River incision

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.^[1] Shear stress ${\displaystyle t}$ is proportional to water mass, gravity, and WSS:

${\displaystyle t=\rho gD\sin {(WSS)}}$

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.^[2]