Diagrams

Sketches are the window into a hydrologist’s soul. And yes, that sometimes means pencil and paper.

Weather Drop

What May?
February, March, April ... June?

Usually May is that month …

That the swamp both bottoms out and bounces back.

The Everglades usually bottom out in May

Or did the water calendar jump straight to June? That’s what it feels like these past few days. A regular onslaught of afternoon rain showers — and I mean some real gully washers — are giving early May a decidedly beginning of June feel. It’s too early to tell if the pattern will persist, but if it does, then make a mental note: 2022 will be remembered as the Year Without a May.

Caption: Calendar chart showing daily rainfall in the Big Cypress Swamp from the mid 1998 to present. The black drops are Big Rain Days (i.e. when over an inch of rain fell in one day). We get a handful of those every year. Orange dots are days without rain which, as you can see, dominate from October through mid May.

Attention: The potential early start of the summer rainy pattern cannot be used as an excuse to forget Mother’s Day, Memorial Day or any other events or scheduled meetings that may occur this month.

Geology of the Swamp
Out of sight, out of mind

Not many people visit the swamp …

To see its geology.

Cross sectional sketch of the swamp’s geology

But really, the geology is an underappreciated treasure of the swamp, and not uncoincidently buried under the ground. Did you know there is about 3 miles of marine limestone underlaying the swamp? In layman’s terms, that’s over 500 million years of deposition, all sitting on top of the Senegal Platform rifted away from the African Plate when the last supercontinent Pangaea rifted apart. Most of south florida’s drinking water is in the top 100 feet. About a thousand feed below ground is the cryptic geologic layer known as the boulder zone where coastal cities pump their treated municipal wastewater. Much farther down is the Sunniland Trend that holds a modest reservoir of hydrocarbons. I’m not saying the geology of Florida is as scenic as Yellowstone or other western parks, but it may be more interesting, even if if visualizing it and understanding it requires a good geology book. In that regard, I highly recommend Geology of Florida by Randazzo and Jones and Land from the Sea by Edward Hoffmeister.

water table

Steephead Valleys
And why they are "spring like"

Steephead valleys aren’t as famous …

Or as charismatic as a Florida spring.

Steephead valleys have a distinctive rounded shape

But they are similar in they are both groundwater fed. Unlike springs that appear in full force out of nowhere, emerging from a cavernous hold in the ground in the form of a “boil,” steephead streams are smaller in scale and at their upstream end pinch back to a vanishing point. And unlike a gully-eroded dendritic (i.e. branching) stream channel that depends on rainwater for its source, and accordingly erodes from top-to-bottom — a steephead valley contains a single stream that depends on groundwater seepage as its source. Grain by grain, that causes erosion to occur from the bottom-up, giving the ravines their trademark rounded and slumping shape. Another key difference: The gradient between its headwater and mouth are low.

What makes steepheads special? The steady flow and constant (cooler) temperature makes both the ravines and the streams home to endemic and rare northern plants. An endangered fish called the Okaloosa darter is only found in steephead streams. As for their location, they are found in isolated patches in the panhandle where the regional groundwater table and alluvial floodplain intercept.

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Thought: Steepheads are larger versions of the little rivulets you see forming in the beachfront during a low tide, but less salty.

ecology

Seeing the mosaic
The art of drawing water

As much as I’ve tried,

Photos always seem to fall a little short.

Photo of the mosaic: From highest to lowest, the “swamp mosaic” pinelands (dark green), cypress (gray), marsh (yellow) and open pool (blue). Difference in elevation: about 4 feet

Not that they don’t tell a thousand words, they do. And sometimes even more (sometimes less). But still, whenever I take a photograph trying to capture the swamp’s mosaic, there’s always something that gets left out. Not that it stops me from trying. Whenever I fly, the pilot says to me: Didn’t take a photograph of that before. “Probably. Actually that’s a definite yes,” is my usual response. Even down on the ground in front of what some would say is a not-so-scenic monolith of concrete better known as a water management gate, I can’t seem to photograph it enough.

Diagram of the mosaic

That’s where diagrams come in handy. You can pack in a diagram everything you couldn’t get in a photograph, even in a helicopter at a thousand feet. As for which is better? I like a combination of both. I’ll continue to take photos and draw. And know, I’m not a photographer (a paid one) or an artist (to be debated, but yes, also unpaid), but I am a hydrologist. The truth about hydrology is that taking photographs and drawing sketches is all part of a days work.

Weather Drop

Dreaded stalled front
And why they are not so dreaded

South Floridians crave cold fronts …

Like a hydrologist craves donuts.

Stalled fronts can bedevil south Floridians

Okay, I’ll admit — that isn’t the best analogy, but you get my point. Then there is the dreaded stalled front. Those occur when cold air stops just short and doesn’t break through, leaving us with a extended period of clouds and humidity. As for the stalled front we’re getting now. I’m actually enjoying it because, in addition to clouds its bringing some much needed rain. Even better, it appears to be bringing in some colder weather behind it, too. So maybe it’s more a “slow front” than a cold front. All good news. Now time for a donut!