Surface Waters Flashcards
Uplift vs. Subsidence
Uplift: upward relative motion of a portion of the Earth’s surface
Subsidence: downward relative motion of a portion of the Earth’s surface
*Erosion vs. Sedimentation
Erosion: removal of material from Earth’s surface
Sedimentation: the deposition of rock fragments, soil, organic matter, or dissolved material that has been eroded, that is, has been transported by water, wind, ice, or gravity
Hydrologic Cycle
Involves the continuous circulation of water in the Earth-Atmosphere system
Laminar vs. Turbulent Flow
Laminar Flow: Shallow, slow moving streams
Turbulent Flow: Broad, deep, fast moving streams
Headward Erosion & Downcutting
Headward Erosion: Upstream erosion of channel
Downcutting: Channel deepening
Tributaries vs. Trunk Channel
Tributaries - a river or stream flowing into a larger river or lake
Trunk Channel - the largest channel of a fluvial-distributive system
Drainage Basin, Drainage Divide
Drainage Basins - Land areas that drain into a specific trunk stream
Also known as catchments or watersheds
Drainage Divide - are uplands that separate drainage basins
*Discharge
The volume of water passing through a cross section of the stream in a unit of time
A = h x w
Q = Ac x Va
Hjülstrom Diagram
A graph used by hydrologists and geologists to determine whether a river will erode, transport, or deposit sediment.
*Transportation
The processes by which the sediment is moved along.
*Deposition
The laying down of sediment carried by wind, flowing water, the sea or ice.
Fluvial
Sediments deposited by the flowing water of a stream
Floodplain
A generally flat area of land next to a river or stream
Levee
ridge of sediments deposited along banks of river
*Delta
a landform shaped like a triangle, created by the deposition of sediment that is carried by a river and enters slower-moving or stagnant water
Deposition & Subsidence
Land subsidence is a gradual settling or sudden sinking of the Earth’s surface due to removal or displacement of subsurface earth materials.
Base level (local & ultimate)
Lowest point to which a stream can flow
Braided stream
channel composed of many smaller (braided) channels
*Meandering stream
has a single channel that winds snakelike through its valley, so that the distance ‘as the stream flows’ is greater than ‘as the crow flies
Oxbow
Oxbow-shaped meanders have two sets of curves: one curving away from the straight path of the river and one curving back.
*Cut bank
The outside bank of a curve or meander in a water channel (stream), which is continually undergoing erosion
*Point bar
A depositional feature made of alluvium that accumulates on the inside bend of streams and rivers below the slip-off slope.
Flash flood
Typically caused by intense rainfall, or dam/levee failure
Seasonal flood
Typically caused by spring melt or long periods of heavy rain
