Everigades, Boulevard and
thence north to within 4 miles of the np~rfhen Pnrimetpr
of Golden Gate Estates (Black, Crow and Eidsness, 1974).
Similarly, the 10 year storm would result in floods to 2
feet from the extreme south end as far north.as Stewart
Boulevard, and north from S. R. 84 for a distance of approxi-
mately 9 miles.
5. Soils north of a line approximating N. E. 20th
Avenue are mostly deep phase Immokalee fine sands which,
because of their specific drainage and water-holding charac-
teristics, are regarded as prime crop-farming soils.
Reference to Figure 20 shows that, in general,
lands deemed most suitable for restoration and conservative
use as recreational or water storage and recharge areas lie
south of S. R. 84. The major water flow-way, into which
runoff should be directed up to its maximum holding and
transport capacity, follows the line of the former main
slough (southeast to S. R. 84 and then due south through the
Picayune Strand). Lands north of northeast 20th Avenue are
those most suitable for crop-farming. Areas which, with
imaginative planning and modification, could be appropriate
urban sites lie generally west of Everglades Boulevard and
north of S. R. 84, with smaller tracts located east of the
main flow-way (north of S. R. 84), and to the west of Everglades
Boulevard for a distance of approximately 7 miles south of
S. R. 84.
Approximately 33,000 acres (30% of the total) are
placed in this category. Roughly 95% of these are located
south of S. R. 84. For the most part they are composed of
mixed swamp forest, and cypress communities of medium to large
trees. The majority of the "dry" prairies are also included
in this category (see Table 8).
_ _1_1 ____ ;_ _
Table 8. Acreages of vegetation communities and land
Wet prairie, ponds
Mixed swamp forests
Pineland saw palmetto
Water storage and conservation
173.5 sq. miles
-- ---i ..._._
Figure 20. Recommendations of land suitability.
Most of these areas would be inundated as a result
of the 10 year storm. In fact, the lower third of this
\system was observed to flood to depths in excess of 16 inches
'ifor the greater part of October, 1975. During this month and
/the preceding one, Naples recorded a rainfall level of 11.6
/ inches; slightly below the 12 year average.
The effects of fires have been severe in roughly
one-fifth of this category, although the areas involved are
scattered and of relatively small individual extent. Recovery
of these severely burned areas will, necessarily, be slow, and
those areas which were formerly dominated by cypress will,
in all probability, become mixed swamp communities with a
large component of cabbage palm.
The majority of the lands within this category can
be readily restored by establishment of maximum normal rainy
season water levels at 2 feet, by preventing the dry season
water table from dropping further than 2 feet below ground
surface, and by maintaining the duration of above-ground
inundation at approximately 5 months (in most years this
would be late June through late December/mid-January). The
specific reactions of the vegetative communities to this water
regime are discussed in the section on vegetation.
The conservation/recreation lands perform, or will
perform, several important functions. They are the areas of
major groundwater recharge and they will also serve as over-
flow lands bordering the major flow-way, up to the point where
urban areas to the north or west become endangered by flood
water; at which point the canal weirs would be opened to permit
rapid draining of excess water.
With the mixed swamp forests, most of which are
contained within the major flow-way, these areas support
the most diverse and important wildlife elements of the
entire system. The restriction of raptorial predators to
these locations (Figure 18) is indicative of a concentration
I r -- -. ,--- --. ---- --, ---------- -
of the small mammals, reptiles and amphibians upon which they
feed. Black bears have been sighted in the lower end of the
system and the Florida panther probably occurs there also.
The majority of the epiphytic orchids, including the ghost
orchid (Polyrrhiza lindenii), at least five species of
Epidendrum, and several species of Maxillaria, which still
survive in the system do so in this area and in the mixed
The conservation lands will serve as recharge and
temporary water storage or overflow areas during a "normal"
rainy season. Water entering these areas from canal overflow
or as excess from the natural flow-way will travel slowly
down-grade to the extreme southern end of the system. In
the process, the major proportion of primary plant nutrients,
suspended sediments and any residual pesticides or heavy
metal it contains will be filtered out or removed by biological
processes; with the result that fresh water flow entering
the coastal mangrove communities of Fahka Union Bay will more
closely resemble its former character. The slower rate of
runoff will also moderate the present extreme fluctuations
in salinity experienced by Fahka-Union Bay. The above effects
have been observed and well-documented by Carter et al. (1973).
A careful distinction should be made between
"conservation" and "preservation". We see no cogent argu-
ment for strict preservation of these lands. They can be
utilized in several rational, mutually compatible ways for
a common benefit.
