Building on karst

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For the past several years, karst has been a frequent topic of conversation in the hills and hollers of Northwest Arkansas, and, whether it’s been in regard to herbicide application on utility right-of-way easements, expansion of overhead power lines, concentrated animal feeding operations, or, more recently, wind power development, one thing is certain – its existence below the surface has been a contentious and passionately debated matter.

It is unfortunate that something so well researched and documented in scientific peer-review reports can still be downplayed, denied, and/or simply ignored, even when ground-truthing techniques provide evidence that flow connections are present.

Methods such as LIDAR, electrical- resistivity imaging, ground penetrating radar, surface-geophysical monitoring, and groundwater tracing using fluorescent dyes provide consistent and defensible evidence, which reveal complex hydrogeologic systems that appear to defy the law of gravity. They don’t defy this law, but it appears they do because of pressure built up if low-permeability layers overlay some of the karst conduits.

While conducting dye-tracing studies near the now shuttered hog facility in Newton County, Dr. John Van Brahana, Emeritus Professor, University of Arkansas, a hydrogeologist and karst researcher and his team discovered that during storms, water flowed upward out of the rocks, thus demonstrating that the process of water flow in karst landscapes is distinctly different from other rock types.

In addition to water flow, karst has unique features and characteristics that set it apart from other landscapes, such as caves, bat habitats, sinkholes, springs, streams that flow directly underground, conduits, fractures, voids, and cavities. It is a vital, dynamic, complex unpredictable integrated hydrogeologic system, with flow from surface streams to groundwater conduits back to the surface through springs.

Water flow in karst is life-giving and life sustaining and needs to be thoroughly studied and understood before undertaking major changes. For example, the rapid expansion in our Northwest Arkansas environment of limestone necessitates that we take a hard and deep look at what lies beneath the surface before giving the green light to major construction projects.

There is scant oversight with regard to the siting and construction of industrial facilities in limestone terrane and, unfortunately, in the absence of any meaningful regulations, neither are there any requirements or guidelines supportive of unbiased geotechnical assessments during the initial and pre-construction phases. Nor is there adequate public notice to alert and involve residents and landowners who live and can identify karst features in the adjacent area of proposed construction.

In a letter to the Arkansas Department of Environmental Quality in 2013, Dr. Brahana set forth a prescient message:

“As we have become aware, we all live downstream, and actions of a few that jeopardize the health of our environmental community and our neighbors are neither just, nor fair, nor legal… Let’s give our decisions the best science underpinnings, in a fair and open forum. We stand at a juncture where we can choose to step back and look at environmental questions fairly, as unemotionally as we can, using science and equality and respect for all stakeholders as our criteria, rather than special-interest concerns of the few. We can strive to minimize intimidation or obfuscation, or we can do nothing and simply ignore the problem, hoping it will go away.”

What lies beneath the surface is of such great importance to the stability and sustainability of the Natural State that it’s time we consider the long-term impacts of all big actions, and understand the system prior to paying a much higher price when we find we have damaged it.

Dane Schumacher

1 COMMENT

  1. Perfectly stated and so true. Next, we all need to be abreast of the fact that windmills cost more to build and maintain than they produce in revenue.

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