GEOL 1001 Chapter 16 - Chapter 16 Running Water 1 Rivers and Streams a Streams any flowing body of water irrespective of size flowing downhill in a

GEOL 1001 Chapter 16 - Chapter 16 Running Water 1 Rivers...

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Chapter 16: Running Water 1. Rivers and Streams a. Streams- any flowing body of water, irrespective of size, flowing downhill in a natural passageway b. River-major branches of a large stream system b.i. Most population centers are built along rivers because of water and transport b.ii. There are risks associated with this proximity c. Channel-natural passageway of a stream d. Load-detritus that a stream moves d.i. Worldwide streams carry d.i.1. 16 billion tons of clastic sediment/yr d.i.2. 2-4 billion tons of dissolved material d.ii. Note: much of load is associated with human interaction i.e. agriculture and accelerated erosion d.ii.1. Prehumen total loads are estimated to be about 9 billion tons/yr. e. Discharge-quantity of water passing point along a stream/unit time 2. How streams flow a. Motion of flowing fluids-depicted by STREAMLINES-lines of fluid motions a.i. Laminar flow-particles move parallel a.i.1. Streamlines do not cross a.i.2. Characteristic of slower moving water a.ii. Turbulent flow-particles move in complex patterns, crossing, mixing, etc. a.ii.1. Streamlines cross and interfere a.ii.2. Characteristic of fast moving flows a.ii.3. Most watercourses in Nature a.ii.3.a. E.g. eddies b. Type of flow depends on b.i. Physical properties of fluid b.i.1. E.g. viscosity, temperature b.i.2. Viscosity-resistance to flow b.i.3. high viscosity-laminar flow b.ii. A stream may have both types of flow- turbulent flow is typically in the center of a channel, and laminar flow along the edges of a channel b.iii. Average velocity of flow (m/sec) as velocity b.iii.1. increases get turbulent b.iii.2. Decreases gets laminar b.iv. Geometry of flow b.iv.1. Deep v. shallow b.iv.2. Channel cross-sectional area (m^2) b.v. As depth increase flow is generally turbulent, as depth decreases flow is generally laminar 3. Stream load and sediment movement a. Stream load carried as 1. Solid portion
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a.i. Suspended load=particles suspended in the water column, more commonly due to turbulent flow a.ii. Bed load=particles moving along stream bottom by rolling, sliding, and bouncing (saltation) a.iii. Competence-ability of a flow to carry materials of a given sixe a.iii.1. Faster current, larger particles can be carried a.iii.2. Increase velocity, increased load a.iv. Capacity-total sediment load carried by flow e.g. larger flow volume
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  • Spring '07
  • BAKSI
  • Geology, Mississippi River, stream, Mississippi, Sediment, stream¬†load, Stream piracy-when stream

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