Wetting front retreat

Water levels have been dropping in Big Cypress National Preserve for the better part of 2 months.
By how much?

With the first official month of the dry season – November – in the books, the wetting front has dropped a solid half foot during that 30 day span, and 9 inches since waters crested in early October.

As a result, the pinelands have officially gone dry, and the wetting front is now hanging around in our wet prairies.

What does that mean?

You guessed it, yet again another peak water season has come and gone in the Big Cypress Swamp.

Here’s a brief overview of how this year’s peak season stacked up against season’s past.

Peak water season is the time of year when standing water rises up and into the pineland high ground.

Of course when that happens, the water isn’t standing … its flowing as a shallow and expansive sheet of water that denizens of the swamps call “sheetflow.”

The wetting front flooded up into the hydric pines for a little over 4 months this year, and into the higher mesic pines for a little over two months.

That’s wetter than usual. (The long term average is around 3 months in the hydric pines and 2-3 weeks in the mesic).

But the water has risen higher and stayed longer in other years.

Most recently 2005 comes to mind.

That year the wetting front stayed above the hydric line for a full half year and in the mesics for 4 months. There was nary a dry drop of land to be found in the swamps that summer.

Currently, preserve-wide water levels are tracking right along the 5-year average for early December, which also is around 4 inches lower than the same point in 2005.


We are also at the point where the sheetflow spigot has turned off.

The sheetflow season lasted for about 5 months this year, and delivered around 850,000 acre feet of water under the Big Cypress stretch of Tamiami Trail down into Everglades National Park.

That’s why the preserve was established in the first place:

To keep that water flowing,
And protect the upstream watershed that feeds water into the Park’s western arm (see map below).
To the east, the sheetflow spigot is still flowing over into Everglades National Park through the S12s (except for S12A which is closed) and the L29 culverts because it’s deeper.

But as I type, with a month to go in the calendar year, the preserve’s flow contribution to the Park has matched the parochial Everglades flow contribution pretty much drop for drop.

That’s not bad for a headwater preserve!


In summary,

The preserve came in at right around average this wet season with around 46 inches of rain (May through October). Fay was our “big rain month,” but September was drier than normal, ending the wet season on a dry note, and starting our dry season off with a gallop.

The greater Everglades is a fun place to watch the interplay of land, water, and weather that we call the water cycle:

Lots of rain, lots of evaporation, big storms, dramatic arrivals of cold fronts, constant vigilance to the Tropics, the biggest expanse of wetlands anywhere, beaches on all sides,
And most of all – lots of numbers!

Not a bad show.
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