PEO 3 - Running Water

Question 1

Define river/stream/creek.

Answer 1

Water flowing in a channel.

Question 2

The flood of the channel is called what?

Answer 2

The bed.

Question 3

When rainfall is very heavy, or snow melts rapidly, streams overflow their channels and natural levees, and water covers the adjacent land called _____?

Answer 3

The floodplain.

Question 4

Rivers _____ runoff water to lakes and oceans, _____ land, and ______ and deposits sediment.

Answer 4

Carry, erode, transports.

Question 5

The water in streams may move as _____ or _____ flow.

Answer 5

Laminar; turbulent.

Question 6

What kind of flow is a planar flow, moves more sheet-like, low-velocity, and is usually confined to the edges/top of a stream where the velocity is very low.

Answer 6

Laminar flow.

Question 7

What kind of flow is a chaotic flow, has an irregular swirling flow, occurs at most rates of stream flow, keeps particles in suspension, and moves sediment in this condition?

Answer 7

Turbulent flow.

Question 8

What are the three ways that streams move material?

Answer 8

Dissolved load, suspended load, and bed load (traction and saltation).

Question 9

Describe dissolved load.

Answer 9

The ions released by weathering/ions delivered by the chemical weathering of rock.
Could be clear water but still carrying a dissolved load.

Question 10

Describe suspended load.

Answer 10

Particles moving in the water.
Think of water filled with clay.

Question 11

Describe bed load (traction and saltation).

Answer 11

Particles moving in contact with the bed/the bottom.
Coarsest particles rolling and sliding along the bottom as bed load.
Saltation is the particles getting picked up and dropped and picked up and dropped.

Question 12

What are the four stream variables?

Answer 12

Competence, capacity, load, and discharge.

Question 13

Define competence.

Answer 13

The measure of the largest size of particles a stream can transport.

Question 14

Define capacity.

Answer 14

The maximum quantity of sediment that CAN be carried by a stream, proportional to Q and V.

Question 15

Define load.

Answer 15

The amount of sediment a stream IS carrying.

Question 16

Define discharge.

Answer 16

Q
The amount of water flow.
The total amount of water that passes a given point in a stream per unit of time.

Question 17

What is the river equation?

Answer 17

Q = va

Question 18

What are some important things to note about the river equation?

Answer 18

You cannot more than double the velocity, but you can increase the area increase.
V typically changes twice as fast as a.

Question 19

What are the two major stream types?

Answer 19

Meandering streams and braided streams.

Question 20

What are some important things to know about meandering streams?

Answer 20

Dominant type on this planet.
Has point bars, oxbow lakes, cut banks, floodplains, and natural levees.
A river will meander more and more over time, and a highly meandering river is an older river.
Sweeps the entire floodplain eventually.
Silt and clay deposits in former channel connections of oxbow lakes.

Question 21

What is a point bar?

Answer 21

The side with sedimentation and accretion/deposition of sand.

Question 22

What is a cut bank?

Answer 22

The side of the river meander that is eroding.

Question 23

_____ (outside) and _____ migration of meanders occurs by erosion at the outside of meander bends, and deposition, and deposition of point bars on the inside.

Answer 23

Lateral, downstream.

Question 24

The floodplain gets _____ over time.

Answer 24

Wider.

Question 25

What is the line of highest velocity flow called?

Answer 25

Thalweg.

Question 26

What are some important things to know about braided streams?

Answer 26

Sediment supply is greater than the stream capacity.
At any given time the active channels may only account for a small proportion of the area of the channel system, but essentially all is used over one season.
Common in glaciated areas, deserts, and where rivers extended from mountains to flat regions.
The channel pieces sort of wander around, looks like a tangled braid.

Question 27

What does the recurrence interval depend on?

Answer 27

Climate of the region, width of the floodplain, size of the channel, amount of urbanization.

Question 28

As streams occur they alter the nature of their channel profile, and become _____ to the base level to which they flow.

Answer 28

Graded.

Question 29

_____ is the highest point of a stream.

Answer 29

Head.

Question 30

_____ is the lowest point of a stream.

Answer 30

Mouth.

Question 31

What is a drainage basin?

Answer 31

Area of land surrounded by topographic divides (high ground), and in which all the water is directed to one integrated river system.

Question 32

All streams are part of drainage systems which are divided into drainage basins by higher grounds called _____.

Answer 32

Divides.

Question 33

Define headward erosion.

Answer 33

Naturally occurring process.
Each of the heads of the streams that feed into rivers moves backwards and carves more and more into where it is originally coming from and that is one way valleys are carved into mountains.

Question 34

Define stream piracy.

Answer 34

A river could intersect another one and steal its flow.

Question 35

What are the four types of typical drainage networks?

Answer 35

Dendritic, radial, rectangular, trellis.

Question 36

Define delta.

Answer 36

A large body of sediment deposited where a river meets a lake, river, or sea.

Question 37

Define alluvial fans.

Answer 37

Delta-like deposits that form where rivers flow from mountains into flat areas in arid environments, where the water evaporates.

Question 38

What are the typical facies (depositional environments (beach, marsh, river floodplain, beach dunes, etc.) where deltas are) of a delta?

Answer 38

Delta plain is above water where vegetation is.
Builds seaward.
Coarsest sediment is dropped first, then finer and finer.
Pro-delta clay/mud is the stuff that’s furthest out from the river.
Delta-front sand is before pro-delta clay/mud.
There is a lot of organic matter in deltas.
A vast majority of the world’s oil is found on old delta fronts, not all, but most.
The upper delta plains is where you would find coal.