Towards a Karst Assessment Standard Practice

The assessment of karst conditions and putative karst geohazards prior to residential and commercial development is currently in its infancy, from a scientific aspect. Borrowing from the medical lexicon, most karst features at proposed building sites are dealt with using an approach wherein the “symptoms and conditions” are treated (e.g. sinkhole remediation), often only after site development activities have commenced. If karst hazards are suspected, roadways, foundations and specific at-risk areas may be investigated using various geophysical methods; however the results of these investigations require specialized knowledge to be interpreted and understood. Thus stakeholders without geological training may find the investigator’s results indecipherable, often leading to unnecessary and expensive supplemental studies, the need for which is entirely based on the non-technical stakeholder’s faith in the investigator’s judgment. In contrast, a recent trend among consulting firms is to attach cursory karst “assessments” to due diligence study reports, particularly Phase I Environmental Site Assessments. These combined assessments are often performed by individuals who are inexperienced in geology, often without any specific training in karst geology. Not unexpectedly, this can lead to numerous mistakes, errors, and oversights. More troubling, these studies often report a lack of karst risks at the site under study, a result that the stakeholders may initially embrace, but which later can result in substantial financial loss and/or significant threats to human health and the environment. To address these concerns, we propose a proactive, “preventative” standard practice for karst assessments. Ideally, this proactive approach will help to delineate potential karst hazards so that they can be avoided, managed, or corrected by remediation. Requirements for investigators, a proposed scope of services, fieldwork and data review checklist, and a template for a follow-up karst management plan are presented. It is our hope that if carried out and reported accurately, the proposed assessments should allow even a nontechnical stakeholder to make informed decisions regarding the relative risk of karst geohazards, the need for further studies, and potential corrective actions that site development may entail. Introduction and Background The study of karst features, in particular karst springs and groundwater stretches back into earliest written human history. One of the first formal descriptions of caves and their hydrography was written in 221 B.C.E. in China, and the solution process of carbonate rocks was described accurately by the Roman Philosopher Seneca (4 B.C.E. – 65 C.E.). Commentary by naturalists and philosophers on karst features and hydrology continued in both Europe and Asia through the subsequent centuries and entered into the era of systematic geomorphological investigation in the 19 century (LaMoreaux and LaMoreaux, 1998). Not surprisingly, in regions where much of the land surface was underlain by soluble bedrock and prone to the development of karst terrain, karst studies were advanced by the interests of regional politics (Zotl, 1974). One such area was central Europe, where the Austro-Hungarian Empire had acquired extensive tracts of karst lands. The need to ensure that water supplies were adequately developed and infrastructure was protected drove these studies forward, and arguably the Austrian studies could be considered the first examination of karst as a geohazard, in particular Cvijic’s 1893 monograph Das Karstphanomen. Nevertheless, the majority of interest in karst remained of a purely scientific nature, and there was little emphasis on assessing the environmental and economic impacts of human development in karst terrains until the latter half of the 20 Century (LaMoreaux, et al, 1975; Moser and Hyde, 1974; Rauch and Werner, 1974). An increased sense of environmental awareness, coupled with increasing residential and commercial development in karst terrains during the 1970s and 1980s led to increased interest in the characterization and mitigation of karst hazards and environmental impacts. The Center for Cave and Karst Studies at Western Kentucky University was one of the first