Scientists at the South Florida Water Management District (SFWMD) established an aquatic plant nursery to help cleanse the water at the C-44 Reservoir/Stormwater Treatment Area (STA) in Martin County. STAs, as they’re called by water managers, are man-made wetlands that help remove nutrient pollution from water. The nursery provides a sustainable source of native aquatic plants that will be transplanted to select locations around the C-44 STA and other STA sites throughout the District.
SFWMD scientists use a variety of native plant species to better mimic nature when planting in the STAs to establish durable populations. When selecting the plants, many factors are considered including the plant’s preferred soil type; seasonal growth habits; resistance to fluctuating water levels, drought, waterflow velocity; and the ability to compete with invasive plants and coexist with desirable plants.
The soil at the C-44 site is sandy, so the scientists are planting giant bulrush to stabilize the soil at the inflow and outflow canal edges to resist erosion and protect submerged plants from wind and waves. Giant bulrush’s strong but flexible stems and deep root systems also help maintain desirable flow patterns by resisting high velocity flows and spreading out the water. Scientists will also plant alligator flag, three-square bulrush, club rush, aquatic grasses, and several other submerged aquatic species. The STAs are then monitored year-round to ensure plants are viable and providing successful function to the STA.
STAs put biology to work by using plants as part of the natural system to cleanse water. Throughout their life cycle, plants remove nutrients from the water through growth, and even after they die through the activity of microbes on the accumulation of dead plant material. For example, decomposing leaves of cattail plants continue to remove phosphorus and settle to the bottom of the marsh to become wetland sediments. The limestone layer beneath the sediment absorbs and holds the phosphorus and stores it for decades.
Once completed, the C-44 Reservoir will store over 50,000 acre-feet of water, including local basin runoff and Lake Okeechobee releases. The project will clean water and reduce harmful releases reaching the St. Lucie Estuary that can fuel harmful algal blooms. The C-44 STA project has successfully reached substantial completion and is on its way to final completion.