|Vol. V, No. 3, Winter 1992|
An Ozarks View by Tom Aley
Karst, that three dimensional matrix of a landscape developed upon rocks which are water soluble, is a largely ignored facet of America. Mention karst, even among those with college degrees, and you are likely to draw a puzzled look or a blank stare. Karst is a poorly known term. Unfortunately, the implications of karst upon rural America are even less well known than the term itself.
For simplicity, we can call karst "cave country'', yet karst exists in areas where caves are rare. To some, karst implies sinkhole areas, yet sinkholes are rare or absent in many karst areas (and in much of the Ozarks). The most workable definition of karst is based on its hydrology, not its geomorphological features. From the hydrologic perspective, karst is a landscape underlain by a soluble rock in which there is appreciable water movement through solutionally widened openings. With this practical definition, karst encompasses about 60% of Missouri and about 20% of the United States.
I once spent several days developing a map of America's karstlands. Shortly after completion of the map I was startled to find a newspaper map depicting a generally similar area. The newspaper map was of areas of rural poverty. In stippled tones, the areas of rural poverty (and the karstlands) stretched across the Ozarks into Kentucky, Tennessee and north Alabama, then up the Appalachians to West Virginia. While there were differences between the two maps (for example, there is little karst in Louisiana or Mississippi) it is the common correlation between karst areas and areas of rural poverty which startled me then and intrigues me now.
Why this correlation between karst areas and areas of rural poverty? The answer lies in the karst environment and in man's adaptation to it.
The answer is entwined in soils and agriculture; water supply and waste disposal; and the com-plexing factors of ignorance and invalid assumptions. The result is poor allocation and utilization of scarce resources, which results in adverse economic consequences for those who are the most closely tied to the resources.
Rates of soil formation in karst areas are among the slowest on earth. The soluble fraction of the bedrock is essentially unavailable for soil formation; it is dissolved in the waters that leave the area. Only the insoluble fraction of the bedrock contributes to the mineral component of soil. Weather away a thickness of 100 feet of insoluble rock, and you derive 100 "feet-worth" of mineral material for soil. Weather away a thickness of 100 feet of typical Ozark karstland rock and you derive perhaps 10 "feet-worth" of mineral material for soil. Regardless of the landscape, some of the mineral material is lost to off-site sediment transport; it is only the remainder, mixed with organic material, which can yield soil.
There are three types of soils found in karst areas. These are the shallow soils, the rocky soils, and the imported soils. The shallow soils would be expected from slow rates of soil formation. The rocky soils result when appreciable portions of the insoluble component of the bedrock occurs as distinct rocks which are highly resistant to physical and chemical breakdown.
Chert is a classic example, as anyone who has worked a typical Ozark garden or field can attest. Good agricultural soils are neither shallow nor rocky.
The least abundant karst soils (and the only ones which are likely to be of good agricultural quality) are those which are imported. The imported soils of karstlands are not derived from the rock upon which they lie. They are the alluvial soils found in the coves of the Smokies or found on terraces along the major streams of the Ozarks. The best of the latter category are now submerged beneath the Ozark megalakes. Some of the imported soils are derived from loess, that windblown glacial dust from Pleistocene time.
A large fraction of the precipitation falling on karst areas moves directly into and through the groundwater system. This water carries with it nutrients critically needed for good plant growth. Rooting depths of most agricultural plants are only a few inches to at most a couple of feet; once plant nutrients move more deeply into the ground they are lost to the surrounding vegetation. In most non-karst areas surface run-off predominates over subsurface flow, thus affording opportunities for plant nutrients to be detained and reused by the vegetation. Nutrient impoverishment of karst soils is the norm.
Surface streams are valuable assets for rural people. While surface streams with perennial flow are common in humid lands, they are generally a denied resource for those of us who live in America's karstlands. My wife and I own over 400 acres of Taney County karstland, yet we have no stream which flows for more than a few days out of the year (except for the stream in our cave, and that stream is 170 feet below the surface). If we want surface water supplies we must construct them, thus explaining the farm ponds which speckle the Ozark karstlands. Yet ponds cost money, they often leak or may go dry in the summer, and unlike many surface streams they freeze during the winter. Ice chopping is a routine winter task if you raise livestock in the Ozarks.
