Feb 13, 2013

"High water" mirage

We're four months into the dry season ...

How can this south Florida lake be so high?

The above graph shows current water stage in Lake Istokpoga relative to the twenty-year record, the ecohydrology of adjacent perimeter marsh and the modern day regulation schedule.  The light blue band on the left hand side of the graph depicts the historic range of water level fluctuation in the lake prior to modern day water management practices. 

Usually by February the water table has gradually moved down, but in this case -- in Lake Istokpoga (just north of Lake Okeechobee -- the water surface is sustaining itself at its October peak.  The trick is partly its regulation schedule and partly that the lake isn't really high.  The light blue vertical band to on the left hand side of the graph depicts the historic "up and down" range of the water surface.  Today, in accordance with modern day regulation schedule and the water controls that implement it, Lake Istokpoga's water surface is maintained between 37 and 39.5 ft above sea level, a relatively tight 2.5 ft range.  Compare that to pre-water management days when the lake rose over 42 ft above sea level, flooding the adjacent landscape and feeding down into the Big Lake.

What looks high by today's standards was low back then.

1 comment:

pguzek said...

Hope you're getting some rain out of this storm today. North Florida is wet!