First Visit to the Florida Everglades: Part III – Excursion into a “River of Grass”

Please visit my two previous posts on the Everglades entitled:
Part I - Geology of Florida and the Everglades
Part II – Intended Change. Unintended Environmental Consequences.

Perhaps your best chance at time travel awaits you in the Florida Everglades. Mine was last April. It was an unforgettable experience. All senses on high alert. In the morning haze with the smell of salt and sawgrass in the air, a thousand birds in flight, vultures soaring overhead, and armies of alligators patiently awaiting their next meal, the marshy wilderness stood frozen in time.

Alligator mississippiensis, apex predator and most important species of the Everglades

But initial perceptions can be deceiving. These Everglades have been changed. What appears to be wild and untamed is in reality a highly engineered ecosystem, seized by man from Mother Nature and harnessed for his own needs: flood control, clean water, land for agriculture and habitation. Man’s success can be measured in the ecosystem’s loss, and ultimately, his own.

FACT
The Everglades contains one of the highest concentrations of species vulnerable to extinction in the U.S. The 5,000-square-kilometer wetland is home to at least 60 endangered species and retains less than 10% of its original habitat.

DECLINE OF THE INHERENT STRUCTURE OF THE EVERGLADES
My plane was seconds from touch down at Miami International Airport when I snapped this photo of the Everglades looking south into the haze along Krome Avenue and Canal, which joins the larger Miami Canal behind us to the north. Notice anything amiss about the marshy terrain?

The landscape to the east (left) of the canal consists of a green structureless, patchy sawgrass wetland, and to the west (right) it is more defined and linear as water flows south to Florida Bay fifty miles away. Self-serving, man-made structures such as roads, canals and levees haven’t exactly been eco-friendly. So evident is the ecosystem’s degradation that it can be seen from the air.
 

RIDGE AND SLOUGH
Two of the main systems that formed in the Everglades marsh are the sawgrass plains in the north and the “ridge and slough” landscape in the south. Ridge and slough consists of parallel arrangements of peat-based ridges and open sloughs (pronounced “slews”) oriented to the direction of sheet flow to the south and southwest. They are the deepest (over 3 feet in the rainy season) water communities that serve as the main avenues of flow through the Everglades. Flow, the steady and continuous movement of water, is THE most important aspect of ecosystem health in the Everglades. 

Many of the sloughs possess tree islands at their upwater heads. Before channeling into Everglades National Park, the waters of the greater Everglades converge into two large sloughs called Taylor and Shark River that are basically low-lying, wide rivers with northeast-southwest axes.  



Notice that the limestone bedrock below the surface has no relationship to the ridge-and-slough landscape
but may have a prominence below the head of tree islands.
From Chris McVoy, 2003

These structures evolved with the natural sheetflow of water, which likely began within the last 6,000 years (see my post Part I for Everglades geology here). The very identity of the Everglades is related to its slow movement across the vast, low gradient, wetland landscape. Drainage and compartmentalization for flood control and water supply have so interrupted the natural hydrology that this crucial habitat has suffered detrimental ecological damage.

LOSS OF HABITAT
As the ridge and slough landscape became topographically and vegetationally more uniform, amorphous sawgrass stands became associated with fewer numbers of animals and a lower diversity. Foraging and nesting of wading birds is closely tied to vegetation patterns which have been altered. The negative impact on the landscape extends throughout the ENTIRE food web of the Everglades. It's all about the water: quantity, quality, timing and distribution.

THE NEW RIVER CANAL AND LEVEE
The quick drive to the Everglades on Alligator Alley from South Florida's densely-settled east coast, where I was staying, parallels a large canal and levee called the New River, one of many that transect the wetlands. Native American canoe trails have crossed the Everglades since pre-Columbian times, but its modern successors are wider, deeper and hundreds of miles longer. Four major drainage canals were dredged through the Everglades in the early 20th century totaling 236 miles.

Constructed for water management and as a navigable connection between the two coasts, the New River canal and others impede the natural flow of water by slicing the Everglades into flood-manageable but ecologically-segregated parts. Canals draw water from the surrounding wetlands. During the dry season, this causes a complete dry-down of the habitat, a diminished aquatic habitat during the wet season, soil loss and degradation of the peat surface.

The excavation of canals through the less permeable peat into the highly permeable aquifer allows the mixing of ground and surface water, and discharging of salty water that is highly damaging to the biological communities. Florida, Congress and ultimately the taxpayers are learning the difficult and expensive lesson of what happens when you “re-engineer” a region’s natural hydrology.

The New River Canal runs along the Alligator Alley and slices through the wilderness
between Everglades Water Conservation Areas 2 and 3. WCA-2A, the locale of my airboat excursion,
 is beyond the levee (left). Follow the canal east 20 miles, and you’ll end up on the Atlantic Coast.

