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J. Steven KiteGeology & Geography

West Virginia University!

Ice Mountain Talus Slope:

A Unique Low-ElevationPaleo-Refugium for Boreal

Plants in the Central Appalachians

WVU Geology ColloquiumWednesday 15 Feb 20064:00 p.m. in 105 White

Fluvial Geomorphology1. Drainage Basins

Kite Stream, Victoria Valley, Antacrtica

Physiography of US & Canada

• Hunt, C. B. 1974. Natural regions of the United States and Canada. San Francisco: W. H. Freeman and Co. 725 p.

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Classification Based on Frequency of Flow

• Perennial• Intermittent• Ephemeral

Scale of Map Influences Stream Networkby Determining the Contour Crenulations That Appear

Not shown or

HORTON-STRAHLER SYSTEM OF STREAM ORDERS

• First - Stream with no tributaries, smallest drainage we can recognize

• Second - Confluence of two First order stream

• Third, 4th, 5th, etc.• Mississippi River: ~ 12th Order

What Constitutes a stream?NOT BLUE LINES ON MAP!

2 or 3 Contour Crenulations in Succession.

This is 3rd Order

Stream!

1st Order Stream?

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4th Order Drainage Basin

Drainage Divide

"Laws of" drainage composition: see p. 151 in

Ritter & others, 2002

Law of stream length:

L = 1.4 Ad0.6

(not 0.5 power)

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D = Sum of Stream Lengths / Drainage Area

Law of Drainage Density:

Bifurcation Ratio:Rb = Nu / Nu+1

Bifurcation Ratio Rb = N1/N2 = 3.6Rb = N2/N3 = 2.5

Drainage Divide

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How Many First Order Streams in Mississippi River Basin?

Assume Mississippi River =12th order, Rb = 4.0

Use this Equation:

Nu (trib) = Rb(Os (basin) - Ou (trib) )

Order Computation Number12 40 111 41 410 42 169 43 648 44 2567 45 10246 46 40965 47 163844 48 655363 49 2621442 410 10485761 411 4194304

Σ = A LOT

Precipitation (Rain or Snowmelt)

Infiltration Overland Flow (Sheetflow)(Recharge) “Zone of No Erosion”

(Raindrop Impact)

Ground- Bursting of Obstacle DamsWaterFlow Rills- Ephemeral Channels

Spring Discharge Gullies - Permanent

Streams

2 Likely Routes for Precipitation

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Stan Schumm, 1977The Fluvial System

Zone 1

Zone 2

Zone 3

Sediment Production

Sediment Transport

Sediment Deposition

Photo Source: Frederick Harrison Edmunds, “The Canadian Landscape,” U. of Saskatchewan Archives

Zone 1

Zone 2

Zone 3

Revised Universal Soil Loss Equation Bloom, 2004, p. 201-202

Dunne & Leopold, p. 521-531Handout Shows Nomograms

Developed for Calculating Soil Loss in Agricultural Areas

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A = RKLSCPA = soil lossR = rainfall erosivity indexK = soil erodibility indexL = hillslope length factorS = hillslope gradient factorC = Crop-management factorP = erosion control practice factor

Average Annual Rainfall Factor (R)

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w.a

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stat

e.ed

u/A

ST32

4/Le

sson

5USL

E.pp

t

USLEFactor

Range “Typical”

R = rainfall erosivity index15 to >350 150 in Morgantown

K = soil erodibility index0.1 to 0.5 0.3 is typical

L = hillslope length factorS = hillslope gradient factor

0.1 to 20 500', 20% slope: LS = 6

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LS Factor Nomogram

ww

w.a

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stat

e.ed

u/A

ST32

4/Le

sson

5USL

E.pp

t

Example: LS of 200 ft long slope with 10%

slope angle = 2.0

FactorRange “Typical”

USLE

C = Crop-Management Factor 0.001 to 0.45 100% canopy to bare ground

P = Erosion Control Practice Factor0.1 to 1.0 terraced 2-7% slopes to none

Factor Range Importance

R 15 to >350 Style of Precip. Varies

K 0.1 to 0.5 Texture: little change

LS 0.1 to 20 LS: little change

C 0.001 to 0.45 Vegetation Change

P 0.1 to 1.0 N/A before Humans

Implications for Climate Change

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Sediment Yield (= Sediment Load)

Total Amount of Sediment Transported

Out of Basin by Streams

How Determined?

Sed Yield X 100Soil Loss

SDR not = 100% !

Why?

