Ch 18 GEOG-111G-D03 DACC Fall 2016

The Missouri River is an example of a _________ of the Mississippi River - drainage basin - tributary - both a & b - none of the above

both a & b - drainage basin - tributary

The highest velocity of flow is found - at the side of the channel - at the floor of the channel - in the middle of the channel just below the surface - on the inside bank of a meander

in the middle of the channel just below the surface

An oxbow lake - is created by the cutoff of a meander - is formed by stream aggradation - is formed by flooding - none of the above

is created by the cutoff of a meander

An alluvial river is a large river of very _________channel gradient, flowing on a thick _________ of alluvium (sediment). - high, bluff - high, floodplain - low, floodplain - low, bluff

low, floodplain

Point bar formation is found - on the inside bank of a meander - on the outside bank of a meander - in the middle of the channel - at any of the above locations

on the inside bank of a meander

Vertical cutting and channel deepening primarily occurs - prior to reaching equilibrium - after reaching equilibrium - occurs once the stream has achieved base level - during the Old Age stage of Davis's cycle of erosion.

prior to reaching equilibrium

Define: * Cross-sectional area * Wetted perimeter * Channel slope (gradient) * Stream discharge

* Cross-sectional area is determined by multiplying channel depth by channel width along a transverse section of the stream. * Wetted perimeter is the portion of the channel that is "wet". The wetted perimeter (WP) is the width plus twice the depth that the water touches. * Channel slope (gradient) is the difference in elevation between two points on a stream divided by the distance between them measured along the stream channel. * Stream discharge is the volume of water passing through a particular cross-section in a unit of time.

Define cross-sectional area, channel slope, and wetted perimeter.

* The cross-sectional area of the stream is determined by multiplying channel depth by channel width along a transverse section of the stream. * Channel slope is the difference in elevation between two points on a stream divided by the distance between them measured along the stream channel. * The wetted perimeter is the portion of the channel that is "wet". The wetted perimeter is the width plus twice the depth that the water touches

What are the two types of floods?

1) where water slowly rises and spills over the banks of a stream or river. 2) flash floods.

List the three types of channels.

1. Straight 2. Meandering 3. Braided

Describe the stream network pattern and structural control over dendritic drainage pattern.

A dendritic drainage pattern is the most common form and looks like the branching pattern of tree roots. It develops in regions underlain by homogeneous material.

Describe how a stream erodes its channel.

A stream erodes its channel: -by dissolving rock from the sides and bed of the channel; -by lifting sediment from the sides and bed of the channel through hydraulic action; and -abrasion by materials suspended in the water used to scour the bed and sides of the channel.

What is an exotic stream? Give an example.

A stream that originates in a moist region that flows into and through a drier region. The Nile Rive is considered an exotic stream.

A flash flood occurs... - In the Desert - from snowmelt - from a hurricane - All of the above

All of the above - In the Desert - from snowmelt - from a hurricane

Why doesn't stream velocity progressively increase in the downstream direction?

As streams grow larger their down stream slope decreases, preventing a continuous buildup of energy and creating a more uniform distribution of stream energy along its length.

Explain the basic difference between the Davisian Cycle of erosion and the Dynamic Equilibrium theory.

Davisian Cycle of Erosion: The major assumption which Davis made was that the erosion starts only after the uplift has stopped. Dynamic Equilibrium a state of balance between continuing processes.

Describe the stream network pattern and structural control over deranged (contorted) drainage pattern.

Deranged or contorted patterns develop from the disruption of a pre-existing drainage pattern

The Colorado River is example of _________ stream. - Seasonal - Intermittent - Prennial - Exotic

Exotic

Describe how cross sectional area relates to stream discharge and velocity.

Generally, the larger the discharge, the smoother the channel, greater the stream velocity. Cross-sectional area and discharge increases down stream due to tributary and ground water flow into the channel.

Describe the stream network pattern and structural control over parallel drainage pattern.

