Algae is an important, natural part of South Florida’s ecosystem. But high levels of nutrients such as phosphorus from surrounding urban and farm areas have led to widespread increases in harmful Blue-green algae blooms in canals,rivers and streams.

Few areas of the Everglades have been untouched by man. This scene from the protected Everglades National Park is a reminder of what most of Florida once was.


in 1900

Before Florida’s development boom, the state’s population was roughly over 500,000. With the absence of man’s urban and agricultural areas, water flowed freely through the middle of the state following a gradual downward slope, and passed what is today’s Everglades National Park before emptying into Biscayne Bay, Florida Bay and the southern Gulf of Mexico.

South Florida’s population has been steadily increasing since the 1920s, and now stands at over 7.5 million people. With that large population comes a great need for clean drinking water.




Since 1900, much of the Everglades has been channeled for agriculture and urban development. Economic prosperity in the early 20th century stimulated tourism to Florida, leading to development of hotels and resort communities. The Florida land boom of the 1920s brought a brief period of intense land development, altering the landscape with the construction of man-made canals and removal of many natural waterways.

The Kissimmee River and other canals north of Lake Okeechobee contribute large amounts of phosphorus to the lake.

Lake Okeechobee receives most of this polluted water, but because its levels have to stay a certain height to avoid flooding communities, large amounts of water is discharged elsewhere.


the Water

Much of the polluted water is discharged to rivers east and west of the lake, eventually ending up polluting those rivers, as well as estuaries on either coast. Water is also discharged south and cleaned to avoid contaminating the Everglades’ natural ecosystem and threatening the drinking water of a large populace. To do this, some water passes through stormwater treatment areas within the Everglades Agricultural Area before continuing south.

At the heart of the problem is the

Everglades Agricultural Area which mainly harvests sugarcane. Irrigation canals like this one are used to water the plants, but also end up collecting phosphorus from the fertilizer runoff.

Too Much


Agricultural areas above and around Lake Okeechobee contribute roughly 67% of the total phosphorus entering the lake, while urban areas contribute 26%, and the atmosphere provides the remainder.

*From Lake Kissimee and other

  agricultural areas, average annual

  total phosphorus loading for water

  years 2005-2009

Although the Everglades Agricultural Area (EAA) has been implementing management

practices to reduce phosphorus

levels, much still makes its way

south past the EAA and into

South Florida waters.




Although some of the phosphorus is redirected to stormwater treatment areas, there isn't enough area to treat all the water


How much pollution

is that in one year?

Even though over 150 metric tons are treated, almost three dozen metric tons go untreated and find its way to waterways throughout South Florida.


The increased phosphorus brings about excessive cattail growth, and invasive species of plant. In this neighborhood, it has overtaken a large portion of a lake, driving wildlife away and affecting views that are important to real estate values.

Affecting Water Quality

Usually massive fish kills are the result of algae blooms caused by phosphorus overloading as fish are left without oxygen and can’t find safer waters, like this one here in the St. John’s River, just east of Lake Okeechobee.

Who Pollutes

and Who Pays

Even though agriculture is responsible for 76% of the pollution threatening the Everglades ecosystem, they only pay 24% of the nutrient removal. The remaining 66% is paid by taxpaying citizens.