Wake up now: Dirty water has grounded Wakulla Springs' iconic glass bottom boats Human burdensWakulla Springs is fed by the Floridan Aquifer.As ...

Wake up now: Dirty water has grounded Wakulla Springs' iconic glass bottom boats Human burdensWakulla Springs is fed by the Floridan Aquifer.As ...Wake up now: Dirty water has grounded Wakulla Springs' iconic glass bottom boats
Human burdens
Wakulla Springs is fed by the Floridan Aquifer.

As rain and other surface waters filter down to the aquifer through the porous limestone that underlies Florida, it carries with it all traces of human existence. As water flows underground to Wakulla County, just south of Leon County, it carries pollution from septic tanks, sewage-treatment systems, agricultural runoff and a myriad of other burdens.

A striking example of the resulting harm is nitrogen leaking from septic tanks, which use a drain field to treat sewage from homes that are not connected to centralized wastewater treatment plants. Many septic tanks, particularly old ones, allow excess nitrogen to seep through to the swiss cheese limestone and pollute the aquifer, Robert Deyle, vice president of the Wakulla Springs Alliance, explained.

The aquifer, in turn, feeds the springs.

There are approximately 9,000 homes in southern Leon County’s “Primary Springs Protection Zone,” where the soil is more permeable and allows more pollutants through to the aquifer, according to Leon County Commissioner Bill Proctor.

Vintage shot of a wooden boat in the water
State Archives Of Florida
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Courtesy
As excess nitrogen filters into Wakulla Springs, it can fuel the growth of algae that smothers native vegetation, allowing nuisance weeds and invasive plants like hydrilla to outcompete and take over the ecosystem.

This over-abundance of plant life that depends on nitrogen, particularly algae, propagates a greenish color in the water, according to the McGlynn lab in a three-part study to measure water quality and visibility. The high nitrogen levels can lead to the formation of algal mats that can shade out native vegetation, already burdened by the invaders.

On a rainy day, things can get much more muddled.

The darkened water conditions are a result of tannins, leaves that stain water a brownish-red, similar to steeped tea. Rains allows these tannins to leach organic matter, creating even muddier brown water.

Tannin buildup in Wakulla and other springs isn’t all natural. While a moderate amount of tannins in the springs is normal, the excessive buildup that has distorted the water’s clarity and ended the glass bottom boat tours is a result of human impact.

Wakulla Springs is connected to a variety of other springs through an elaborate network of underground waterways. Among these are over a dozen springs that make up the Springs Creek Springs Group. When rainfall is scarce, saltwater from the Gulf is no longer blocked by the spring’s outflow. Contaminating salts can form a “plug” that limits the spring’s freshwater from flowing out into the Gulf, Deyle explained.

As a result, connected springs like Lost Creek reverse the direction of their flow. Instead of bubbling up from the aquifer, Lost Creek dumps in and flows north to Wakulla Springs. The discharge carries the color-leaching tannins that turn the water dark brown.

Groundwater overpumping aggravates the problem, as pollution concentrates in shrinking water bodies. An estimated 3.6 billion gallons of groundwater are pumped in Florida every day, according to the US Geological Survey. And demand may be growing in one of the nation’s fastest-growing states, with an estimated 950 people moving to Florida every day, according to a 2020 Miami Report.

(right) A glass bottom boat on turquoise-blue Wakulla Springs in 1980, before the boats were grounded due to poor visibility.