Parallel drainage patterns form where there is a pronounced slope to the surface. A parallel pattern also develops in regions of parallel, elongate landforms like outcropping resistant rock bands. Tributary streams tend to stretch out in a parallel-like fashion following the slope of the surface.

Compare and contrast straight, meandering, and braided channels.

Straight channel exhibit a linear though rarely is a channel perfectly straight in nature. A meandering channel is one that takes twists and turns over its length.

Which of the following physiographic features would display a rectangular drainage pattern? - The Appalachian Mountains - The San Andreas Fault - Mount Rainer - The Black Hills of South Dakota

The Appalachian Mountains

Describe the stream network pattern and structural control over centripetal drainage pattern.

The centripetal drainage pattern is typical of basins in arid regions with interior drainage. During wetter portions of the year streams feed ephemeral lakes, which evaporate away during dry periods leaving salt flats.

Describe the various stream system features found in a drainage basin.

The drainage divide represents the boundary between adjacent drainage basins and determines into which basin precipitation flows. Streams within the drainage basin are either perennial or intermittent in flow. Perennial streams flow all year. The base flow of these streams is provided by groundwater seepage into the channel. Tributary streams are small streams that enter into the main stream. Tributary streams, especially the smaller ones around the periphery of the basin, are intermittent. Intermittent streams only flow during wetter times of the year. Much of their flow is provided by surface runoff and when the water table is higher as a result of moist conditions. The upland between tributaries is called an interfluve.

Describe the stream network pattern and structural control over radial drainage pattern.

The radial drainage pattern develops around a central elevated point. This pattern is common to such conically shaped features as volcanoes.

Describe the stream network pattern and structural control over rectangular drainage pattern.

The rectangular drainage pattern is found in regions that have undergone faulting. Faulting off-sets the direction of the stream with tributary streams making sharp bends and entering the main stream at high angles.

What is the sinuosity ratio and what is it used for?

The sinuosity ratio is used to determine whether a channel is straight or meandering. It is calculated as the distance between two points on the stream measured along the channel divided by the straight line distance between the two points. If the sinuosity ratio is 1.5 or greater the channel is considered to be a meandering one.

Which of the following drainage patterns typify the Ridge and Valley physiographic province of North America? - Rectangular - Centripetal - Radial - Trellis

Trellis

Describe the stream network pattern and structural control over trellis drainage pattern.

Trellis drainage patterns look similar to their namesake, the common garden trellis. Trellis drainage develops in folded topography like that found in the Appalachian Mountains of North America.

How do deltas form? - when sediment is flitered at the mouth of stream where water flows into a lake or ocean - when sediment is deposited at the mouth of stream where water flows into a lake or ocean - From Earthquakes - From volcanic eruptions

When sediment is deposited at the mouth of stream where water flows into a lake or ocean

A drainage basin that has undergone urbanization - is likely to experience higher peak discharges - decreased infiltration - shorter lag times - all the above

all the above - is likely to experience higher peak discharges - decreased infiltration - shorter lag times

The upland between two tributaries is called - an interfluve - a neck - a levee - none of the above

an interfluve

Streams develop ______________ - they cut into the land and erode the landscape over time - meanderings - slopes - graded profiles - ox-bow lakes

graded profiles

Deposition of alluvium - takes place on the outside bank of a meander - occurs when stream velocity increases - takes place on the inside bank of a meander - occurs with an increase in discharge

takes place on the inside bank of a meander

__________ flow is fast and _________ the bottom, while __________ flow is slow and _________________ the bottom. - turbulent, erodes, laminar, doesn't erode - turbulent, doesn't erode, laminar, does erode - laminar, does erodes, turbulent, doesn't erode - laminar, doesn't erode, turbulent, does erode

turbulent, erodes, laminar, doesn't erode

A stream's capacity to carry sediment increases sharply with its ________. - velocity - meandering - load - alluvium

velocity

Under constant discharge, an increase in the width of a channel - will decrease the cross-sectional area of the stream - will likely decrease stream velocity - will likely increase stream velocity - will do none of the above

will likely decrease stream velocity