The canals that drain the glades have reduced groundwater levels, which stopped the flow from natural springs. Saltwater from the sea has backfilled the freshwater “void” both to the detriment of the ecosystem and man’s water supply. Along estuaries at the sea, freshwater releases from canals abruptly changes the salinity, which few species can tolerate, including vegetation. Indigenous fish and oysters in coastal estuaries at the outlets of canals are on the decline, while nonindigenous predators are on the rise. Additional details of change can be found on my earlier post Part II here. 

ROAD ECOLOGY
Alligator Alley’s four-lane highway has many bridges designed with the concept of “road ecology.” The intent is to allow water and wildlife to pass underneath, thereby reducing the environmental impact to the ecosystem. Unfortunately, the road acts as a dam and a formidable wildlife barrier by restricting flow, while the culverts are equivalent to mere leaks. The Comprehensive Everglades Restoration Project plans to elevate long sections of roadways to allow water to proceed unimpeded into the major sloughs and Everglades National Park to the south.

 

Section of Alligator Alley with "eco-designed" structure between the compartments of WCA-2B and WCA-3A
Google Earth

EXCURSION INTO THE EVERGLADES
Our Everglades excursion was led by Captain Randy of "Ride-The-Wind", a private charter touring company. Captain Randy was quick to assure us of our safety under his command. In addition to over thirty years of experience in the Everglades, he served for many years as a captain in the U.S. Coast Guard, as a certified 100-ton Master, and afterward as a gator handler and Certified Dive Master. Captain Randy comforted us by proudly stating, “We’ve never had an occupant eaten by an alligator or strangled by a python!”

 
Our Everglades-worthy vessel was an airboat, but fanboat is more descriptive. It’s a flat-bottomed craft propelled forward by a massive fan enclosed in a protective cage driven by an equally large (and loud) aircraft engine and steered by two rudders at the boat’s stern. A conventional motorboat with a keel would be useless in the shallow, propeller-clogging sawgrass of the Everglades. Speaking of sawgrass, the indigenous vegetation of this marshy habitat, those are nonindigenous cattails lining the canal, another symbol of ecosystem change.

INITIAL OBSERVATIONS
At the launch site, a large, imposing flood control gate dominated the head of the canal, a reminder of the regulatory capabilities of WCA-2A, one of many compartmentalized water conservation area of these Everglades that I had entered. Remember, this is an engineered wilderness!

I was also surprised by the appearance of the water. I expected it to be cloudy, foul-smelling and swamp-like. Instead, it flowed clear and clean, albeit slowly, but far from stagnant. The waters of the Greater Everglades are funneled to the south and southwest of the Florida peninsula on a tilted-gradient of the Florida Platform that’s virtually imperceptible (see Post I for details here).

FROM A SINK TO A SOURCE
As mentioned, I expected to see sawgrass, the ubiquitous flora of the Everglades. Instead, the canal was bordered by dense, tall invasive Southern cattails. Once seen in localized small populations, they thrive on the high phosphorus content of the water filtering downstream from the north. Most ecosystems are nutrient-limited in composition, especially nitrogen and phosphorus, the principal components of fertilizers. Not here. 

The original, un-engineered Everglades system held 4-10 ppb of phosphorus. With the establishment of the Everglades Agricultural Area upstream and below Lake Okeechobee (that contains high levels of natural phosphorus), the northern Everglades has become a nutrient "source" rather than its historic role as a nutrient “sink.”

Pre-engineered, pre-1900 Everglades natural flow patterns (left) and current,
restricted flow patterns (right). In discussion is the relationship between the Everglades downstream
from Lake Okeechobee and the Everglades Agricultural Area.
Modified from Unknown Source

Thus, cattails began to thrive downstream on high levels of nutrients (in excess of 500 ppb). The impact of this change may seem unimportant, but cattails could prove to be devastating for plant and animal life in the area by completely changing the ecology. Not only did the theme of anthropogenic change resonate throughout my excursion, but that the changes are not well understood, yet are a reality and a priority.  

SAWGRASS
The dominant plant in the Everglades marsh and prairie is Jamaica swamp sawgrass. Preferring the wet soils of the Everglades, sawgrass is not “true grass” but a sedge, in a different plant family with sharp teeth along the edges of each blade. Grass stems are round and hollow, while sawgrass has a triangular stem. Rush stems are flat or round.

Fires in the Everglades play a vital role by limiting the colonization of woody vegetation that would eventually invade Everglades marshes and replace the sawgrass, changing the the marsh into the next successional habitat. Fire beneficially sets succession back and has the positive effect of releasing and redistributing locked-up nutrients in plant tissues during their growth. Thus, "natural" fires regenerate the marshes. The wet soil of the Everglades protects the roots of the sawgrass, which enables it to survive fires and then regenerate.



Modified from finegardening.com
Illustration by Allison Starcher

Sawgrass thrives on shallow water depths, whereas cattails flourish in deeper areas. Another hypothesis to the cattail’s radiation is that the fragmentation of the Everglades has altered the watershed’s natural hydrology, and in many areas, increased the water level beyond the sawgrass’s ecological preference. With over $11 billion in federal and state funds devoted to restoriation, all-out war is being waged against the cattails with controlled burns and “safe” chemical poisons. 

