The lowest level to which a land surface can be reduced by the action of running water.
The lowest level to which land can be eroded, esp. by a river; sea level.
Base-level Sentence Examples
Excepting the embayment region, Missouri lies wholly within the Carolinian area of the Upper Austral life-zone; the There has been some controversy as to whether this condition is due to the elevation and corrosion of original flood-plain meanders after their development in a past base-level condition - which theory is probably correct - or to the natural, simultaneous lateral and vertical cut of an originally slightly sinuous stream, under such special conditions of stream declivity and horizontal bedstrata (conditions supposed by some to be peculiarly fulfilled in this region) as would be favourable to the requisite balance of bank cutting and channel incision.
This local tectonic signature often conceals the more regional tectonism and changes in base-level.
A land may thus be characterized by its position in the " geographical cycle," or cycle of erosion, as young, mature or old, the last term being reached when the base-level of erosion is attained, and the land, however varied its relief may have been in youth or maturity, is reduced to a nearly uniform surface or peneplain.
Each of the disturbances altered the attitude of the mass with respect to the general base-level of the ocean surface; each movement therefore introduced a new cycle of erosion, which was interrupted by a later movement and the beginning of a later cycle.