Wakulla Springs is the worlds' largest and deepest freshwater spring. It was once famous for its crystal-clear waters. Tourists flocked to what's now Wakulla Springs State Park for a chance to look deep into the water on a glass-bottom boat tour. But the water has since darkened, and the tours haven't run in years. But for at least a moment, the waters are clear again.
For the past seven years, Sean McGlynn has measured the clarity of Wakulla Springs. He operates a private lab that runs water samples from different lakes across the country. On June 10, he journeyed to Wakulla Springs and could see more than 80 feet deep.
"This is a miracle. It brings me back to my childhood," McGlynn says.
McGlynn grew up around Wakulla Springs. He says before the 60s, people could peer over a boat and see 110 feet beneath the water's surface. But as the watershed became developed, problems emerged.
"A big part was the sewage disposal in the watershed. Tallahassee—they used to put the sewage in Lake Munson where it went down the sinkhole and went directly to Wakulla Springs," McGlynn says.
The sewage brought more nitrogen to the springs. Nitrogen is a nutrient that plants feast on, and when there's a lot of it, plants can grow rapidly. McGlynn says back in the 70s, Wakulla Springs was choked with plants, particularly an invasive species called hydrilla. He says back then, Wakulla Springs looked more like a landmass than a water body.
Since then, Tallahassee has upgraded its wastewater treatment plant, reducing the nitrogen going into Wakulla Springs. But McGlynn says septic tanks are still an issue. Nitrogen comes out of them and goes into the springs, causing algal blooms. The Northwest Florida Water Management District has been working on getting people off septic tanks and onto central sewer. The district's Kathleen Coates says once people are on sewer, their wastewater is piped to a treatment plant.
"That results in a lot lower nitrogen getting back into the environment compared to septic tanks which have higher nitrogen loading to the environment," Coates says.
Coates says Wakulla Springs usually clears up following periods of low rainfall. That's due to a lack of tannins in the water. Tannins from leaves seep into streams. Those streams flow into sinkholes. And the water drains down into the aquifer and comes out at Wakulla Springs. Tannins can give the water a dark, tea-like color. But if it doesn't rain, tannins from leaves don't get dissolved into the streams. Coates says tannins are natural, and Wakulla Springs has had periods of tannic water dating back to the 1940s.
"This is not a new phenomenon at the spring. Now, anecdotally, what we're hearing from people who've lived in the area for a long time and looking at photographs—there's a possibility that these periods of more tannic water are more frequent, but if that is occurring, it's not clearly understood why that would be occurring," Coates says.
McGlynn points to Spring Creek as another reason why Wakulla Springs' waters are suddenly clear. He says the creek hasn't reversed flow in a while.
"See when spring creek reverses flow that kicks up all of the sediment that's in the caves and flushes it out to the spring backward. It's a backflow. So that naturally cleans the caverns, but it makes the springs rather dark," McGlynn says.
But McGlynn says Wakulla Springs' clear waters won't last long. He says that's because Lake Jackson in Leon County recently drained into a sinkhole, bringing lots of extra sediment into the aquifer with it. That murky water will show up eventually in Wakulla Springs. He also expects Spring Creek will reverse flow soon because its waters recently stopped flowing.
"We don't know exactly when these will happen, but in the next month, I think that these two things will obscure the clarity of Wakulla Springs," McGlynn says.
McGlynn encourages people to see Wakulla Springs while it's still clear.
