Feb 12, 2014

Why the water cycle is stuck in 2013

Recent rain has the water cycle going in reverse:

Current water levels have bounced back to December 2013 heights.

The hydrograph above provides an overview summary of surface water stage in Big Cypress National Preserve.  The dark blue line shows current conditions.  The dotted white line shows the long-term median (based on a 25-year period of record).  The horizontal shading highlights the major ecological zones of the preserve.  Blue at the top indicates the level of the preserve's hydric and mesic pinelands.  The dark green the elevation of the marl prairies.  The light green coding indicates the height of the cypress domes and strands.  Orange indicate pond apple and marsh habitats.  Red shows the level when surface water is absent.

Just a few weeks ago the marl prairies were going dry and the wetting front was predictably receding into the swamp's deeper holes, i.e. cypress domes, strands and marshes.  Recent rains have put the wetting front back out on the march into and across the swamp's vast marl prairie plains.  Current water levels are about 3 inches higher than normal for this time of year and about 10 inches higher than early February of last year.

Where will the water table go from here?
This calendar chart shows the history of surface water flooding in Big Cypress National Preserve, from 1992 to present.  This chart reads like a page of a book: ascending years from top to bottom and months of the year across the page from left to right.  The advantage of this display of data is that it allows you compare current eco-hydrological conditions to any time in the historic record.  For example, can you see how this February is wetter than the past three Februaries, but not as wet as 2010?  

Answer:  Probably down.

Winter rains rarely sustain a fully flooded swamp, rather they play the unsung role of keeping wildlfire-vulnerable spring drought at bay by preventing the water table from dropping too low.  Current water stage in the swamp is about 2 feet higher than the normal early may nadir of the dry season water table and about 2.2 feet higher than the level that the swamp bottomed out last year in early April.

The story for now is a rain rejuvenated swamp:

Almost feels like 2013.

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