As part of Everglades Restoration

The coastal receiving waters for the major southward flows of the Everglades are Florida Bay. It’s position, directly at the south end of the Everglades, makes it a recipient of hydrologic and water quality changes in the Everglades. Florida Bay was historically renowned for its excellent commercial and sport fishing and for its abundance of wading birds. Beginning in the 1970s, however, ecosystem decline was observed, which greatly intensified from the mid-1980s into the 1990s. About 15 square miles of seagrass beds died in the western half of the bay between 1987 and 1990, and about 90 square miles were damaged. Sporadic planktonic algal blooms and extensive losses of wading birds, fish, spiny lobsters, shrimp, sponges, and even mangroves of the islands were documented. (A similar decline began in 2015 and is ongoing at the time of writing.) Initial investigations focused on hypersalinity from diverted freshwater flows.

Aerial view of northeastern Florida Bay, looking westward over Little Blackwater Sound (left foreground) and Long Sound (center), Everglades National Park. Photo by Tom Lodge

In April 2017, skiffs and boats — and a floating tiki — lined up near Islamorada to send a message to lawmakers demanding help to improve water conditions in Florida Bay.

Lake Okeechobee and its watershed lakes and wetlands historically stored vast amounts of water from rainfall in the south-central Florida interior, south of Orlando. Most of this water was carried southward by the lake’s largest tributary, the Kissimmee River. The lake annually spilled into the Everglades, adding substantial water flow and hydroperiod to the already flooded ecosystem. With this function, Lake Okeechobee was the hydrologic hub of the South Florida ecosystem. Today, that function has been curtailed by flood control projects through the Kissimmee watershed and diversion of Okeechobee’s waters to the coasts, often in ecologically damaging heavy flows to the St. Lucie and Caloosahatchee, and altered flows to other coastal ecosystems. Containment of the lake by the Hoover Dike and water control has constrained the important littoral zone to the smaller lake, unable to move outward in response to changing water levels. Since about 1970, nutrient enrichment, mostly from agriculture, has changed the lake’s chemistry and threatened its biological functions. Nutrient enrichment was exacerbated by canalization of, and levees along, the Kissimmee River, and by the Hoover Dike. These modifications have served to retain entrained sediments in the river and lake rather than allowing them to exit and settle in the larger, natural wetlands and littoral zone, including the northern Everglades. The phosphorus load now embodied in lake sediments (greatly resuspended by the hurricanes of 2004 and 2005) may require centuries to assimilate, and unless loading of phosphorus from the watershed is substantially reduced, the internal recycling will never decline. Clearly, ongoing and planned phosphorus reductions and improved watershed storage are critical to improving the lake’s health. In the end, the ability to provide flood control and water supply without (1) impairing the ecology of Lake Okeechobee and (2) damaging the Caloosahatchee, St. Lucie, and other estuaries, is essentially hopeless without implementing expansions under Everglades restoration projects for moving much more treated water out of the lake and south to the Everglades.

An annotated satellite image (2004) of the entire Everglades region, showing Lake Okeechobee in the context of modern peninsular Florida. Courtesy of SFWMD

Lake O flyover during a massive toxic blue-green algae bloom during the summer of 2018. Photo by Jacqui Thurlow Lippisch

**Recent research supports the existence of a human health crisis stemming from Lake Okeechobee discharges is on the rise. The Army Corps of Engineers is in the process of developing a new regulation schedule, known as the Lake Okeechobee System Operating Manual (LOSOM). It’s a once-in-a-decade opportunity to finally and dramatically improve the way water is managed in South Florida — and mitigate the Sunshine State’s worsening toxic algae crisis.