[2] Lake Apopka has a history of more than 100 years of human alteration, beginning with construction of the Apopka-Beauclair Canal in 1888.

The discharge of water, rich in nutrients from agricultural and other sources, produced conditions that created a chronic algal bloom and resulted in loss of the lake's recreational value and game fish populations.

A series of canals and high capacity pumps allowed the water to be introduced for irrigation and flooding or to discharge it when necessary.

Over the decades, this condition caused the sandy bottom lake to be covered by a deep layer of muck.

In 1996, Governor Lawton Chiles signed the Lake Apopka Restoration Act that provided funding to purchase the farmland responsible for the discharges.

The shuttering of the farms allowed for the St. Johns River Water Management District (SJRWMD) to begin plans to convert the fields back to the marsh area it had once been.

The 1996 Lake Apopka Improvement and Management Act authorized the District to set a phosphorus concentration target.

Subsequently, the District established a restoration phosphorus-loading target for Lake Apopka of 15.9 metric tons of phosphorus per year.

The inversion process reduced contaminants in the biologically active soil layer to safe levels on about 1,600 hectares (4,000 acres) in the NSEA.

The infrastructure is designed to help establish full wetland habitat with a wide range of water levels.

Newly flooded phases are carefully monitored for at least one year to ensure that any accumulation of pesticides through the aquatic food web do not present a risk to water birds.

In addition, weekly bird surveys are conducted to monitor usage and to ensure that problems are detected quickly.

[4] The Marsh Flow-Way, which is a constructed wetland, is located along the northwest shore of Lake Apopka and west of the Apopka-Beauclair Canal.

It began operation in November 2003 and the goal of the project is to remove phosphorus and suspended material already in Lake Apopka water.

The system covers approximately 760 acres (310 ha) and contains four individual wetland cells, in addition to levees, canals and ditches.

Water flows west to east and is controlled by screw gates and riser boards in the individual cells.

Dominant vegetation communities growing in flow-way cells are shallow marsh and shrub swamp species.

Shallow marsh includes species such as pickerelweed (Pontederia cordata), arrowhead (Sagittaria lancifolia), cattail (Typha sp.

Retention time of lake water within the flow-way system typically ranges between two and seven days in the individual wetland cells.

Through the fall of 2011, gizzard shad harvesting has removed about 8,400 metric tons (18.5 million pounds) of fish from the lake.

Organochlorine pesticide (OCPs) residues remaining from agricultural practices were primary the cause of bird deaths.