One of the most obvious and logical uses would be
general recreation and seasonal hunting. There is no reason
why a reasonable number of private or public hunting lodges
or guest houses should not be established, provided they are
elevated above specified flood levels and that careful control
is exercised over sewage treatment. Access would be via
airboat, swamp buggy or conventional vehicle along existing
road alignments. Fishing could be improved measurably in the
existing canals if their margins were modified at intervals
to provide the shallows necessary for spawning of bass and
Rigid fire control programs would still be necessary
during drought years, and prescribed burning of roadside margins
would be standard practice, both for wildfire prevention and
to maintain certain game habitats. The option should be
retained to prohibit entry to the conservation areas if
wildfire probability reaches high levels at any time.
Similarly, the expectation of extremely high water levels
would result in prohibited entry.
Existing roads within the conservation lands should
be allowed to degrade. They will rapidly do so if flooded
frequently. The probable succession of plants, and the
possibilities of speeding-up this process is discussed in
the section on 'Ecology of Disturbed Surfaces'.
The cypress forests within the conservation areas,
while not of the quality of the former Fahkahatchee and Picayune
Strands, could, under careful forestry management, yield
substantial quantities of timber on a sustainable basis.
Revenue thus obtained could help defray the costs of fire
surveillance and protection, minimum road or trail maintenance.
Flanked for the most part by lands in the category
of conservation/recreation, these tracts represent the pathway
by which the system was drained, at least at low flow levels
until its capacity was exceeded. At higher water stages we
believe that overland flow probably occurred in a sheet-flow
fashion, since we were unable to locate any other major
sloughs within the Golden Gate drainage basin.
_ ;__II~1~__~ j;? jl ~ __ ~____l_~i ~1--~X7-.rli.-
As can be seen from Figure 20 the flow-way receives
water from the northwest near the southern.extremes of
Corkscrew Swamp, and from the north in the vicinity of the
east-west extension of S. R. 858. From the junction of these
two flows the slough continues southeasterly to a point
roughly one mile from S. R. 84. At this point it is joined
by a wide shallow slough which connects to the Fahkahatchee
Strand. This slough probably acted as a "safety valve" in
pre-drainage times, with water flowing either to or from
the Fahkahatchee from this point, depending on the relative
flood stages of the two systems.
The flow-way occupies approximately 18,300 acres,
of which fully two-thirds is situated south of S. R. 84.
We envision its utilization to transport low stage flood
waters gradually southward, thus approximating former natural
conditions. Once its capacity is exceeded the adjacent lying
conservation lands will receive excess and provide temporary
storage. In times of severe flooding, e.g. from hurricane
rains, the canal control structures would open and the normal
water flow through the flow-way system would be "short-circuited."
Human usages of the flow-way system could be similar
to those suggested for conservation/recreation lands, with the
exception that permanent hunting camps and similar structures
should not be installed within its confines.
Those lands which appear most eminently suitable for
crop farming lie generally north of.Golden Gate Boulevard, and
occupy approximately 19,500 acres. Previous farming activities
within the Golden Gate Estates total almost 13,500 acres,
although not all of this was simultaneously in use.
Most of the lands within this category are Immokalee
fine sands, characterized by a soft organic hardpan at depths
between 2 and 3 feet below the surface, representing the
approximate location of the pre-drainage water table. If the
water table is restored to approximately this level, the
deep phase Immokalee fine sands, which are the most desirable
agricultural soils, can be once more productively utilized.
This topic is discussed in greater detail in the section on
It should be pointed out that the lands we have
placed in the agricultural category could also become
residential sites if so desired. However, we feel that
their most logical use is agricultural.
Subject to the limitations and modifications outlined
below, slightly over 40,000 acres (36 %) of Golden Gate Estates
could be made suitable for residential sites without signifi-
cantly hindering the proposed restoration of natural communities.
In addition, those lands categorized as "agricultural" could be
used for urban development if so desired.
The bulk of the "residential" category lies north of
S. R. 84 and west of Everglades Boulevard. Comparison of
Figure 20 and the vegetation map (Figure 15) shows that almost
half of the area suggested as residential is currently
characterized by the pine-dwarf cypress community, and lies
on or adjacent to the "Golden Gate Highlands" (Figure 10).
This land is not subjected to excessively deep flooding; a
"normal" present-day flood level would be 7 inches while the
pre-historic rainy season levels were annarently in the neighbor-
hood of 2 feet. Consequently, modification of the land
surface to provide elevated flood-free sites would be less
extensive than in many other locations within the system.
