Ft. Pierce, Florida

This is a 20 acre pond in Ft. Pierce, just west of the Indian River, that collects stormwater from the southern half of the city and from agricultural areas to the west. In 2014, we installed 12 floating treatment wetland islands, each one 3,520 square feet in size. The total FTW area is 42,240 square feet, equaling 5% of the pond’s surface area.

Initially, The islands were planted with native freshwater aquatic species, but we had to convert to halophytes due to salt water intrusion during droughts and hurricanes. The nutrient removal rates have been consistent over the past eight years, averaging 451.41 grams of nitrogen per square meter per year, and 34.96 grams of phosphorus per square meter per year. For this project, that means we have removed 3,906.7 pounds of nitrogen  and 301.1 pounds of phosphorus annually, preventing 31,253.6 pounds of nitrogen and 2,408.8 pounds of phosphorus from reaching the Indian River Estuary  over eight years.