Base level

The base level is the elevation level to which the erosion of a stream is effective. No river can erode deeper than the height of its mouth. This is the sea level in the rule. Above the base level of erosion tried the flow through headward erosion an ideal gradient curve to produce a smooth curve in the longitudinal profile between source and mouth.

The absolute base level for a river network is the sea level in the rule. For tributaries in the receiving water, the height of the junction forms a local base level of erosion. In addition, local erosion bases can occur, such as swelling in the river bed or a river flowing through it from the lake, so places where a discharge - in passes a Aufschüttungsstrecke. The balance of the gradient curve is then in sections one on the elevation of the local base level of erosion. For the endorheischen rivers in drylands represent the endorheic basin, the erosion base dar. So is the base level of erosion of the Jordan River, the Dead Sea, about 420 m below sea level.

Changes the base level, the steady state - whether or not obtained by the flow - disturbed and it follows an adaptation of the erosion and the accumulation behavior. If the base, for example by lowering of sea level or by eliminating a previous threshold decreases, the flow proceeds to enhanced depth erosion and cuts into the previously heaped sediments. Increases the other hand by a sea level rise or emergence of a new barrier, the base level of erosion, the river accumulates until it reaches its balanced gradient again. Changes in the base level of erosion are often associated with tectonic activity.