Streams and Rivers Flashcards
1
Q
These river scientists study rivers and their channels - form and behavior
A
Geomorphologists
2
Q
These river scientists study precipitation, groundwater, surface flow and connections
A
Hydrologists
3
Q
These river scientists study how physical processes influence organisms and influence each other
A
Ecologists
4
Q
Are there standard distinctions between rivers, streams, brooks and creeks?
A
No
5
Q
These rivers, including the Amazon, Mississippi and Mekong, are in a class of their own
A
Great rivers
6
Q
What shape are streams and rivers?
A
Dendritic
7
Q
The smallest permanently flowing stream is called this
A
First order stream
8
Q
When two first order streams meet, they produce this
A
Second order stream
9
Q
1 stream + 1 stream = ?
A
2 stream
10
Q
1 stream + 2 stream = ?
A
2 stream
11
Q
2 stream + 2 stream = ?
A
3 stream
12
Q
3 stream + 2 stream = ?
A
3 stream
13
Q
3 stream + 3 stream = ?
A
4 stream
14
Q
3 stream + 4 stream = ?
A
4 stream
15
Q
4 stream + 4 stream = ?
A
5 stream
16
Q
Stream order only increases when this happens
A
When 2 like streams come together
17
Q
This part of the stream includes the source
A
Headwaters
18
Q
This part of a stream is where the stream flows into a larger body of water
A
Mouth
19
Q
This part of the stream is the main stream channel
A
Trunk stream
20
Q
This part of a stream is the area of the stream between the headwaters and the mouth
A
Longitudinal profile
21
Q
This is a channel with flowing water at least part of the year
A
Stream channel
22
Q
This is a variable area on the sides of the stream channel that is inundated by floodwaters at some interval
A
Floodplain
23
Q
This is the portion of upland that serves as a transitional zone between the floodplain and the surrounding landscape
A
Transitional upland fringe
24
Q
This is a section of a river with multiple pools and riffles
A
Reach
25
How long should a stream reach be in relation to a stream?
20x the width
26
These are deep, slow-moving sections of a stream
Pools
27
Pools drop this, causing riffles
Sediment
28
These are parts of a stream where water moves turbulently over substrate
Riffles
29
Riffles cause pools by digging out this
Sediment
30
This is formed by piled up sediment dropped by water as velocity slows near stream pools
Point bar
31
This is an imaginary line tracing the deepest/fastest parts of a stream
Thalweg
32
This is an outside vertical bank of a curve in a river produced by erosion from the thalweg or water movement
Cut bank
33
This is the ability of a stream to curve or bend flexibly
Sinuosity
34
What is the equation for sinuosity?
River distance from A to B / Straight distance from A to B
35
Above what level of sinuosity is a stream considered meandering?
> 1.5
36
A cut-off stream meander forms this
Oxbow lake
37
What are four characteristics of a floodplain in phase 1 of development?
1. High topographic areas; 2. Downcutting and erosion; 3. Rapids & waterfalls; 4. Steep gradients
38
What are three characteristics of a floodplain in phase 2 of development?
1. Floodplain is cut; 2. Velocity decreases; 3. Gradient decreases vertically
39
What are three characteristics of a floodplain in phase 3 of development?
1. Wider valley; 2. Lateral migration in sediment/meanders; 3. Gradient decreases further
40
What characterizes a fully developed floodplain (phase 4)?
Flat valley floor cut out by stream meander
41
This is made up of direct precipitation falling on stream channel or channel interception and the lateral movement of water from land to channel
Streamflow or discharge
42
What are the two components of streamflow?
Stormflow and baseflow
43
This is the water that enters a stream in a short period after a precipitation event
Stormflow
44
What are two components of stormflow?
Subsurface runoff and surface runoff
45
This is water that percolates into the ground water moving into the stream channel at a slow rate, sustaining streamflow during periods of little or no precipitation
Baseflow
46
This shows how long a stream takes to rise from baseflow to maximum discharge then return
Hydrograph
47
What are two parts of a hydrograph?
Rising limb and recession limb
48
This occurs when the river reaches its highest level
Peak discharge
49
This is the time difference between the peak of a rain event and the peak discharge
Lag time or basin lag
50
Stormflow is the sum of what four processes?
1. Channel interception; 2. Overland flow; 3. Subsurface flow; 4. Baseflow
51
What is the effect of urbanization/impervious surfaces on peak discharge?
Increase in peak discharge
52
What is the effect of urbanization/impervious surfaces on baseflow?
Decrease in baseflow
53
What is the effect of urbanization/impervious surfaces on lag?
Reduction in lag
54
What is the equation for stream discharge?
Q=VA
55
What are used to measure stream discharge?
Precalibrated weirs/flumes
56
The height of a stream is measured with this
Gaging station
57
This establishes the relationship between gage height and streamflow (Q)
Rating curve
58
Is the relationship of streamflow to gage height linear or nonlinear?
Nonlinear
59
This is the most widely used method for stormflow analysis
Unit hydrograph theory
60
What does the unit hydrograph theory propose?
A standard measurement that estimates stormflow resulting from 1 unit of effective (excess) precipitation over a time and over a specified area
61
What are four problems with the unit hydrograph theory?
