Monday, January 30, 2017

Dead Spring Running

Hornsby Spring Run

Hornsby Spring is dying. Once a deep blue gusher that added over 60 million gallons of cool artesian spring water to the Santa Fe River basin every day--the only first magnitude spring in Alachua County--its cobalt blue water has turned tannic brown.

The tipping point came in the early 2000’s, when a one-two punch of extreme drought followed closely by high flooding, caused the spring to reverse flow. Geologists call this kind of reversed spring an estevelle. When conditions returned to normal, Hornsby and a few other springs in the upper Santa Fe River basin were brown.

Wood stork plodding through Hornsby Swamp
People who love these springs visit them like concerned family members. We arrive with guarded optimism, pay quiet respects, conjure a few happy memories and then walk away saddened by the mounting acceptance that these springs are dying. 
Yes, the pool is still full and yes, the water that gushes from the vent still flows in an elegant stream through a spectacular swamp hardwood forest. But much of the water is brown river water that fell into the plumbing system and regurgitated by the same forces that have always powered the spring. Because we Floridians are pumping out more than is being replenished by rainwater (the source of all water in the aquifer) it contains less artesian water than it once did; less of the water that had filtered slowly through the limestone and re-merged only after a relatively-long residence time underground. This spring is as dying as surely as a lightning struck pine.

In my early years as an arborist, it took many hope-filled disappointments before I learned to confidently tell my customers that their beautiful, lightning-struck pine tree was dead as a rock, even though it was still vibrant green. I would point to the narrow streak running down the trunk and into the ground and explain that the trees roots were fried. But because the vascular system of xylem and phloem was still intact and it was still full of life-giving nutrients and water, it would continue going through the motions for weeks or even months to come. Like the death row prisoner who they call a “dead man walking,” these vibrant-looking pines were actually dead trees standing. Sometimes it would take as long as a year. But, in the end, the tree would die and I’d get the “you were right” call and we’d schedule a removal.

 Like the pine, the vascular system under Hornsby is still intact, still full of fluid. But it’s not the purely artesian spring water that once flowed from the vent, not the clear, calcium-rich water to which every habitat, every species and every individual creature that lives along the spring run and Santa Fe River, from here to the Gulf of Mexico, is adapted. The chemistry of tannic brown river water is different from artesian water. The temperature, too, is different. It’s also less clear, which means less light penetrates to the bottom and fewer plant species can thrive. Fewer plants means fewer animals. Many species have survived the transition. Some have not.

Just as I learned that green pines with lightning streaks running  into the ground are actually dead, I'm learning from watching Hornsby, Graham, Columbia and several other once-blue springs of the upper Santa Fe that, even though the plumbing is still working, browning springs are in their death-throes. But, there are a couple of big differences between dying pines and dying springs. 

For one thing, humans are not responsible for lightning struck trees. Insurance companies label them, “acts of God.” The death of our springs, on the other hand, is being caused by humans. It’s a reversible tragedy. But saving the springs would take special kind of miracle—a committed effort by Florida voters (that's us) and decision-makers we elect.