Springs and Swallets

There is spring-fed and then is “Florida Spring” fed, perhaps the most charismatic groundwater you’ll find anywhere else in the world. Usually out of sight and out of mind, Florida springs pump groundwater to the surface creating water gardens of Eden to which humans and animals flock. | Major water bodies | Estuaries and coast | Rivers and creeks | Lakes and ponds | Springs and swallets | Canals and levees | Sky and clouds | Florida’s water districts | Underlying aquifers

Second life of Kissengen Spring?
Search for the headwater source

The Peace River isn’t what it used to be.

For starters, its headwater source – Kissengen Spring – is gone.

Peace River’s then (1940-1955) and now (1995-2010)

The culprit?

Groundwater pumping associated with phosphate mining substantially lowered the water table in the 1950s which in turn reversed the direction of flow. No, the river didn’t start flowing north! By “reversed” I mean that the river isn’t recharged “up” from the groundwater any longer, but rather ends up leaking “down,” and quite prodigiously at times, into the aquifer instead.

Kissengen Spring flowed at 30 cubic feet per second (20 million gallons per day). That may not sound like much, but it was incredibly steady in the sense that it flowed all year round. That was particularly important during the seasonal spring drought when without it the Peace would run dry. It was its sole source of flow.

Peace River near Arcadia

The hydrograph above shows how in recent times the river routinely drops below 100 cfs, yet rarely did so when the spring was still intact. Work is underway to repair the river with an upstream reservoir called Hancock Lake and by strategically adding berms in the river bed to keep flow in the river from sinking down into the karst aquifer instead. (view article) The goal is to keep a minimum of 20-30 cfs in the river channel at all times.

Or in other words, replicate the flows of Kissengen Spring!

Silver Spring Cheatsheet
The story of the falling baseline

A visiting tourist would be amazed …

At the discharge pumping up from Silver Spring.

Silver Spring Cheatsheet

Meanwhile, an old timer standing right next time him would be underwhelmed compared to what he saw (and remembered) from his youth. The reason? The area around the spring has been protected. But that area isn’t big enough to prevent depletion of headwater flows in the surrounding springshed through municipal groundwater pumping. I’ll leave it to the experts on this one (a combination of new and old timers), but to my knowledge groundwater pumping in and around the Ocala is the cause of the spring’s pre and post 2000 inflection point.

animate drop sweater

High or normal?
It depends on your baseline

Discharge from Silver Spring …

Appears to have risen in recent years.

Animated chart showing current year discharge rates compared to the recent (post 1993) and distant (pre 1993) past

But that’s only the case if you compare what you see now to what we’ve seen in the past thirty years, i.e. the recent past. I like to say that everyone has a “born on date” for understanding places. The Big Cypress Swamp for example was born five to six thousand years ago, but I didn’t arrive until 1998. So for me, in a way that was my personal “born on” date. The only change I know is what’s happened after I arrived.

So yes, Silver Spring has been flowing bountifully this past month and year compared to the recent past. But a deeper look at the historic record shows that today’s same “high” discharge rate is actually just “normal” compared to the sixty year span from 1932 to 1992.

Thus the question: Can Silver Spring’s past glory be reclaimed? And if so, how? The first step is protecting what we have.

Steady decline
And can it be stopped?

Nobody can shut off a Florida Spring …

Or can we?

History of discharge (in cfs) from Crystal Spring, FL

The answer is yes. It happened to Kissengen Spring. Once a popular tourist draw and water hole, nearby groundwater pumping dried up the spring the river run it fed. But surely that could never happen to Silver Springs, a first order magnitude artesian spring. Some would call it Florida’s crown jewel. Just a few year back I was at the spring marveling at the volume of water it produced. If you’ve never seen a Florida spring, they are a “must see.” The water manifests itself as the surface as a crystal clear boil of rolling water flowing non-stop day and night all year long.

Looking back at the historical data for the site — and we should all thank the U.S. Geological Survey for having the foresight to start collecting it in 1932 — the volume of water gushing out of the spring has declined over the decades, starting in the 1990s and dropping down even more in the 2000s. The good news? Spring volume rebounded back to near normal levels (between 700-900 cfs) in recent years. It’s still not what it was (prior to 1990), and future depletion is a real threat. But there is a plan in place to save the spring and its flows. Click here to find out more.

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Trends: Baselines decline over time that only an old-timer can tell you. And yes, please listen to them!

water table

All season spring
Sheet flow and spring flow compared

Florida’s Silver Spring …

Almost looks like it’s boiling.

The swamp’s sheet flow and Ocala’s Silver spring are currently flowing at about the same rate

And during the winter it is quite warm. But only because the air temperature is cold, or cooler than the water below. So yes, it is therapeutic to swim in during the winter at the same time getting out is quite cold. Paradoxically, the same boil of water water turns refreshingly cool each summer. And not because it’s appreciably cooler. Rather, the onset of Florida’s hot and humid season makes a plunge underneath its surface invigoratingly crisp.

The magic behind Florida’s freshwater springs are that they are ground-water fed. That keeps its water at a constant 72 degrees Fahrenheit and keeps it at a fairly constant flow rate all year round. Compare that the boom and bust wet and dry season cycle of the swamp’s sheet flow.

Which one flows more? At one spot, I’ll go with the springs. But spread out across the landscape, the swamp wins every time. Caveat: It has to be summer.