Ridge 101: Sand Fire & Water Part 1

Uploaded by MyFWCsocial on 16.10.2012

>> Um, so let's talk a little bit about sand and water and this is really thinking about
physics of the Ridge. Usually when you see a watershed map, people always draw up the
rainfall in the mountains, and it goes down the rivers, into the estuaries, out into the
sea, it evaporates back, and the whole cycle starts again. Well, the Ridge is a little
bit different from that.
We have lots of evaporation, that's evaporated water coming off open water surfaces like
seasonal wetlands or a lake. We have water coming out of the transpiration of plants
- when plants give off water as they open their little stigmata and leaves. We also
have lots of water coming from adjacent wetlands off the Ridge -- the Ridge acts as sort of
a system where wet, moist air rises over the Ridge and lots of precipitation as a result
of that. That's the water cycle here on the Ridge.
What happens when that precipitation falls on the Ridge? Well, some of it, particularly
if the sand is very wet, will run off into little seasonal wetlands. A lot of it infiltrates
down through the sand; you can think of it as the biggest sandy water tank in the region
-- think of the Lake Wales Ridge as a giant kid's sand box that's often full of water.
Of course when you fill up a big sand tank like that, it releases water slowly, it takes
a long time to fill up, water goes down - and we'll talk about that in a minute - and water
also goes outside this sand box. So, when water rains (pause - laugh) when rain falls
on the Lake Wales Ridge, we get a lot of infiltration into the sand. And that can go either into
the first aquifer system we have which is called the surficial aquifer, the one right
below your feet. In some parts of the Ridge it might be just two or three feet below you,
in other parts of the Ridge it might be eighty or ninety feet down before it hits water.
On Archbold around the station, those of you that are familiar, the surficial aquifer – which
is shown by this line here – is only, at the weather station, maybe six to ten feet
down depending on the time of year . If we go to our high point on the station, which
is the red hill, it's eighty to ninety feet down, so it depends a bit where you are on
the Ridge as to how far down is the surficial aquifer.
The rain falls, seeps through here, and may often seep sideways into seasonal wetlands.
All those little seasonal wetlands we have -- yes of course they are charged by rain
coming on into the wetland -- but there's also a lot of seepage from the surrounding
sands into these low points. By low points, I'm often meaning one to two feet lower than
where you're standing in the Ridge system. There's a lot of seepage this way. After it's
been dry for a while, what happens to those little seasonal wetlands is the water then
leaves them and seeps out, back into the sand and down; they're sort of like little saucers
filling up, releasing the water, filling up, releasing the water.
Some of the water actually infiltrates through our surficial aquifer and keeps going down
and may, go through these – there's a series of breaks through the sort of clay layer,
called the confining layer - and may go down into the intermediate aquifer (and I'm going
to talk about the Floridan aquifer next). But I want you to think of a system where
there's this big sand box, there's a lot of seepage and movement down on the sand box
and the other thing that happens is water seeps off the side of the Ridge and we'll
come to that in a little bit. But when you think about water moving on the Ridge, think
about it moving down, moving laterally, and then eventually often seeping off the side
of the Ridge on the East side or the West side. So when you come off the Ridge -- when
you drive over Highway70 or Highway 60 and you feel yourself diving off the Ridge -- when
you get to the bottom of that, the toe of the Ridge is a very wet place. That's where
all the bay heads are, that's where all the deeper, peat-ier soils are. So the Ridge releases
water sideways and it seeps out as well as releasing water down. If you had been here
100 years ago, you would have found deep bay heads all the way up and down the East and
the West side of the Ridge. Many of them have been cleared, but the Ridge used to be bordered
by very deep, peat bay heads – these are wetlands that are dominated by bay trees – so
that was the edge of both ridges, at the bottom of the Ridge.