# Shared Flashcard Set

## Details

Exam 4 Geology
Streams (4-27)
37
Geology
04/28/2009

Term
 Streams
Definition
 -body of water flows downslope (on passageway) -transports detrital particles & dissolved substance (weather off rocks & landscape) -transports to ocean
Term
 Stream Components
Definition
 -channel -load=material -discharge=how fast the stream is flowing
Term
 Human uses of Streams
Definition
 -transportation -fertile soil=when it floods -Available water=freshwater
Term
 Drawbacks of Streams
Definition
 -floods -pollution
Term
 Geologic Agents (more)
Definition
 -hydrologic cycle -sediment transport
Term
 Cross-Sectional Shape
Definition
 -stream channels -measuring the streams    -volume of water moving through channel ↑ downstream -ratio of channel width to depth changes downstream
Term
 Long Profile
Definition
 -streams channel -determining long profile=is a line drawn along surface of a stream (from source to mouth) -curve that ↓ in gradient downstream
Term
 Long Profile irregularities
Definition
 not perfectly smooth curve bc gradients  produced by: -beds of resistant -landslides -lava flows -hydroelectric dams
Term
 Factors in Streamflow
Definition
 -gradient=(m/km) slope -stream-cross-sectional area=(A;m2) width & average depth -average velocity=(V;m/s) velocity -discharge=(Q;m3/s) how much water moving past certain point -load=(kg/m3) dissolve material being carried
Term
 Q=VxA
Definition
 relationship b/w  -discharge -velocity -channel shape
Term
 Changes Downstream
Definition
 from head to mouth -discharge  ↑ -stream cross-sectional area ↑ -velocity  ↑ -gradient ↓
Term
 Flood
Definition
 stream discharge becomes so great that it exceeds capacity of channel; causing stream to overflow its banks -hydrograph -during a flood=velocity ↑ as discharge ↑ resulting in stream carrying (greater load, larger particles)
Term
 Hydrograph
Definition
 graph that plots stream discharge with time
Term
 discharge
Definition
 quantity of water passing by a point on the steambank in a given interval of time
Term
 Recurrence Interval (flood prediction)
Definition
 -measure of how often a flood at given magnitude is likely to occur -flood having recurrence interval of 10 years "10- year flood"
Term
 Base Level
Definition
 -limiting level below which a stream cannot erode the land  -most streams is global sea level
Term
 Straight Channel
Definition
 -highest velocity segment found near surface in mid-channel
Term
 Meanders (common channel pattern)
Definition
 loop-like bend in a stream channel while meander upstream migrating more rapidly, intersect the slower moving meander (migrate down) -point bar -meanders cut off -oxbow lake (picture)
Term
 Point Bar
Definition
 arcuate deposit of sand or gravel along the inside of bend of meaner loop (picture)
Term
 Oxbow Lake
Definition
 cut off meander that is crescent shaped lake (picture)
Term
 Braided Channels (common channel patterns)
Definition
 channel system conisting of tangled networks of 2 or more smaller branching & reuniting channels, seperated by islands or bars (found near glaciers) -high discharge -lots of sediment -easily eroded banks
Term
Definition
Term
Definition
 course particles move along stream bed
Term
Definition
 fine particles suspended in water
Term
Definition
 streams carry dissolved substances
Term
 Placer Deposits
Definition
 deposit of heavy minerals concentrated mechanically -behind rock bars -in bedrock holes -below waterfalls -inside of meander bed (density-big part/orginal places of mountains)
Term
 Downstream Changes
Definition
 -sediment size decrease -in mountainous headwaters, rivers transport large boulders -stream reaches sea, bed load may consist of sediments no coarser than sand
Term
 Floodplain (stream deposits)
Definition
 flat area about level with top of the channel, lies on either side of channel
Term
 Terraces (stream deposits)
Definition
 erosional remnants of former floodplains, meaning change in baselevel
Term
 Delta
Definition
 location of significant sedimentatiton, where river meets the sea
Term
 Drainage Basin
Definition
 area of land, surronded by topographic divides, which all water is directed to single point
Term
 runoff
Definition
 portion of precitoptation that flows over the land surface
Term
Definition
 measure the vertical distance that a stream channel falls b.w two points a known distance apart along its course
Term
 overland flow
Definition
 water initally tends to move down slope in broad, thin sheets
Term
 streamflow
Definition
 overland flow begins to concentrate into well defined channels
Term
 laminar flow
Definition
 (eriosion of running water) waver very slow, water particles travel parrallel layers of motion
Term
 turbulent flow
Definition
 increasing velocity, the movement becomes more erratic and complex, rise of swirls and eddies
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