VULTURES GALORE IN SEARCH OF GORE
As Captain Randy was readying his airboat, an inquisitive American Black Vulture dropped by to investigate the activity. Black Vultures have black plumage, a small, featherless grayish head and neck, and a short hooked-beak. The word "vulture" is derived from the Latin word vulturus meaning “tearer” of flesh. Being scavengers (and raptors), they dine on carrion (including roadkill), attracted to it by their keen vision. The vultures will circle gracefully overhead of a carcass riding thermals of rising air but often hunt from a perch in a tall tree.   

Less than a minute after the Black Vulture's arrival, it was physically displaced by this characteristically more aggressive American Turkey Vulture. Unlike the Black Vulture, this scavenger has both a keen sense of sight and smell, which helps attract the Black Vulture to carcasses. These "buzzards" are easily distinguished by a bald, red head and silvery wings on the undersides best seen in flight. They resemble a turkey when seen from a distance and hiss when threatened. 




LET’S "RIDE-THE-WIND"
Donning ear muffs for protection against the noise and latching up our seatbelts for safety, we effortlessly launched into a subdivision of the New River Canal and immediately veered off into a smaller ditch. Many of the ditches that crisscross the Everglades are remnants of Native American trails, which have persisted by the airboats frequent usage. As early as 300 A.D., many were built by the native Ortona and, later, Calusa and Tequesta people to connect villages to coastal trade routes.

I commented to Captain Randy that I was surprised to see so few insects. He responded that it depends on the time of the year. He also mentioned that if you catch one in your mouth while on the airboat, it’s considered Everglades “fast food.” Randy had a rather unique sense of humor.

FLORIDA’S OFFICIAL STATE REPTILE (ALONG WITH LOUISIANA AND MISSISSIPPI)
No other species defines the Everglades as does Alligator mississippiensis. It's the most important species in the Everglades. The American alligator is not only the "apex" predator at the top of the Everglades food chain, but it’s the "indicator" species for gauging the health and restoration of the imperiled ecosystem. It’s also a "keystone" species that affects nearly all aquatic life in the Everglades. 

In the 1900's and 1960's, alligators were literally disappearing from the wetlands by poachers that sold their hides. Finally, the federal Endangered Species Act of 1973 made it illegal to deal in any alligator parts including skulls, teeth, claws, meat and hides. They have since rebounded tremendously, yet the main threat today facing the American alligator is the destruction and degradation of its wetland habitat.

Crocodiles and alligators belong to a group of reptiles called crocodilians, and uniquely, both reside within the Everglades, but alligators are far more common. Once occupying all wetland habitats in south Florida, development and water-management practices have reduced both the quantity and quality of these habitats. Today, the alligator inhabits freshwater wetlands of the southeastern United States but has declined throughout the Greater Everglades; whereas, the croc, being a tropical species, maintains its northern-most range in brackish, coastal mangrove areas of south Florida including Florida Bay.

Amongst other notable features, the alligator is distinguished by its broader snout, darker or blackish coloration and overlapping, upper jaws. Crocs have a tapered, triangular snout, are grayish-green and have a signature tooth jutting out from its lower jaw.

Being a patient and opportunistic feeder (on whatever comes along but especially apple snails and crayfish),
evolution has provided the alligator with nostrils and eyes that stealthily project just above the surface
with the rest of its body submerged. Its vertically flattened tail allows it to silently glide through the water.

ALLIGATOR HOLES
Alligators are pond-builders and worthy of their role as "ecological engineers." They alter the landscape by using their mouths, bodies and tails to remove vegetation from small depressions within the bedrock and push soil sediments onto the banks, thereby creating and maintaining "alligator holes." Their construction may not be intentional but a consequence of herding fish and foraging for food.

The holes contribute to an increase in habitat diversity and species richness both in and around the holes. Therefore, an increase in holes, nests and occupancy rates translates into a healthy ecosystem and a sign of successful restoration efforts. 

The small open area ringed by trees is an alligator hole
National Park Service

In the dry season, the holes serve as an aquatic refugia for alligators and other aquatic organisms such as fish, amphibians and invertebrates, and as foraging sites for wading birds that prey upon the resident species.

Gators also construct many channels or trails (seen above) that lead to the holes. Many holes are surrounded by a low ring of trees or are near a tree island as this one. Typically, they are ringed by a sawgrass marsh. Many gator holes are centuries old and are maintained by successive generations of alligators.

Knowing the wetlands like the back of his hand, Captain Randy knew precisely where gator holes were located. He shut off the fan and glided us into a hole where a female was thermoregulating in the morning sun.

Captain Randy has spotted a large female at the periphery of a gator hole.
A low ring of trees, shrubs and even cattails often helps locate the holes.