Similarly, the pineland communities are at even higher eleva-
tion and flood less frequently than most areas. Many of these
cypress-pine-palmetto communities have been included in the
_ ____ i__XI~____ ___ ___ _Crii__ _____ ___ ___
The cypress-pine-palmetto mosaic lying south of
Golden Gate Boulevard and generally west of Everglades Boulevard
is also classed as "residential". Again, it stands at rela-
tively high elevation except for the irregularly occurring
small cypress heads. Heavy, frequent fire impact has been
the major cause of the "mosaic" effect of intermingling
communities, and further leads us to suggest their utilization
to residential sites.
South of S. R. 84 a strip of land 6 miles lon- and
1 mile wide to the west of the westernmost canal has been
suggested as residential sites. Although this area is
predominantly pine/cypress mix and stands at elevations
below 10' for the most part, it has been so severely impacted
by fires that restoration attempts would not be justified.
Finally, included within the 40,000 acres "residential"
category are approximately 3,700 acres which constitute the
present cleared and inhabited communities of the City of Golden
Gate and North Golden Gate.
In defining those areas most suitable for residential
use we have assumed that the present format of single residence
lots will not prevail, and that residences will be "clustered"
in units of more than one story. We have also assumed that
these units will be elevated to levels in excess of "normal"
historic rainy season flood heights (7 to 24 inches). Roads
will also, of necessity, be similarly elevated. This will
undoubtedly require large deep lakes to furnish the necessary
Several significant advantages are provided by
adoption of the above criteria, as follows:
1. Unmodified lands in the vicinity of the "cluster"
developments can act as overflow areas for any event other
2. The natural flow-way, which has a limited volume
and transmittal capacity, can be fully used to handle most
summer rains, with overflow lands on its margins.
3. By use of the flow-way and associated overflow
lands for temporary flood-water storage, the requirement for
numerous finely-adjusted automatic water control structures to
control normal summer rains becomes less stringent. The major
of the control structures can be set to release hurricane and
severe storm rains only, remaining closed at all other times.
4. There is probably no need to deepen or widen
any of the existing canals, nor is there any need to construct
new canals, since extensive shallow water storage areas (in
excess of 50,000 acres) will be available for all but extreme
5. Permanent blockage of the easternmost canal near
its southern end will probably be feasible.
6. Control structures in the extreme southern end
of the system can be set to elevations permitting a greater
degree of flooding without causing damage or inconvenience in
residential areas to the north.
I i__ ______1__1
WATER MANAGEMENT STRATEGIES
The primary objective of any water management scheme
for Golden Gate Estates is to provide adequate flood protection
to urban areas, while maintaining a hydrological regime com-
patible with other valuable uses such as fresh water storage,
ground water recharge, wildlife habitat maintenance, and
agriculture. The difficulties inherent in satisfying such
conflicting needs in a lowland area were aptly described by
Black, Crow and Eidsness (1974).
If the restraint of single family residences spread
over the entire watershed is removed, as suggested in the
section on land suitability, the conflicts are lessened and
natural systems can be utilized to perform some of the impor-
tant functions of drainage and water storage. Those areas
most useful as drainage systems, wildlife habitats, recharge
areas, or water storage areas have been identified (Figure 20).
In order to perform such functions the natural communities
concerned must be allowed to "operate" under hydrological
conditions approaching those which pertained prior to the
major drainage activities of the past decade. This means
that peak rainy season levels should be slightly higher than
at present, the period of inundation should be extended, and
the dry season low water levels should be some 2 feet higher
than at present.
The key to successful management lies not so much
in the maximum height at which rainy season water levels can
be established, or even in the number of months for which water
stands above the ground surface, as in the length of time that
the upper soil layers can be kept damp following the onset of
the dry season. The most efficient ways to achieve this pro-
longation are by first holding back water for as long as
possible in the upper (north) end of the system, and secondly
by raising the water table by a modest amount in the lower
(south) end. Overlying such a strategy is, of course, the
need for efficient and rapid drainage from residential areas
at extreme high water stages.
