Wednesday, August 28, 2013

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.
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

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.
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 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
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

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

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.

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.

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

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”

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

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.