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Any Idea Where Our Water Comes From?

April 13, 2012


When you turn on the tap in your kitchen or take your morning shower, do you ever wonder where that water comes from?  I did, and when I started looking into it, the answer was not totally reassuring.

Turns out that virtually all of the water we consume in South Florida comes from wells that tap a large underground water system called the Biscayne Aquifer which basically underlies all of the inhabited parts of southeastern Florida and extends into the Everglades.  It is what’s known in the trade as a “sole source” aquifer, which means that there is “no alternative drinking water source(s) that could physically, legally, and economically supply all those who depend upon the aquifer for drinking water.” More than 6 million people from south Palm Beach County to Key West are dependent on water drawn from the aquifer.

Most of the water pumped from the aquifer goes into municipal water systems, but a substantial portion is used for agriculture, and smaller amounts for industry and private wells.  The problem is that as the area’s population has grown, in dry spells the amount of water extracted can exceed the amount that enters the aquifer to “recharge” it.  That’s why in years of drought like last winter and this one, our restrictions on yard watering are more stringent than those in Los Angeles, even though LA is climatologically a semi-desert.  Remember Chinatown?

The aquifer is increasingly threatened with contamination from several different sources:  salt water, sewage and surface pollution, and agricultural chemicals.  The US Geological Survey published an interesting paper about threats to the Biscayne Aquifer in the 90’s, but the problems have, if anything, deepened since then.  You can read the report here, but this is a brief summary as I understand it:

The water in the Biscayne Aquifer moves slowly down and eastward from the Everglades toward the Atlantic.  Inland, the water table may be only a few feet (or even inches) from the surface, but as it goes under the ocean it is much deeper—a couple of hundred feet.  But because the aquifer is “uncontained”, as it meets salt water near the coast, there is a shifting boundary between salt and fresh water.  Basically, the fresh water column needs to be high enough to keep the salt water from pushing inland.

Salt water has already intruded far inland since the early 1900s when Miami was just a small village.  (See map here.)  Once water at a well head becomes salty, it is no longer usable for drinking or agriculture.

To stem this process, an elaborate series of measures—including canals, pumps, and locks—has been developed by the South Florida Water Management District to keep the aquifer recharged by distributing fresh water flowing down from Lake Okeechobee through the Everglades.  That’s why the TV newscasts report the lake level:  It’s not that we get our water directly from the lake, but when the level drops, there is less water to distribute and recharge the aquifer.  It’s also why even a small rise in sea level could be disastrous because it could overwhelm the means available to control salt water intrusion.

The good news is that because the covering limestone and soils are so porous, a good rain can recharge the aquifer quite rapidly.  The bad news is that contaminants from the surface can enter the aquifer equally easily.  These can include waste from municipal sewage treatment plants and septic tanks, agricultural chemicals, lawn fertilizers, pesticides, all the nasty stuff that washes off our streets every time it rains, and anything people dump on the ground.  The canals that crisscross our area cut into the aquifer and therefore both directly feed and are fed by the aquifer depending on the water level. Unfortunately, they contain a pretty noxious soup of chemicals and bacteria that you wouldn’t want in your drinking water.

Ultimately, the viability of the Biscayne Aquifer depends mostly on the health of the “River of Grass” trickling through the Everglades, since that’s where most of the water comes from to flush and dilute the pollutants and to recharge the system in dry times.

This is also where it gets really political.  Huge tracts of land around Lake Okeechobee have been converted from ‘glade to agriculture so that the rest of the country can have hard, tasteless, but reddish tomatoes year-round and so that growers can sell us US-produced sugar that is profitable only because tariffs keep the domestic price of sugar artificially inflated.  Chemical runoff from these farms continues to pour into the lake and the Everglades, and agribusiness continues to resist efforts to clean it up.

At the same time, pressure from developers continues for pushing new subdivisions in Miami-Dade and Broward westward into the Everglades regardless of the fiscal impact on residents and heedless of the environmental implications for the future.

The state government seems to have lost interest in protecting the Everglades and, indeed, has become actively hostile to environmental protection in general.  The assaults come in obscure legislation that gets little or no attention in the media.  And local decisions are made in boring commission meetings too tedious for any but the most determined to keep an eye on.  The stalwart bloggers of Eye on Miami have followed these issues with a tenacity and depth that I could never hope to match. For starters, take a look at these posts that deal with these issues.  It behooves the rest of us to pay attention too.

As demand becomes greater, fresh water is increasingly regarded as a commodity to be bought and sold rather than a basic benefit of civilized societies.  We will probably be paying more for it, and that may be a good thing if it makes us more mindful of how we use it.  The question is why we should support politicians who favor private economic interests over the broader public good–I just wish it weren’t so hard to find some that don’t.

So what are the odds of a real water crisis in South Florida before your mortgage is paid off?  I don’t know, but when it comes down to it, we’re all crossing our fingers and betting the house that it won’t happen.

From → Environment

  1. Thanks for mentioning us…

    The cooling canals at FPL are causing salt water intrusion. The reason we have our wells so far West in the county is because of the salt water intrusion problem. But then we have the lake belt West that poses a new problem – the empty rock mine pits fill with water and become a conduit for pathogens to enter that underground river — the aquifer. River? Google Pink Water + New Times.

    Keep up the good work…I liked this post!

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