In this section
- History of Lake Apopka
- Lake Apopka Marsh Flow-Way
- Lake Apopka North Shore
- Gizzard shad harvesting at Lake Apopka
- Continuous sensor-based water quality data
- Map of the regions (flood control areas) where water control structures operated by the District are designed to reduce flood impacts
Lake Apopka shad harvesting
- Setting Water Quality Goals for Restoration of Lake Apopka: Inferring Past Conditions (technical report)
- Total Maximum Daily Load for Total Phosphorus for Lake Apopka, Lake and Orange Counties, Florida (technical report)
- Florida Fish and Wildlife Conservation Commission aquatic plant management strategy for Lake Apopka
Lake Apopka Basin
The story of Lake Apopka is familiar to many Floridians — the state’s fourth-largest lake was once a world-class bass fishery but impacts to the lake over many decades led the lake to be named Florida’s most polluted large lake.
In recent years, 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 total phosphorus and other solids in the water, improvements in water quality and the restoration of wildlife habitat.
Support for the lake’s restoration was evident at a December 2011 Lake Apopka Summit. Spearheaded by Florida Sen. Alan Hays, the summit brought together state, county and city elected officials throughout the region, along with officials from the Florida Department of Environmental Protection, the District, the University of Florida, Florida Fish and Wildlife Conservation Commission (FWC), Lake County Water Authority, Friends of Lake Apopka, and the Harris Chain of Lakes Restoration Council.
Ongoing projects to restore the lake include:
- Shad harvesting — Harvesting gizzard shad from Lake Apopka removes the nutrients (phosphorus and nitrogen) contained in the fish bodies and reduces the internal recycling of these nutrients within the lake. This improves water clarity by reducing the severity of algal blooms, which depend on phosphorus for growth. Through December 2014, 21.5 million pounds of shad had been removed from the lake, thus removing the total phosphorus contained in the shad’s bodies, as well as reducing the internal recycling of total phosphorus within the lake. Algae depend on total phosphorus for growth.
- Marsh Flow-Way — The Lake Apopka Marsh Flow-Way is a 760-acre constructed wetland along the northwest shore of Lake Apopka. The wetland system removes phosphorus and suspended material already in Lake Apopka water, moving water through four individual wetland cells, in addition to levees, canals and ditches. As of 2012, the marsh flow-way had removed about 23 metric tons of total phosphorus and it eliminates approximately 4,200 metric tons of total suspended solids per year from incoming Lake Apopka water.
- Aquatic vegetation planting — The FWC is planting native aquatic vegetation to provide fish habitat and to provide wave protection for the shoreline.
- Fish attractors — FWC is building six, 2-acre underwater structures that resemble small tree limbs and other brush, anchored with concrete blocks to provide game fish habitat.
- Innovative technologies — The Florida Department of Environmental Protection is investigating new techniques and technologies for removing phosphorus from the lake and will be implementing test projects.
Eelgrass beds are reocurring in Lake Apopka as water conditions improve.
In the early years of restoration, the District planted wetland plant species behind protective barriers in Lake Apopka to provide habitat for fish and wildlife. These planting efforts are becoming less necessary as the lake’s water quality and clarity improve and native aquatic plants re-establish themselves. An ongoing effort is under way to map the locations and extent of more than 350 native submersed plant beds. This total number varies from year to year.
Improved water clarity has also made it possible for the nonnative invasive plant hydrilla to grow in the lake. Hydrilla can quickly outcompete native plants, so staff efforts are also focused on locating and treating these undesirable plants with herbicides.
Lake Apopka has responded to restoration efforts and its water quality has improved. Total phosphorus, chlorophyll and Secchi transparency showed improving trends between 1987 and 2011. However, during this 23-year period, three events contributed to a worsening of water quality within a given year. The first coincided with a storm in March 1993. However, the improving trend in water quality resumed the following year. The second occurred in 2001 and 2002 at the end of a severe drought when the lake lost nearly 80 percent of its volume and total phosphorus concentrations increased. Despite this short-term perturbation, water quality continued to improve during the following year. Total phosphorus concentrations between 2004 and 2006 were under 100 parts per billion (ppb) and approached the total maximum daily load (TMDL) target of 55 ppb. These long-term improvements persisted despite the hurricanes in 2004 and 2005. The most recent event was a severe drought in 2007 and 2008, in which the lake lost up to 52 percent of its volume. Total phosphorus concentrations increased sharply at low lake stages, but total phosphorus concentrations declined again in 2009 and continued to decline with water quality continuing to improve through 2011. The most recent data during the last five years (2007–2011) indicate that total phosphorus concentrations improved by 41 percent when compared to the baseline period (1987–1992). Chlorophyll a and water transparency showed similar improvements.
Improvements already evident at the lake make it attractive for public recreation. A partnership between the District and Orange and Lake counties led to opening about 10 miles of the Lake Apopka Loop Trail. The District improved existing trails and levees within its North Shore property that benefitted the loop trail, while Orange County built a connector from Magnolia Park (a county park) into the North Shore property, which included building picnic shelters, trail signs and providing trash cans and collection. Lake County is installing additional trail at the western side of the District’s property, as well as building an observation area, with construction expected to be completed in late 2014. Lake County may also operate a boat ramp within the District’s property as a county park, providing boating access to the Apopka-Beauclair Canal and to Lake Apopka. When all phases are completed, the loop trail will encompass 18 miles of trails through District property along the lake’s north shore.
The restoration at Lake Apopka is a work in progress that features adaptive approaches that have helped restore the lake in recent years, as well as new technologies that should lead to continued improvements.
Updated on 2-12-2015