Threading the Needle: Designing and Implementing Roadway Improvements in South Central Texas in Areas with Potential Threatened and Endangered Species Karst Habitat

Throughout Central Texas burgeoning development and population growth in urban and semi-rural areas have led to increased demand for alternative traffic routes, as well as improvements of existing roadways. As growth occurs around urban and suburban centers, traffic alignment alternatives are increasingly planned for previously undisturbed areas dominated by karst zones with a high probability for presence of threatened and/or endangered karst invertebrate and endangered bird species habitat. In this area, routine geologic assessments conducted in association with roadway design have recently expanded methodologies to include the application of various geophysical techniques as field-screening tools to better determine possible extent of subsurface caverns and sinkholes. The potential for endangered species habitat, specifically the Bone Cave Harvestman (Texella reyesi), the Coffin Cave mold beetle (Batrosides texanus) and the Tooth Cave ground beetle (Rhadine persephone) have led to the need for early coordination with regulatory agencies and establishing creative techniques for evaluating construction-related impacts. These innovative approaches have proven key to the engineering design, approval and implementation of roadway improvements and the development of sound environmental plans to mitigate and protect natural resources while meeting the demands of construction schedules.