Seven miles long, the St. Lucie River estuary is linked to a coastal river system in St. Lucie and Martin counties. Both the river and estuary are “ecological jewels” of the Treasure Coast and central to the health and well-being of the surrounding communities. As part of the Indian River Lagoon system, it is the most diverse estuarine environment in North America. There are more than 4,00 plant and animal species which includes, manatees, oysters, dolphins, sea turtles and seahorses.
Back in the 19thcentury, the St. Lucie was a freshwater river with no connection to either the Atlantic Ocean or Lake Okeechobee, but then underwent a series of modifications. The purpose of the modifications was for navigation, flood control, and water supply.
The North Fork flows south from St. Lucie and Martin counties where it joins the South Fork, which was once called the Halpatiokee River. When the river reaches the northern end of Sewall’s Point peninsula, it flows into the Indian River Lagoon. The lagoon is directly west of the St. Lucie Inlet and goes into the Atlantic Ocean. Using the Okeechobee Waterway, the entire river is accessible to Lake Okeechobee.
While most of the length is brackish, the South Fork pass through Palm City. The headwaters of the South Fork are located in ranchland and scrub forest, east of I-95 and northwest of Hobe Sound.
As well, the North Fork is also brackish long most of its length but has the character of a fresh-water creek from White City northward. Headwaters for the North Fork are the farmlands in St. Lucie County near I-95 at an elevation of 20 feet above sea level.
Impacting the water quality have been the historical modifications to the river. Specifically, the digging of the Okeechobee Waterway (C-44 Navigational Canal). Further, intermittent freshwater discharges from Lake Okeechobee have negatively affected the river itself and the connected Indian River Lagoon.
During the heavy rains of 2013, resulted in high runoff into the lake. With the rising lake levels, the U. S. Army Corps of Engineers released large volumes of polluted water from the lake. The water went through the St. Lucie River estuary to the east and the Calooshatchee River estuary to the west. Ecological damage occurred when the normal mix of fresh and salt water in those estuaries was replaced by a flood of polluted fresh water. Again in 2016, the USACE discharged another 237 billion gallons into the river. At the time they noted that they, “Do not share the concern about the quality of the water being released.”