Lake Okeechobee and EAA Reservoir

Lake Okeechobee covers more than 700 square miles, yet its maximum depth is just 12 feet. The liquid heart of the Everglades watershed, the lake would spill over its southern banks during the wet season, initiating a “sheet flow” of fresh water up to 60 miles wide that created the “River of Grass” that eventually flowed through the Everglades to Florida Bay. Starting in the 1920s, dikes were built along the southern end of the lake for flood control and to drain land for agriculture. Over the next 50 years, the flow of water to the Everglades was shut off piecemeal. The excess water is now redirected east and west through the St. Lucie and Caloosahatchee rivers—starving the Everglades of fresh water and inundating estuaries on both coasts. To make matters worse, in the 1990s, scientists discovered that agriculture north of the lake had created a large phosphorus sediment load, which led to huge blooms of dangerous algae in the lake and in the St. Lucie and Caloosahatchee estuaries.

By law, water sent south into Everglades National Park must be clean, so managers can’t just open the spigot from Lake Okeechobee. The Everglades Agricultural Area (EAA) Reservoir, currently under construction, will be an above-ground reservoir covering more than 16 square miles and able to hold 78.2 billion gallons of water. But because water will move through it, the reservoir will hold much more over the course of a year. Water from the reservoir will be filtered through four stormwater treatment areas (STAs)—man-made wetlands that remove nutrients, such as nitrogen and phosphorus, from the water and store it in plant life and soils. The EAA Reservoir is an important but incremental step. Achieving the full potential of Everglades restoration will require at least four times as much water storage and STA acreage.