Earth Science Chapter 14
What technique do the men in the villages of Bangladesh use to catch their fish?
The fishermen in the villages of Bangladesh fish using otters
What is suspended load?
The fine-grained particles that travel in the water column above the stream bed
Imagine a valley containing four stream terraces. Where would the youngest stream terrace be found?
The lowest terrace
Bangladesh has more than 700 rivers. What is the name of the country's primary river?
The primary river in Bangladesh is the Padma River
The flow of water is faster in what part of a river?
Water flows faster in the upper reaches of a river
When do streams erode laterally?
When downcutting is occurring in easy-to-erode sediment or rock
A stream is more likely to deposit its load of sediment when which of the following occurs?
When its speed decreases
When do stream terraces form?
When streams exist under alternating erosional and depositional conditions
As the discharge of a stream increases, which of the following also happens?
Width, depth, and/or velocity increase
Stream drainage patterns are determined by which of the following?
Climate, regional steepness and relief, landscape characteristics, and variations in rock resistance
Besides flood control, a(n) ___ can also be used to generate hydroelectric power. However, they are expensive to build and maintain.
Dam
This tree-like drainage pattern efficiently moves water and sediment through its system due to minimization of the total length of each branch.
Dendritic
Where do deposition and erosion of material occur along a meander?
Deposition occurs on the inside of the meander, whereas erosion occurs on the outside
An ___ is a bend in a steep narrow bedrock valley
Incised meander
If you live in an area that was flooded by the 100-year flood last year, you can conclude that
There is a 1% chance you could be flooded by the 100-year flood again this year
What is a river's primary job?
To transport silt, sand, and rocks (sediment) out of the mountains and down to the sea
Which processes result in the widening of the floodplain of a meandering stream?
Undercutting and lateral erosion
___ is/ are cheap to implement, but it/they can adversely affect property values
Zoning regulation
Often measured in "cfs" (cubic feet per second), the amount of water moving past a given spot over a given amount of time is referred to as a stream's
Discharge
What is the dominant fluvial process in a clear, sediment-poor stream moving down a steep slope?
Downcutting
The geographical area where all surface water converges to one location is called its
Drainage basin
What instrument was used in this video to measure flow rates in the river?
A water wheel was used to measure flow rates in the river
In Bangladesh life revolves around the water. What percent of this delta country floods each year?
Approximately 60 percent of Bangladesh floods each year
A(n) ___ confines water flow and can experience significant erosion. Constant maintenance is required
Artificial levee
As a river flows from its upper reaches to its lower reaches, how does the shape of the stream channel change?
As a river flows from its upper reaches to its lower reaches, it gets wider
Incised meanders and terraces are __________.
Erosional features
Processes that are related expressly to streams and rivers are termed
Fluvial
In a meandering river, where does most of the channel erosion occur?
In a meandering river, most of the channel erosion occurs on the outside bend of the stream
Complete this analogy: Sliding is to gravel as dissolution is to_____________.
Ions
This drainage pattern is associated with steep slopes
Parallel
Which one of the following represents a common way that water feeds into a stream bed?
A subterranean pool of groundwater reemerges as a spring
The ___ of a river have a steep gradient, high channel roughness, and low water volume.
Headwaters
A(n) ________ is a meander that becomes isolated from the rest of the river
Oxbow lake
How are oxbow lakes formed?
Oxbow lakes form when one meander erodes into another, cutting off water to part of the stream channel
This drainage pattern results when streams flow off a central peak or dome
Radial
The drop in stream elevation per unit distance is known as
Gradient
Which of the following are part of the bed load?
Gravel Sand
Maximum velocity in a straight channel is found
At the center and near the surface, corresponding with the deepest parts of the stream channel
Bangladesh's natural increase rate is high; how many people are added to the population in this country each year?
Bangladesh gains 2 million additional people per year
The lowest level to which a stream can erode is called
Base level
What are the three types of loads carried by streams?
Bed load, suspended load, dissolved load
Removing obstructions from a river channel is a form of a(n) ___. It can make a river more navigable, but may also increase bank erosion due to increased water flow
Channelization
As a stream's velocity decreases, which of the following sizes of sediments will be deposited last?
Clay
What type of stream is associated with the formation of an oxbow lake?
Meandering stream
What is a meander scar?
A landscape feature formed after an oxbow lake dries up
What is an oxbow lake?
A meander that has been cut off from the original stream channel
What is a stream terrace?
A remnant of an older floodplain that sits above the stream valley
Where along a meandering stream would erosion occur most intensely?
Along the outside of a bend where water moves fastest
Complete this analogy: Bouncing is to sand as suspension is to_____________.
Clay
The volume of water flowing past a certain point in a given amount of time is a river's
Discharge
Watersheds are defined by
Drainage divides
________ streams begin in moist regions and flow downstream into arid landscapes with high evapotranspiration.
Exotic
A river with a well-developed ___ has a flat low-lying channel and experiences flooding during periods of high discharge
Floodplain
The flat, broad area surrounding a stream is referred to as a(n)
Floodplain
Examples of local base level include a stream or an
Lake
Base level refers to
Level below which a stream cannot erode its valley
A sweeping bend of a stream which is migrating laterally in a wide, flat valley is called a(n) .
Meander
A stream with a low to moderate gradient, carrying most of its load in suspension, should be characterized by many curves and bends called
Meanders
A delta forms at the ___ of a river, where the velocity of the water flow decreases and deposition is highest
Mouth
In a given section of channel, the greatest flow velocities are usually
Near the surface, near the center
How many stream terraces can exist along a single valley?
No limit exists. Stream terraces will keep forming as long as lateral erosion and downcutting continue
Which of the following is not an example of humans impacting river systems?
Rivers and streams provide recreation to humans
How can pieces of rock in contact with a stream bed move?
Rolling, sliding, bouncing
The general term for channelized water flow, regardless of size, is
Stream
Are stream terraces depositional or erosional landforms?
Stream terraces can be either depositional or erosional
An ___ is the remnant of a former floodplain
Terrace