Notice how the sawgrass has been trampled by mama's movements around the hole.

Alligators are ectothermic (externally regulating their body temperature) and are generally active when temperatures are 82-92º F. They stop feeding when the temp drops to 70º F, and they become dormant and inactive at 55º F. On this cool 65º morning, that explains the female's indifference to our presence. Of course, we did remain at an unthreatening distance.

I spotted six juveniles basking on the periphery of the hole with likely more present within the tall sawgrass. The average clutch size is 32-46 eggs, which are laid in late June and early July, and hatch in late August or early September. That makes these youngsters about 8 months old. Many of the eggs succumb to predation from raccoons and otters, while juveniles face danger from wading birds and larger cannibalistic alligators. Interestingly, the temperature of the female's nest of vegetation and mud determines the sex of the hatchlings with more males produced at higher temperatures.

I counted four more youngsters here.

Many adult alligators, males in particular, have taken residence in larger, man-made canals throughout the Everglades. They are attracted by the large numbers of native and non-native fish and invertebrates, by the dry-season refugia and escape from saltwater incursion into their habitat.

Everglades pre- versus post-drainage in regards to wet and dry seasons
Source: Christopher McVoy, SFWMD

Canals are not suitable habitats to sustain a healthy alligator population. Smaller alligators are vulnerable to predation and cannibalism. Hatchlings are unlikely to survive, and nests are frequently flooded out. And most important to the ecosystem, alligators that rely on canals for sustenance no longer build and maintain alligator holes. Again, man's efforts to control flooding have adversely impacted the ecosystem.

FLORIDA GREEN WATERSNAKE
Just beyond the hole, I spotted what I thought was a Burmese Python by its size. It's an invasive snake that has been wreaking havoc with the small, indigenous mammals of the Everglades since 2,000 when it was released by pet owners. The snake turned out to be a Green Watersnake, the largest and most dominant watersnake in North America found throughout most of Florida.

They prefer heavy, wetland vegetation and quiescent waters of marshes and swamps. Overall, it is dark olive-green or brownish and has no distinctive markings such as stripes, spots or crossbands but is speckled with muted colors on each scale. Its size is intimidating, but it's totally harmless and non-venomous, although it may bite when cornered. Apparently, it's commonly mistaken for the venomous Florida Cottonmouth (aka water moccasin), which has a white lining around its mouth and vertically-slit eyes; whereas, the eyes of the watersnake are rounded. It dines on frogs and fish.

GREAT BLUE HERON
Over 400 species of birds have been identified in South Florida of which 60% are winters residents having migrated from the north. Many of those are in transit to more southerly tropical locations. Spotting this Great Blue was a majestic event. This stately bird with its subtle blue-gray plumage and wide, black stripe over the eye, in typical fashion, was alternately wading and motionless as it watched for prey. It’s the largest of the North American herons and yet weighs only 5-6 pounds. It can strike with lightning speed to grab or even impale a fish, frog or small mammal with its dagger-like bill.

Concealed by sawgrass as we airboated down a canal, I caught this Great Blue in flight

THE GREAT EGRET
Also called a Great White Heron, the Great Egret is slightly smaller than a Great Blue. They too hunt in classic fashion by standing immobile or wading through both fresh and saltwater, capturing fish with a lightning fast jab of their yellow bill. They were nearly hunted to extinction for their plumage for the hats of Victorian-era fashionable ladies. By 1900, more than 5 million birds were killed every year, including 95% of Florida's shore birds. Most were shot in the spring when their plumage was the most colorful.

Great Egrets nest in the trees of islands within the glades. In flight, they retract their S-curved neck and trail their black legs behind. Looking similar but larger and with yellow-gray legs, there is also a “white morph” of the Great Blue in South Florida. 

THE ROSEATE SPOONBILL
The Spoonbill is a wading bird of the ibis family that feeds on crustaceans, aquatic insects, frogs and small fish. Like the American Flamingo, which it is closely-related and often mistaken, the color of its brilliant pink wings is diet-derived from pigments found in shrimp and algae. It is highly recognizable by its odd, flat bill, which it uses to strain small culinary delicacies from the water. Like so many other colorful birds of the Everglades (especially snowy-white egrets), they were hunted to the verge of extinction for their plumes.

SNOWY EGRET
Herons are long-legged freshwater and coastal birds. Some are called egrets and are mainly white with decorative plumes. They resemble birds in other families but fly with their necks retracted, not outstretched. This small white heron is also protected under federal law by the Migratory Bird Act Treaty of 1918. The area of the upper bill in front of the eyes is yellow to red, and its feet are yellow. 

HAMMOCKS AND TREE ISLANDS
The Everglades is not all sawgrass marsh. It is blessed with a great variety of habitats and biological communities. We spotted one such habitat in the distance, a "tree island", which is actually a blanket term for a region with noticeably taller trees within the marsh and on higher ground of typically woody peat, a limestone outcrop or marl closer to the coast.

