Downcutting, also called erosional downcutting, downward erosion or vertical erosion is a geological process by hydraulic action that deepens the channel of a stream or valley by removing material from the stream’s bed or the valley’s floor . ... The steeper the gradient, the faster the stream flows.
What causes a river to Downcut?
Causes. As observed above, an entrenched river can be caused by either tectonic uplift in the area or when the lowering of the sea level occurs. It can also be caused by increased level of downcutting or a collapse of moraine-dammed lake downstream, or capture of the river by another river.
Which factors increase the amount of Downcutting?
Which factors increase the amount of Downcutting? Whether a river erodes its channel or deposits sediment depends primarily on three factors: base level, the amount of water passing a certain point in the river (its discharge), and the amount of sediment supplied to the river .
What factors control a stream’s velocity?
The velocity of a river is determined by many factors, including the shape of its channel, the gradient of the slope that the river moves along , the volume of water that the river carries and the amount of friction caused by rough edges within the riverbed.
Which two factors will increase the rate of a streams flow quizlet?
Which two factors will increase the rate of a streams flow? increased precipitation and increased slope .
How do streams become graded?
The factors that make a river larger and the factors that make it smaller balance out . This is when it becomes a graded stream. ... Well, the faster, thinner and steeper parts of the stream erode a lot of material. But the slower, wider, and shallower parts of the stream deposit more material than they erode.
Where is lateral erosion the greatest?
A meander is a bend in a river. On the outside of the bend the river is fastest flowing and therefore erosion is greatest. This creates a deep area of water and a river cliff. On the inside of the bend water is forced to slow down, which reduces its energy, making it deposit its material.
What factor affects the rate of Downcutting in a river?
The speed of downcutting depends on the stream’s base level, the lowest point to which the stream can erode . Sea level is the ultimate base level, but many streams have a higher “temporary” base level because they empty into another body of water that is above sea level or encounter bedrock that resists erosion.
What are the three main zones of a river system from highest to lowest?
Three zones are usually recognized – headwaters , where flow is usually lowest of any where along the system, slope is often steepest, and erosion is greater than sediment deposition; transfer zone, the middle range of the stream where slope usually flattens somewhat, more flow appears, and deposition and erosion are ...
What factor causes a river to be braided?
Braided streams typically get their start when a central sediment bar begins to form in a channel due to reduced streamflow or an increase in sediment load . The central bar causes water to flow into the two smaller cross sections on either side. The smaller cross section results in a higher velocity flow.
What factors control a stream’s velocity quizlet?
Factors that influence a stream’s velocity include gradient, channel shape, and channel roughness .
What stream type has the highest velocity?
Stream Processes. Stream velocity is the speed of the water in the stream. Units are distance per time (e.g., meters per second or feet per second). Stream velocity is greatest in midstream near the surface and is slowest along the stream bed and banks due to friction.
What factors affect stream flow?
- Runoff from rainfall and snowmelt.
- Evaporation from soil and surface-water bodies.
- Transpiration by vegetation.
- Ground-water discharge from aquifers.
- Ground-water recharge from surface-water bodies.
- Sedimentation of lakes and wetlands.
Which two factors will increase the rate of streams flow?
Human factors include run-off from farm fields and parking lots and water releases from dams that increase the amount of water flowing in streams. Removal of trees and shrubs from stream banks and deadfall from within the stream makes them more susceptible to erosion and increases stream flow.
Which two factors will increase the rate of a streams flow earth science?
decreased precipitation and decreased slope 1 .
What is it called when two streams join together the smaller one?
Stream Order
It is common for one stream to flow into another. The smaller of the two streams is a tributary of the larger stream. A stream with no tributaries is a first order stream. A stream with only first-order tributaries is a second order stream.