1. Unreliable methods; 2. Unit hydrographs are particular to each watershed and change with changes in the watershed; 3. Lack of previous information about extreme events in some places; 4. Assumption of linear behavior
62
This discharge occurs when water just begins to leave the channel and spread onto the floodplain
Bankfull discharge
63
Bankfull discharge is more often than not is the same as this discharge
Channel-forming discharge
64
At bankfull discharge, stage height slows while this goes up
Discharge
65
How many times per year does bankfull discharge normally occur?
1-2 times per year
66
Bankfull varies depending on this
Channel shape
67
Are streams always connected to ground water?
No
68
What are the two ways streams can be connected to ground water?
Effluent and influent
69
These streams are also known as 'gaining streams' and tend to be in moister climates where they get their water from groundwater sources
Effluent streams
70
These streams are also known as 'losing streams' and tend to be in drier climates, where they lose their water downstream as it soaks into the ground
Influent streams
71
Streams with this substrate have a good connection to ground water
Gravel/alluvium
72
Streams where this is present do not have a good connection to ground water
Non-water bearing bedrock
73
What is a source of streamflow for influent streams?
Overland flow
74
What are the three types of streams based on timing of stormflow and baseflow?
1. Ephemeral streams; 2. Intermittent streams; 3. Perennial streams
75
These streams only flow during or immediately after periods of precipitation
Ephemeral streams
76
What is the maximum amount of days that ephemeral streams have flow?
30 days
77
What is ephemeral streamflow primarily composed of?
Runoff from adjacent uplands
78
Do ephemeral streams have any streamflow contribution from baseflow?
No
79
This type of stream flows only during certain times of the year
Intermittent streams
80
How long does seasonal flow last in intermittent streams?
> 30 days/year
81
What are three sources of streamflow for intermittent streams?
1. Runoff from adjacent uplands; 2. Contributions from tributaries; 3. Ground water (to a small extent)
82
This type of stream flows continuously during both wet and dry seasons
Perennial streams
83
Perennial stream baseflow is dependably generated from this
Ground water
84
What are three sources of streamflow for perennial streams?
1. Baseflow; 2. Tributaries; 3. Runoff from adjacent uplands (to a smaller degree)
85
Are ephemeral streams protected by the Clean Water Act?
No
86
Are intermittent streams protected by the Clean Water Act?
Yes (in some cases)
87
What percent of public drinking water comes from intermittent, ephemeral or headwater streams?
58%
88
What are five classifications of streams based on channel shape?
1. Meandering; 2. Contained; 3. Anastomosing; 4. Braided; 5. Straight
89
This type of river has a single channel, fine sediments, large alluvial plains and low slopes
Meandering river
90
Meandering rivers change course on this timescale
Decadal scale
91
This type of river flows over bedrock or through valleys, has little or no floodplain, and can have dangerous, scouring floods
Constrained/constricted river
92
This type of river has multiple semi-permanent channels, lower discharge, lower slope, finer sediments, and deep channels with stable banks and spaces between channels
Anastomosing river
93
On what timescale do anastomosing river channels change?
Century/multidecadal scale
94
This type of river has many temporary channels, changes course daily, has steep and high discharge, and a large sediment load of gravel/sand
Braided river
95
Why are braided rivers not a preferred habitat for aquatic organisms?
Braided rivers are a harsh environment with little habitat predictability
96
This type of river made by human activity such as channelizing
Straight river
97
This is a vegetated area near a stream that links aquatic and terrestrial systems
Riparian zone
98
What is another name for riparian zone?
Buffer strip
99
What are the three layers of vegetation that occur near a healthy riparian zone?
1. Tall trees; 2. Shorter trees and shrubs; 3. Flowering plants and ferns
100
This ideal riparian zone system was described by Welsch in 1991
Three Zone System
101
In this zone of the three zone system, large native trees provide shade and bank stabilization
Zone 1 Undisturbed Forest
102
In this zone of the three zone system, native shrubs provide habitat for wildlife and absorb contaminants
Zone 2 Managed Forest
103
This zone of the three zone system is the first line of defense against contaminants, slows water runoff, and contains mostly native grasses
Zone 3 Runoff Control
104
In this zone of the three zone system, fallen limbs, trees and tree roots slow water flow, reduce erosion and increase habitat and cover for aquatic species
Streambed zone
105
What are four factors that affect the size of the riparian zone?
1. Stream size; 2. Position of stream in drainage network; 3. Hydrologic regime; 4. Geomorphology
106
What are four types of riparian plants?
1. Invaders; 2. Endurers; 3. Resistors; 4. Avoiders
107
These riparian plants propagate in the alluvial surface of the riparian zone
Invaders
108
These riparian plants resprout after events in the riparian zone
Endurers
109
These riparian plants withstand changes in the riparian zone
Resistors
110
These riparian plants lack adaptations to riparian zones
Avoiders
111
What are five functions of riparian zones?
1. Filter pollutants; 2. Prevent erosion; 3. Supply shade/moderate temperature; 4. Provide habitat; 5. Provide food
112
What are four ways riparian zones can improve water quality?
1. Intercepting sediment/nutrients; 2. Intercepting pesticides; 3. Decreasing runoff; 4. Bank stabilization
113
What percentage of sediment can be removed by a 20m riparian zone?
80-90%
114