The standard jargon for them are "heads," which are characterized by the kinds of trees that dominate each of them. Thus, you have bayheads, willow heads, cypress heads, and so on. In addition to their clusters of trees, each of the various tree islands possesses distinctive shrubs and ferns. They are singular ecological entities as much as they are insular land features. In the 1940's there were 1,251 tree islands in the central Everglades; today there are 581. Scientists are racing against time to these "forgotten" islands to discover their formative dynamics and ecological secrets.

The early Everglades, beginning perhaps 6,000 years ago, didn't possess tree islands, which began to form about 3,500 years ago. Three main geological processes form tree islands: formation on a "fixed" high point of bedrock which acts as a nucleus for tree development; on a peat "pop-up" (the most common) of interwoven roots where bottom peat acquires buoyancy from the release of mostly methane gas from water lily roots and rhizomes; and elongated strand islands similar to the sawgrass ridges previously discussed.

Many tree islands have a teardrop shape with a bulbous, upland head and a downstream tail aligned with the direction of sheetflow. The head of the tree island is generally a tropical hardwood hammock, a localized mature forest of broad-leafed trees (as opposed to pines) that is rarely inundated by flooding. The tail can take 1,000 to 2,000 years to develop as peat accumulates above the marsh.

Fire and flooding are of key importance in the integrity of tree islands. Prolonged high water has a devastating effect in particular related to water management practices, but prolonged low water puts them at risk to peat-consuming soil fires. Natural fire actually has an important ecological role in sawgrass habitats by limiting the invasion of woody vegetation that would eventually change the marsh into the next successional habitat. Submerged sawgrass roots are able to rebound following a damaging fire. The ecosystem is now at the mercy of human intervention, and Everglades restoration is contingent on man's efforts at revitalization, including tree islands.

Diagram of tree islands by origin
U.S. Geological Survey Fact Sheet 2004-3095

 

Many of the tree islands have been found to have a prehistoric history of human use and habitation dating as far back as 12,000 years. Today, many are privately owned and surprisingly have air-conditioned houses, connecting sheds, decks and docks for airboats. Many of the islands and hammocks have colorful names such as as Jimmie Tiger, Gumbo Limbo and Charley Jumper.

Tree islands greatly enhance the ecological value of the Everglades. They are important centers of biodiversity with two to three times the plant and animal diversity of the surrounding wetlands.

A flock of Black-necked Stilts exercising precise aerial maneuvers

This island sported a half-dozen Turkey Vultures roosting in trees, waiting for warm morning air to develop into rising thermals. Notice the large nest down below.

 

Near the end of our airboat Everglades tour, Captain Randy readied us for this "money shot." A sky filled with egrets, herons, spoonbills, storks, ibises, cranes and pelicans. 

Nourished by rain and defined by annual rhythms of drought and flood, fire and sunshine, the Everglades is totally unique. No other place possesses such a stunning diversity of plants and animals. "There are no other Everglades."


RIDE-THE-WIND
For private airboat charters in the Everglades, I highly recommend Captain Randy here.

SPECIAL THANKS
With great appreciation, I thank amateur ornithologist Ian Starr for his expertise in identifying many of the Everglades birds.

VERY INFORMATIVE SOURCES
Geologic History of Florida by Albert C. Hine, 2013.
Geology of Florida by Albert C. Hine, College of Marine Science, University of South Florida (PDF available online).
Geologic Map and Text of Florida, Florida Geological Survey, Open-File Report 80 by Thomas M. Scott, 2001 (available online).
The Everglades Handbook: Understanding the Ecosystem, Third Edition, by Thomas E. Lodge, 2010.
The Geology of the Everglades and Adjacent Areas by Edward J. Petuch and Charles E. Roberts, 2007.
Roadside Geology of Florida by Jonathon R. Bryan et al, 2008.



First Visit to the Florida Everglades: Part II – Intended Change. Unintended Environmental Consequences.

“There are no other everglades in the world.
Nothing anywhere else is like them.”
Marjory Stoneham Douglas (1890-1998)
 

Great Egrets, Snowy Egrets, pink Roseate Spoonbills, Glossy Ibises, White Ibises,
a Wood Stork and an American White Pelican

Please visit my previous post here for Part I: - The Geology of Florida and the Everglades.

 

ALLIGATOR ALLEY
In April, I visited the Everglades for the first time. It was only a forty-five minute drive on Everglades Parkway (I-75) from Florida’s densely-populated, southeast Gold Coast. My destination was an airboat landing just off Alligator Alley, a section of the highway named derogatorily by the AAA in 1969 and regarded by them as a highway “with a flagrant disregard for safety” because of its formerly impassable location. 

 

Today, the “Swamp Pike” is an essential east-west connection between the Atlantic and Gulf Coasts between Fort Lauderdale and Naples, a distance of about a hundred miles. Twenty miles to the south, the Tamiami Trail (US 41) was completed in 1928 and parallels Alligator Alley as it zigzags across the state from Miami to Naples.

