Week 8 Exercises (GEOG 102)

What are the three types of loads carried by streams?

bed load, suspended load, dissolved load

incised meander

bend in a steep narrow bedrock valley

Complete this analogy: Bouncing is to sand as suspension is to

clay

If the velocity of a stream decreases, competence __________ and sediment is _____

decreases, deposited

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

Incised meanders and terraces are

formed by a graded stream

mouth

gentle to flat terrain, high deposition, low velocity, and high discharge.

Which of the following are part of the bed load?

gravel and sand

Velocity and turbulence are _____ at the __________.

greatest; outside of a meander

bed load

highly affected by the velocity of stream

scroll bars

inside of meander in vegetation

Complete this analogy: Sliding is to gravel as dissolution is to

ions

base level

lowest level to which a stream can erode

Imagine a valley containing four stream terraces. Where would the youngest stream terrace be found?

lowest terrace

What is suspended load?

the fine-grained particles that travel in the water column above the stream bed

What is a river's primary job?

to transport silt, sand, and rocks (sediment) out of the mountains and down to the sea

Dissolved load

unaffected by the velocity of stream

discharge

volume of water flowing past a certain point in a given amount of time

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.

meanders

stream with a low to moderate gradient, carrying most of its load in suspension, should be characterized by many curves and bends

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

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.

At Mouth

Slope is lower, discharge is higher, flow velocity is mroe

What is a stream terrace?

a remnant of an older floodplain that sits above the stream valley

suspended load

affected by both flow velocity and settling velocity of stream

Where along a meandering stream would erosion occur most intensely?

along the outside of a bend where water moves fastest

drainage basin

an area from which all precipitation flows to a single stream at a lower elevation

point bar

on inside of meander

cut bank

outside of meander

floodplain

outside of meander

terrace

remnant of a former floodplain

floodplain

river that has a flat low-lying channel and experiences flooding during periods of high discharge

How can pieces of rock in contact with a stream bed move?

rolling, sliding, bouncing

headwaters

steep or rugged slopes, high erosion, high velocity, and low discharge

Are stream terraces depositional or erosional landforms?

Stream terraces can be either depositional or erosional.

At Headwaters

channel size is smaller, channel roughness is high