|Coordinates:||30.2760 N 84.1488 W|
|No:||241 (list of all attractions)|
|Address:||North America, United States, Florida, Leon County, 11 km south-east from Woodville.|
|Average discharge:||14,700 l/s|
|Cave length:||~ 3,000 m|
As it is usual with many Floridan rivers, St. Marks River sometimes disappears underground to emerge on the surface shortly after. The last such rise before entering into the Gulf of Mexico is St. Marks River Rise.
Is it a spring or not?
Technically this is spring pf the 1st magnitude. Average discharge of this giant spring is 14,700 l/s and it starts as a 130 m wide river. Only four other springs in Florida have higher discharge – and Florida has some of the largest springs worldwide.
River rises though seem not to be true springs. Water of river rises is not lucid and clean, as it is with true springs. After all this is just a river, which has passed some distance underground.
What happens below the ground?
St. Marks River submerges at Natural bridge – true natural bridge, famous site of important battle in American Civil War.
Afterwards the river flows underground for approximately 1.1 km until the Rise. In between the river reappears on the surface several more times.
Woodwille Karst Plain Project in 2006 spent some time researching this part of St. Marks River. It turns out that several underwater caves join the river, bringing in additional streams and thus increasing the power of the stream in the river. Joint length of these explored passages is more than 3 km.
Future protected area?
The area around Natural Bridge and St. Marks Rise is not entirely wilderness - here and there are built houses and the forest is dissected with roads. Nevertheless the hardwood hammock has been preserved here.
The land around the sink and rise belongs to several owners and soner or later there will be a possibility, and, lets hope, a wish to purchase it and to create a nature protected area.
See St. Marks River Rise on the map of Florida!
- Chris Werner. Natural Bridge – St. Marks River Rise Exploration. Global Underwater Explorers. Accessed on July 17, 2011.