Base level in the context of "Messinian salinity crisis"

An endorheic basin (/ˌɛndoʊˈriː.ɪk/ EN-doh-REE-ik; also endoreic basin and endorreic basin) is a drainage basin that normally retains water and allows no outflow to other external bodies of water (such as rivers and oceans). Instead, the water drainage flows into permanent and seasonal lakes and swamps that equilibrate through evaporation. Endorheic basins are also called closed basins, terminal basins, and internal drainage systems.

Endorheic regions contrast with open lakes (exorheic regions), where surface waters eventually drain into the ocean. In general, water basins with subsurface outflows that lead to the ocean are not considered endorheic; but cryptorheic. Endorheic basins constitute local base levels, defining a limit of the erosion and deposition processes of nearby areas. Endorheic water bodies include the Caspian Sea, which is the world's largest inland body of water.

River incision is the narrow erosion caused by a river or stream that is far from its base level. River incision is common after tectonic uplift of the landscape. Incision by multiple rivers result in a dissected landscape, for example a dissected plateau. River incision is the natural process by which a river cuts downward into its bed, deepening the active channel. Though it is a natural process, it can be accelerated rapidly by human factors including land use changes such as timber harvest, mining, agriculture, and road and dam construction. The rate of incision is a function of basal shear-stress. Shear stress is increased by factors such as sediment in the water, which increase its density. Shear stress ${\displaystyle t}$ is proportional to water mass, gravity, and WSS:

where t is shear stress (N/m2), ρ is density of flowing water, g is gravity on Earth, D is average water depth, and WSS is Water Surface Slope. This is analogous to the basal shear stress commonly used in glaciology. Increases in slope, depth, or density of water increase the water's potential to cause erosion.

The geographic cycle, or cycle of erosion, is an idealized model that explains the development of relief in landscapes. The model starts with the erosion that follows uplift of land above a base level and ends, if conditions allow, in the formation of a peneplain. Landscapes that show evidence of more than one cycle of erosion are termed "polycyclical". The cycle of erosion and some of its associated concepts have, despite their popularity, been a subject of much criticism.