In the past, both highways were touted as triumphs of modern engineering, since they pass through the heart of the formerly impenetrable wilderness of the Everglades. Today, both highways are recognized as ecological barriers that have had a devastating effect on the Everglades ecosystem by interfering with the natural flow of its waters.

 

 

Florida’s densely settled Gold Coast encroaches on land reclaimed from the Everglades. Below leveed and diked Lake Okeechobee (top left) is the patchwork Everglades Agricultural Area, and below it, the Everglades is subdivided into Water Conservation Areas (WCA's) by roads, highways, levees and canals.
Google Earth

 

 

AN EVERGLADES DIVIDED
The region of the Everglades I entered is designated Water Conservation Area No. 2A (WCA-2A for short) by the Central and South Florida Project. At 210 square miles, WCA-2 is the smallest of three compartmentalizations created as wildlife refuges but primarily for flood control and water management. The A's and B's designate subdivisions.

At times of impending flood or drought, water can be selectively stored, released and shunted from one WCA to another by a system of levees, canals, floodgates and pumps. The WCA’s are only a part of the water management system called the Kissimmee-Okeechobee-Everglades watershed, also referred to as the Greater Everglades. It doubles as one of the largest and most complex natural ecosystems in the world, which has been engineered to be regulated by man instead of nature.

 

ECOLOGICAL DETERIORATION
Facing east toward Florida’s Gold Coast, the WCA’s (see Google Earth above) are south of Lake Okeechobee between the patchwork crops of the Everglades Agricultural Area (left) and Everglades National Park (not seen). Below the lake, the watershed is crisscrossed by roads, highways, levees and canals that have so fragmented the Everglades that it has resulted in its ecological deterioration while benefiting man’s existence and making his land habitable. Note the location of Alligator Alley and the Tamiami Trail coursing through the heart of the Everglades. Not seen to the south are Big Cypress Swamp, Everglades National Park and Florida Bay. 

A Great Blue Heron majestically soars over the river of grass.

THE K-O-E WATERSHED

The Kissimmee-Okeechobee-Everglades watershed is both a highly-engineered, water-management system and a complex ecosystem. Central and South Florida are grappling with the challenges of preserving both.

The K-O-E’s waters begin their 225-mile journey to the sea from the Chain of Lakes below Orlando in central Florida. Directed into the once-meandering and now canal-straightened Kissimmee River (along with four other tributary sources), water is funneled south to the diked and leveed shallow bowl of 730 square-mile Lake Okeechobee. Today, Lake Okeechobee is intensely managed with 5 gated outlets and inlets, 33 primary and secondary culverts, 9 navigation locks and 9 pump stations.



US Army Corps of Engineers

Below the lake, flow is channeled through sugar cane farmlands of the extensively-irrigated Everglades Agricultural Area before reaching the aforementioned floodgate-controlled, pump-regulated Water Conservation Areas. Along the way, numerous canals divert water to population centers along Florida’s southeast coast. Eventually, the greatly reduced flow converges south and southwest upon Big Cypress National Preserve and Everglades National Park before entering the sea at Florida Bay and the Gulf of Mexico.

The National Academies Reports on Everglades Restoration

 

 

GO WITH THE FLOW!
The historic, natural flow of a broad sheet of slowly-moving water that built and sustained the ecosystem some 6,000 years ago no longer exists. Today, the sheet flow that characterized the natural condition is highly interrupted and no longer free-flowing, and the volume of flow to the Everglades is diminished by as much as 70%.

The satellite photo on the left depicts the historic and natural, pre-1882, pre-drainage pattern of flow. The yellow line depicts the hydrologic boundary and denotes where vegetation has changed from marsh to higher ground along the border of the Everglades. The photo on the right (2004) shows the historic Everglades boundaries, the EAA, the WCA's, the man-made features of subdivision and the sprawling Gold Coast population centers that have advanced into the Everglades at its expense.

Historic, natural versus current pattern of flow superimposed on satellite photo.
Modified from Landscapes and Hydrology of the Pre-drainage Everglades, 2009.

In less than a hundred years of (mis)management, the Everglades has become over-regulated and over-drained. The Comprehensive Everglades Restoration Plan (CERP) hopes to restore the natural pattern of flow in such a way as to protect the interests of man and insure the viability of the ecosystem. In essence, the CERP Plan mimics the historic pattern of flow but preserves flow to the EAA and population centers, while somewhat reducing flow to the Everglades in the south peninsula.

Historic, natural flow versus current and planned flow
Evergladesplan.org

UNINTENDED ENVIRONMENTAL CONSEQUENCES
Man has won the battle of regulation but is losing the battle of preservation. Undoubtedly on paper, the heavily-engineered solution looked great, but it ecologically fragmented the Everglades resulting in the overall deterioration of the wetlands and ecosystem. The adverse effects can be seen throughout the entire length of the watershed.

