Feb 23, 2017

Dropping lake in action

Lake levels are in the desired range ...

About 8 feet lower than the level it historically overflowed its banks south.

This hydrograph shows the stage of Lake Okeechobee over the past two years.  The background color-coding indicates the hydro-eco-operational thresholds and the background shading shows the long-term historical statistics, from 1993 to present.  The dotted white line is the long-term median stage over the same time period.
In more modern terms,

We're about 1 foot below the normal late February stage ...


But still in the desired range because the wetting front is within the littoral zone.

Feb 22, 2017

Subsidence in action

South of the Lake, the oldest houses are on stilts ...

As a result of land subsidence due to oxidation of the farmed peat.

Cross sectional diagram
of Lake O, its levee and
the farm land it protects
(not to scale)

That in part explains why the levee is so tall:

Forty two feet above sea level and 143 miles around.

Big rain day in action

Here's an image of the radar
derived rainfall total for the day
as it comes in.

Should be fun to watch!

Feb 19, 2017

Happy Presidents Day!

“Do more good than harm.”

That’s what colleague (actually he was quite a few years older than me) told everyone at a group gathering just before he left. There was a tinge of self righteousness in what he said, but it was also about the closest you’d ever hear him admit to any regret. He was a man of action and strong opinions who loved to play Devil’s Advocate ... to the chagrin of quite a few.

Had Nixon not saved the swamp,
it would have been swallowed up
by a metropolis springing up around
the Miami-Dade Jetport instead

Funny how people leave and you never hear from them again.

But for some reason those words with me always stuck.


That brings us to President’s Day.

I’m old enough to remember when Washington’s Day and Lincoln’s Day were separate holidays. Then at some point they got combined into a single day to commemorate the Presidential office and all those that served from 1 to 44.

Diagram from a Nixon-era study 
that helped save the swamp

Who is my favorite president?

For me it's Richard Nixon without a pause.


What hydrologist can resist picking a president who made water gates, or was it Watergate, a household term.  Or that he has the same birthday as Elvis, American icon and singer/songwriter behind the meteorologic masterpiece Cold Kentucky Rain.  But most of all there's the fact that he single-handedly saved the swamp.  Well, maybe that's stretching it, but he was the president when the political wheels went in motion to create Big Cypress Nat'l Preserve.

Thank you Richard Nixon

Did he do more good than harm?

It’s hard to say no if you live in the swamp.

Feb 17, 2017

Florida Trail

That's caprock
of the Tamiami
Formation

"Toss of the coin" drought

The swamp has two types of dry seasons:

"Normal" dry and "dry" dry.

Annual duration of drought (in weeks)
in Big Cypress Nat'l Preserve, 1992 - present

Unless we have an El NiƱo like we did last winter.

Then its a "wet" dry season.


This year is shaping up like a "dry" dry season.

But it's not there yet.

Monthly probability of drought
in Big Cypress Nat'l Preserve,
1992-present


Deep dry downs (i.e. as defined by moderate or severe above) usually doesn't strike until April through June.

Historically in those months our chance of getting them is a fifty-fifty chance.


Or in other words a flip of the coin.

My guess for this year is heads!

Feb 16, 2017

Symbiosis of fire and water

Swamps are wet places, right?

In south Florida they are also highly adapted to fire, too.

Historical calendar of drought severity
in Big Cypress Nat'l Preserve, 1992-present

Names are of major wildfires
But the two are not opposites.

They work hand in hand in fact.


The fire depends on the water to keep the low spots flooded as fire breaks.

Feb 15, 2017

Watershed reader

Understanding the hydrology of a watershed is no simple matter.

Unraveling its mystery requires reading many books.

Timeline of major hydrology,
water management, water quality
and geology reports for the preserve 
Oftentimes re-reading them too!