Binnenströme

Binnenströme are streams that flow entirely within the interior of a landmass and do not empty into the sea. The term, used in German-language hydrology and geography, describes watercourses whose drainage basins are closed or end in inland features such as lakes, salt flats, or playas rather than oceans. They are characteristic of endorheic regions and arid to semi-arid climates, where the balance of inflows and evaporation prevents an open outlet.

Geographically, Binnenströme occur in closed drainage basins and along basins with internal drainage systems. Their discharge is often variable and typically lower than that of external rivers, with episodic flow during rare rain events. Evaporation concentrates salts at the termini, leading to salt pans or saline lakebeds. Sediment transport is frequently gradient- and climate-controlled, yielding braided or meandering channels that may shift position over time.

The existence of a closed outlet is controlled by basin geometry, tectonics, and climate. Human activities such as irrigation, groundwater pumping, and damming can reduce inflows or alter drainage, increasing salinity, or transforming perennial reaches into ephemeral streams.

Binnenströme support specialized wetland habitats and adapted flora and fauna but are particularly sensitive to water withdrawal and land-use change. They serve as indicators of regional hydrology and climate variability and influence the chemical and physical characteristics of inland basins.

See also endorheic basin, playa, evaporite, inland delta.