Tennessee’s superconducting super collider proposal: A proposed large scalesurface/subsurface construction project located in a karst environment

The Tennessee proposed Superconducting Super Collider Site was located in a regionally stable geologic environment with a shallow karst terrain. It was in close proximity to Snail Shell Cave, the largest and most intricate cave system in Middle Tennessee. Placement of the Collider Ring, Booster systems and construction of the Campus/Injector Complex, if not designed correctly, could have severely impacted the karst environment. Regional investigations were conducted to determine the general depth to water around the SSC Site. Most of the water occurs within 61 meters (200 feet) of the surface where solution cavities are developed. The Collider Ring was placed below this at 107 meters (350 feet) MSL to avoid the shallow groundwater system. An extensive hydrologic investigation was carried out to study the impacts on the shallow karst from construction and operation of the Campus/Injector Complex. The investigation included a karst hydrologic inventory, construction of a potentiometric map of the upper karst aquifer and seventeen dye tracer investigations. Two main subsurface flow routes were identified in the upper part of the drainage basin. These cave streams merge downstream to form the subsurface/surface Overall Creek. A spill or leak of hazardous materials on the site could contaminate the groundwater for as much as 15.5 kilometers (9.7 miles). A groundwater monitoring and emergency containment system was recommended. It included continuous monitoring instrumentation located in the cave stream under the Campus Complex. Groundwater contaminated by a spill would be detected and immediately pumped into a retention basin located on the surface for treatment before being released back into the groundwater system.