Water supplies in karst areas come predominantly from groundwater because of the paucity of surface supplies. Most drinking water supplies in non-karst areas of rural America are also groundwater, yet there are distinct differences between the karst and non-karst wells. The typical rural American well in non-karst areas is probably 50 to 75 feet deep. The comparable figure for such wells in karst is probably 300 to 350 feet; depths of 700 feet or more are not uncommon in many areas.
The equipment needed to drill the shallow well is not nearly as expensive as that needed for drilling in karst areas; the cost of a new air rotary rig well suited to the Ozarks karstlands approaches a half million dollars. Wells are expensive investments in karstlands. Karstland poverty and expensive investments do not mesh; as a result, expediency in well construction routinely predominates over prudence and craftsmanship. Casing depths and grout seals are minimized. Drillers are usually selected by price, not by the quality of their work. Unsafe or inadequate wells which should be abandoned and sealed are retained in service.
Thousands of people in karst areas drink waters contaminated by sewage, animal wastes, landfill leachates, or spilled petroleum products. The problems are magnified by rapid groundwater travel rates in karst, and by commonly ineffective natural cleansing of the waters prior to their withdrawal from groundwater. In many cases, today's groundwater was yesterday's wastewater discharge; that is recycling at its worst. It is worth remembering that illness has economic consequences. Karst groundwater supplies can easily be contaminated by waste disposal activities. Much of the water which enters and moves through karst groundwater systems traverses networks of solutional openings rather than seeping and oozing through soil and rock. A network of flow conduits provides far less effective natural cleansing than is provided by a predominantly diffuse flow system. In karst areas the networks of flow conduits predominate in the groundwater systems. In most non-karst landscapes diffuse flow systems generally predominate.
It is obvious that far greater care is needed to protect karst groundwater quality than is the case
for most other types of groundwater supplies. Yet how many times have we heard the business or
community "leader" argue that because a karst area is poor and has high unemployment that
environmental restrictions should be eased to enhance employment? Once again, karstland
poverty imposes a course of action 180 degrees off course.
If you do not understand how something works, you are unlikely to be able to do a good job of using it. If a car has three pedals on the floor and you assume that the car will operate just fine regardless of which pedal you tromp upon, I submit that the folly of your ignorance and invalid assumptions will soon become apparent. Similarly, you must understand how the land works if you are to do a good job of using it. Unfortunately, follies of ignorance and invalid assumptions associated with karstlands do not appear as quickly (and with as much noise) as they do with cars. In fact, many who commit the follies never recognize them; the costs of the follies are often borne by those who were not involved in creating the problem.
The economic consequences of karst ignorance and associated invalid assumptions are enormous, wide spread, and often long-lasting. As an illustration, one industrial plant discharging to a losing stream rendered 60 square miles of groundwater unusable for most high quality purposes. The direct economic loss, plus the cost of developing replacement water supplies for the affected area, equaled about ten million dollars. That is one case; there are hundreds of others. While there are major economic losses associated with karst ignorance, the economic losses associated with missed opportunities may be of even greater magnitude.
We can do little to change the soils or water regimes of karst areas. We can, however, improve our understanding of interactions between man and karst. The better the interactions are understood the better our decisions in karst areas will be, and the better able we will be to utilize unique opportunities of karst areas. The understanding of the interactions must be broadly based; it cannot simply reside in the halls of academic institutions or the cubicles of professional technocrats. And understanding alone will not carry the day; our understanding must be effectively and routinely applied.
Demand creates supply. The gains we have made in tailoring land use to site conditions in karstlands have been the direct result of public demand for such tailoring. The demand which must be fostered is a strong and persistent demand for decisions and actions which insure good utilization of resources without impacts which offset benefits.
During the past 15 years there has been a tremendous increase in citizen group action, and in the effectiveness of this action. This action has been spawned by an emerging American land ethic and fed by a growing public disenchantment with the competence and commitment of state and federal environmental regulatory agencies. Public hearings, which once could be held in the meeting room of the town bank, now fill the high school gym to overflowing and attract the regional press. It has been ordinary people, looking out for their local natural resources, who have demanded good, thorough professional work to insure the maintenance of natural resources. From their actions have come many benefits, not the least of which is a broader public understanding of the nature of karstlands.
I think there is a yellow brick road which will loosen the bond between karst areas and areas of rural poverty. I think that road is paved with the bricks of better and broader public understanding of karst and karst resources, and with the bricks of citizen group action. The yellow brick road is under construction; some brick makers and brick layers are at work, but more are needed.
Tom Aley is Director of the Ozark Underground Laboratory at Protem, Missouri.
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