Patapsco River Bloede's Dam leaves Daniels Dam, upstream, as the last remaining dam along the mainstem Patapsco River. Removal of Bloede's Dam in September, 2018 opened up of the Patapsco River watershed which will potentially restore spawning runs of at least six species of native anadromous fish: alewife ("Alosa pseudoharengus"), blueback herring ("Alosa aestivalis"), American shad ("Alosa sapidissima"), hickory shad ("Alosa mediocris"), striped bass ("Morone saxatilis"), sea lamprey ("Petromyzon marinus"), as only one species, sea lamprey, were found using the Bloede's Dam fish ladder in 2012. One catadromous species would likely also benefit, the American eel ("Anguilla rostrata"), a fish species which
Subterranean river Subterranean river A subterranean river is a river that runs wholly or partly beneath the ground surface – one where the riverbed does not represent the surface of the Earth (rivers flowing in gorges are not classed as subterranean). It should also not be confused with an aquifer which may flow like a river but is contained within a permeable layer of rock or other unconsolidated materials. Subterranean rivers may be entirely natural, flowing through cave systems. In karst topography, rivers may disappear through sinkholes, continuing underground. In some cases, they may emerge into daylight further downstream. Some fish (popularly