Managing Lake Okeechobee
At the heart of the greater Everglades ecosystem, Lake Okeechobee historically overflowed its banks, sending a sheet flow of water south through the Everglades. Today, the 730-square-mile lake is part of a massive flood control system known as the Central & Southern Florida Project, which stretches from just south of Orlando to Florida Bay and serves 8.1 million people.
The U.S. Army Corps of Engineers manages Lake Okeechobee water levels with the goal of balancing flood control, public safety, navigation, water supply and ecological health. The Corps bases operational decisions – whether to retain or release water in the massive lake – on its regulation schedule and the best available science and data provided by its staff and a variety of partners, including the South Florida Water Management District.
Lake Okeechobee Releases to Coastal Estuaries
In a fixed regional water management system with limited storage, the Corps must sometimes release water from Lake Okeechobee to the Caloosahatchee and St. Lucie rivers to protect public safety when lake levels get too high.
Under its revised 2008 regulation schedule, the Corps strives to maintain Lake Okeechobee's water level between 12.5 feet and 15.5 feet NGVD, in part to protect the integrity of the aging Herbert Hoover Dike that surrounds the lake. The lake's water level can rise up to six times faster than water can be discharged. For example, heavy rains from Tropical Storm Isaac in August 2012 raised the lake level by 3 feet in a month.
The Corps continuously monitors the effects of any releases on the estuaries and consults with its partner agencies and stakeholders to modify releases to help minimize impacts to coastal waters.
During dry periods, the Corps may also release fresh water from Lake Okeechobee to help maintain appropriate salinity levels in the Caloosahatchee Estuary. In their advisory capacity, SFWMD water managers use a guidance document known as Adaptive Protocols to make recommendations to the Corps on lake operations in these situations.
- FYI: Lake Okeechobee Operations – Goals, Roles and Responsibilities [PDF]
- Just the Facts: Lake Okeechobee Coastal Releases [PDF]
- FYI: Adaptive Protocols for Lake Okeechobee Operations [PDF]
- System Constraints to Moving Water South [PDF]
- Water's Role in South Florida History
Frequently Asked Questions – Lake Okeechobee Releases
A number of constraints limit how much water can be sent south from Lake Okeechobee to the Everglades.
- Sending more water south from Lake Okeechobee is physically limited by the capacity of South Florida's flood control system of canals and water control structures. This system was built many decades ago to send excess Lake Okeechobee water east and west to the coasts instead of south to the Everglades.
- Further, sending nutrient-rich water south risks harming Everglades water quality, potentially violating federal court orders.
- Sending more water south into the Stormwater Treatment Areas (STAs) risks damaging their ability to perform as treatment wetlands and could violate state and federal regulations.
- Sending more water south into the three Water Conservation Areas jeopardizes flood control for Broward and Miami-Dade residents and can cause damage to habitat and wildlife.
- In addition, federal regulations that protect endangered wildlife, such as the Endangered Species Act and the Migratory Bird Treaty Act, prohibit certain operations that could increase flows south.
For details on the volumes of water being sent south from Lake Okeechobee and available storage capacity, visit www.sfwmd.gov/movingwater.
In making its management decisions for lake releases, the U.S. Army Corps of Engineers must balance flood control, public safety around the lake's Herbert Hoover Dike, navigation and water supply — in addition to considering impacts to the estuaries. Because Lake Okeechobee's water level can rise up to six times faster than water can be released through the canal system, large-volume lake releases are sometimes required, as we saw in the summer of 2013 and its historic rainfall.
Vast tracts of land plus massive pumps and water control structures would be needed to build a flow-way south of Lake Okeechobee – a multibillion-dollar effort. Science and modeling show that the Central Everglades Planning Project accomplishes the same goal of sending more water south and providing relief to the estuaries – in a more achievable and cost-effective way.
The scale of ecosystem restoration in South Florida is one of the largest environmental restoration efforts in the world. Achieving the right water quality and water quantity in the right locations with the right timing is the ultimate goal. This is complicated by factors such as unpredictable weather – including extreme rainfall or prolonged drought – and by policy issues that determine where funding and projects are needed most.
South Florida's environment has the benefit of many caring and involved stakeholders. To ultimately be successful, restoration must be a cooperative effort among many partners.