Concept
Valley
Related concepts (33)
Thalweg
In geography and fluvial geomorphology, a thalweg or talweg (ˈtɑːlvɛɡ) is the line of lowest elevation within a valley or watercourse. Under international law, a thalweg is taken to be the middle of the primary navigable channel of a waterway that defines the boundary line between entities such as states. Thalwegs can acquire special significance because disputed river borders are often deemed to run along the river's thalweg. The word thalweg is of 19th-century German origin.
Entrenched river
An entrenched river, or entrenched stream is a river or stream that flows in a narrow trench or valley cut into a plain or relatively level upland. Because of lateral erosion streams flowing over gentle slopes over a time develops meandering (snake like pattern) course. Meanders form where gradient is very gentle, for example in floodplain and delta. Meandering is the feature of the middle and final course of the river. But very deep and wide meanders can also be found cutting hard rocks.
Abrasion (geology)
Abrasion is a process of erosion which occurs when material being transported wears away at a surface over time. It is the process of friction caused by scuffing, scratching, wearing down, marring, and rubbing away of materials. The intensity of abrasion depends on the hardness, concentration, velocity and mass of the moving particles. Abrasion generally occurs in four ways: glaciation slowly grinds rocks picked up by ice against rock surfaces; solid objects transported in river channels make abrasive surface contact with the bed and walls; objects transported in waves breaking on coastlines; and by wind transporting sand or small stones against surface rocks.