Feb 20, 2013

Spring rain delay

Dry season rains can't turn back time,

But they do help delay the onset of deep spring drought.


The above hydrograph depicts the rise and fall of water levels in Big Cypress Nat'l Preserve from 2011 to present.  Background shading places recent fluctuations relative to the historical record (since 1992) and major ecological habitats, i.e. from lowest to highest, dry season refugia, pond apple forests, cypress domes and strands, marl prairies and pinelands.  Last week's big rain storm raised water levels several inches in the swamp, thus in most areas refilling the strands and domes with water.  Water levels from this point forward will drop at an increasing rate without the help of more rain.


And the swamp isn't as dry as it may appear:

Consider that current water levels (as of February 20th) in Big Cypress Nat'l Preserve are the same height as the 20th of June, a full month into the wet season. In ecological terms, that means the pinelands aren't flooded (not even close) but the lower lying cypress domes, strands and sloughs still are. Starting in late February, however, the water levels drop at a faster rate in response to (1) increasing air temperatures and (2) increasing plant transpiration. Currently, the cypress are mostly still bare, but the deep interior of the strands are already greening out. By March the cypress will be completely green.


Don't confuse that verdant green with lush.

Under the shade of the March cypress is usually exposed peat, not water.


It isn't until April and May that the water table in the swamp bottoms out.

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