|Raise a Glass to the River of Grass|
|Written by Jim W. Harper -- BT Contributor|
The Everglades gives us some of the nation’s cleanest drinking water
Thank you, Everglades. Thank you, limestone.
Every time you drink a glass of water, take a moment to appreciate its origins. South Florida has some of the best water in the nation, and some of the world’s most productive aquifers. It’s a miracle of nature that deserves more attention.
“A lot of people don’t know where their water comes from,” says René Price, a hydrogeologist and associate professor at Florida International University. “They need to realize that the Everglades is the lifeblood of Miami.”
That water you drink from the tap? It pooled in the River of Grass and percolated through the limestone beneath it. Have you thanked your ecosystem today?
If you look at other places within a similar latitude -- Baja California, Saudi Arabia, Libya -- you’ll wonder why Florida isn’t a desert. These places, like Florida, have extensive shorelines, but they’re bone-dry.
Many elements came together to create this unique peninsula with plentiful fresh water, the world’s most essential resource. The foundation comes from Africa.
Eons ago, before the continents divided, Florida was wedged in between Africa and South America as part of the supercontinent Gondwana. It eventually drifted into North America.
For most of history, sea level was much higher, and most of Florida was an oceanic ledge. Ancient marine organisms discarded or built their shells on the sea floor, and over millions of years, this layer became compacted as the sediment that traps and filters water far below our feet. At more than 1000 feet deep, this layer holds the Floridan Aquifer, which runs throughout much of the state and serves much of northern Florida.
In South Florida, however, the aquifer runs too deep and salty to be of much use. But we may need it in the future to abate saltwater intrusion from sea level rise. Salt water has already ruined the freshwater supply of the City of Hallandale in Broward County, which must import its drinking water.
Miami-Dade County was wise to place its supply wells far from the coastline and close to the Everglades. That investment, made a few decades ago, may have been Miami’s smartest moment.
Across South Florida, the main source of drinking water is the Biscayne Aquifer, less than 250 feet below ground. Above it sits an incredible system of small caves and porous limestone that allow rainwater to settle in a matter of minutes.
The same is true of the oil that spills from your car -- it flows through the cracks and into our supply of drinking water. You drink what you spill. (Well, not exactly, since it undergoes treatment, but who wants to start the process with dirty water?)
As its name implies, the Biscayne Aquifer connects with the bay and the ocean. With less water pressure from above, owing to dry conditions or excessive usage, more saltwater seeps into the system from below.
You can do your part to prevent saltwater intrusion by using water wisely.
“Always try to conserve water,” says Price. “We just ended a six-year drought in 2012.” This six-year pattern, which follows the cycle of El Niño, suggests that the next six years should be relatively wetter. But such assumptions could be upended by climate change.
To help us appreciate our source of water, Rice offers an experiment: Go outside and find a rock in the dirt. Clean it and break it into pieces or scrape it. Then look closely. Do you see tiny chalky dots everywhere? Those compacted dots are called oolites (pronounced oh-uh-lights). The spherical grains of calcium carbonate become exposed and solidify over time, and form oolitic limestone, the rocks in your backyard and under your building. While Miami’s oolitic limestone formed ages ago, today a similar process is happening in the sand banks of the Bahamas.
Many residents mistakenly call Miami’s near-surface limestone “coral rock,” perhaps because its many pores resemble those of coral fossils. Local rock created primarily by coral skeletons is called Key Largo limestone. But most of the limestone below your feet comes not from coral, but from non-living oolites.
Thank your lucky oolites today for doing such a good job of filtering your water.
Lastly, we must thank the Miami-Dade Water and Sewer Department for delivering a consistently good product. Our tap water is high in quality and low in price, despite what your neighbors might say. Google it.
Tap water deserves your support -- but bottled water doesn’t. Sitting inside a plastic shell for unknown amounts of time, bottled water creates waste that we can do without. Bottle your own tap water.
Water is the ultimate renewable resource, and the Everglades watershed is one of the world’s greatest suppliers of clean, abundant fresh water. We should be grateful to be living near a swamp instead of a desert.
Raise a glass (of water) to the River of Grass.
Volume 12, Issue 12, February 2015
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