Mississippi

Mississippi South Florida Style
The Lake Okeechobee measuring cup

Hydrology numbers get big, confusing …

And obtuse.

Mississippi River’s annual discharged measured in Okeechobees

Millions of gallons per day, acre feet per year, cubic feet per second … the list goes on. The fact is, at some point it all just turns into a jumble of numbers. That’s where Lake Okeechobee comes in handy as a giant measuring spoon. Did you know that each year on average 100 Lake Okeechobee volumes worth of water discharges into the Gulf of Mexico from the Mississippi River. I could have said 400 million acre-feet of water, or some gargantuan number in gallons or cubic feet. But if you’ve ever stood on the levee of Lake Okeechobee and looked out at the expanse, it kind of puts it in perspective: The Mississippi discharges about one hundred Okeechobees into the Gulf each year. That’s one mighty river!

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Tidbit: The Mississippi River discharged over 160 Okeechobees into the Gulf during the flood year of 2000, and just over 60 during the drought years of 2006 and 2012.

animation lake canoe

Caloosahatchee meets Mississippi
And how the two compare

The Caloosahatchee is …

The king of freshwater flows in South Florida.

Comparison of annual freshwater discharge from the Caloosahatchee (red), Apalachicola (dark green) and Mississippi River (light green)

Currently flowing at around 5,000 cubic feet per second (cfs), it’s the single highest flowing point in the Greater Everglades. But not only is that flow rate dwarfed by the 17,000 cfs discharging out the mainstem of north Florida’s Apalachicola River, both are dwarfed by the nearly 700,000 cfs discharging from the Mississippi River into the Gulf. How much is 700,000 cfs … in more relatable lay audience terms? Answer: Every year, on average, the Mississippi River discharges about 100 Lake Okeechobee’s worth of freshwater into the Gulf. Note: The calculation is based on the assumption of a Lake stand of 15 ft above seas level, or the top of the Lake’s interior-levee littoral zone at which time its water volume is around 4 million acre feet. On average, the Caloosahatchee discharges about a quarter Lake Okeechobee volume worth of freshwater into the Gulf per year. Of course in the case of both, it’s just not water quantity — water quality matters, too, if not the most.

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Tidbit: The Mississippi starts its 2,552 mile journey to the Gulf of Mexico at Minnesota’s Lake Itasca, as photographed in 2014.