As sea levels dropped, the barrier islands prevented water from flowing east to the ocean. Water collected in the flat valley and began to flow north, making St. Johns one of the few rivers in the United States that flows from south to north.
The fact that St. Johns flows north is not as unusual as you may think. Water follows the path of least resistance since it cannot drain east due to the barrier island, the river had to find other ways to empty into the Atlantic. As a result, the river flows 310 miles north and since its headwaters are a mere 27 feet higher in elevation than its drainage basin, St. Johns is one of the laziest rivers in the world.
The slow drop in elevation allows St. Johns to morph from a swampy marsh near Blue Cypress Lake into a broad waterway with expansive views.
Basins of the St. Johns River
St. Johns River is separated into three basins and two watersheds. The upper basin, located at its southernmost point, is perhaps the most distinctive part of the river. The sawgrass marsh is teeming with alligators, wading birds, and waterfowl. In the early 1900s, this area was diked and drained for agricultural purposes which diminished water quality in the lagoon and reduced the size of the marsh.
Much of this land has been reclaimed by creating reservoirs to enhance the wetland habitat. As the river flows north, it widens in size to reveal a tapestry of lakes and dark water tributaries. St. Johns River has had many names in its 10,000 year history, the most famous being Wekiva or “river of lakes.”
As the Econlockhatchee River joins the St. Johns, the river widens and the middle basin becomes the fastest part of St. Johns. About 100 springs can be found along this section along with Lake George, the largest lake on the St. Johns River.
The lower basin is a wider river channel characterized by strong tides. Towards the end of its journey, the river turns east to empty into the Atlantic Ocean. Incoming tide from the ocean causes the river to reverse its flow twice a day. As a result, 42,000,000 gallons of saltwater is flushed into the St. Johns every day.
The St. Johns ecosystem supports a wide variety of plant and animal species including manatees, river otters, blue herons, largemouth bass and many other types of fish, and shellfish.
St Johns River Timeline
Today, if you were to journey upstream from the Atlantic through 18 counties to the Orlando metro area, you would encounter swamps and lakes. There are several recreational areas along its course, in addition to farm- and pastureland, including the Blue Spring State Park, Lake Woodruff National Wildlife refuge, and Silver Glens Spring Recreation area.
Going back a few hundred years to the mid-1800, as one of the most navigable rivers in the Sunshine State, St. Johns was often the best – if not the only – way for people to make their way into Orange County. Steamboat commerce made Mellonville the center of trade in Central Florida and opened the state to winter tourists and new settlers.
But, the Wekiva River was a narrow and shallow stream with plenty of twists and turns. Without skillful captains, steamboats would run aground get stuck, leaving crew and passengers stranded. So, perhaps it’s not surprising that tales of St. Johns River involve shipwrecks between Jacksonville and Sanford.
Several ships were sunk on the river, during the Civil War as Confederate and Union soldiers battled for Florida. Steamboats continued to be used for transportation on the River until the 1920s and remains a vital part of Florida’s economy to this day.
Fast Facts About St. Johns River
Aside from flowing northwards and being Florida’s longest river, St. Johns is distinctive due to several exceptional physical features.
It’s one of the flattest major rivers in North America since the headwaters are less than 30m above seal levels. As a result, the area is prone to flooding during storms and the rainy seasons.
St. Johns receives saltwater from several springs including the Blue Springs and Silver Glen Springs.
The St. Johns is a dark, black water river. Dissolved organic matter, from decaying plant materials give the river its color and limit light penetration, and therefore photosynthesis.
- Rising sea levels are increasing water levels in the St. Johns by one inch per decade
In 1998, St. Johns was designated an American Heritage River by President Clinton and is one of 14 rivers to receive the title. The St. Johns is rich in history and holds invaluable environmental and aesthetic value for the State of Florida.