Streams 2
Terms
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- No stream can erode...
- below sea level
- Examples of fresh water
-
-streams
-lakes
-ground water
-glaciers - Dry climate cycles of erosion
-
-dominated by sparse vegitation
-water is sparse
-erosion is parallel to cliff retreat
-rain = tremendous amount of erosions
-becomes wider - Humid climate cycles of erosion
-
-rain fall is plentiful
-vegitation is lush
-may create a peneplain (nearly level/flat) - discharge
- Volume of water in a stream or river moving past a specific point in a given interval of time
- hydraulic action
- The removal of loose particles by the power of moving water
- abrasion
- "Grinding away" process/ sand paper effect
- suspended load
- The smallest particles (silt and clay) carried by running water, which are kept suspended by fuild turbulence.
- bed load
- The part of a stream's sediment load, mostly sand and gravel, transported along its bed.
- alluvium
- A collective term for all detrital sediment transported and deposited by running water.
- braided stream
- A stream with mutiple dividing and rejoining channels.
- meandering streams
- A stream that has a single, sinuous channel with broadly looping curves.
- point bar
- The sediment body deposited on the gently sloping side of a meander loop.
- oxbow lakes
- A cutoff meander filled with water.
- cut bank
- Deeper side of the channel.
- floodplains
- Low-lying, flat area adjacent to a channel that is partly or completely water covered when a stream or river overflows its banks.
- delta
- A fan shaped deposit at the mouth of a stream.
- alluvial fan
- A cone shaped accumulation of mostly sand and gravel deposited where a stream flows from a mountain valley onto an adjacent lowland.
- drainage pattern
- The regional arrangement of channels in a drainage system.
- base level
- The level below which a stream or river cannot erode; sea level is ultimate base level.
- graded stream
- A stream that has an equilibrium profile in which a delicate balance exists among gradient, dischare, flow, velocity, channel characteristics, and sediment load so that niether significant deposition nor erosion takes place within its channel.
- valley
- A linear depression bounded by higher areas such as ridges or mountains.
- downcutting
- When a river or stream has more energy than it needs to transport sediment, excess energy is used to deepen its valley.
- lateral erosion
- Valley walls are undercut my stream action.
- stream piracy
- Breaching of a drainage divide and diversion of part of the drainage of another stream.
- stream terrace
- An erosional remnant of a floodplain that formed when a stream was flowing at a higher level.
- headward erosion
- Entering runoff at the upstream end of a valley cause the valley to become longer.
- incised meander
- A deep, meandering canyon cut into bedrock by a stream or river.
- superposed stream
- A stream that once flowed on a higher surface and eroded downward into resistant rocks while maintaining its course.
- Running water is...
- a major force in shaping of the earth's surface.
- A stream is...
- any flow of water confined between channels.
- drainage basin
- The area from which a stream transports water.
- Fluvial processed include:
-
-erosion
-transportation
-deposition - gradient
- Vertical drop of a stream bed over a given distance.
- Good examples of trellis drainage patterned stream systems can be found...
- in the Appalachian Valley and Ridge province.
- A stream's flow is measured by the amount of its...
- discharge.
- A stream flows from its source to its...
- mouth.
- solution
-
process of dissolving minerals by water.
(chemical process) - traction load
- > than sand particles / gravel
- saltation
-
-moves sand size particles
-move by jump
-rise about 3 ft than fall down - capacity
- amount (quantity) of sediment carried by a stream.
- Early stage capacity
-
-low capacity
-high competence
-capacity increases downstream - competence
-
capacity relates to size
-high velocity/steep gradient
-high competence = pushing large rocks - Late stage capacity
-
-high capacity
-low competence - As competence decreases...
- capacity increases.
- dissolved load
- The part of a stream's load consisting of ions in solution.
- sheet flow
- unconfined fluid/inefficient
- channel flow
- occurs in streams/sufficient
- drainage divide
- All the high group that seperates this basin from all other basins.
- at high/early stage RGQV
-
(R) High
(G) Highest
(Q) Lowest
(V) Fast - at middle stage RGQV
-
(R) Decreases
(G) Decreases
(Q) Increases
(V) Should decrease can increase - at low/late stage RGQ
-
(R) Lowest
(G) Lowest
(Q) Highest - high/early stage channel
-
-V shaped
-straight
-no flood planes
-narrow - middle stage channel
-
-broadens
-trough shaped
-flood planes
-starts to bend/meander - low/late stage channel
-
-very broad
-very sinuous
-broad flood planes - high/early stage erosion
-
-downward
-downcutting its channel
-creates unstable slope by mass wasting - low/late stage erosion
-
-less erosion
-more treposition
-dominated by deposition - high/early stage flow
-
-fast speed
-turbluent flow - low/late stage flow
-
-even more laminar
-slows down
-has greatest volume - top set beds
- sand
- foreset beds
- sand, silt
- bottom set beds
- mud, silt
- leeves
- poorly sorted sand deposits
- middle stage sediment
-
-mud fines
-graded bedding - Dendritic drainage pattern
- Irregular pattern of channels that branch like a tree.
- Rectangular drainage pattern
- Channels have a right angle bends developed along perpendicular sets of rock fractures or joints.
- Radial drainage pattern
- Channels radiate outward like spokes of a wheel from a high point.
- Centripetal drainage pattern
- Channels converge on the lowest point in a closed basin from which water cannot drain.
- Annular drainage pattern
- Long channels form a pattern of concentric circles connected by short radial channels.
- Trellis drainage pattern
- Pattern resembling a vine growing on a trellis.
- Deranged drainage pattern
- Channels flow randomly.