Water 2Ww3 Lecture 3

Front 1

What is throughflow?

Back 1

Water travelling through the ground, on top of the saturated soil

Front 2

What is the drainage basin or watershed?

Back 2

The total area drained by a river or stream

Front 3

What is the Source?

Back 3

The upper reaches of the drainage basin

Front 4

What is the mouth?

Back 4

The area where the stream joins another water body at the bottom of the drainage basin

Front 5

How is Streamflow measured?

Back 5

Discharge: the volume of water flowing past a point in a unit of time

m^3 / second

Measured using velocity and cross sectional area

Front 6

Where should discharge velocity be measured?

Back 6

At approx. 40% depth, where maximum velocity occurs

Front 7

On a hydrograph:

1) What is Peak Flow?

2) What is the Falling Limb?

3) What is the Rising Limb?

4) What is the Lag time?

5) What is the little bump after the rainfall?

6) What is the larger bump later?

7) How does urbanization change this?

Back 7

1) The highest point of discharge

2) The decrease in discharge after peak flow

3) The increase in discharge leading up to the peak flow

4) The amount of time between the rainfall and peak flow

5) The water falling directly on the river itself and nearby soil saturating

6) Water coming from the drainage basin

7) The second peak would occur faster, and both peaks would be higher

Front 8

What is a flood plain?

How is a flood plain built up?

Back 8

Flat portion of a river valley adjactent to a channel, gets covered up by water during a flood.

Built up by deposition of sediments from river

Front 9

What is a thalweg?

What does a thalweg indicate?

Back 9

Line that connects the deepest portions of the stream.

Indicates line of maximum velocity

Front 10

What are pools and riffles?

Back 10

Deeper sections (pools) and shallow grained deposits (riffles)

Front 11

What is typically the distance between pools?

Back 11

5-7x the width of the stream itself.

Front 12

What are the 4 stream patterns?

Back 12

1) Parallel

2) Trellised

3) Dendritic

4) Deranged

Front 13

What is the most common stream pattern? Where do they occur?

Back 13

Dendritic, occur where local geography controls them to. Randomly slope around everything.

Front 14

Where do Parallel streams occur?

Back 14

Areas of steep slope

Front 15

Where do Trellsed streams occur?

Back 15

Areas with strong regional structural control i.e. Appallachians

Front 16

Where do deranged streams occur?

Back 16

Areas of highly irregular topography, where lakes can form

Front 17

What is a meander?

Back 17

Series of curves or loops in the main course of the stream

Front 18

What is the measure of how curvy a stream is?

How is it calculated?

What are the two categories, and what values correspond to them?

Back 18

Sinuosity Ratio = actual length / straight line length

SR < 1.5 = straight channel

SR > 1.5 = meandering channel

Front 19

What is the most common channel pattern in Southern Ontario?

Back 19

Meandering Channel

Front 20

What conditions are predisposed to creating a meandering channel?

Back 20

Where unconsolidated sediment is present; easily erodable material.

Front 21

What is a point bar and a cut bank?

Back 21

Point Bar - Deposition on the inside of the channel

Cut Bank - erosion on the outside of the bend

Front 22

How quickly do meandering channels migrate across floodplains?

Back 22

Up to 10 m / year

Front 23

How does grain size change up a point bar? What is this called?

Back 23

Diminished up a point bar.

"Fining Upwards"

Front 24

Why does erosion occur on the outer side of the meander and deposition on the inner side?

What is this type of flow called?

Back 24

Corkscrew flow, because the of the speed difference between the point bar and the cut bank.

"Helicoidal Flow"

Front 25

What type of feature does Helicoidal flow produce over time?

Back 25

Oxbow Lake

Front 26

What is a braided channel?

Back 26

When you have large channels that split apart and rejoin.

Front 27

What seperates braided channels?

Back 27

Deposition inbetween called Braid Bars

Front 28

What are 3 characteristics of Braided Channel Systems?

Back 28

1) Large fluctuations in discharge

2) Large amounts of bedload - lots of course material

3) Easily erodable banks

Front 29

Where are braided channels often found? Give 2 specific examples.

Back 29

Areas of high relief.

1) Glacial Meltwater Systems

2) Mountainous Terrain

Front 30

Are you able to map braided channels? Why or why not.

Back 30

No, because they change everyday.

Front 31

Describe Anastomosing channels in terms of:

1) # of channels

2) Stability

3) Areas they form

4) Slow-moving

Back 31

1) Multi-channel systems

2) Stable

3) Floodplains with stable banks and sediment gain

4) Slow-moving

Front 32

What are the 3 common channel types?

Back 32

1) Meandering

2) Braided

3) Anastomosing

Front 33

What are the 4 different kinds of deposits within a floodplain?

Back 33

1) Colluvium - material slumping into the valley from the sides (not been moved by water)

2) Channel Fill Deposits - material deposited in the stream by itself (gravel, silt, sand)

3) Channel Lag - material deposited within that can't be moved

4) Splay - material deposited when a break occurs in a levee

Front 34

What are meander scrolls?

Back 34

Alternating ridges and troughs on a floodplain, caused by point bar migration

Front 35

What are vertical accretion deposits?

Back 35

1) Deposits that sit on top of lateral accretion deposits

2) Made up of finer materials

3) Deposited as a flood recedes

i.e. Levee

Front 36

What is Laminar Flow? What Reynolds number corresponds to it?

Back 36

Calm, linear flow, w/out mixing

Re < 500

Front 37

What is turbulent flow? What Reynolds number corresponds to it?

Back 37

Water flowing in a nonlinear fashion with variable velocity

Re > 2000

Front 38

What is the formula for the Reynolds number?

Back 38

Re = VRp/u

V - velocity (m/s)

R - hydraulic radius (m)

p - density of water (1000 kg/m^3)

u - molecular viscosity of water (1)

Front 39

How do you find the hydraulic radius of water?

Back 39

R = A / P

A - cross sectional area

P - Wetted Perimeter

Front 40

What happened in Horse Cave City Kentucky?

Back 40

Town built around a base of a cave, where drinking water was taken from. CHrome Plant was built, and began dumping waste into local sinkhole. However, because they were connected, it polluted the drinking water and people got sick.

Closed 40 years b/c of pollution

Front 41

What latin word does Pollution come from? What does it mean?

Back 41

Pollutus - to soil or defile

Front 42

When is water considered polluted?

Back 42

If unusable for a purpose

Front 43

What are the 4 classes of pollution, and what do they correspond to?

Back 43

1) Class AA and A - good enough to drink from

2) Class B - good enough to swim in

3) Class C - boating, fishing, fish propogation

4) Class D - fishing

Front 44

What percentage of lakes are considered polluted by the EPA in 2010?

When was the peak level of increase? To what extent? What was it caused by?

Back 44

40%

1995-1999, 26% increase, caused by industrial

Front 45

Describe the Clean Water Act Ammendment in terms of:

1) Year of origin

2) Requirements for cities

3) Effect of act

Back 45

1) 1972

2) Cities required to have water treatment plant

3) Only 1/3 of lakes acceptable for fishing/swimming, now up to 2/3

Front 46

Who is stricter about Water Pollution; Canada or US?

Back 46

US

In Canada we can drill for natural gases in the Great Lakes, in US they cannot.

Front 47

What is Point Source Pollution?

Back 47

Pollution discharged through a discrete identifiable location.

Easy to evaluate and easy to fix.

Front 48

What is Nonpoint Source Pollution? What are two examples?

Back 48

Pollution from broad, diffuse sources.

Hard to identify and quantify, and fix.

I.e. Road Salt, Pesticide.