Database Development and GIS Modeling to Develop a Karst Vulnerability Rating for I-66, Somerset to London, KY

This study evaluated potential interstate alignments traversing Kentucky's Eastern Pennyroyal karst region in Pulaski and Laurel Counties. Data collected during the karst inventory and field assessment was used to evaluate the potential for karst development and determine a karst vulnerability rating for the resident karst ecosystem. The inventory and assessment consisted of three main components: karst terrain features; karst hydrology; and karst (cave) fauna. This paper principally reports on the components and structure of the karst feature database and the use of GIS to develop a vulnerability rating for karst areas within the study bands. The study was conducted in three phases; literature search, field reconnaissance, and vulnerability assessment. The field reconnaissance covered over 25 miles along three 1,000-foot wide bands. Over 1,100 karst features were located by Global Positioning System (GPS), classified, described, and photographed. Sixty-three caves were visited with 114 taxa found as part of the cave fauna studies. Of the cave sites sampled, 29 were inhabited by globally rare species. Both the physical and biological field data gathered as part of the field studies was entered into the database before being incorporated into a 4-step GIS model. The karst feature database, GIS model, and vulnerability rating were adapted based on Karst Inventory Standards and Vulnerability Assessment Procedures for British Columbia (Ministry of Forestry; 2003). The vulnerability potential was based on a qualitative evaluation of the following attributes: epikarst development; surface karst feature density; subsurface karst potential; surficial material character; and bedrock type and proportion. The presence of unique fauna or habitat was used to increase the potential vulnerability rating. The assessment delineated and graphically depicted areas of low, moderate, high, and very high karst vulnerability. The study results will be used to present karst impacts in the Environmental Impact Statement for the project.