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
Upper Ocklawaha River Basin
The Upper Ocklawaha River Basin underwent major declines in water quality and loss of river and marsh habitat over a century beginning in the late 1800s.
Impacts came from a combination of dredging and canals dug for navigation, draining of marshes to establish farms, a series of locks and dams that altered water levels, and discharges of untreated wastewater and agricultural and industrial effluents into the region’s lakes.
These excessive nutrients fed the growth of algae, which turned the waters pea-green. Underwater plants, essential for fish spawning and habitat, died because sunlight could not penetrate the murky waters. Likewise, deep organic sediments rich in nutrients accumulated on the lake bottoms as dead algae settled, and stabilized water levels further degraded water quality.
The St. Johns River Water Management District began work to restore water quality and fish and wildlife habitat in the Upper Ocklawaha River Basin in 1988 as part of the Surface Water Improvement and Management (SWIM) program. Restoration of surface water quality, guided by the SWIM plan, began with purchase of the former muck farms — a process completed in the early 1990s — which brought an end to the agricultural stormwater discharges to the lakes. Each property became a wetland restoration area. Other projects improved the way lake levels and flows were managed to sustain the water quality and habitat improvements already under way.
Since 1988, most major construction projects designed to improve water quality in the basin have been completed. The following are the ongoing and completed projects:
- Ocklawaha Prairie
Purchased in 1991, this property occupies 3,000 acres of the old Ocklawaha River floodplain and about six miles of the historic channel. As part of a lease agreement with the district, the previous owner completed restoration work, including cleaning out the river channel and filling in ditches. The U.S. Department of Agriculture also funded some of the restoration. Currently, the Ocklawaha Prairie Restoration Area is open to passive recreation and duck hunting in the winter.
- Sunnyhill Restoration Area
After purchase in 1988, the district restored about 2,800 acres of former floodplain marshes along the Ocklawaha River. More than eight miles of the historic river channel runs through a variety of wetlands habitat. Improvements included installing water control structures, levee building and enhancement, and clearing vegetation that hindered flow through the restoration area. Part of the restoration was funded by the U.S. Department of Agriculture. Many miles of recreational trails lie within the property, which is adjacent to Ocala National Forest.
- Moss Bluff Lock and Dam
Moss Bluff Lock and Dam was originally built by the U.S. Army Corps of Engineers in 1925, primarily for navigation purposes in the basin. After upstream flooding in 1959 and 1960, the dam was rebuilt and enlarged as part of the federal Four River Basin Flood Control Project. Although the Corps owns the lock and dam, the district is responsible for its operation and maintenance.
- Emeralda Marsh Conservation Area
The purchase of the properties that make up this 7,000-acre conservation area was completed in the early 1990s. Wetlands have been restored on several parcels and about 2,000 acres have been reconnected to Lake Griffin. Wetland restoration activity continues on the remaining properties and planning is under way to reconnect the remaining area. The district partnered with Lake County to construct a one-way drive through trail that has become popular with visitors and residents.
- Harris Bayou
The former S.N. Knight Leesburg farm lies between Lake Harris and Lake Griffin. After purchase by the district in 1992, wetlands were restored on the property. Renamed Harris Bayou, this project plays an important role in the district’s ability to manage lake levels and flood control throughout the basin. The project allows up to 1,000 cubic feet per second of water to flow from Lake Harris to Lake Griffin. This supplements the flow through Haynes Creek from lakes Eustis, Harris, Dora and Beauclair.
- Gizzard shad harvesting
In addition to reducing the amount of nutrients entering the waterways from surrounding land in Lake Griffin, reducing the amount of internal nutrient recycling in the lake has vastly improved lake water quality. Gizzard shad, a natural component of the fish population in the Harris Chain, grow to dominate numbers with high levels of nutrients. The large populations of fish may contribute to nutrient recycling by the fish feeding in the sediments and then excreting available nutrients into the water column. In 2002, 96 percent of the fish biomass in Lake Griffin consisted of gizzard shad. Between 2002 and 2007, about 2.5 million pounds of gizzard shad were harvested from Lake Griffin. Removing one million pounds of shad reduces total phosphorus levels by about 25,000 pounds. Through late 2012, the shad numbers remained low, 85 percent lower than a decade earlier, and water quality has improved dramatically. Other improvements include large beds of submersed aquatic vegetation found across the lake and sport fish numbers are climbing. No additional shad harvesting has been necessary since 2008, thanks to the steadily improving health of the lake.
- Lake level management and minimum flows and levels
The district adopted interim lake level schedules for lakes Harris, Eustis, Dora, Beauclair and Griffin in June 2012. The district continues to work with the public and stakeholder groups to implement revised regulation schedules and set minimum flows and levels for the Harris Chain of Lakes and Lake Apopka. This new water regulation/management plan will help sustain the improvements in lake water quality and habitat, as well as protect recreation and navigation, improve fishing, and continue to provide flood control for the communities around the lakes.
- Lake Apopka restoration
The district has undertaken many projects to restore Lake Apopka, including ongoing efforts. Among those projects are construction and operation of the marsh flow-way where phosphorus and other sediments are filtered and removed from lake water through recreated marsh cells, harvesting of gizzard shad to remove the phosphorus in the bodies of the fish, restoring native grass beds along the shoreline and increasing fluctuations in lake levels.
A limpkin parent and chick walk along a well-traveled path in the Upper Ocklawaha River Basin.
Updated on 1-28-2013