Live and let dye: Researchers plumb depths of sinkhole to help heal Wakulla Springs

Jennifer Portman
Tallahassee Democrat
Wakulla Springs Alliance Chair Sean McGlynn pumps more than 100 pounds of non-toxic dye into a sink hole on Upper Lake Lafayette Monday as part of a study that seeks to better understand the connections between local lakes and the spring system. His group will measure traces of this dye at Wakulla Springs and other springs connected through a system of caverns in the aquifer.

UPPER LAKE LAFAYETTE  – The only thing this largely dry prairie lake, tucked south of Buck Lake Road between Costco and Interstate 10, seems to share with lush Wakulla Springs is alligators.

On an overcast Monday morning, a half-dozen idle nearby as Sean McGlynn puts his jon boat into the pool of remaining water, motors to a spot about 20 feet offshore from a limestone outcropping and heaves overboard an anchor of three red bricks.

The bricks are tied to the end of a thick black hose, not much bigger than a garden hose. Down, down, down goes the hose about 30 feet or so until McGlynn, chair of the Wakulla Springs Alliance announces, “I’ve hit bottom.”

Well, not really.

What isn’t visible above the surface of the deep murky green water is what connects this meandering lake turned urban runoff-fed wetland to Wakulla, one of the largest freshwater springs in the world.

Mysteries of the deep:

McGlynn’s homemade brick anchor is parked at the opening of Lafayette Sink, an entrance to an elaborate subterranean cave system. Etched through the Florida Aquifer over eons, the karst conduits twist and turn and rise and fall, carrying freshwater southward.

In about 30 days, evidence of the harmless pinkish-red dye pumped out of McGlynn’s hose will prove — not for the first time — that what goes in at Lafayette Sink comes out at Wakulla Springs.

The dye trace study will show water travels the 15 to 17 miles from the sinkhole to the spring at a speed of a half-mile a day.

“Groundwater usually moves feet by the day,” McGlynn said. “This is jet speed, this is a pipe.”

The Wakulla Springs Alliance is conducting a dye trace study at Lafayette Sink, at the deepest part of the lake.

McGlynn and his fellow Wakulla Springs Alliance members are conducting their second dye trace study in two years at Lafayette Sink to discover where else the water from here goes on its trip south. Using new, cheap, small charcoal packs, the group’s Cal Jamison said they will be able to look for traces of the dye at about a dozen springs and sinks throughout the basin, including Horn Spring in the northeast of the basin and Emerald Sink to the southwest.

“We are going to find out where all the caverns go between here and Wakulla Springs,” said McGlynn.

The work, supported by a grant from the Fish and Wildlife Foundation of Florida, is messy. McGlynn and Alliance member Bob Deyle wrestled three five-gallon buckets of the dye over a wide ring of giant apple snail shells to the lakeshore. They donned thick gloves to stay dye free and squatted at the water’s edge, manning little battery powered pumps to push the fluid through the hose and into the depths.

The effort relies on neighborly cooperation and goodwill. Upper Lake Lafayette has no public access. As he did last January, Bob Brown, whose property abuts the roughly 300-acre lake area, worked with Alliance members to facilitate the study and lend an extra hand.

Beyond showing where the water goes, such studies highlight why the quality of the water matters. Lafayette Sink is largely fed by the Northeast Drainage Ditch and Lafayette Creek which carry storm water from nearby development. The runoff is often high in pollutants that hurt fragile freshwater ecosystems.

High nitrate levels have long been known to fuel growth of invasive plants and algae in Wakulla Springs, compromising its clarity and health. In 2015, the Alliance team began suspecting another pollutant might be causing the dark and greening water that has ended the spring’s iconic glass-bottom boat tours — chlorophyll made by algae blooms in lakes.

Studies by Leon County found Upper Lake Lafayette has high levels of chlorophyll. The city of Tallahassee recently upgraded Weems storm water treatment facility, which is intended to improve the quality of water entering the lake.

Other lakes in basin connected to Wakulla Springs, including Jackson and Munson, also contain contaminants and have algae blooms that likely impact the spring system, Alliance members and other scientists say. They hope their research will provide the basis for further lake water quality improvements

“We want to make sure WS is clean and the glass bottom boats get to run again,” McGlynn said. “For that we are looking at different kinds of pollution, septic tanks and spray fields and fertilizers, but also lakes and sinking streams can pollute Wakulla Springs. Everything in the spring shed needs to be clean.”

The hose that was used to pump more than 100 pounds of non-toxic dye into a sink hole on Upper Lake Lafayette Monday as part of a Wakulla Springs Alliance study that seeks to better understand the connections between local lakes and the spring system. The group will measure traces of this dye at Wakulla Springs and other springs connected through a system of caverns in the aquifer.