Okeechobee Foothill?
How time turned a dike into a levee
For as easy as it is to see on a map …
Lake Okeechobee is deceivingly hard to find on the ground.
The reason?
Hoover Hill would seem partly to blame.
Listen to the podcast to find out more.
Sometimes called a levee and other times a dike …
The earthen embankment both blocks the view from its base and promises a scenic vista from its top only to leave you wondering –standing at its crest and looking inward — where the lake starts and if it’s there at all.
With everyone thinking about how to optimally regulate the Lake’s stage, its important to remember that from a design standpoint, the dike-turned-levee was built first and foremost to control (repress) water levels on the outside, not inside, of the levee …
And with the design goal (on the outside) being dry arable ground.
Flying south
Loop around Loop Road
There’s always lots to see …
On a flight over Big Cypress Nat’l Preserve.
We flew clockwise around Loop Road
On this trip south of Tamiami Trail, we see a swamp mirror (reflecting the clouds), the Pinecrest Chain of Hammocks, Gum Slough, Loop Road, Sweetwater Strand and Gator Hook Strand and Trail.
More than one?
And four to be exact
Big Cypress National Preserve has four major watersheds:
(1) Central Preserve, (2) Okaloacoochee Slough, (3) Mullet Slough and (4) the Everglades.
Within each watershed are major drainages …
Were water is deepest and flows longest.
Those include sloughs and strands.
Between the strands are higher lying (but still soggy) marl and dwarf cypress prairie.
Deepest lake?
Or is it only pond worthy?
By most metrics,
Deep Lake should be called a pond.
Considering that it’s only 300 feet across …
And its circumference is 300 feet less a quarter mile, that sounds more like a pond. But if you consider that its open pool is five times deeper than Lake Okeechobee’s 20-ft depth, and – here’s the icing on the cake – that it isn’t enclosed by a 35-ft tall levee, thus allowing its waters to naturally overflow into the swamp.
By definition, that sounds like a lake to me.
Kissimmee Valley
Headwaters of the headwater lake to the Everglades
Once upon a time, the Kissimmee Valley was a chain of loosely-connected isolated lakes separated by a marshy expanse. Unconnected was the operable term. It simply wasn’t a place that drained very fast. Farther to the south formed two lakes, one called Kissimmee and the other Istokpoga. The waters made its journey from Lake Kissimmee to Lake Okeechobee by way of 103 miles of meandering river that often overflowed its banks and filled the floodplain. Lacking a similar river, Lake Istokpoga sent its water to Lake Okeechobee through a grassy waterway dotted with tree islands that resembled a miniature version of the Everglades.
And then came channelization.
Audio Introduction
The modern-day Kissimmee Valley still drains into Lake Okeechobee, just like it always did, but the journey from Point A to Point B is largely through canals, and you guessed it – as mediated by a series of regulation schedules. Channelization has made the Kissimmee both more navigable and drier than its previous self, and also affected water delivery and quality to downstream Lake Okeechobee. The good news is that starting the 1990s restoration work has been done to redivert and resuscitate flow back into the nature river channel that the canal and levee works shut off.
Even so, drainage has dramatically changed the lakes. Prior to channelization, large rain events swept away sediments that kept the lake bottoms clean and fed nutrients into the wetlands below. Today, the lakes are maintained a at a lower level, and with less natural variability, causing an accumulation of sediments in the lakes.
Big Cypress Watershed
Or is the term "mosaic" a better descriptor?
In the modern era, we’ve come to know the Big Cypress as a watershed. But what if I were to tell you, use of that term for the Big Cypress is as new as the preserve? Yes, that’s right, the day Big Cypress National Preserve was established in 1974, it was dubbed a watershed – it’s own watershed, a watershed separate from the Everglades and the Lake – and has been thought of in that pristine, almost utopian way, ever since. But the truth is the Big Cypress is only a watershed because its original “other sources” of water were drained away, or diverted.
Listen to Audio Introduction
What were those sources? Lake Okeechobee and the Everglades definitely flowed into the swamp. If you don’t believe me, just read the Buckingham Report from 1848. And prior to the destruction of the Ft. Thompson Falls and drainage of the Upper Caloosahatchee Basin (Lake Flirt, Lake Bonnet and Lake Hicpochee), the swamp was fed water through groundwater seeps from the Immokalee Rise.
