Oct 24, 2012

Swamp set for long seasonal sag

The swamp looks as though it's peaked.

That means its predominant direction for the next half year will be down.

Follow the "dotted white" line in the hydrograph above.  It represents the median water stage in Big Cypress Nat'l Preserve, as calculated from 1992 to 2011.  Can you see how it drops steadily through the first half of the dry season (October through February) and then at a much faster pace through the dry season's second half (March through May)?  It isn't until June with the arrival of the summer rains that the water table finally rebounds.

Mesic then hydric pines will be the first to go dry, probably later this fall.  By mid winter the marl prairies will follow course.  Cypress domes and strands should hang onto water into March.  By April, even the pond apple forests and marshes will start to go dry.  Last year the relatively minuscule dry season refugia pools held onto water even in the deepest driest part of May -- the alligators liked that -- but can you see in the hydrograph above how in May and June of 2011 even they went dry.

The dry season also has aperiodic continental fronts.


Their unreliable rain is the swamp's only hope
for keeping its winter water table up.

1 comment:

Caroline said...

After a day of working with high school students, maybe it is swamp sag I feel, not just weariness. :o)