A subterranean river is an underground watercourse, often formed through the dissolution of soluble rocks, leading to the development of caves and karst landscapes. These rivers are significant in hydrogeology for understanding groundwater flow, aquifer systems, and the evolution of cave systems.
Reference: Ford, D. C., & Williams, P. W. (2007). “Karst Hydrogeology and Geomorphology.” John Wiley & Sons.