So yes, in a way the Big Cypress we know today is a rainfall-sustained ruins of a pre-drainage cathedral of of headwater flows, now largely collapsed (by drainage). That doesn’t make the swamp any less special. In fact it makes it more interesting than we knew. And it also points to our need to steward water. The sky provides the Big Cypress with a bounty of water. But it needs help, our help, to make sure its clean, connected to its remnant headwaters where possible, and help it spread out.
And the swamp needs fire, too. Every square inch of flora and fauna in the swamp depends on a regular return interval and dosage of flood and fire. Those are the two forces that give the swamp its distinctive mosaic of habitats. The cypress may look “old as the hills” but they are actually holes — although it is incorrect to call it a homogenous swamp.
More correctly stated, it’s a malleable swampy mosaic that’s semi-fixed in time and space. Or as we like to say around here:
So goes flood and fire, so goes the swamp.
Creek-sized river
And why Turner is a river all the way!
By most metrics, Turner River qualifies …
As a “creek,” not a river.
Or does it deserve the higher rank?
Listen to Firelight Radio to find out.
Hoover Hill
A retrospective of the dike that controls the Lake
By William J. Sobczak and Robert V. Sobczak
Introductory excerpt from a draft paper
Did you know that if you straightened it out, the 143-mile long earthen mound that surrounds Lake Okeechobee would stretch from Florida’s East to West Coast (i.e. Palm Beach to Sanibel, Florida). Yet few people make the trek into central Florida to visit the dike.
Lake Okeechobee – not Herbert Hoover Dike – is the more common destination point.
Listen to the Audio Introduction
How big is Lake Okeechobee?
- Okeechobee originates from the Seminole Indian terms “oki” and “chubi,” which literally translates into “Big Water,” and indeed it is. Situated in the center of the peninsula, it is the largest freshwater body in the Southeastern United States (2nd largest in the U.S., excluding Hawaii and Alaska), spanning 730 square miles and 5 counties (Glades, Marketing, Hendry, Palm Beach, and Okeechobee counties), and contains water as far as the eye can see. Standing at its eastern shore – at Port Mayaka or the Pahokee Marina – the expansive lake looks more reminiscent of the Gulf of Mexico or some other saltwater sea, not a land-enclosed lake.
- The Lake is so large that it even influences regional precipitation patterns by stifling daytime heating and the convectional rise of air that brings ample afternoon showers to much of peninsula Florida. As a result, the Lake receives less rainfall than the rest of south Florida.
- And who could deny, from a bird’s eye view, Lake Okeechobee’s place as perhaps the Sunshine States most iconic geographic feature other than its long coastline. Simplified maps of the state invariable include three things: the panhandle to the west, the peninsula jutting to the south and Lake Okeechobee, in the middle of it all, also known as the “Big O,” “liquid heart of Florida,” “Lake O,” or simply “The Lake” which is always capitalized in homage to the oversized area and role it consumes in Florida life (Figure 1).
Yet, despite the oversized aura it invokes both inside and outside the state – somewhat surprisingly the most common experience for those closest to it, driving by it from either coast, is to miss it completely.
How is that even possible?
The reason is the 12 meter (35 ft) high grassy hill or mound that blocks the view. Not a natural feature at all, the well-trimmed rise is a 143-mile long levee that forms the perimeter of the modern-day lake.
Interestingly – and a hint to the primary thesis of this paper – it is the shape of the levee, not the Lake itself, that forms the recognizable 730 square mile area that we know as the modern-day lake today. With the exception of an opening at Fisheating Creek that allows the stream to free flow into the Lake’s at its western shore, the rest of the Lake (almost its entirely) is walled off from the lands that surrounded it. Surface-water inflows and outflows to the lake no longer occur naturally, but rather are regulated through a series of human-operated structures and gated culverts.
Thus the question can be raised:
Is it still appropriate to call Lake Okeechobee a lake at all? Would the name Okeechobee Reservoir be a better fit?
As for a clear view of the lake, one would think climbing to the top of the levee, the highest spot for miles around, would reveal its large expanse. But not even that is a guarantee. The majority of the view from atop the 143-mile long levee is obscured by some combination of wetlands, canals, islands or other vegetation. It’s peaceful, often sunny and quite bucolic view, just not the open expanse a first-time viewer would expect.
Despite difficulty (and adventure) in trying to catch a view of it – and the sense of reward when you finally do – the Lake lies in the center of a simmering debate on how it’s water stage should be managed.
Why Lake stage matters at all isn’t intuitively obvious.
- Like any reservoir, the Lake fluctuates up and down both naturally and through anthropogenic controls – and most importantly by an official and legally-binding regulation schedule developed and operated by the U.S. Army Corps of Engineers (USACE).