The arrival of this nonindigenous, Southeast Asian Burmese python in the Everglades, which became established around 2000, coincides with a rapid decline of native mammals such as opossums, raccoons and rabbits. This 162-pound, 15-foot fellow was captured shortly after having eaten a six-foot alligator.
AP Photo/University of Florida

A RIVER OF CHANGE
Following the canalization and dredging of the Kissimmee River, at the top of the watershed, its steep banks were no longer inviting to wading birds and fish, and nesting alligators and turtles. Deleterious phosphorus-rich fertilizers filtering downstream from the Agricultural Area into the Everglades are facilitating the invasion of nonindigenous plants. Beneficial fires that rejuvenated the Everglades are reduced by the unintended fire-breaks created by canals and roads.

Man-made canals facilitate the establishment of non-native fishes by offering permanent thermal and drought refuges. Canals also serve as pathways of invasion for non-indigenous species into interior wetlands, increasing the impacts that may adversely alter the ecosystem's structure and function. Pest-plants become invasive as well, lured into deeper, nutrient-rich canal habitats.

The canals are also inviting to alligators but are undesirably dominated by adults. Nesting in the canals is negligible at the expense of the construction and maintenance of alligator holes. Gator holes found throughout the Everglades provide a critical dry-season habitat for wetland fishes, amphibians and wading birds. The alligator is a "keystone species" that other species rely on, hence a reduction in alligator holes impacts the entire ecosystem.

The deep-water, nutrient-rich, man-made canal and levee that forms the boundary
between WCA-2A and Coral Springs on the other side.

This is what lies immediately on the other side of the above canal and levee. What a juxta-position!
Google Earth

Salt water is entering the aquifers in place of withdrawn freshwater during dry periods. Cypress and palms intolerant of salt are beginning to die. Coastal mangroves are moving inland. One million acres of the ecosystem are under health advisories for mercury contamination.

Periphyton, a mixture of algae, cyanobacteria, fungi, microbes and detritus, serves as a crucial part of the food web and egg-laying medium for invertebrates and fish. It absorbs contaminants from the watercolumn and is an excellent biotic indicator of Everglades health. It requires nutrient-free water for growth and is in jeopardy due to rising levels of phosphates and nitrates from the Agricultural Area. In its absence, the entire ecosystem would be adversely impacted and would allow invasive cattails to thrive. 

Wading bird populations are experiencing a 90-95% reduction. 68 plant and animal species are on the threatened or endangered list. Commercially and recreationally important fish and invertebrate species in the estuaries are on the decline. Nonindigenous Southeast Asian Burmese pythons, released by pet owners and hurricane-escapees, are thriving and killing native species. The Florida panther is on the IUCN’s Red List for “extinction in the wild.” Only 100-120 are thought to live within the state. The American crocodile and West Indian manatee are on the list as well. 


 

An acrobatic flock of Black-necked Stilts

The Everglades has among the highest mercury levels in fish in Florida. The average male Florida panther has higher estrogen levels than females, due to the estrogenic properties of mercury in the fish they eat. The mercury comes from coal-fired power plants and industrial facilities like cement plants.

Water from Everglades National Park and other areas drains into the Biscayne Aquifer, which is the source of drinking water for Dade, Broward and some Palm Beach County residents. Meaning more than 7.7 million people depend on the Everglades for drinking water. Without the Everglades to “recharge” this underground water supply, the aquifer would be in danger of running dry or being contaminated by salt water.

These are but a few signs of Florida's shrinking and imperiled ecosystem. The Everglades are clearly in decline.

HOW DID THIS HAPPEN IN ONE HUNDRED AND TWENTY-FIVE YEARS?
The history of draining and development of the Everglades dates back to the 19th century and the Seminole Wars. The United States military’s mission was to seek out indigenous Seminole people in the Everglades to capture, enslave or kill them. That gave the military the opportunity to map the Everglades, opening the door for wetland draining for agricultural use. A lack of understanding of the geography and the ecology have plagued the Everglades ever since.
 

 



Early painting of U.S. Marines searching for Seminoles amongst the mangroves during the Second Seminole War
From Wikipedia

The first major change began back in 1882, a seminal year for the watershed referenced on the maps above. That's when Hamilton Disston, a wealthy Philadelphian, began to drain overflowed lands in return for reclaimed lands. Although his reclamation venture was a failure, he succeeded in creating a new Gulf outlet for Lake Okeechobee to the saltwater of the Gulf of Mexico that considerably dropped the level of the lake. Notably, it was the first large scale project to alter the wetlands of South Florida, a major part of which is functioning (or dysfunctioning) to this day. In 1903, Napoleon Bonaparte Broward ran successfully for governor with the intent to drain “the fabulous muck.”

“Drain the Everglades” gubernatorial political cartoon of Napoleon Bonaparte Broward
“A Big Job” Times Union (Jacksonville), January 14, 1905.