Sediment Delivery Ratio:

Production of Sediments in Zone 1:Slope ProcessesRill & Gully Erosion, Sheetwash

Downstream from Zone 1Decrease in Slope Processes, etc.Increase in Bank Erosion Decrease in New Sediment Production

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Zone 2:

"The Transport Zone"

Dominated by Channel Processes

Fundamentals of Stream Flow

Discharge (Q) = volume / time

Q = A V (area x velocity)

Stage: Height of

Water Surface

Typical Older-Style USGS

Stream GageStilling

Basin

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Flow Meter

Colorado River Rating Curve: Q vs. Stage

UT-CO State Line

Real-Time USGS Data

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HydrographRainfall

Discharge

“Base Flow”New

“Base Flow”

Crest

Ris

ing

Lim

b

Falling Limb

0 cfs

Cheat River at Hwy 50, Near Rowlesburg, WVStage Station Number 03069870

Drainage Area: 911mi2 Datum: 1405 ft a.s.l.http://www-wv.er.usgs.gov/rt-cgi/gen_stn_pg?station=03069500

Cheat River at Hwy 50, Near Rowlesburg, WVDischarge Station Number 03069870

Drainage Area: 911mi2 Datum: 1405 ft a.s.l.http://www-wv.er.usgs.gov/rt-cgi/gen_stn_pg?station=03069500

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Velocity profiles, w/ isovels)

Shallow channel

Deep channel

Max Velocity

Max Velocity

Empirical Stream-Flow Velocity Equations

Chezy Equation *** save for GEOL 427 ***

V = c (R S)0.5

c = factor varies w/ channel slope,bed roughness

R = hydraulic radius (≅ mean depth)= A/P (x-sect. area / wetted perim.)

S = slope

Manning Equation *** know equation ***

V = (R0.667 S0.5) / nmetric units

V = 1.49 (R0.667 S0.5) / n"American" units

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Manning Equation V = (R0.667 S0.5) / n metric

n = Manning coefficient of roughness

0.015 on large, smooth channel0.150 on bouldery mountain stream

R = hydraulic radius (nearly = mean depth)= A/P (x-sect. area / wetted perim.)

S = slope

Flow Regimes: Laminar Flow

• No Mixing Between Layers

Laminar-Turbulent Threshold Defined by Reynolds Equation:

NR = Re = dimensionless Reynold's number

Re = ρ v R / μ

ρ = [Rho] = densityμ = [Mu] = viscosity

Re between 500 and 2500, marks transition from laminar to turbulent flow

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Flow Regimes: Turbulent Flow

• Mixing Between Layers

Turbulent flowFroude number = F = V / (g D)0.5

a. subcritical flow (F < 1) tranquil flow, streaming flow, lower flow regime (flat water)

b. supercritical flow (F > 1)jet flow, rapid flow, shooting flow, upper flow regime (white water)

Turbulent Flow

• Tranquil = Subcritical Flow

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Debris FanRapids

http:// ww

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Copyr ight 2001 iPlayO

utside, Inc.

Rapids

SubcriticalFlow

SubcriticalFlow

SupercriticalSupercriticalFlowFlow

Upper Railroad Rapids, NRG: SubcritcialFlow Transforms into Supercritcal Flow

WVU GEOL 621 Field Trip Supercritical Flow, Gauley River, West Virginia

I Swam!

I Swam!

I Swam!

I Didn’t, So the Guide Got an A!

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Wave Train - NRG

TYPES OF TURBULENCE:

Type 1: surge phenomena -- - -- - -->

Type 2: water rollersbank rollersbottom rollers

Type 3: eddies (local vortex, tornado-like)

Type 4: helical flow (like parallel coiled springs) may lead to meanders in streams.

Where Is Maximum Turbulence in a Stream?

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Maximum Turbulence

..

. .

.

Erosionwith SlightDownward Component

Maximum Turbulence

.

Erosionwith SlightDownward Component

Deposition = Accretion

Lateral “Accretion”

Cut-BankErosion

Point-Bar Accretion

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λ = MeanderWavelength

P = Sinuosity = River Distance / Straight-Line Distance

Meander Development

Maximum Erosion Occurs Downstream from Outside Bend:

Thus, Meanders “Grow” & Migrate

Downstream with Time

Cut-BankErosion

Point-Bar Accretion

Cut-BankErosion

Point-Bar Accretion

Flow

Meander Development

Maximum Erosion Occurs Downstream from Outside Bend:

Thus, Meanders “Grow” & Migrate Downstream with Time

Constriction

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Meander Development

Meander Development

Meander Development

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Meander DevelopmentNote “Kinks”

w/in Meanders

Meander Neck

Ox-BowLake

Cut-Off Meander

Meandering Stream, Sinuosity >3

Abandoned Meanders

Ox-Bow Lakes

http://www.geosurv.gov.nf.ca/education/features/geomorph.html

Photo: Geolgical Survey ofNewfoundland & Labrador

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Meander-Scroll Topography Showing Downstram Migration

Oxbow Lakes

Point Bar

Neck

Cut Off

Meanders and Oxbow Lakes

Hide This slide!

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Stream Entrainment, Erosion, Transportation

& Deposition

Erosion in a Fluvial Landscape

Corrosion Chemical ErosionCorrasion Mechanical WeatheringCavitation Pressure Decrease in Constriction

Increasing Velocity - Air Bubbles Decreasing Velocity - Bubbles Collapse:

Shock Waves, Rapids, Waterfalls

Hjulstrum's Diagram, (Ritter & others, 2002, p. 197, Fig. 6-7 )

Deposition

Entrainment

Transportation

Clay Silt Sand Gravel

Mea

n Ve

loci

ty

UnconsolidatedClay

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Transportation

Total Sediment Load =Dissolved Load +

Suspended Load +Bed (Tractive) Load +

Floatation Load