We contend that by diversion of water (by lateral
overflow from the existing canals) into the flow-way and
adjacent "conservation" lands up to their maximum storage
and transmission capacity, the seaward flow in normal rainfall
years would be sufficiently slow to extend the hydroperiod to
the desired five months. This action must be accompanied by
artificial control structures on the existing canals, other-
wise overdrainage would still occur, albeit more slowly than
The schematic diagram shown in Figure 21 is presented
as a tentative outline of water management possibilities. We
should emphasize that these suggestions have not been subjected
to detailed analysis by qualified hydrological engineers; such
action is an essential early step in any future phase of the
The salient points are as follows:
The Golden Gate Canal system, draining to the west,
introduces far more fresh water into Naples Bay than the
original drainage basin would have contributed (Figure 9).
We recommend that the volume of this flow be reduced by control
structures or permanent plugs to divert runoff from roughly
40% of the Golden Gate Estates area which currently feeds
this canal. Runoff would be diverted into the Cocohatchee
Basin, and also to the southeast into the natural flow-way.
Structure Cl (Figure 21) may be a permanent plug
which diverts water from extreme northwest Golden Gate and
from the lower end of the Corkscrew system into the Cocohatche
Basin. From this same watershed structure C2 (also possibly
a permanent plug) would divert water to the southeast into
Figure 21. Outline of water management possibilities.
Cl C11 are permanent blocks or water
control structures; arrows denote direction
I = --- --
... 1 ------
SR 31 3
7ht r -;-0 3
4 5 -----
0- -- F -- A -
i2 V- -I
N '"9\ y I-N
1 US 41
- -"lk I' II
o.. .. .
i, r\ ~rl
the head of the natural flow-way. Both these actions restore
some semblence of the pre-drainage flow pattern of the
northwest extremes of Golden Gate Estates.
Structure C3, an automatic control gate, would
force water to the east at low water stages, opening to permit
flow to the Golden Gate Canal during high water periods.
Structure C4, probably a plug, serves to divert water from
the north in an easterly direction at all water stages.
Structure C5 collects water from the north and the
west. An adjustable gate, it holds back water and forces its
diversion into the flow-way until flood capacity is reached,
at which time it opens to permit flows directly south.
Structure C6 (permanent block or adjustable gate)
is placed at the southern end of the "agricultural" area,
and in conjunction with C5 would conserve water levels for
From this point south, as far as S. R. 84, the
flow-way is relatively narrow and its capacity is limited.
Within the confines of this "bottleneck" there may be a need
to construct a low berm on both margins of the flow-way to
increase its carrying capabilities.
Structure C7 on the Fahka Union Canal would be a
control gate located just north of S. R. 84. In order to
prevent loss of contact between the water table and the over-
lying soils, the control should be set such that it closes to
prohibit southward passage of water when levels fall to 2 feet
below ground surface. It would act as a safety valve for the
northern portion of the system and would allow the flow-way to
be "short-circuited" when necessary.
Water within the flow-way system would pass beneath
S. R. 84 via a series of culverts equipped with stop-logs, and
via the existing spillway east of Frances Boulevard. A second
safety-valve can be provided by using the borrow canal on the
north side of S. R. 84 to convey excess water to the Fahkahatch
Strand. Removal of the existing earth plugs along this canal
east of the Fahka-Union Canal plug would be necessary.
South of S. R. 84 on the eastern side of the system,
control structure C8 assists in diverting water into the head
of the Picayune Strand, which constitutes the flow-way from
this point south.
The easternmost existing canal should be solidly
plugged at C9, or filled from this point north to Stewart
Boulevard. This canal should not be excavated northward to
S. R. 84 as proposed, nor should its proposed companion canal
on the east side of Golden Gate Gardens. These canals are not
necessary in the absence of residential use (which we have
recommended against) and there is a distinct possibility, even
probability, that they would be capable of drawing water from
the periphery of the Fahkahatchee drainage system.
At the extreme southern end of the Golden Gate
Estates a levee will probably be needed on the south bank of
the canal complex from point X to Y and from Y to Z on Figure
21. A control structure (C10) would be installed across the
Fahka Union outfall canal where the levee is interrupted.
This structure should probably be adjusted to contain water
to an elevation of +4.0 feet (m.s.l.) above which it would
open to allow unhindered flow.
On the west side of the system south of S. R. 84
the Fahka-Union Canal and the westernmost canal would flow
unimpeded; their efficiency being controlled by structure C10.
Drainage of residential sites in this parcel would thus be
Finally, although not within the confines of Golden
Gate Estates, some measure of control should be established on
the Blackwater River at Collier-Seminole State Park. A contr
structure (Cll) should be considered at the U. S. 41 bridge t
___._ 1 _~
prevent saline intrusion into the U. S. 41 canal and to prevent
overdrainage of the southeastern portion of the Belle Meade
The Golden Gate canal system and waters of adjacent
natural wetlands contain representatives of a large percentage
of the aquatic and semi-aquatic native plants of Florida as
well as a large component of introduced species. Many miles of
the major canals within the system are completely covered by
growth of such plants.
