Some novelists, although writing stirring tales, can't quite seem to get it right when it comes to nature. Consider, for example, the writer who has a spring bubbling forth at the top of a hill. Not likely! Many of our desert mountain ranges have springs or seeps, but always some distance below the top. After all, springs are gravity fed and flow downwards, not up. Well then, you might ask, what about artesian springs? Those valley-floor pools gurgling up from the depths, far from any highlands, might seem an exception. But no, such waters usually originate in the mountains, sometimes miles distant. Trapped by impervious rock above, the water sinks downward by gravity until encountering a break in the roof, possibly far out into the bolsón.
Think of the system that supplies water to your home. A tank located
far above you delivers water into your spigots located well above ground level, but
nonetheless, far below the source! It's the weight of the water above combined with
impervious pipes that turns your faucets into miniature, gushing artesian
springs.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.
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