watershed myths Archives – Go Hydrology!

watershed myths

Mythical watershed
How rain saved (and ruined) the swamp

May 18, 2022May 8, 2022 by Go Hydrology

One of the biggest myths of the swamp …

Is that it’s a watershed untouched by time.

*A map of how water used to flow into and through the Big Cypress*

So the story goes:

Unlike the highly-engineered Everglades management system that depends on a complex operation of gates, pumps, water treatment areas and regulation schedules …

The Big Cypress escaped from drainage unscathed.

*A diagram showing how the modern “watershed myth” compares to the pre-drainage and actual present day condition (for the northeast corner of the Big Cypress)*

The true(r) story:

Yes, the swamp gets most of its water straight from the sky, but it relies on upstream flows too. And here’s the big catch: The size of its upstream drainage (or watershed) has shrunk over time.

Or in other words, the swamp is (primarily) rain-driven because all the other “pre-drainage” sources of water got drained away or boxed out.

*Timeline showing the history of drainage in the Big Cypress*

The good news:

There are a lot worse fates that could befall an ecosystem than to become a watershed. And why cry over spilt milk of drainage past when there is a lot of work big and small that can be done to help achieve the goal of making the swamp the very best rain-driven work it can be.

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Quotable: “Myths that are believed in tend to become true.” Bernard Shaw

Optical illusion swamp
Where appearance and reality morph

May 18, 2022October 20, 2021 by Go Hydrology

The swamp is full of optical illusions …

Or do they actually reflect a deeper reality?

Photograph of optical illusion no. 1

Take for example the oval groves of cypress trees called domes. They look like hills, but they are actually the low spots in the swamp. It’s the adjacent pinelands (foreground) that mark the high and dry ground. But the domes are also where water depth is tallest. So if you’re a fish or a bird or an alligator, the tallest depth of water coincides with the center of the hill-shaped domes.

Narrated video of optical illusion no. 2

Then there’s the case of the optical illusion you see in a helicopter flying over a fully flooded swamp. The reflection from the below reveals the strange effect of trees moving at a fast clip backwards and the mammoth clouds staying put (see video above). Of course, in reality we know it’s the clouds that are on the move (from hour to hour and day to day) whereas the trees are rooted down in one place. But over time, as the years and decades pass, the forest below is in fact on the move. Habits shift, retracting and expanding in, in response to the seasonal dosage and return interval of flood and fire on the landscape.

I‘m not saying that optical illusions are right or wrong. All I’m saying is that they hint at the deeper reality of the swamp.

Hydrology of the Swamp
Is it or isn't it a watershed and/or swamp?

May 30, 2022October 1, 2021 by Go Hydrology

The video isn’t the best …

And the audio is muffled because of my mask.

As presented at the Nathaniel P. Reed Visitor Center in Big Cypress Nat’l Preserve

But there’s no better way to cover all the bases (and ins and outs) than with a Power Point presentation and a patient crowd. A fun Q&A session afterwards helps, too.

Big Cypress Watershed
Or is the term "mosaic" a better descriptor?

May 18, 2022August 23, 2021 by Go Hydrology

Animated cross section of the rise and fall of the water table in Big Cypress National Preserve — *Swamp water cycle in motion*

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.

Before, Current and Future Restored Maps of the Big Cypress Swamp — *The rainfed swamp we know today was once fed by upstream water sources*

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.

Wrong way clouds?
Winds shift and unleash from the west

September 5, 2021August 3, 2021 by Go Hydrology

South Florida’s clouds are larger than life …

And unleash torrential rains.

*You know it’s a strange day in the swamp when the summer afternoon clouds are moving from West to East*

And most of all …

They move the wrong way.

Unlike properly-behaving clouds on up the continent that predictably move from West to East (i.e. the Westerlies), south Florida’s summer clouds migrate from East to West on the wings of the Trade Winds.