After the devastating hurricanes of 1926 and 1928, when Lake Okeechobee floods killed upward of 2,500 people with vast destruction of property, flood-control became the priority. In 1931 the Herbert Hoover Dike was built around the perimeter of Lake Okeechobee, and later, channels, control gates and levees were added. A tireless advocate of preservation, in 1947 Marjory Stoneham Douglas published The Everglades: River of Grass about the fragile ecosystem of the Everglades. The environmental awareness was greatly enhanced, but the economic drive for development proved too strong. Ultimately, her book could do nothing to stop drainage and flood control for urbanization, agriculture and development. 

It wasn’t until 1948 that Congress established the Central and South Florida Project to control flow within the Everglades. Flood control was accomplished with an elaborate and effective management system of 1,000 miles of levees, 720 miles of canals, and almost 200 water control structures. In 1992, the plan was modified by the "Restudy" (short for Review Study) by the Comprehensive Everglades Restoration Plan (CERP), a joint effort of the federal government and the State of Florida.

RIVER OF HOPE
In what is the world’s largest ecosystem restoration effort with more than 60 components, the plan is simple in its intent but massive in its proportions: restore the ecosystem, preserve and protect water resources, and provide flood protection. The plan is estimated to take more than 30 years to complete, and the current estimate in October 2007 dollars is $13.5 billion.

The goal of the CERP (found here) is to capture fresh water that now flows unused to Florida Bay, the Gulf of Mexico and the Atlantic Ocean, and redirect it to areas that need it most, the Everglades. The majority of the water will be devoted to environmental restoration, reviving a dying ecosystem. The remaining water will benefit cities and farmers by enhancing water supplies for the south Florida economy.

The Plan includes such elements as: the backfilling of the 56 mile-long, C-38 Canal and replacing it with the restoration of the 103 mile-long, naturally-meandering Kissimmee River and its surrounding marsh floodplain; reducing flows to the Caloosahatchee and St. Lucie Rivers from Lake Okeechobee; the construction of over 300 wells to store excess water from Lake Okeechobee (saline-safe underground with 30% less loss from surface storage-evaporation); the decompartmentalization ("decomp") of WCA-3 so that unrestricted, passive flow can occur; filling-in of the Miami Canal and others; the removal of many levees; the rehydration of coastal marshes and mangroves with increased sheet flow; partially restoring flows to Biscayne and Florida Bays; and, the conversion of flow-choking, road-barriers such as the Tamiami Trail to an elevated Everglades Skyway.

An artist's vision of the elevated Tamiami Trail and a rejuvenated Everglades
flowing under the eco-friendly Everglades Skyway.
Artist Unknown/Everglades Skyway Coalition

CLIMATE CHANGE
On a note of closure, great extremes in water quantity are anticipated to occur in the coming years. Even now, sea level appears to be rising at the rate of one foot per century. What appears certain is the uncertainty associated with annual temperatures and annual rainfall. As stated by Lodge in the The Everglades Handbook, "The implications of rising water relative to street or building elevations is easy to comprehend, but ecological consequences are far more involved."

The following maps graphically illustrate Florida's very low topographic relief. The implications are obvious for storm surges but also for climate-related rising sea level. A rise of 33 feet would submerge the majority of southern Florida and drown the entire ecosystem.

Southern Florida's very low topography is evident in these color-shaded relief maps,
especially along the coastline but notwithstanding the entirety of the Greater Everglades ecosystem.
On the left, green colors indicate low elevations rising through tan and yellow to white
at 60 meters (197 feet) above sea level. On the right, elevations below 5 meters (16 feet)
have been colored blue with lighter blue indicating elevations below 10 meters (33 feet).
Modified from NASA Earth Observatory

How will the Everglades fair when confronted with forecasted periods of severe drought and floods? The region was recently challenged in this regard. In 2011, 60% or more of the land in the Everglades water conservation areas went dry (South Florida Water Management District). The answer can be found underfoot, or in the case of the Everglades, underwater. Past climate change resulted in the deposition of seafloor stacked upon seafloor in a rhythmic and cyclical sequence in the Everglades. If geological history repeats itself, that much we can anticipate. 



Please join me on an airboat tour of the Everglades: Part III – Excursion into a “River of Grass”

SPECIAL THANKS
With great appreciation, I thank amateur ornithologist Ian Starr for his expertise in identifying many of the Everglades birds.

VERY INFORMATIVE SOURCES
Geologic History of Florida by Albert C. Hine, 2013.
Geology of Florida by Albert C. Hine, College of Marine Science, University of South Florida (PDF available online).
Geologic Map and Text of Florida, Florida Geological Survey, Open-File Report 80 by Thomas M. Scott, 2001 (available online).
The Everglades Handbook: Understanding the Ecosystem, Third Edition, by Thomas E. Lodge, 2010.
The Geology of the Everglades and Adjacent Areas by Edward J. Petuch and Charles E. Roberts, 2007.
Roadside Geology of Florida by Jonathon R. Bryan et al, 2008.