In the 1850s Florida’s pioneers assumed that Silver Springs had always existed and would continue to flow for all eternity. Yet, Silver Springs’ average flow (nearly 500 million gallons per day [MGD]) declined to about one-half its long-term average in 2011 (247 MGD) and is currently about one third of its long-term average flow (160 MGD). Silver Springs is literally dying before our eyes – without flow a spring becomes a stagnant sinkhole with the almost complete loss of aquatic life.
So, what causes a spring with more than 150 years of recorded history to stop flowing? There are only two possible factors that could have caused the observed flow declines at Silver Springs: a drastic reduction in rainfall and/or a drastic increase in groundwater pumping. In Marion County, rainfall has remained relatively constant, averaging about 54 inches per year over the past 96 years and 52 inches per year over the past decade. Luckily for us rainfall has not stopped. On the other hand, groundwater pumping in Marion County was non-existent 150 years ago. Today there are 931 active groundwater consumptive use permits (CUPs) in Marion County for a permitted allocation of 84 MGD. This figure does not include the thousands of private self-supply wells in the county. Even more significant are the 28,630 CUPs with a combined pumping capacity of 4,700 MGD in the three water management districts that surround the groundwater basin that feeds Silver Springs.
This astounding number of permits and allocated withdrawals have lowered the regional groundwater levels from coast-to-coast, resulting in reduced flow to springs and rivers, lower lake levels, and coastal salt water intrusion.
We can’t control the rain. But fortunately, we can control how much groundwater we pump. There is a precedent where we have reduced our reliance on groundwater. The Tampa Bay “water wars” are a case in point. In the late 1980s it became increasingly obvious that groundwater pumping was lowering lake levels and drying up wetlands near Tampa. After an extended legal battle, in 1997 the Florida legislature required the opposing parties to settle their dispute and reduce their dependence on groundwater by increasing their use of surface water supplies.
The answer to the question above “How can we save our endangered springs?” is simple. Florida needs to cut back significantly on groundwater pumping. If we cannot live without that water, then we must shift to surface water supplies. The first target should be to cut back to pre-1990 pumping rates. Once we see how much that will restore flows at Silver and other imperiled springs, we may need to cut back further.
These cuts need to be across the board, not only in Marion County, but from Weeki Wachee to Jacksonville and from Daytona to Tallahassee. Our “eternal” springs are dying the “death by a thousand cuts” wherever they are in Florida. And so too is our state’s future.
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