Data

When expectations fall short …

Usually its June or September …

That ends up being the rainiest month of the wet season.

Chart showing monthly rainfall in Big Cypress Nat’l Preserve.  The background gray coloring shows the historical norm and range.


Incredibly, defying normal odds, it was May.

With most of that rain falling in its second half.

That led everyone to anticipate a much wetter wet season than the one we actually got.

The day the swamp “clicked”

Have you ever had to look at something …

For a very long time before it clicked?

Historic map of the three major
watersheds of the Big Cypress Basin,
as defined by Klein (1970).

That’s what happened to me with the above map.

It wasn’t until Jack Meeder clued me in to its tie in to (as Jack calls it) “Immokalee Mountain” (i.e. max elevation 42 ft above sea level) and the Caloosahatchee’s Fort Thomson Falls (no longer in existence), that the pivotal role the Big Cypress Swamp played in the pre-drainage Everglades finally snapped into place.

Ft Thompson Falls were located
about 2 miles east of LaBelle and formed
the headwater source of the Caloosahatchee
River, with a 4-10 ft drop.

Sometimes A-HA Moments take time (and a little help!).

Past Year of Rain

The rain you see falling …

Is usually local (out through the window.)

The figure above shows monthly rainfall in chart form and yearly (i.e. past 365 days) in map form.  Shades of blue and red show rainfall amounts.  Units are inches.

Turns out not all basins get equal doses.

Upper Kissimmee and Naples/Ft Myers coast has been the wettest,

And the Everglades the driest over the past year.

Green out marks “shift” in swamp

The green out of the cypress is a big swamp’s milestone:

The second half of the winter dry season has now begun.

The above bar chart reports the annual duration (in months) that the floor of the pond apple forest has gone dry in Big Cypress National Preserve, from 1992 to present.  The years 2005, 2007, 2009 and 2011 also coincided with major wildfires.


The cooler temperatures of the first half (Nov-Feb) put evaporation on hold.

Look for it to heat up now that the second half (Mar-May) has begun.

That means water levels will start dropping faster and — more and more — surface water will be harder and harder to find.  The place you find it last is in the center of the cypress domes and strands where the pond apple trees call home.

The surest sign that deep drought has hit the swamp?

Late March 2011

Answer: That’s when the pond apple roots become exposed. Last year it happened just for just two weeks.  Two years before that (see photo above) over four months.

Swamp has size of 51st state

How big is the swamp?

Big Cypress Nat’l Preserve alone is expansive enough to be called a “state.”

Comparable in size, yes, but the swamp has considerably less congestion

By state-like I mean as big as Rhode Island, or in other words 1,214 square miles … or almost. Big Cypress Nat’l Preserve covers some 1,139 square miles.

I call that close enough.