Many locals, if asked to describe the Kendall County terrain, would look at the horizon saying, “Well, it’s hilly, of course.” On the other hand, a geologist or a hydrologist might study things for a bit longer before replying, “Clearly this is a karst landscape.”

As it drops through the air, rain partners with carbon dioxide in a recipe for a mild acid that’s created before it even hits the ground. Such precipitation, dropping on Boerne and its surrounds, doesn’t merely moisten soil and flow away in creeks. For millennia rain has insistently sought out every hairline crack or flaw in an otherwise impenetrable barrier of bedrock. Gently, mercilessly, water consumes stone.

According to a University of Texas at Austin Web site, “the water begins to dissolve away the rock creating a network of passages. Over time, water flowing through the network continues to erode and enlarge the passages; this allows the plumbing system to transport increasingly large amounts of water.”

Sometimes laser-straight “pipes” are formed, sometimes oddly contoured caves, sometimes irregular drainage systems �“ but always, in the way that water will, it finds a way to go where it must. This sort of honeycombed topography is classified as karst.

The Hill Country’s karst is irregular, mostly uncharted, and somewhat unpredictable, demonstrating nature’s eon-old lack of submission to man’s centuries-old understanding. Back during the Earth’s raging, tumultuous adolescence, the tiny patch of globe now known as Kendall County was being laid down in the form of sea-floor sediment – layers that would eventually become rock. The layers weren’t placed according to any geometric design or pattern, instead they followed the leadership of water beneath which they settled: now a deposit of sea creatures, later a stratum of gravel, here the product of decomposing marine coral, there soft drifts of sand.

It was a cake of diverse materials, unevenly layered, some of it porous and crumbly, some of it not. As the sea retreated and the continent shifted, the stony confection broke into a bewildering arrangement of juxtaposed pieces and the rain fell upon it. Much of this rock was impenetrable, much was splintered, compliant in the face of the rain’s perseverance. And so was shaped the karst landscape.

Of the many words used to describe Boerne, karst may be the least expected, but most significant of them all, since karst means storage for the region’s water supply. Karst is the essence and ongoing evolution of the system we call the Trinity Aquifer.

In his book, “Springs of Texas,” Gunnar Brune explains that when precipitation falls, evaporation takes the first cut, leaving further moisture to be absorbed by the soil and roots upon which it falls. Even more of the rain goes to feed of rivers and streams. However, in the event of enough rainfall, small amounts eventually soak deep, making their way into the vast arterial network sculpted from those many broken stone layers the whole of which is now called the Trinity Aquifer.

It is unquestionably the region’s lifeblood – the circulatory system of the Hill Country, yet the Trinity Aquifer remains an arrangement without blueprints. Where the Edwards Aquifer is a recognized entity, the Trinity is something of a stepchild, and even among authorities, much of the structure is an unmapped mystery. Although the word “aquifer” is always floating about, many residents who live off its liquid largesse know almost nothing about it.

The aquifer’s thickness in Kendall County ranges between 50 to 350 feet thick. According to local geologist, Bill Ward it is “highly varied in rock type”,  a medley of stone that changes in its top-to-bottom strata as well as its side-by-side arrangements. While to most people it’s just “rock,” to somebody like Ward these layers are identifiable as Hensell Sand or Cow Creek Limestone or Hammett Shale.

To a layperson, legal aspects of the aquifer may be just as confusing. The Trinity Aquifer extends south all the way from the Red River to Travis County before beginning a broad curve to the southwest with western edges reaching into Real and Uvalde counties. In its mapped form, the aquifer washes across Texas like a huge subterranean wave of almost 32,000 square miles. More than three dozen conservation districts share responsibility for the aquifer’s management. These districts are grouped under an assortment of Groundwater Management Areas (GAMs), which in their turn are under the direction of the Texas Water Development Board.

While Boerne’s water use is overseen by the Cow Creek Groundwater Conservation District and GMA 9, the region’s water use is also under the administration of “Regional Water Plan Review Region L.”

Rule of capture is the prevailing ideology writes Milan Michalec, master naturalist and secretary for the Cow Creek Groundwater Conservation District.