It is generally accepted that such weed growth is
undesirable, because they hinder canal function, may harbor
disease-carrying mosquitoes, and contribute by their decay to
lowered dissolved oxygen levels. There is an enormous cost
to weed "eradication" or control both in money and in environ-
mental disruption where herbicides are used. Furthermore, we
believe that, in the case of Golden Gate, such control may be
undesirable, at least in some areas.
Regarding disease problems we must defer to U. S.
Public Health Service and the Florida Department of Health
and Rehabilitative Services epidemiologists. Generally, however,
it is our impression that their main concern is that conditions
not favor the mosquitoes Coquillotibia (formerly Mansonia)
peterbans, Mansonia indubitans and M. tittibans. We believe
that marginal aquatics such as cattails, form breeding areas
for such mosquitoes and would hope that spot control rather
than wholesale eradication might be the answer for this problem.
There can be no argument that they hinder canal flow
but in the present case, where too-rapid runoff may be considered
a detriment, such retardation may become, in company with
engineering structures, an asset.
_ __ _
In 1955, Bogart and Ferguson (in Parker et al.,
1955) had the following to say about water hyacinth.
"The retarding effect of water hyacinth on
flow of water is not merely a matter of a
certain part of the channel cross section
being occupied. The roots hang 10 to 12
in. below the plants, and the net obstruction
averages possibly a foot which would be
10 percent of a canal 10 ft. deep. It is
the restriction of flow by increased friction
that reduces capacity. Because, not only is
there the usual friction caused by the bottom
and sides of the channel, but also, where
complete hyacinth cover exists ..., a large
amount of friction occurs at the top, and the
canal is, in effect a closed conduit with
rough surfaces all around. Bogart and Clayton
(1948) show that, because of complete hyacinth
cover, North New River Canal (which was 70 ft
wide at the point of observation) was only
57 percent efficient. The efficiency of
Cross Canal, about 45 ft. wide, was found to
be about 53 percent. Such efficiencies, of
course, vary with the stage the higher the
stage of any canal, other factors being equal,
the higher the efficiency will be, and conversely.
Loss of conveyance capacity caused by hyacinth
cover increases as the size of the channel
decreases, until the point is reached (in
small farm ditches) where flow efficiency may
"It is ironical that, in spite of the concern
over the adverse effect of weeds and hyacinths
in canals, these aquatic plants were beneficial
at times. When water levels and discharges
fell so disastrously low in the drought periods
of 1943, 1944 and 1945, the plants, by their
blocking action, held water to only small
flow on relatively steep slopes thus holding
up levels locally and preventing excessive
wastage. In the Miami area, weed growth retarded
inland movement of salty water in the tidal
canals. As a further paradox in the situation,
the highly undesirable salty water killed the
weed in the canals and cleaned long reaches that
had been clogged for many years."
1 _i ___~ __
The above discussion could apply, with reasonable
accuracy, to canal surfaces covered with water lettuce as
well. Rooted aquatics such as water milfoil, widgeon grass
and coontail complicate the equation considerably but all
have a cumulative effect in retarding flow. Wang and Odum
(1975, unpublished) recognized the possibility of using
this characteristic and, in a complicated logic process,
concluded that a raise of about 1 foot of water level per
5 miles could be achieved by plant growth alone.
Those same authors also made two somewhat shaky
assumptions that "the use of submerged and natural littoral
vegetation will be sufficiently flexible to allow for rapid
discharge of exceptional rain, and that the accumulation of
sedimentation on the canal bottom due to reduced flow velocity
will not over-enrich the receiving estuaries."
The "flexibility" they mention is not at all proven.
If flooding velocity is sufficient to dislodge masses of
weeds, these often become jammed against bridges and water
control structures, causing severe obstruction to flow.
By the same token, once the canal is freed of weeds, either
by natural forces or by harvesting, accumulated sediments
can be swept into nearby estuaries at the next high flow
However, we feel that the concept of control of
flow rate by weed accumulation has merit, and its use should
be considered, particularly for the easternmost canals and
for those portions of the canals north of Golden Gate Boulevard.
In all probability, however, those canals which are expected
to convey large volumes of water during extreme storm condi-
tions should be kept relatively free of weeds.