- Yet to the naked eye, the levee towers high above the Lake’s water surface – well above the level that any flood could conceivably overtop – and also appears as equally strong at its base.
- The more common observation by the casual observer is that the levee is overdesigned. The threat of the Lake breaching such a mammoth feature seems fanciful at best.
The same casual observer may find it surprising to learn that it was problems with the structural integrity of the levee, and the threat of it breaching, that caused the government agency who built and maintains the levee – the U.S. Army Corps of Engineers (USACE) to adopt an interim (i.e. emergency) regulation schedule in 2008 until such time that the levee could be fixed. The interim regulation schedule protects the levee by keeping the Lake at a lower level.
Over a decade later, with most of the primary fixes either in place or nearing completion, the newly fortified levee is in capable of handling higher water. But how high? And what were the pros and cons of the interim operation schedule and, going back into time, all the operational schedules that came before?
The USACE is currently leading a new effort called the Lake Okeechobee System Operation Manual (or LOSOM for short) for the purpose of adoptive a new regulation schedule reflective of the fixes to the levee and other regional water management features that have come on line since 2008. As it does with all its projects, the USACE is actively engaging and seeking collaborative input from individuals and organizations with diverse perspectives.
Many stakeholders are interested in the Lake and how it is managed for the integral role it plays from environmental and human-use perspectives both internal and external to the levee.
Yet going back to the casual observer standing on top the levee at the Moore-Haven S-77 Lock and Dam on a sunny day, the overriding reaction would be a bit of a headscratcher:
- How could such a large levee be not strong enough?
- And other that breaching the levee, why does water level matter at all?
Click HERE to see a detailed history of Lake Stage.
Hoover’s Hill (to True Scale)
And why you can't see the Lake or Everglades
At first glance, the Herbert Hoover Dike appears to tower high above the Lake’s water surface – well above the level that any flood could conceivably overtop – and also seems to be equally stout at its base, to the point that the mound almost seems to be overdesigned.
But the strength of the dike also depends on its internal composition and the foundation where it rests, both of which are faulty to a degree. The reason? The dike mammoth dike is composed of native water-solvent limestone sand and shell and also rests on a layer of organic peat (underlain by more porous limestone) that has dissolved and settled over time.
And so it is: Lake water cannot go overtop the gigantic earthen mound, but it can (and has) found and formed subterranean channels inside and underneath the dike.
The dike is in fact designed and maintained to accommodate this seepage to a degree. By merit of its girth and other design features, such as a collector ditch on its exterior side which serves as a slow drip relief valve for the dissipating water pressure within the water blockade, the, the erosional effects of seepage have been kept at bay. Periodic patching of problem areas (i.e. anywhere seepage features were detected) has also been performed throughout the history of the dike.
Everything seemed find until Hurricane Katrina and Wilma passed by in 2004 and 2005.
Monsoonally Mediterranean
Also known as a Tropical Savannah climate
How to best describe south Florida’s climate?
For that we need to look overseas.
During the summer, it’s downright monsoonal.
Hot and humid, we can count on showers most every day. And very powerful storms, too. When I first moved down to Florida, sometime told me about the summer monsoons. Technically, I would later learn – Florida doesn’t have monsoons. But still, during summer, if you had to pick a comparison point: The monsoons of India probably best describe its afternoon downpours.
During the winter, Mediterranean weather moves in.
Mild, little rain, and beautiful sunsets, the southwest coast of Florida fancies itself a newer version of the Italian coast. Architectural, Tuscan architecture is the rage. Although unlike Naples, Italy – the one thing you won’t see it it’s new world namesake is anyone hanging out their clothes to dry.
I often hear people complain …
That Florida doesn’t have seasons.
My view is that its two seasons are continents apart!
Everglades Watershed
There was a time when the water in the Everglades did whatever it wanted to do. No gates, no pumps, and most of all no time table. It just sat there and flowed, really wherever it wanted to go. Well, not any longer. At some point humans intervened and decided water would obey its rules – turning (or trying to) the Everglades into the Schedule Glades. Not that nature ever listens. Yes, water is a bit of a rebel force. You can domesticate it, but only so much.
Listen to the Audio Introduction
Virtues of wet walks
A walk in the water on a swampy day
What fun is hiking a trail …
If you can’t also get your boots wet.
And socks!
You’ll also get those wet (and dirty).
And don’t expect the boots to last long.
Unseen put also present were the mosquitoes.
Just good swamp living all in all.