“This is the State doctrine where the biggest pump prevails,” he said.

Thus a piñata mentality readily develops, with 37 districts each requesting their share. As with any political structure, district officials are elected to ensure their own jurisdiction’s welfare.

Gregg Eckhardt, an environmental scientist who manages an Edwards Aquifer Web site maintains that while everybody likes the idea of “local control,” these regional districts may not be the answer to the aquifer’s health as a whole.

Whatever the arrangement of these oversight groups, nobody seems to dispute the idea that the Trinity Aquifer is on the “endangered” list. Leslie Anderson of the Texas Water Development Board reports that between 2000 and 2008, an average of 30,000 new wells per year were drilled across Texas. Although these statistics are not “aquifer-specific,” rapid growth along the I-35 corridor and heavy development in Kendall County would seem to indicate that a large portion of those yearly numbers were wells sunk into the Trinity Aquifer. Indeed, the Edwards Aquifer informational site warns that “the Trinity is expected to be one of the most stressed aquifers in the state over the next 50 years,” with some models showing water-level drops of up to 100 feet.

Such a scenario means more than just drying wells.

“Think of an aquifer as a saturated sponge with pipes,” Eckardt says. “The rock matrix has many pore spaces similar to the holes in a sponge and some of them are connected by well-defined conduits through which water can readily flow.”

Taking Eckhardt’s illustration further, this saturated sponge can be indented with either the pad of a thumb or with the length of a finger to demonstrate the relationship between an aquifer and the lakes and rivers with which it shares the earth.

Texas State University’s Edwards Aquifer Research and Data Center notes that rivers, streams, and lake bottoms contribute to continuous recharge of the Trinity Aquifer, while a 2000 study by the Texas Water Development Board asserts that one of the primary functions of the Trinity Aquifer is to feed creeks and rivers. In fact, another report submitted to the CCWCD states that “water within the major rivers in the Hill Country area such as the Guadalupe River is maintained because of this discharge.” In other words, creeks and underwater reservoirs are heavily dependent upon each other, whichever happens to be enjoying an abundance sharing freely with the other.

Stephen Grigory, a civil engineer who maintains the Web site www.hillcountrywater.org expresses concern over the Guadalupe River’s reaction to the current drought.

“The Guadalupe was not flowing at the Spring Branch gauge just before the rain started,” Grigory writes. “The ponds are hardly enough for frogs and babies to play in.  However, 17 cubic feet per second or about 11 million gallons per day disappeared between Comfort and Spring Branch making the Guadalupe a losing stream to an extent greater than any time in recorded history.  In the 1950s and ’60s the river was a gaining stream as it dried up meaning there was more water flowing at Spring Branch than at Comfort.”

According to Michalec, it’s not so much the drought that’s to blame. Although he says that the scarcity of precipitation does have an effect on the aquifer’s levels, the area’s population growth is affecting it even more. The drought, Michalec said, merely proves that demand has outstripped supply; and, the scientist warns, damage to the Trinity Aquifer can be irreversible.

Current management plans are out-of-date, according to CCGCD General Manager Micah Voulgaris. Models due to be released in September of next year will include Cibolo Creek contributions to the aquifer that were not incorporated into the old model. According to Voulgaris, aquifer “deficit” is not projected until between 2040 and 2060.

Unfortunately, no single Trinity Aquifer informational source seems to be out there– in fact the greatest quantity of reference material is most readily found at www.edwardsaquifer.net.

Informational “drought” aside, sources agree that the Trinity, in the manner of a water “bank,” will be overdrawn in the not-so-distant future, given the recent growth in Kendall County and growth projected over the coming years.

Graphics provided by the Texas Water Development Board provide Code Red type figures to this respect. The Trinity Aquifer, an abundant water resource for thousands of years, is presently in decline.

It’s not easy to think of limestone as a fragile part of Boerne’s beautiful scenery, but that’s precisely how the Vancouver Island University refers to karst, in which “airflow and water flow can be dictated by man’s surface activities.”

However eternal it may appear to be, karst such as Boerne enjoys, is said to be a “vulnerable landscape.”

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