Hydrologic Characterization of a Karst Spring in North-Central Arkansas

Nesbitt Spring, located in north-central Arkansas, lies within the Springfield Plateau section of the Ozark Plateaus physiographic province (Fenneman and Johnson, 1946) and is known to be an important habitat for the Hell Creek Cave crayfish (Cambarus zophonastes), a federally listed endangered species. Nesbitt Spring, a privately owned spring, is one of two known locations where the rare crayfish is found (Graening and others, 2006). The source, occurrence, local recharge, and age of the waters discharging from Nesbitt Spring were characterized to better understand threats to the endangered species ’ habitat. The hydrogeologic framework of the area includes karst terrain; hence, the cave is susceptible to contamination from surface sources within its local-recharge area. The predominant land use within the local recharge area of Nesbitt Spring is agricultural (poultry and cattle) and mixed forest. Nesbitt Spring discharges from the Ordovician-age Plattin Limestone but it receives recharge through the overlying Mississippian-age Boone Formation of the Springfield Plateau aquife