its length, but takes on the character of a fresh-water creek from White City northward. The headwaters of the North Fork are in the farmlands of St. Lucie County near Interstate 95 at an elevation of above sea level. Discharges In 2016, 237 billion gallons of water was discharged into the St. Lucie River from Lake Okeechobee by the U.S. Army Corps of Engineers between January and November. In 2013, the U.S. Army Corps of Engineers dumped 137 billion gallons of water into the St. Lucie River from Lake Okeechobee. The USACE noted they "do share the concern about the quality of the water being released" but also noted that poor water quality was the state's fault in a release called "setting the record straight." Environmental concerns Historic modifications to St. Lucie River, most notably digging of the Okeechobee Waterway (C-44 Navigational Canal), connections with the C-24 and C-23 drainage canals, and the associated water control structures, have had impacted water quality throughout the river basin. Intermittent freshwater discharges from Lake Okeechobee have negatively affected the river itself and the connected Indian River Lagoon. The impact takes several forms. First, this water tends to be rich in nutrients as a result of agricultural runoff, and thus has a tendency to cause algae blooms and other imbalances. Second, it contains pollutants found in street runoff and other urban sources, which are carried south by the Kissimmee River from the southern Orlando suburbs into Lake Okeechobee. Third, it is a source of turbidity and particulates that settle along the river bottom as a layer of muck. Fourth, the freshwater brings in high levels of humid substances that limit how far below the surface light can reach, affecting plant and animal life. Finally, the discharges radically reduce salinity levels, making the river temporarily uninhabitable by fauna and flora that are intolerant to fresh water. In 2013, heavy rains in southern Florida resulted in high runoff into the lake; rising lake levels forced the U.S. Army Corps of Engineers to release large volumes of polluted water from the lake through the St. Lucie River estuary to the east and the Caloosahatchee River estuary to the west. Thus the normal mix of fresh and salt water in those estuaries was replaced by a flood of polluted fresh water resulting in ecological damage. Algae blooms Harmful algal blooms have been documented in the St. Lucie River