Chapter 16 Flashcards
A general term for sediment deposited by streams
Alluvium
A stream down cuts its bed at a pace equal to the rate of uplift
Antecedent stream
Small scale channel deposits where streams continually pick up sediment in one part of their channel and deposit it down stream
Bar
The lowest elevation to which a stream can erode its channel; level at which the mouth of a stream enters the ocean, a lake, or a trunk stream
Base level
Coarse material, including coarse sands, gravels, and even boulders typically move along the bed of a channel
Bed load
Form at the end of glaciers, where there is a large seasonal variation in discharge
Braided stream
The maximum load of solid particles a stream can transform per unit time
Capacity
The measure of a streams ability to transport particles based on size rather than quantity
Competence
the outside of a meander is a zone of active erosion; debris acquired by the stream at the ________ moves downstream where the coaster material is generally deposited as point bars
Cut bank
Form where sediment-charged streams enter the relatively still waters of a lake, an inland sea, or the ocean
Delta
Characterized by irregular branching of tributary streams that resemble the branching pattern of a deciduous tree
Dendritic pattern
The quantity of water in a stream that passes a given point in a period of time
Discharge
The portion of a streams load that is carried in solution
Dissolved load
A section of stream that leaves the main flow
Distributary
An imaginary line that separates the drainage of two streams, often found along a ridge
Divide
The land area that contributes water to a stream
Drainage basin
The overflow of a stream channel that occurs when discharge exceeds the channels capacity. The most common and destructive geologic hazard
Flood
The flat, low lying portion of a stream valley subject to periodic inundation
Floodplain
A stream that has the correct channel
Characteristics to maintain exactly the velocity required to transport the material supplied to it
Graded stream
The slope of a stream, generally expressed as the vertical drop over a fixed distance
Gradient
The extension upslope of the head of a valley due to erosion
Headward erosion
The unending circulation of Earths water supply. The cycle is powered by energy from the sun and is characterized by continuous exchanged of water among the oceans, atmosphere, and the continents
Hydrologic cycle
A meandering channel that flows in a steep, narrow valley. It forms when an area is uplifted or when the base level drops
Incised meander
They movement of surface water into rock or soil through cracks and pore spaces
Infiltration
The movement of water particles in straight line paths that are parallel to the channel. The water particles move downstream without mixing
Laminar flow
The level of a lake, resistant rock layer, or any other base level that stands above sea level
Local base level
A loophole bend in the course of a stream
Meander
The point downstream where a river empties into another stream or water body
Mouth
An elevated landform composed of alluvium that parallels some streams and acts to confine their waters, except during flood stage
Natural levee
A curved lake that is created when a stream cuts off a meander
Oxbow lake
A crescent shaped accumulation of sand and gravel deposited on the inside of a meander
Point bar
A system of streams running in all directions, away from central elevated structure, such as a volcano
Radial pattern
A drainage pattern characterized by numerous right angle bends that develop on jointed or fractured bedrock
Rectangular pattern
Tiny channels that develop as unconfined flow begins producing threads of current
Rills
Water that flows over land rather than infiltrating into the ground
Runoff
Transportation of sediment through a series of leaps or bounces
Saltation
Runoff moving in unconfined thin sheets
Sheet flow
Diversion of the drainage of one stream that results from the headscarf erosion of another stream
Stream piracy
A stream that cuts through a ridge lying across its path. The stream established its course on uniform layers at a higher level without regard to underlying structures and subsequently downcut
Superposed stream
A flat, bench like structure produced by a stream, which was left elevated as the stream cut downward
Terrace
A system of streams in which nearly parallel tributaries occupy valleys cut in folded strata
Trellis pattern
Erratic movement of water often characterized by swirling, whirlpool like eddies. Most streamflow is of this type.
Turbulent flow
Sea level; the lowest level to which stream erosion could lower the land
Ultimate base level
A pass through a ridge or mountain in which a stream flows
Water gap
Consists of coarse sediments that are deposited when mountain streams reach flat lowlands; where rapid streams emerge from a mountainous area onto a flatter surface, a distinctive cone-shaped accumulation of sediment forms
Alluvial fan
