A paleochannel is an ancient, inactive river or stream channel that has been filled or buried by younger sediments. These channels are important for reconstructing past drainage patterns, sedimentary environments, and the history of fluvial systems, as well as for locating potential reservoirs of groundwater or hydrocarbons.
Reference: Bridge, J. S. (2003). “Rivers and Floodplains: Forms, Processes, and Sedimentary Record.” Blackwell Science.