Lake Apopka — the state’s fourth-largest lake — was once a world-class bass fishery, making it central Florida’s first tourist attraction. However, impacts to the lake over many decades degraded its water quality and fisheries and led the lake to be named Florida’s most polluted large lake. The St. Johns River Water Management District and its partners have been writing a new chapter to the story — a story about wetlands restoration, the reduction of phosphorus and suspended solids in the water to improve water quality and clarity and the restoration of fish and wildlife habitats.
Lake Apopka is the headwaters of the Ocklawaha Chain of Lakes, located in northwest Orange and southeast Lake counties. Lake Apopka is fed by a natural spring, rainfall and stormwater runoff. Water from Lake Apopka flows through the Apopka-Beauclair Canal and into lakes Beauclair and Dora. From Lake Dora, water flows into Lake Eustis, then into Lake Griffin and then northward into the Ocklawaha River, which flows into the St. Johns River.
Lake Apopka’s water quality restoration has been based on a multipronged approach of diet and exercise. “Diet” has focused on reducing the amount of phosphorus entering the lake. The largest “diet” improvement occurred following the Florida Legislature’s 1996 direction to the district to buy out the farms on the lake’s north shore. This area, formerly a floodplain marsh, was diked, drained and put into agricultural production in the 1940s. Phosphorus from these farms fueled the continuous algal bloom that shaded the lake’s vegetation and caused the bass fishery to collapse.
Key to reducing phosphorus loading from the North Shore was restoring the area’s wetlands, to reduce the volume of water pumped to the lake. Now all discharges are treated to inactivate phosphorus and in 2003 the passage of the Lake Apopka Stormwater Rule enhanced the lake’s diet to the entire watershed.
“Exercise” is removal of phosphorus already in the lake, which has included harvest of rough fish (largely gizzard shad) from the lake and operating the marsh flow-way continuously filter algae, suspended solids and associated nutrients. The combined effect of the diet and exercise has been a dramatic improvement in water quality. Since the late 1980s, phosphorus concentrations have declined 71% and water clarity increased 55%, as of the end of 2021. The recovery of clearer water and return of sunlight to the lake’s bottom has caused the regrowth of submerged aquatic vegetation, missing for 50 years, and the critical bass habitat.
Like many restoration projects, the district has partners at Lake Apopka, including the Florida Fish and Wildlife Conservation Commission (FWC), which has planted native aquatic vegetation, stocked largemouth bass and installed fish attractors, and the Florida Department of Environmental Protection (DEP), which is investigating innovative technologies for removing phosphorus from the lake.